Hãy trả lời em tại sao? Tập 11

["kh\u00f4ng ph\u1ea3i song sinh nh\u01b0ng b\u00e0 \u0111\u00e3 k\u1ebft lu\u1eadn r\u1eb1ng l\u00e0 do c\u00e1c c\u1eb7p song sinh v\u1ed1n c\u00f3 khuynh h\u01b0\u1edbng suy ngh\u0129 gi\u1ed1ng nh\u01b0 nhau ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u00e0 chia s\u1ebb nh\u1eefng suy ngh\u0129 b\u1eb1ng th\u1ea7n giao c\u00e1ch c\u1ea3m. C\u00e1c th\u1eed nghi\u1ec7m kh\u00e1c th\u00ec t\u1eadp trung v\u00e0o vi\u1ec7c li\u1ec7u m\u1ed9t thay \u0111\u1ed5i trong h\u00e0nh \u0111\u1ed9ng n\u00e3o b\u1ed9 c\u1ee7a m\u1ed9t ng\u01b0\u1eddi c\u00f3 th\u1ec3 k\u00edch th\u00edch m\u1ed9t thay \u0111\u1ed5i t\u01b0\u01a1ng t\u1ef1 \u1edf ng\u01b0\u1eddi anh em c\u1ee7a m\u00ecnh kh\u00f4ng. N\u0103m 1965, t\u1edd b\u00e1o Science uy t\u00edn c\u1ee7a Hoa K\u1ef3 \u0111\u00e3 xu\u1ea5t b\u1ea3n k\u1ebft qu\u1ea3 c\u1ee7a c\u00e1c th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c h\u1ed7 tr\u1ee3 b\u1edfi CIA, g\u1ee3i \u00fd r\u1eb1ng c\u00e1c d\u1ea1ng s\u00f3ng n\u00e3o b\u1ed9 c\u1ee7a m\u1ed9t c\u1eb7p song sinh gi\u1ed1ng nhau c\u00f3 th\u1ec3 cho th\u1ea5y d\u1ea5u hi\u1ec7u v\u1ec1 m\u1ed9t li\u00ean k\u1ebft nh\u01b0 v\u1eady; tuy nhi\u00ean c\u00e1c ch\u1ee9ng c\u1ee9 th\u00ec r\u1ea5t \u00edt thuy\u1ebft ph\u1ee5c. C\u00e1c k\u1ebft qu\u1ea3 \u1ea5n t\u01b0\u1ee3ng h\u01a1n n\u1ed5i l\u00ean v\u00e0o n\u0103m 1994 t\u1eeb m\u1ed9t nh\u00f3m nghi\u00ean c\u1ee9u \u1edf \u0111\u1ea1i h\u1ecdc National Autonomous, Mexico, ph\u00e1t hi\u1ec7n c\u00e1c ch\u1ee9ng c\u1ee9 r\u1eb1ng ho\u1ea1t \u0111\u1ed9ng n\u00e3o b\u1ed9 c\u00f3 li\u00ean k\u1ebft \u1edf kho\u1ea3ng 25% ng\u01b0\u1eddi v\u1edbi m\u1ed9t li\u00ean k\u1ebft x\u00fac c\u1ea3m ch\u1eb7t ch\u1ebd. T\u00f3m l\u1ea1i, c\u00f3 m\u1ed9t s\u1ed1 ch\u1ee9ng c\u1ee9 g\u1ee3i \u00fd r\u1eb1ng c\u00e1c c\u1eb7p song sinh - \u0111\u1eb7c bi\u1ec7t l\u00e0 c\u00e1c c\u1eb7p gi\u1ed1ng nhau v\u1ec1 c\u1ea3m x\u00fac - c\u00f3 th\u1ec3 c\u00f3 m\u1ed9t v\u00e0i m\u1ed1i li\u00ean k\u1ebft \u0111\u1eb7c bi\u1ec7t nh\u01b0ng v\u00ec thi\u1ebfu m\u1ed9t nghi\u00ean c\u1ee9u l\u1edbn v\u00e0 ho\u00e0n ch\u1ec9nh, \u0111i\u1ec1u n\u00e0y v\u1eabn c\u00f2n r\u1ea5t \u00edt thuy\u1ebft ph\u1ee5c. 87 Ng\u01b0\u1eddi ta c\u00f3 th\u1ec3 \u201ct\u1ef1 b\u00f9ng ch\u00e1y\u201d nh\u01b0 th\u1ebf n\u00e0o? Sau 150 n\u0103m k\u1ec3 t\u1eeb khi Dickens m\u00f4 t\u1ea3 v\u1ec1 c\u00e1i ch\u1ebft c\u1ee7a nh\u00e0 bu\u00f4n v\u1ea3i Krook trong truy\u1ec7n Bleak House (Ng\u00f4i nh\u00e0 \u00e2m u), h\u00e0ng tr\u0103m tr\u01b0\u1eddng h\u1ee3p t\u1ef1 ch\u00e1y r\u1ea5t r\u00f5 r\u00e0ng \u1edf 100","con ng\u01b0\u1eddi \u0111\u00e3 \u0111\u01b0\u1ee3c ghi nh\u1eadn. Ch\u00fang th\u01b0\u1eddng li\u00ean quan t\u1edbi vi\u1ec7c m\u1ed9t ng\u01b0\u1eddi t\u1ef1 nhi\u00ean b\u1ecb b\u1ed1c ch\u00e1y ra tro, ch\u00e1y ho\u00e0n to\u00e0n v\u00e0 r\u1ea5t nhanh, kh\u00f4ng c\u00f3 m\u1ed9t ngu\u1ed3n nhi\u1ec7t r\u00f5 r\u00e0ng n\u00e0o \u1edf b\u00ean c\u1ea1nh. Ph\u1ea3n \u1ee9ng c\u1ee7a c\u00e1c nh\u00e0 khoa h\u1ecdc (kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1c ph\u1ea3n \u1ee9ng th\u00f4ng th\u01b0\u1eddng ki\u1ec3u nh\u01b0 b\u1ecf m\u1eb7c n\u00f3 v\u00e0 xem n\u00f3 nh\u01b0 m\u1ed9t s\u1ef1 \u0111am m\u00ea c\u1ee7a tr\u1ebb con) \u0111\u00e3 t\u1eadp trung v\u00e0o \u201chi\u1ec7u \u1ee9ng b\u1ea5c n\u1ebfn\u201d m\u00e0 \u1edf \u0111\u00f3 qu\u1ea7n \u00e1o c\u1ee7a n\u1ea1n nh\u00e2n b\u1ecb b\u1eaft ch\u00e1y t\u1eeb m\u1ed9t c\u00e2y n\u1ebfn hay \u0111i\u1ebfu thu\u1ed1c b\u1ecb r\u01a1i r\u1ed3i ho\u1ea1t \u0111\u1ed9ng nh\u01b0 b\u1ea5c c\u1ee7a c\u00e2y n\u1ebfn, l\u00e0m n\u00f3ng c\u01a1 th\u1ec3 t\u1edbi nhi\u1ec7t \u0111\u1ed9 m\u00e0 ch\u1ea5t b\u00e9o trong c\u01a1 th\u1ec3 b\u1ecb tan ra, cung c\u1ea5p cho ng\u1ecdn l\u1eeda m\u1ed9t ngu\u1ed3n n\u0103ng l\u01b0\u1ee3ng trong nhi\u1ec1u gi\u1edd. \u0110i\u1ec1u n\u00e0y \u0111\u00e3 \u0111\u01b0\u1ee3c th\u1eed nghi\u1ec7m v\u00e0o n\u0103m 1999 b\u1edfi John de Haan, m\u1ed9t nh\u00e0 nghi\u00ean c\u1ee9u h\u1ecfa ho\u1ea1n \u1edf M\u1ef9. Ng\u01b0\u1eddi \u0111\u00e3 s\u1eed d\u1ee5ng x\u00e1c heo \u0111\u1ec3 ch\u1ec9 ra r\u1eb1ng \u201chi\u1ec7u \u1ee9ng b\u1ea5c n\u1ebfn\u201d c\u00f3 th\u1ec3 sinh ra nhi\u1ec7t \u0111\u1ed9 v\u01b0\u1ee3t qu\u00e1 7600C. Trong khi \u0111i\u1ec1u n\u00e0y ch\u1eafc ch\u1eafn c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch s\u1ef1 ch\u00e1y ho\u00e0n to\u00e0n m\u00e0 c\u01a1 th\u1ec3 \u0111\u00e3 \u0111\u1ea1t t\u1edbi khi b\u00f9ng ch\u00e1y t\u1ef1 ph\u00e1t, n\u00f3 v\u1eabn ch\u1eb3ng gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c g\u00ec cho t\u1ed1c \u0111\u1ed9 c\u1ee7a hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y: c\u00f3 nhi\u1ec1u tr\u01b0\u1eddng h\u1ee3p \u0111\u01b0\u1ee3c ghi l\u1ea1i r\u1eb1ng con ng\u01b0\u1eddi \u0111\u00e3 bi\u1ebfn th\u00e0nh tro b\u1ee5i ch\u1ec9 trong v\u00e0i ph\u00fat. T\u00f3m l\u1ea1i, c\u00e1c nh\u00e0 khoa h\u1ecdc hi\u1ec7n nay r\u1ea5t s\u1eb5n s\u00e0ng th\u1eeba nh\u1eadn r\u1eb1ng s\u1ef1 b\u00f9ng ch\u00e1y t\u1ef1 ph\u00e1t \u1edf con ng\u01b0\u1eddi l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng c\u00f3 th\u1eadt nh\u01b0ng v\u1eabn c\u00f2n kh\u00e1 nhi\u1ec1u vi\u1ec7c ph\u1ea3i l\u00e0m 101","tr\u01b0\u1edbc khi gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c t\u1ea5t c\u1ea3 c\u00e1c t\u00ednh ch\u1ea5t ngh\u1ecbch l\u00fd c\u1ee7a n\u00f3. 88 C\u00f3 ph\u1ea3i ch\u00fang ta m\u1ea5t 20% th\u00e2n nhi\u1ec7t qua \u0111\u1ea7u c\u1ee7a ch\u00fang ta kh\u00f4ng? \u0110\u1ea7u chi\u1ebfm \u00edt h\u01a1n 10% t\u1ed5ng di\u1ec7n t\u00edch b\u1ec1 m\u1eb7t c\u1ee7a c\u01a1 th\u1ec3 nh\u01b0ng m\u1eadt \u0111\u1ed9 m\u1ea1ch m\u00e1u cao c\u1ee7a n\u00f3 ng\u1ee5 \u00fd r\u1eb1ng n\u00f3 ch\u1ecbu tr\u00e1ch nhi\u1ec7m cho m\u1ed9t t\u1ec9 l\u1ec7 m\u1ea5t th\u00e2n nhi\u1ec7t l\u1edbn h\u01a1n nhi\u1ec1u. Ti\u1ebfn s\u0129 Dusan Fiala c\u1ee7a \u0111\u1ea1i h\u1ecdc De Montfort, Leicester, ng\u01b0\u1eddi \u0111\u00e3 s\u1eed d\u1ee5ng m\u00f4 h\u00ecnh tr\u00ean m\u00e1y t\u00ednh c\u1ee7a m\u00ecnh \u0111\u1ec3 th\u0103m d\u00f2 l\u01b0\u1ee3ng nhi\u1ec7t tho\u00e1t ra t\u1eeb c\u01a1 th\u1ec3 con ng\u01b0\u1eddi. \u0110\u01b0a v\u00e0o c\u00e1c con s\u1ed1 d\u00e0nh cho m\u1ed9t ng\u01b0\u1eddi m\u1eb7c \u0111\u1ed3 \u0111\u1ea7y \u0111\u1ee7, \u0111ang \u0111i b\u1ed9 trong m\u1ed9t ng\u00e0y m\u00f9a \u0111\u00f4ng l\u1ea1nh l\u1ebdo (00C), ti\u1ebfn s\u0129 Fiala ghi nh\u1eadn r\u1eb1ng c\u01a1 th\u1ec3 m\u1ea5t nhi\u1ec7t l\u01b0\u1ee3ng v\u00e0o kho\u1ea3ng 260 watt, v\u1edbi g\u1ea7n 16% xu\u1ea5t ph\u00e1t tr\u1ef1c ti\u1ebfp t\u1eeb b\u1ec1 m\u1eb7t da \u0111\u1ea7u. C\u1ed9ng th\u00eam m\u1ed9t v\u00e0i ph\u1ea7n tr\u0103m do t\u00e1c \u0111\u1ed9ng c\u1ee7a vi\u1ec7c th\u1edf ra h\u01a1i \u1ea5m v\u00e0 con s\u1ed1 20% th\u1eadt s\u1ef1 l\u00e0 m\u1ed9t con s\u1ed1 ch\u00ednh x\u00e1c. Khi \u0111\u1ed9i m\u0169, l\u01b0\u1ee3ng nhi\u1ec7t m\u1ea5t \u0111i tr\u1ef1c ti\u1ebfp t\u1eeb \u0111\u1ea7u gi\u1ea3m xu\u1ed1ng t\u1edbi 50% - kh\u1eb3ng \u0111\u1ecbnh l\u1ea1i s\u1ef1 kh\u00f4n ngoan c\u1ee7a vi\u1ec7c \u0111\u1ed9i m\u0169 trong th\u1eddi ti\u1ebft l\u1ea1nh. 102","89 C\u00f3 \u0111\u00fang l\u00e0 \u00e1o gil\u00ea s\u1ee3i t\u1ed1t h\u01a1n l\u00e0 \u00e1o gil\u00ea b\u00ecnh th\u01b0\u1eddng kh\u00f4ng? \u00cdt nh\u1ea5t theo l\u00fd thuy\u1ebft, \u00e1o gil\u00ea s\u1ee3i \u0111\u01b0\u1ee3c cho r\u1eb1ng \u1ea5m h\u01a1n v\u00ec ch\u00fang ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t c\u00e1i khung b\u1eb1ng b\u00f4ng (cotton), h\u00ecnh th\u00e0nh c\u00e1c t\u00fai kh\u00ed c\u00e1ch nhi\u1ec7t gi\u1eefa da v\u00e0 nh\u1eefng th\u1ee9 ph\u1ee7 b\u00ean ngo\u00e0i \u00e1o gil\u00ea. Nh\u01b0ng c\u00f2n m\u1ed9t c\u00e1ch m\u1eb7c \u1ea5m n\u1eefa c\u0169ng r\u1ea5t hi\u1ec7u qu\u1ea3, \u0111\u00f3 l\u00e0 m\u1eb7c nhi\u1ec1u l\u1edbp \u00e1o m\u1ecfng. Khi \u0111\u00f3 l\u1edbp kh\u00ed gi\u1eefa c\u00e1c l\u1edbp \u00e1o s\u1ebd \u0111\u00f3ng vai tr\u00f2 nh\u01b0 m\u1ed9t l\u1edbp c\u00e1ch nhi\u1ec7t, gi\u1eef cho nhi\u1ec7t \u0111\u1ed9 l\u1ea1nh ngo\u00e0i tr\u1eddi kh\u00f4ng ti\u1ebfp x\u00fac v\u1edbi c\u01a1 th\u1ec3 b\u1ea1n. 90 B\u1ed9 n\u00e3o c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 b\u1ecb t\u1ed5n th\u01b0\u01a1ng khi b\u1ea1n suy ngh\u0129 qu\u00e1 nhanh kh\u00f4ng? Th\u1eadt k\u00ec l\u1ea1, b\u1ed9 n\u00e3o thi\u1ebfu c\u00e1c c\u01a1 quan ti\u1ebfp nh\u1eadn c\u1ea3m gi\u00e1c \u0111au v\u00e0 do v\u1eady ch\u00ednh n\u00f3 kh\u00f4ng th\u1ec3 tr\u1ea3i nghi\u1ec7m c\u1ea3m gi\u00e1c \u0111au. \u0110i\u1ec1u n\u00e0y cho ph\u00e9p c\u00e1c b\u00e1c s\u0129 ph\u1eabu thu\u1eadt th\u1ea7n kinh ng- hi\u00ean c\u1ee9u ch\u1ee9c n\u0103ng b\u1ed9 n\u00e3o v\u1edbi c\u00e1c b\u1ec7nh nh\u00e2n ho\u00e0n to\u00e0n t\u1ec9nh t\u00e1o, ch\u1ec9 s\u1eed d\u1ee5ng m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p v\u00f4 c\u1ea3m c\u1ee5c b\u1ed9 khi m\u1edf m\u00f4 v\u00e0 h\u1ed9p s\u1ecd xung quanh 103","b\u1ed9 n\u00e3o. Cho n\u00ean trong khi \u0111\u00f4i ch\u00e2n v\u00e0 \u0111\u00f4i tay ch\u00fang ta cho ta r\u1ea5t nhi\u1ec1u c\u1ea3m gi\u00e1c sau m\u1ed9t ng\u00e0y l\u00e0m vi\u1ec7c v\u1ea5t v\u1ea3 th\u00ec b\u1ed9 n\u00e3o c\u1ee7a ch\u00fang ta c\u00f3 th\u1ec3 tr\u1ea3i qua nhi\u1ec1u gi\u1edd suy ngh\u0129 \u201cn\u00e1t \u00f3c\u201d m\u00e0 kh\u00f4ng h\u1ec1 kh\u00f3 ch\u1ecbu. Ngu\u1ed3n \u201c\u0111au n\u00e3o\u201d th\u1eadt s\u1ef1 r\u1ea5t c\u00f3 th\u1ec3 l\u00e0 s\u1ef1 c\u0103ng th\u1eb3ng qu\u00e1 l\u00e2u c\u1ee7a c\u01a1 c\u1ed5 v\u00e0 c\u01a1 da \u0111\u1ea7u g\u00e2y ra do tr\u1ea3i qua nhi\u1ec1u gi\u1edd trong m\u1ed9t t\u01b0 th\u1ebf c\u0103ng th\u1eb3ng, cong g\u1eadp. 91 C\u00f3 th\u1eadt l\u00e0 n\u00fai Everest kh\u00f4ng ph\u1ea3i l\u00e0 \u0111i\u1ec3m cao nh\u1ea5t tr\u00ean tr\u00e1i \u0111\u1ea5t? T\u1ea5t c\u1ea3 \u0111i\u1ec1u \u0111\u00f3 ph\u1ee5 thu\u1ed9c v\u00e0o kh\u00e1i ni\u1ec7m \u201ccao nh\u1ea5t\u201d c\u1ee7a b\u1ea1n. \u0110\u1ecbnh ngh\u0129a th\u00f4ng th\u01b0\u1eddng l\u00e0 chi\u1ec1u cao so v\u1edbi m\u1ef1c n\u01b0\u1edbc bi\u1ec3n trung b\u00ecnh, trong tr\u01b0\u1eddng h\u1ee3p \u0111\u00f3 th\u00ec kh\u00f4ng ph\u1ea3i nghi ng\u1edd g\u00ec n\u1eefa, n\u00fai Everest \u0111\u00fang l\u00e0 \u0111i\u1ec3m cao nh\u1ea5t tr\u00ean h\u00e0nh tinh v\u1edbi \u0111\u1ed9 cao 8.848m. Tuy nhi\u00ean, m\u1ed9t s\u1ed1 ng\u01b0\u1eddi l\u1ea1i tranh lu\u1eadn r\u1eb1ng \u0111i\u1ec3m cao nh\u1ea5t ph\u1ea3i \u0111\u01b0\u1ee3c xem nh\u01b0 \u0111i\u1ec3m xa nh\u1ea5t so v\u1edbi t\u00e2m tr\u00e1i \u0111\u1ea5t. Trong tr\u01b0\u1eddng h\u1ee3p \u0111\u00f3, ta ph\u1ea3i t\u00ednh \u0111\u1ebfn m\u1ed9t \u0111i\u1ec1u l\u00e0 s\u1ef1 quay c\u1ee7a tr\u00e1i \u0111\u1ea5t \u0111\u00e3 khi\u1ebfn n\u00f3 ph\u00ecnh l\u00ean \u1edf \u0111\u01b0\u1eddng x\u00edch \u0111\u1ea1o kho\u1ea3ng 22,5 km so v\u1edbi \u1edf v\u00f9ng c\u1ef1c. Do \u0111\u00f3, n\u00fai Chimborazo \u1edf Ec- uador, ch\u1ec9 n\u1eb1m l\u1ec7ch 10 so v\u1edbi \u0111\u01b0\u1eddng x\u00edch \u0111\u1ea1o v\u00e0 m\u1eb7c d\u00f9 \u0111\u1ec9nh 104","c\u1ee7a n\u00f3 ch\u1ec9 cao 6.309m t\u00ednh t\u1eeb m\u1ef1c n\u01b0\u1edbc bi\u1ec3n, nh\u01b0ng do v\u1ecb tr\u00ed c\u1ee7a n\u00f3 n\u1eb1m \u1edf ch\u1ed7 ph\u00ecnh ra c\u1ee7a tr\u00e1i \u0111\u1ea5t n\u00ean \u0111\u1ec9nh c\u1ee7a n\u00f3 \u0111\u00e3 cao h\u01a1n Everest 2.133m n\u1ebfu t\u00ednh t\u1eeb t\u00e2m tr\u00e1i \u0111\u1ea5t. B\u1ea5t ch\u1ea5p t\u1ea5t c\u1ea3 nh\u1eefng c\u00e3i v\u00e3 v\u1ec1 \u0111o \u0111\u1ea1c n\u00e0y, n\u00fai Ever- est v\u1eabn \u0111\u01b0\u1ee3c nh\u00ecn nh\u1eadn l\u00e0 kh\u00f4ng c\u00f3 \u0111\u1ed1i th\u1ee7 v\u1ec1 chi\u1ec1u cao tr\u00ean h\u00e0nh tinh n\u00e0y. V\u00ec n\u00fai Everest ch\u1ec9 cao h\u01a1n 4.000m so v\u1edbi v\u00f9ng \u0111\u1ea5t tr\u1ef1c ti\u1ebfp \u1edf xung quanh, \u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 t\u00e1c \u0111\u1ed9ng t\u1edbi t\u1ea7m nh\u00ecn t\u1eeb \u0111\u1ec9nh n\u00fai. Tuy nhi\u00ean, ph\u00eda T\u00e2y Nam th\u00ec l\u1ea1i d\u1ed1c xu\u1ed1ng \u0111\u1ee7 l\u1edbn \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o m\u1ed9t t\u1ea7m nh\u00ecn li\u00ean t\u1ee5c kho\u1ea3ng 340km t\u1eeb \u0111\u1ec9nh n\u00fai. C\u00e1c hi\u1ec7u \u1ee9ng kh\u00fac x\u1ea1 c\u1ee7a kh\u00ed quy\u1ec3n th\u1eadm ch\u00ed c\u00f2n c\u00f3 th\u1ec3 t\u0103ng con s\u1ed1 n\u00e0y l\u00ean t\u1edbi 370km hay h\u01a1n n\u1eefa. 92 T\u1ea1i sao khi cho m\u1ed9t c\u00e1i mu\u1ed7ng v\u00e0o m\u1ed9t chai r\u01b0\u1ee3u s\u1ee7i b\u1ecdt th\u00ec gi\u00fap gi\u1eef l\u1ea1i b\u1ecdt kh\u00ed? M\u1ed9t s\u1ed1 ng\u01b0\u1eddi kh\u1eb3ng \u0111\u1ecbnh r\u1eb1ng mu\u1ed7ng b\u1ea1c s\u1ebd l\u00e0m vi\u1ec7c n\u00e0y r\u00f5 nh\u1ea5t. M\u1ed9t chai r\u01b0\u1ee3u s\u1ee7i b\u1ecdt v\u1edbi m\u1ed9t c\u00e1i mu\u1ed7ng \u1edf c\u1ed5 chai th\u00ec gi\u1eef l\u1ea1i b\u1ecdt kh\u00ed t\u1ed1t th\u1ea5y r\u00f5. V\u1ea5n \u0111\u1ec1 l\u00e0, m\u1ed9t c\u00e1i chai m\u00e0 kh\u00f4ng c\u00f3 c\u00e1i mu\u1ed7ng \u1edf c\u1ed5 chai c\u0169ng l\u00e0m \u0111\u01b0\u1ee3c nh\u01b0 th\u1ebf. N\u00f3i kh\u00e1c \u0111i, n\u1ebfu kh\u00f4ng b\u1ecb l\u1eafc l\u00ean qu\u00e1 nhi\u1ec1u, m\u1ed9t chai r\u01b0\u1ee3u s\u1ee7i b\u1ecdt 105","s\u1ebd gi\u1eef l\u1ea1i b\u1ecdt kh\u00ed c\u1ee7a n\u00f3 m\u1ed9t c\u00e1ch ho\u00e0n h\u1ea3o trong c\u1ea3 m\u1ed9t ng\u00e0y m\u00e0 kh\u00f4ng c\u1ea7n s\u1ef1 tr\u1ee3 gi\u00fap n\u00e0o t\u1eeb b\u00ean ngo\u00e0i. 93 C\u00f3 th\u1eadt l\u00e0 ch\u00fang ta th\u01b0\u1eddng ch\u1ec9 d\u00f9ng 10% b\u1ed9 n\u00e3o c\u1ee7a m\u00ecnh kh\u00f4ng? B\u1ed9 n\u00e3o ch\u1ee9a kho\u1ea3ng 100 t\u1ec9 neuron, m\u1ed7i neuron c\u00f3 h\u00e0ng ng\u00e0n m\u1ed1i li\u00ean k\u1ebft v\u00e0 kh\u00f4ng c\u00f3 g\u00ec nghi ng\u1edd, t\u1ea5t c\u1ea3 ch\u00fang ta \u0111\u1ec1u kh\u00f4ng th\u1ec3 d\u00f9ng h\u1ebft kh\u1ea3 n\u0103ng t\u00ednh to\u00e1n v\u00e0 ghi nh\u1edb phi th\u01b0\u1eddng n\u00e0y. Tuy nhi\u00ean, m\u1eb7c d\u00f9 m\u1ed9t s\u1ed1 ph\u1ea7n c\u1ee7a b\u1ed9 n\u00e3o ho\u1ea1t \u0111\u1ed9ng t\u00edch c\u1ef1c h\u01a1n c\u00e1c v\u00f9ng kh\u00e1c khi th\u1ef1c hi\u1ec7n m\u1ed9t v\u00e0i nhi\u1ec7m v\u1ee5 chuy\u00ean bi\u1ec7t, m\u00e1y qu\u00e9t b\u1ed9 n\u00e3o l\u1ea1i cho th\u1ea5y r\u1eb1ng c\u1ea3 b\u1ed9 n\u00e3o \u0111ang ho\u1ea1t \u0111\u1ed9ng \u1edf c\u00f9ng m\u1ee9c \u0111\u1ed9, g\u1ea7n nh\u01b0 m\u1ecdi l\u00fac. Li\u1ec7u b\u1ea1n c\u00f3 th\u1ec3 \u0111i v\u00f2ng quanh 94 th\u1ebf gi\u1edbi b\u1eb1ng c\u00e1ch bay th\u1eb3ng l\u00ean trong m\u1ed9t chi\u1ebfc tr\u1ef1c th\u0103ng v\u00e0 \u0111\u1ee3i \u0111i\u1ec3m \u0111\u1ebfn c\u1ee7a b\u1ea1n t\u1ef1 \u0111\u1ebfn b\u00ean d\u01b0\u1edbi b\u1ea1n kh\u00f4ng? B\u1ec1 m\u1eb7t c\u1ee7a tr\u00e1i \u0111\u1ea5t xoay v\u1edbi v\u1eadn t\u1ed1c kho\u1ea3ng 1.600 km\/gi\u1edd t\u1ea1i \u0111\u01b0\u1eddng x\u00edch \u0111\u1ea1o, nhanh g\u1ea5p \u0111\u00f4i so v\u1edbi m\u1ed9t chi\u1ebfc 106","Boeing 747 b\u00ecnh th\u01b0\u1eddng. V\u1eady t\u1ea1i sao kh\u00f4ng c\u00f3 h\u00e3ng h\u00e0ng kh\u00f4ng n\u00e0o cung c\u1ea5p m\u1ed9t chuy\u1ebfn bay l\u01a1 l\u1eedng \u00eam \u0111\u1ec1m, r\u1ebb ti\u1ec1n t\u1edbi \u0111\u1ecba \u0111i\u1ec3m m\u00e0 b\u1ea1n ch\u1ecdn? L\u00ed do l\u00e0 ngay c\u1ea3 khi chi\u1ebfc tr\u1ef1c th\u0103ng d\u01b0\u1eddng nh\u01b0 \u0111ang n\u1eb1m tr\u00ean m\u1eb7t \u0111\u1ea5t th\u00ec n\u00f3 c\u0169ng \u0111ang xoay c\u00f9ng v\u1edbi ph\u1ea7n c\u00f2n l\u1ea1i c\u1ee7a h\u00e0nh tinh v\u00e0 khi n\u00f3 c\u1ea5t c\u00e1nh \u0111\u1ec3 bay th\u1eb3ng l\u00ean, n\u00f3 ph\u1ea3i mang theo qu\u00e1n t\u00ednh \u0111\u00f3, \u0111i song song v\u1edbi m\u1eb7t \u0111\u1ea5t b\u00ean d\u01b0\u1edbi. M\u1ed9t c\u00e1ch t\u1ed1t h\u01a1n l\u00e0 bay l\u00ean \u0111\u1ee7 cao \u0111\u1ec3 \u0111\u00f3n l\u1ea5y c\u00e1c d\u00f2ng kh\u00f4ng kh\u00ed sinh ra b\u1edfi \u00e1p su\u1ea5t kh\u00ed quy\u1ec3n. Nh\u1eefng d\u00f2ng kh\u00ed n\u00e0y th\u1ed5i \u1edf t\u1ed1c \u0111\u1ed9 h\u01a1n 600 km\/gi\u1edd so v\u1edbi b\u1ec1 m\u1eb7t tr\u00e1i \u0111\u1ea5t. N\u0103m 2002 ch\u00fang \u0111\u00e3 cho ph\u00e9p khinh kh\u00ed c\u1ea7u c\u1ee7a Steve Fossett bay v\u00f2ng quanh tr\u00e1i \u0111\u1ea5t ch\u1ec9 trong 13 ng\u00e0y, g\u1ea7n nh\u01b0 kh\u00f4ng c\u00f3 th\u00eam m\u1ed9t ph\u01b0\u01a1ng ti\u1ec7n n\u00e2ng \u0111\u1ee1 hay \u0111\u1ea9y n\u00e0o. 95 T\u1ea5t c\u1ea3 nh\u1eefng chi\u1ebfc v\u1edb l\u1ebb \u0111\u00e3 bi\u1ebfn \u0111i \u0111\u00e2u? M\u1ed9t v\u00e0i n\u0103m tr\u01b0\u1edbc, gi\u00e1o s\u01b0 Stephen Hawking \u0111\u00e3 c\u00f3 m\u1ed9t bu\u1ed5i thuy\u1ebft tr\u00ecnh v\u1edbi c\u00f4ng ch\u00fang v\u00e0 t\u1ea1i \u0111\u00f3 \u00f4ng tuy\u00ean b\u1ed1 ni\u1ec1m tin c\u1ee7a m\u00ecnh r\u1eb1ng v\u1edb bi\u1ebfn m\u1ea5t v\u00e0o trong nh\u1eefng l\u1ed7 \u0111en nh\u1ecf t\u1ef1 xu\u1ea5t hi\u1ec7n do c\u00e1c hi\u1ec7u \u1ee9ng tr\u1ecdng l\u1ef1c l\u01b0\u1ee3ng t\u1eed. \u0110i\u1ec1u n\u00e0y nghe c\u00f3 v\u1ebb t\u00e1o b\u1ea1o nh\u01b0ng n\u00f3 th\u1eadt s\u1ef1 \u0111\u00e3 gi\u00fap cho vi\u1ec7c gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c s\u1ef1 bi\u1ebfn m\u1ea5t ng\u1eabu nhi\u00ean c\u1ee7a b\u00fat bi, l\u01b0\u1ee3c v\u00e0 gi\u00e0y tr\u1ebb em. N\u00f3 c\u0169ng gi\u1ea3i th\u00edch 107","\u0111\u01b0\u1ee3c t\u1ea1i sao vi\u1ec7c thu gom nh\u1eefng chi\u1ebfc v\u1edb l\u1ebb trong m\u1ed9t c\u00e1i t\u00fai v\u1edbi hi v\u1ecdng k\u1ebft \u0111\u00f4i ch\u00fang l\u1ea1i \u0111\u01b0\u1ee3c \u0111\u00e3 ch\u1eb3ng \u0111em l\u1ea1i s\u1ef1 thay \u0111\u1ed5i: ch\u00fang ch\u1eb3ng bao gi\u1edd t\u1eadp h\u1ee3p l\u1ea1i \u0111\u01b0\u1ee3c, nh\u01b0 th\u1ec3 ch\u00fang \u0111\u00e3 ho\u00e0n to\u00e0n r\u1eddi b\u1ecf v\u0169 tr\u1ee5 n\u00e0y. Nghi\u00eam tr\u1ecdng h\u01a1n, ta c\u00f3 th\u1ec3 l\u00e0m m\u1ed9t v\u00e0i ph\u00e9p t\u00ednh cho v\u1ea5n \u0111\u1ec1 v\u1edb l\u1ebb n\u00e0y v\u00e0 c\u00e1c k\u1ebft qu\u1ea3 th\u1eadt s\u1ef1 c\u00f3 v\u1ebb gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c t\u1ed1c \u0111\u1ed9 t\u00edch t\u1ee5 \u0111\u00e1ng kinh ng\u1ea1c s\u1ed1 v\u1edb l\u1ebb. H\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng r\u1eb1ng m\u1ed9t chi\u1ebfc v\u1edb b\u1ecb m\u1ea5t ng\u1eabu nhi\u00ean - v\u00e0o m\u1ed9t l\u1ed7 \u0111en, ph\u00eda sau gh\u1ebf sofa hay b\u1ea5t c\u1ee9 th\u1ee9 g\u00ec - do \u0111\u00f3 \u0111\u1ec3 l\u1ea1i m\u1ed9t chi\u1ebfc v\u1edb l\u1ebb trong ng\u0103n k\u00e9o. B\u00e2y gi\u1edd, h\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng m\u1ed9t chi\u1ebfc v\u1edb kh\u00e1c c\u0169ng b\u1ecb m\u1ea5t. Chi\u1ebfc v\u1edb th\u1ee9 hai n\u00e0y c\u00f3 th\u1ec3 l\u00e0 chi\u1ebfc v\u1edb l\u1ebb v\u1eeba m\u1edbi \u0111\u01b0\u1ee3c t\u1ea1o ra hay - nhi\u1ec1u kh\u1ea3 n\u0103ng h\u01a1n - l\u00e0 m\u1ed9t chi\u1ebfc v\u1edb t\u1eeb m\u1ed9t \u0111\u00f4i nguy\u00ean v\u1eb9n. R\u00f5 r\u00e0ng l\u00e0 khi chi\u1ebfc v\u1edb th\u1ee9 hai m\u1ea5t \u0111i, n\u00f3 s\u1ebd t\u1ea1o th\u00eam m\u1ed9t chi\u1ebfc v\u1edb l\u1ebb kh\u00e1c trong ng\u0103n k\u00e9o, d\u1eabn \u0111\u1ebfn vi\u1ec7c t\u1ea1o th\u00e0nh m\u1ed9t t\u1eadp h\u1ee3p v\u1edb l\u1ebb. Ta c\u00f3 th\u1ec3 l\u1eadp ra m\u1ed9t c\u00f4ng th\u1ee9c m\u00f4 t\u1ea3 hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y v\u00e0 c\u00e1c k\u1ebft qu\u1ea3 l\u00e0 b\u1ed5 \u00edch. V\u00ed d\u1ee5, n\u1ebfu ch\u00fang ta b\u1eaft \u0111\u1ea7u v\u1edbi 15 \u0111\u00f4i v\u1edb, cho t\u1edbi khi m\u00e0 ta \u0111\u00e3 m\u1ea5t h\u1ebft m\u1ed9t n\u1eeda s\u1ed1 v\u1edb \u0111\u00f3 m\u1ed9t c\u00e1ch ng\u1eabu nhi\u00ean, kh\u1ea3 n\u0103ng l\u1edbn nh\u1ea5t l\u00e0 ch\u00fang ta s\u1ebd c\u00f2n l\u1ea1i ba \u0111\u00f4i nguy\u00ean v\u1eb9n c\u00f9ng v\u1edbi ch\u00edn chi\u1ebfc v\u1edb l\u1ebb. Kh\u00f4ng c\u00f3 g\u00ec ng\u1ea1c nhi\u00ean khi ta th\u1ea5y r\u1ea5t kh\u00f3 t\u00ecm \u0111\u01b0\u1ee3c ch\u00fang trong m\u1ed9t bu\u1ed5i s\u00e1ng. Gi\u1ea3i ph\u00e1p l\u00e0 mua nh\u1eefng \u0111\u00f4i v\u1edb c\u00f3 thi\u1ebft k\u1ebf gi\u1ed1ng y nh\u01b0 nhau hay ph\u1ea3i \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed9t \u0111\u00f4i v\u1edb ph\u1ea3i lu\u00f4n \u1edf c\u1ea1nh nhau trong m\u1ecdi giai \u0111o\u1ea1n t\u1eeb ch\u00e2n t\u1edbi m\u00e1y gi\u1eb7t r\u1ed3i t\u1edbi ng\u0103n k\u00e9o. 108","96 T\u1ea1i sao rau bina (rau ch\u00e2n v\u1ecbt) l\u1ea1i r\u1ea5t t\u1ed1t cho s\u1ee9c kh\u1ecfe? Trong khi rau bina l\u00e0 m\u1ed9t lo\u1ea1i rau r\u1ea5t ngon, vi\u1ec7c cho r\u1eb1ng n\u00f3 nh\u01b0 l\u00e0 m\u1ed9t th\u1ef1c ph\u1ea9m k\u00ec di\u1ec7u l\u1ea1i c\u00f3 ngu\u1ed3n g\u1ed1c t\u1eeb m\u1ed9t sai l\u1ea7m ng\u1edb ng\u1ea9n b\u1edfi m\u1ed9t chuy\u00ean gia dinh d\u01b0\u1ee1ng ng\u01b0\u1eddi \u0110\u1ee9c n\u0103m 1870, ng\u01b0\u1eddi m\u00e0 trong khi \u0111ang ghi l\u1ea1i h\u00e0m l\u01b0\u1ee3ng s\u1eaft c\u1ee7a n\u00f3, \u0111\u00e3 \u0111\u1eb7t d\u1ea5u ph\u1ea9y th\u1eadp ph\u00e2n sai v\u1ecb tr\u00ed, l\u00e0m t\u0103ng gi\u00e1 tr\u1ecb l\u00ean g\u1ea5p 10 l\u1ea7n. Sai l\u1ea7m n\u00e0y \u0111\u00e3 kh\u00f4ng \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n cho t\u1edbi nh\u1eefng n\u0103m 1930, cho t\u1edbi th\u1eddi \u0111i\u1ec3m \u0111\u00f3 th\u00ec doanh s\u1ed1 \u1edf Hoa K\u1ef3 \u0111\u00e3 t\u0103ng l\u00ean 30% nh\u1edd th\u00e0nh t\u00edch th\u00fac \u0111\u1ea9y vi\u1ec7c mua rau bina. 97 L\u00ed do \u0111\u1eb1ng sau vi\u1ec7c s\u1eed d\u1ee5ng d\u1ea5m \u0111\u1ec3 ch\u1eefa v\u1ebft ch\u00edch c\u1ee7a ong b\u1eafp c\u00e0y l\u00e0 g\u00ec? Kinh nghi\u1ec7m d\u00e2n gian \u201cgi\u1ea5m cho v\u1ebft ch\u00edch c\u1ee7a ong b\u1eafp c\u00e0y, bicarbon- ate cho ong th\u01b0\u1eddng\u201d xu\u1ea5t ph\u00e1t t\u1eeb l\u00ed do gi\u1ea5m, m\u1ed9t acid r\u1ea5t y\u1ebfu, s\u1ebd trung h\u00f2a nhanh ch\u00f3ng m\u1ed9t h\u1ee3p ch\u1ea5t ki\u1ec1m. \u0110i\u1ec1u n\u00e0y nh\u00ecn chung l\u00e0 \u0111\u00fang, ngo\u1ea1i tr\u1eeb m\u1ed9t \u0111i\u1ec1u r\u1eb1ng v\u1ebft ch\u00edch c\u1ee7a ong b\u1eafp c\u00e0y kh\u00f4ng ph\u1ea3i l\u00e0 ki\u1ec1m, cho n\u00ean cho gi\u1ea5m v\u00e0o \u0111\u00f3 th\u00ec g\u1ea7n nh\u01b0 v\u00f4 d\u1ee5ng. M\u1ed9t 109","v\u00e0i chuy\u00ean gia y h\u1ecdc \u0111\u00e3 n\u00f3i r\u1eb1ng d\u00f9ng bicarbonate natri s\u1ebd t\u1ed1t cho c\u1ea3 v\u1ebft ch\u00edch c\u1ee7a ong th\u01b0\u1eddng v\u00e0 ong b\u1eafp c\u00e0y. Tuy nhi\u00ean c\u00f2n m\u1ed9t \u0111i\u1ec1u quan tr\u1ecdng h\u01a1n l\u00e0 ph\u1ea3i l\u1ea5y kim ong ra th\u1eadt nhanh, kh\u00f4ng \u0111\u01b0\u1ee3c b\u00f3p t\u00fai ch\u1ee9a \u0111\u1ed9c, r\u1ed3i r\u1eeda v\u00f9ng b\u1ecb t\u00e1c \u0111\u1ed9ng v\u00e0 theo d\u00f5i c\u00e1c tri\u1ec7u ch\u1ee9ng b\u1ecb s\u01b0ng l\u00ean v\u00e0 kh\u00f3 th\u1edf hay c\u00e1c d\u1ea5u hi\u1ec7u kh\u00e1c c\u1ee7a m\u1ed9t ph\u1ea3n \u1ee9ng d\u1ecb \u1ee9ng c\u00f3 kh\u1ea3 n\u0103ng g\u00e2y ch\u1ebft ng\u01b0\u1eddi. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y x\u1ea3y ra \u1edf kho\u1ea3ng 1% tr\u1ebb em nh\u01b0ng th\u01b0\u1eddng g\u1eb7p h\u01a1n g\u1ea5p hai l\u1ea7n \u1edf ng\u01b0\u1eddi tr\u00ean 40 tu\u1ed5i. 98 C\u00f3 th\u1eadt l\u00e0 d\u00e2n s\u1ed1 th\u1ebf gi\u1edbi hi\u1ec7n nay nhi\u1ec1u h\u01a1n l\u00e0 t\u1ea5t c\u1ea3 nh\u1eefng ng\u01b0\u1eddi \u0111\u00e3 t\u1eebng s\u1ed1ng? D\u00e2n s\u1ed1 c\u1ee7a tr\u00e1i \u0111\u1ea5t hi\u1ec7n nay l\u00e0 kho\u1ea3ng 6,2 t\u1ec9 v\u00e0 \u0111\u00fang r\u1eb1ng \u0111\u00e2y l\u00e0 con s\u1ed1 l\u1edbn nh\u1ea5t t\u1eeb x\u01b0a t\u1edbi gi\u1edd: g\u1ea5p \u0111\u00f4i d\u00e2n s\u1ed1 c\u1ee7a nh\u1eefng n\u0103m 1960 v\u00e0 g\u1ea5p 6 l\u1ea7n con s\u1ed1 c\u1ee7a n\u0103m 1800. V\u1ea5n \u0111\u1ec1 l\u00e0, m\u1eb7c d\u00f9 d\u00e2n s\u1ed1 th\u1ebf gi\u1edbi \u0111\u00e3 b\u00f9ng n\u1ed5 trong nh\u1eefng th\u1eadp k\u1ec9 g\u1ea7n \u0111\u00e2y, n\u00f3 \u0111\u00e3 t\u0103ng tr\u01b0\u1edfng \u1edf m\u1ed9t t\u1ed1c \u0111\u1ed9 kh\u00e1 l\u1edbn trong nhi\u1ec1u th\u1ebf k\u1ec9 v\u00e0 khi c\u1ed9ng l\u1ea1i n\u00f3 s\u1ebd th\u00e0nh m\u1ed9t con s\u1ed1 r\u1ea5t l\u1edbn. \u0110\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng xem n\u00f3 l\u1edbn t\u1edbi m\u1ee9c n\u00e0o, c\u00e1c nh\u00e0 nh\u00e2n ch\u1ee7ng h\u1ecdc ph\u1ea3i s\u1eed d\u1ee5ng c\u00e1c d\u1eef li\u1ec7u l\u1ecbch s\u1eed \u0111\u1ec3 t\u1ea1o ra c\u00e1c bi\u1ec3u \u0111\u1ed3 m\u00f4 t\u1ea3 d\u00e2n s\u1ed1 th\u1ebf gi\u1edbi \u1edf c\u00e1c th\u1eddi \u0111i\u1ec3m kh\u00e1c nhau. C\u00e1c 110","bi\u1ec3u \u0111\u1ed3 n\u00e0y th\u01b0\u1eddng cho th\u1ea5y m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng kh\u00e1 \u1ed5n \u0111\u1ecbnh v\u00e0 d\u1ed1c l\u00ean d\u1ea7n d\u1ea7n cho t\u1edbi gi\u1eefa th\u1ebf k\u1ec9 18 th\u00ec \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3 b\u1eaft \u0111\u1ea7u v\u00fat th\u1eb3ng l\u00ean. Vi\u1ec7c chuy\u1ec3n c\u00e1c bi\u1ec3u \u0111\u1ed3 n\u00e0y th\u00e0nh m\u1ed9t \u01b0\u1edbc \u0111o\u00e1n v\u1ec1 t\u1ed5ng s\u1ed1 ng\u01b0\u1eddi \u0111\u00e3 t\u1eebng s\u1ed1ng th\u00ec c\u1ea7n ph\u1ea3i \u0111\u01b0a ra m\u1ed9t s\u1ed1 gi\u1ea3 \u0111\u1ecbnh, \u0111\u01b0\u01a1ng nhi\u00ean bao g\u1ed3m c\u1ea3 th\u1eddi \u0111i\u1ec3m b\u1eaft \u0111\u1ea7u c\u1ee7a nh\u00e2n lo\u1ea1i. V\u00ed d\u1ee5, gi\u00e1o s\u01b0 nh\u00e2n ch\u1ee7ng h\u1ecdc n\u1ed5i ti\u1ebfng c\u1ee7a Canada Nathan Keyfitz \u0111\u00e3 ch\u1ecdn th\u1eddi \u0111i\u1ec3m m\u1ed9t tri\u1ec7u n\u0103m TCN l\u00e0 th\u1eddi \u0111i\u1ec3m m\u00e0 ch\u1ec9 c\u00f3 hai ng\u01b0\u1eddi tr\u00ean h\u00e0nh tinh n\u00e0y. M\u1eb7c d\u00f9 ch\u1eafc ch\u1eafn nhi\u1ec1u ng\u01b0\u1eddi s\u1ebd ph\u1ea3n \u0111\u1ed1i c\u00e1ch ch\u1ecdn n\u00e0y, \u0111i\u1ec1u \u0111\u00f3 c\u0169ng kh\u00f4ng th\u00e0nh v\u1ea5n \u0111\u1ec1: t\u1ed5ng s\u1ed1 ng\u01b0\u1eddi t\u1eebng \u0111i tr\u00ean tr\u00e1i \u0111\u1ea5t cu\u1ed1i c\u00f9ng \u0111\u00e3 tr\u1ed9i h\u01a1n d\u00e2n s\u1ed1 hi\u1ec7n nay r\u1ea5t nhi\u1ec1u l\u1ea7n, v\u1edbi kho\u1ea3ng 60 t\u1edbi 100 t\u1ec9 ng\u01b0\u1eddi. N\u00f3i c\u00e1ch kh\u00e1c, nh\u1eefng ng\u01b0\u1eddi \u0111ang s\u1ed1ng \u0111\u1ea1i di\u1ec7n cho kh\u00f4ng h\u01a1n 10% t\u1ed5ng s\u1ed1 ng\u01b0\u1eddi \u0111\u00e3 t\u1eebng s\u1ed1ng. Do m\u1ed9t s\u1ef1 tr\u00f9ng h\u1ee3p k\u00ec l\u1ea1 (l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c l\u01b0u \u00fd b\u1edfi nh\u00e0 v\u0103n khoa h\u1ecdc gi\u1ea3 t\u01b0\u1edfng Arthur C.Clarke), trong thi\u00ean h\u00e0 c\u1ee7a ch\u00fang ta c\u0169ng c\u00f3 kho\u1ea3ng 100 t\u1ec9 ng\u00f4i sao. Do \u0111\u00f3 m\u1ed7i ng\u01b0\u1eddi \u0111\u00e3 t\u1eebng s\u1ed1ng \u0111\u1ec1u c\u00f3 \u0111\u01b0\u1ee3c m\u1ed9t ng\u00f4i sao chi\u1ebfu m\u1ec7nh. 99 C\u00f3 ph\u1ea3i c\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 tr\u00e1ch b\u1ecb s\u00e9t \u0111\u00e1nh l\u00e0 n\u1eb1m d\u00e0i tr\u00ean m\u1eb7t \u0111\u1ea5t kh\u00f4ng? \u0110\u00e2y l\u00e0 m\u1ed9t l\u1eddi khuy\u00ean tuy\u1ec7t v\u1eddi d\u1ef1a tr\u00ean \u00e2m thanh v\u1eadt l\u00fd, nh\u01b0ng ch\u1ec9 \u0111\u00fang khi s\u1ea5m s\u00e9t \u0111i xa. B\u1ea5t k\u00ec ai b\u1ecb s\u00e9t 111","\u0111\u00e1nh m\u1ea1nh \u0111\u1ec1u c\u00f3 th\u1ec3 nh\u1eadn ra h\u1ecd b\u1ecb \u0111\u00e1nh m\u1ea1nh khi \u1edf tr\u1ea1ng th\u00e1i kh\u00f4ng di chuy\u1ec3n. Trong su\u1ed1t m\u1ed9t c\u01a1n gi\u00f4ng b\u00e3o l\u1edbn, nh\u1eefng v\u1eadt th\u1ec3 c\u00f3 \u0111\u1ea7u nh\u1ecdn nh\u01b0 nh\u1eefng ng\u01b0\u1eddi l\u00ednh h\u00e0nh qu\u00e2n xuy\u00ean qua nh\u1eefng n\u01a1i c\u00f3 \u0111\u1ecba h\u00ecnh b\u1eb1ng ph\u1eb3ng \u0111\u1ec1u c\u00f3 th\u1ec3 g\u1eb7p nguy hi\u1ec3m do t\u00ednh d\u1eabn \u0111i\u1ec7n c\u1ee7a c\u01a1 th\u1ec3 con ng\u01b0\u1eddi. \u0110i\u1ec7n tr\u01b0\u1eddng t\u1ea1o b\u1edfi b\u00e3o c\u00f3 khuynh h\u01b0\u1edbng t\u1eadp trung xung quanh nh\u1eefng v\u1eadt th\u1ec3 c\u00f3 d\u1ea1ng nh\u1ecdn, l\u00e0m gia t\u0103ng nguy c\u01a1 ph\u00e1 h\u1ee7y \u0111\u1eb7c t\u00ednh c\u00e1ch \u0111i\u1ec7n c\u1ee7a kh\u00f4ng kh\u00ed xung quanh, cho ph\u00e9p c\u00e1c \u0111i\u1ec7n t\u1eed (electron) ch\u1ea1y gi\u1eefa v\u1eadt th\u1ec3 \u0111\u00f3 v\u00e0 c\u00e1c \u0111\u00e1m m\u00e2y ph\u00eda tr\u00ean \u0111\u1ea7u v\u00e0 k\u00edch th\u00edch m\u1ed9t c\u00fa s\u00e9t \u0111\u00e1nh. B\u1eb1ng vi\u1ec7c n\u1eb1m d\u00e0i tr\u00ean m\u1eb7t \u0111\u1ea5t, \u0111i\u1ec7n tr\u01b0\u1eddng xung quanh c\u01a1 th\u1ec3 s\u1ebd tr\u1ea3i d\u00e0i ra m\u1ed9t c\u00e1ch t\u01b0\u01a1ng \u0111\u1ed1i, gi\u1ea3m nguy c\u01a1 b\u1ecb s\u00e9t \u0111\u00e1nh nh\u01b0ng c\u0169ng v\u1eabn c\u00f3 kh\u1ea3 n\u0103ng b\u1ecb s\u00e9t \u0111\u00e1nh v\u00e0 c\u00f3 th\u1ec3 g\u00e2y nguy hi\u1ec3m \u0111\u1ebfn t\u00ednh m\u1ea1ng. T\u1ed1t nh\u1ea5t l\u00e0 n\u00ean ch\u1ea1y \u0111i t\u00ecm m\u1ed9t ch\u1ed7 tr\u00fa, xe h\u01a1i l\u00e0 m\u1ed9t ch\u1ed7 tr\u00fa l\u00fd t\u01b0\u1edfng, tr\u00e1nh c\u00e1c c\u00e2y xanh v\u1edbi v\u00f4 s\u1ed1 c\u00e1c \u0111i\u1ec3m nh\u1ecdn. Ngo\u00e0i ra ph\u1ea3i gi\u1eef cho c\u01a1 th\u1ec3 lu\u00f4n th\u1ea5p v\u00e0 cong g\u1eadp. N\u1ebfu t\u00f3c c\u1ee7a b\u1ea1n b\u1eaft \u0111\u1ea7u c\u00f3 c\u1ea3m gi\u00e1c nh\u01b0 ki\u1ebfn b\u00f2 v\u00e0 d\u1ef1ng \u0111\u1ee9ng l\u00ean c\u00f3 ngh\u0129a l\u00e0 b\u1ea1n n\u1eb1m trong s\u1ed1 ng\u01b0\u1eddi b\u1ecb s\u00e9t \u0111\u00e1nh. Trong tr\u01b0\u1eddng h\u1ee3p \u0111\u00f3, h\u00e3y ng\u1eebng ch\u1ea1y v\u00e0 \u0111\u1eb7t hai b\u00e0n tay c\u1ee7a b\u1ea1n l\u00ean hai \u0111\u1ea7u g\u1ed1i: d\u00f2ng \u0111i\u1ec7n s\u1ebd ch\u1ea1y qua c\u00e1nh tay b\u1ea1n v\u00e0 \u0111i v\u00e0o m\u1eb7t \u0111\u1ea5t m\u00e0 kh\u00f4ng \u0111i qua tim c\u1ee7a b\u1ea1n. N\u1ebfu may m\u1eafn, b\u1ea1n s\u1ebd tr\u00e1nh kh\u00f4ng tr\u1edf th\u00e0nh m\u1ed9t trong s\u1ed1 m\u01b0\u1eddi ph\u1ea7n tr\u0103m ho\u1eb7c nhi\u1ec1u h\u01a1n ch\u1ebft v\u00ec b\u1ecb s\u00e9t \u0111\u00e1nh. 112","CH\u1eee S\u1ed0, TR\u00d2 CH\u01a0I V\u00c0 C\u00c1C TR\u00d2 GI\u1ea2I TR\u00cd 100 Ph\u01b0\u01a1ng c\u00e1ch nh\u1edb m\u00e3 PIN t\u1ed1t? C\u00e1c chuy\u00ean gia v\u1ec1 b\u1ea3o m\u1eadt s\u1ebd tr\u1ea3 l\u1eddi ngay r\u1eb1ng kh\u00f4ng n\u00ean vi\u1ebft ra c\u00e1c m\u00e3 PIN nh\u01b0ng h\u1ecd h\u1ea7u nh\u01b0 th\u1ea5t b\u1ea1i trong vi\u1ec7c t\u00ecm ra b\u1ea5t k\u00ec ph\u01b0\u01a1ng ph\u00e1p thay th\u1ebf n\u00e0o kh\u00e1c. H\u01a1n n\u1eefa, n\u1ebfu c\u00e1c chuy\u00ean gia gi\u1ecfi nh\u01b0 v\u1eady th\u00ec h\u1ecd s\u1ebd nh\u1eadn ra r\u1eb1ng m\u00e3 PIN g\u1ed3m s\u00e1u k\u00ed t\u1ef1 s\u1ebd t\u1ea1o n\u00ean nhi\u1ec1u s\u1ef1 k\u1ebft h\u1ee3p h\u01a1n v\u00e0 d\u1ec5 nh\u1edb h\u01a1n. M\u1ed9t s\u1ed1 ng\u01b0\u1eddi \u0111\u01a1n gi\u1ea3n ch\u1ec9 thay \u0111\u1ed5i c\u00e1c s\u1ed1 PIN th\u00e0nh c\u00e1c s\u1ed1 d\u1ec5 nh\u1edb h\u01a1n, nh\u01b0 ng\u00e0y sinh nh\u1eadt ch\u1eb3ng h\u1ea1n. \u0110i\u1ec1u n\u00e0y kh\u00f4ng n\u00ean l\u00e0m, v\u00ec k\u1ebb gian c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng t\u00ecm ra ch\u1eef s\u1ed1 \u0111\u00fang. \u0110i\u1ec1u n\u00e0y c\u0169ng x\u1ea3y ra khi ta \u0111\u01b0a c\u00e1c ch\u1eef s\u1ed1 d\u1ec5 nh\u1edb ho\u1eb7c quen thu\u1ed9c v\u00e0o m\u00e3 PIN. T\u1eeb \u0111\u00e2y ch\u00fang ta r\u00fat ra k\u1ebft lu\u1eadn r\u1eb1ng: c\u00e1c ch\u1eef s\u1ed1 d\u1ec5 nh\u1edb ho\u1eb7c quen thu\u1ed9c c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111o\u00e1n ra d\u1ec5 d\u00e0ng h\u01a1n l\u00e0 ch\u00fang ta ngh\u0129. Khi c\u00f2n l\u00e0 m\u1ed9t nghi\u00ean c\u1ee9u sinh, nh\u00e0 v\u1eadt l\u00fd \u0111o\u1ea1t gi\u1ea3i Nobel, \u00f4ng Richard Feynman, 113","\u0111\u00e3 m\u1edf th\u00e0nh c\u00f4ng k\u00e9t s\u1eaft ch\u1ee9a k\u1ebf ho\u1ea1ch ch\u1ebf t\u1ea1o bom nguy\u00ean t\u1eed b\u1eb1ng c\u00e1ch \u0111o\u00e1n m\u1eadt m\u00e3 k\u1ebft h\u1ee3p l\u00e0 2718 - v\u1edbi m\u1eadt m\u00e3 c\u00f3 s\u1ed1 \u0111\u1ea7u ti\u00ean l\u00e0 s\u1ed1 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong ng\u00e0nh v\u1eadt l\u00fd l\u00fd thuy\u1ebft. C\u00f3 nhi\u1ec1u ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c nhau \u0111\u1ec3 gi\u1eef b\u00ed m\u1eadt m\u00e3 PIN, nh\u01b0 l\u01b0u gi\u1eef trong s\u1ed5 \u0111i\u1ec7n tho\u1ea1i ho\u1eb7c s\u1ed5 \u0111\u1ecba ch\u1ec9 nh\u01b0 m\u1ed9t s\u1ed1 gi\u1ea3 (\u0111i\u1ec1u n\u00e0y nghe c\u00f3 v\u1ebb c\u00f3 nhi\u1ec1u r\u1ee7i ro, nh\u01b0ng c\u00e1c k\u1ebb ph\u1ea1m t\u1ed9i l\u1ea1i kh\u00f4ng th\u1ec3 g\u1ecdi th\u1eed h\u1ebft c\u00e1c s\u1ed1 \u0111i\u1ec7n tho\u1ea1i \u0111\u1ec3 t\u00ecm ra ch\u00fang). Nhi\u1ec1u ph\u01b0\u01a1ng ph\u00e1p cho r\u1eb1ng s\u1eed d\u1ee5ng t\u1eeb ng\u1eef s\u1ebd d\u1ec5 nh\u1edb h\u01a1n ch\u1eef s\u1ed1 v\u00e0 \u0111\u01b0a ra lu\u00f4n ph\u01b0\u01a1ng ph\u00e1p chuy\u1ec3n \u0111\u1ed5i t\u1eeb ng\u1eef ra m\u00e3 PIN. Tuy nhi\u00ean, c\u00f3 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p an to\u00e0n, hi\u1ec7u qu\u1ea3 v\u00e0 kh\u00f4ng c\u1ea7n ph\u1ea3i vi\u1ebft ra: \u0111\u01a1n gi\u1ea3n ch\u1ec9 c\u1ea7n nh\u1edb c\u1ee5m t\u1eeb ng\u1eef \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb nh\u1eefng t\u1eeb c\u00f3 s\u1ed1 k\u00ed t\u1ef1 t\u01b0\u01a1ng \u1ee9ng v\u1edbi m\u00e3 PIN. V\u00ed d\u1ee5 nh\u01b0 m\u1eadt m\u00e3 s\u1ed1 c\u1ee7a b\u1ea1n l\u00e0 323346, c\u1ee5m t\u1eeb ng\u1eef t\u01b0\u01a1ng \u1ee9ng c\u00f3 th\u1ec3 l\u00e0 \u201cy\u00eau em nh\u01b0 c\u1ea7u v\u1ed3ng khuy\u1ebft\u201d. S\u1ed1 0 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng b\u1eb1ng c\u00e1c t\u1eeb \u0111\u1ed3ng ngh\u0129a nh\u01b0 \u201ckh\u00f4ng\u201d. Ch\u1eb3ng h\u1ea1n, m\u00e3 PIN l\u00e0 022334, c\u1ee5m t\u1eeb ng\u1eef t\u01b0\u01a1ng \u1ee9ng c\u00f3 th\u1ec3 l\u00e0 \u201ckh\u00f4ng c\u00f3 g\u00ec qu\u00fd h\u01a1n ti\u1ec1n\u201d. 101 T\u1ea1i sao nh\u00e2n hai s\u1ed1 \u00e2m v\u1edbi nhau cho ra k\u1ebft qu\u1ea3 l\u00e0 m\u1ed9t s\u1ed1 d\u01b0\u01a1ng? K\u1ebft qu\u1ea3 s\u1ebd r\u00f5 r\u00e0ng v\u00e0 h\u1ee3p l\u00fd h\u01a1n khi c\u1ed9ng hai s\u1ed1 \u00e2m s\u1ebd cho k\u1ebft qu\u1ea3 l\u00e0 m\u1ed9t s\u1ed1 \u00e2m nh\u1ecf h\u01a1n (\u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 114","ki\u1ec3m ch\u1ee9ng v\u1edbi ng\u01b0\u1eddi c\u00f3 t\u00e0i kho\u1ea3n ng\u00e2n h\u00e0ng r\u00fat qu\u00e1 m\u1ee9c c\u00f3 trong t\u00e0i kho\u1ea3n). C\u0169ng hi\u1ec3n nhi\u00ean v\u1edbi tr\u01b0\u1eddng h\u1ee3p nh\u00e2n c\u00e1c s\u1ed1 \u00e2m v\u1edbi c\u00e1c s\u1ed1 d\u01b0\u01a1ng s\u1ebd cho ra k\u1ebft qu\u1ea3 l\u00e0 s\u1ed1 \u00e2m (g\u1ea5p \u0111\u00f4i s\u1ed1 ti\u1ec1n r\u00fat qu\u00e1 t\u00e0i kho\u1ea3n c\u00f3 s\u1ebd l\u00e0 m\u1ed9t kho\u1ea3ng ti\u1ec1n b\u1ecb r\u00fat ra l\u1edbn h\u01a1n nhi\u1ec1u). Tuy nhi\u00ean c\u00e2u h\u1ecfi \u0111\u1eb7t ra l\u00e0 t\u1ea1i sao ph\u1ea3i \u0111\u1ed5i d\u1ea5u khi nh\u00e2n hai s\u1ed1 \u00e2m v\u1edbi nhau? C\u00f3 th\u1ec3 gi\u1ea3i th\u00edch \u0111i\u1ec1u n\u00e0y b\u1eb1ng c\u00e1ch h\u00ecnh t\u01b0\u1ee3ng h\u00f3a hai s\u1ed1 \u00e2m v\u00e0 d\u01b0\u01a1ng tr\u00ean \u0111\u01b0\u1eddng th\u1eb3ng: v\u1ebd m\u1ed9t \u0111\u01b0\u1eddng tr\u1ee5c th\u1eb3ng ngang (tr\u1ee5c ho\u00e0nh) tr\u00ean t\u1edd gi\u1ea5y v\u00e0 x\u00e1c \u0111\u1ecbnh \u0111i\u1ec3m gi\u1eefa c\u1ee7a \u0111\u01b0\u1eddng th\u1eb3ng; \u0111\u00e2y l\u00e0 \u0111i\u1ec3m b\u1eb1ng kh\u00f4ng. Ph\u00e2n chia c\u00e1c kho\u1ea3ng b\u1eb1ng nhau v\u00e0 \u0111\u00e1nh c\u00e1c s\u1ed1 d\u01b0\u01a1ng t\u1eeb 1 \u0111\u1ebfn 10 ph\u00eda b\u00ean ph\u1ea3i c\u1ee7a \u0111\u01b0\u1eddng th\u1eb3ng t\u00ednh t\u1eeb \u0111i\u1ec3m b\u1eb1ng 0. L\u00e0m t\u01b0\u01a1ng t\u1ef1 v\u1edbi ph\u00eda b\u00ean tr\u00e1i c\u1ee7a \u0111i\u1ec3m b\u1eb1ng 0 tr\u00ean \u0111\u01b0\u1eddng tr\u1ee5c ngang: -1; -2... -10. Ph\u00e9p nh\u00e2n b\u00e2y gi\u1edd tr\u1edf th\u00e0nh qu\u00e1 tr\u00ecnh d\u1ecbch chuy\u1ec3n theo m\u1ed9t h\u01b0\u1edbng c\u1ee5 th\u1ec3 t\u1eeb s\u1ed1 kh\u00f4ng v\u1edbi m\u1ed9t s\u1ed1 b\u01b0\u1edbc nh\u1ea3y cho tr\u01b0\u1edbc, m\u1ed7i b\u01b0\u1edbc nh\u1ea3y c\u00f3 \u0111\u1ed9 l\u1edbn kh\u00f4ng \u0111\u1ed5i. V\u00ed d\u1ee5 nh\u01b0 nh\u00e2n 2 v\u1edbi 3, b\u1eaft \u0111\u1ea7u t\u1ea1i \u0111i\u1ec3m 0 v\u00e0 h\u01b0\u1edbng v\u1ec1 b\u00ean ph\u1ea3i: s\u1ed1 2 s\u1ebd l\u00e0 m\u1ed9t s\u1ed1 d\u01b0\u01a1ng, t\u1ecbnh ti\u1ebfn qua b\u00ean ph\u1ea3i hai l\u1ea7n v\u1edbi ba \u0111\u01a1n v\u1ecb m\u1ed7i l\u1ea7n ti\u1ebfn (trong \u0111i\u1ec1u ki\u1ec7n s\u1ed1 3 l\u00e0 s\u1ed1 d\u01b0\u01a1ng). V\u00e0 k\u1ebft qu\u1ea3 l\u00e0 b\u1ea1n s\u1ebd \u1edf t\u1ea1i v\u1ecb tr\u00ed s\u1ed1 6, b\u00ean ph\u1ea3i c\u1ee7a \u0111i\u1ec3m 0, l\u00e0 s\u1ed1 d\u01b0\u01a1ng. Tr\u01b0\u1eddng h\u1ee3p ng\u01b0\u1ee3c l\u1ea1i, khi nh\u00e2n -2 v\u1edbi 3, b\u1eaft \u0111\u1ea7u t\u1ea1i \u0111i\u1ec3m 0, nh\u01b0ng l\u1ea7n n\u00e0y h\u01b0\u1edbng v\u1ec1 b\u00ean tr\u00e1i v\u00e0 s\u1ed1 2 s\u1ebd l\u00e0 m\u1ed9t s\u1ed1 \u00e2m, sau \u0111\u00f3 t\u1ecbnh ti\u1ebfn qua b\u00ean tr\u00e1i hai l\u1ea7n v\u1edbi ba \u0111\u01a1n v\u1ecb m\u1ed7i l\u1ea7n ti\u1ebfn (trong \u0111i\u1ec1u ki\u1ec7n s\u1ed1 3 c\u0169ng l\u00e0 s\u1ed1 d\u01b0\u01a1ng). 115","Theo c\u00e1c quy \u01b0\u1edbc t\u01b0\u01a1ng t\u1ef1, khi nh\u00e2n -2 v\u1edbi -3, h\u01b0\u1edbng v\u1ec1 b\u00ean tr\u00e1i (v\u00ec s\u1ed1 2 l\u00e0 s\u1ed1 \u00e2m), nh\u01b0ng l\u1ea7n n\u00e0y t\u1ecbnh ti\u1ebfn theo h\u01b0\u1edbng ng\u01b0\u1ee3c l\u1ea1i t\u1eeb \u0111i\u1ec3m 0 hai l\u1ea7n v\u1edbi ba \u0111\u01a1n v\u1ecb m\u1ed7i l\u1ea7n ti\u1ebfn, b\u1edfi v\u00ec s\u1ed1 3 c\u0169ng l\u00e0 m\u1ed9t s\u1ed1 \u00e2m. V\u00e0 k\u1ebft qu\u1ea3 l\u00e0 b\u1ea1n s\u1ebd \u1edf t\u1ea1i v\u1ecb tr\u00ed s\u1ed1 6, b\u00ean ph\u1ea3i c\u1ee7a \u0111i\u1ec3m 0, l\u00e0 s\u1ed1 d\u01b0\u01a1ng. 102 T\u1ea1i sao nhi\u1ec1u s\u1ef1 vi\u1ec7c \u0111\u01b0\u1ee3c nh\u1eadn \u0111\u1ecbnh chung qua t\u1ec9 l\u1ec7 ph\u00e2n chia 80\/20? Con s\u1ed1 t\u1ec9 l\u1ec7 l\u1ea1 k\u00ec n\u00e0y g\u00e2y b\u1ea5t ng\u1edd nhi\u1ec1u l\u0129nh v\u1ef1c, v\u1edbi s\u1ef1 tr\u00f9ng l\u1eb7p m\u1ed9t c\u00e1ch ng\u1ea1c nhi\u00ean, t\u1eeb c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh t\u1eeb thi\u1ec7n \u0111\u1ebfn c\u00e1c t\u00e0i li\u1ec7u \u0111\u00e0o t\u1ea1o qu\u1ea3n tr\u1ecb. Ch\u1eb3ng h\u1ea1n, theo t\u1ed5 ch\u1ee9c Buy Nothing Day, nh\u1eefng qu\u1ed1c gia ph\u00e1t tri\u1ec3n, v\u1edbi 20% d\u00e2n s\u1ed1 th\u1ebf gi\u1edbi, l\u1ea1i s\u1eed d\u1ee5ng 80% ngu\u1ed3n t\u00e0i nguy\u00ean thi\u00ean nhi\u00ean tr\u00ean th\u1ebf gi\u1edbi, trong khi kho\u1ea3ng 20% tr\u01b0\u1eddng h\u1ee3p b\u1ed3i th\u01b0\u1eddng b\u1ea3o hi\u1ec3m l\u1ea1i chi\u1ebfm 80% t\u1ed5ng s\u1ed1 c\u00e1c kho\u1ea3ng ti\u1ec1n b\u1ed3i th\u01b0\u1eddng ph\u1ea3i chi tr\u1ea3. Kh\u00f4ng c\u00f3 l\u1eddi gi\u1ea3i th\u00edch n\u00e0o r\u00f5 r\u00e0ng t\u1ea1i sao nguy\u00ean nh\u00e2n v\u00e0 h\u1ec7 qu\u1ea3 l\u1ea1i \u0111\u01b0\u1ee3c ph\u00e2n chia theo t\u1ec9 l\u1ec7 nh\u01b0 v\u1eady, t\u1ea1m th\u1eddi xem t\u1ec9 l\u1ec7 80\/20 nh\u01b0 l\u00e0 m\u1ed9t c\u00f4ng c\u1ee5 nh\u1eadn \u0111\u1ecbnh t\u1ed5ng quan v\u1ec1 v\u1ea5n \u0111\u1ec1. Tuy nhi\u00ean s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a t\u1ec9 l\u1ec7 n\u00e0y \u0111\u00e3 g\u00e2y ng\u1ea1c nhi\u00ean v\u00e0 l\u00e0m cho c\u00e1c nh\u00e0 khoa h\u1ecdc ph\u1ea3i nghi\u00ean c\u1ee9u trong h\u01a1n m\u1ed9t th\u1ebf k\u1ec9 qua v\u00e0 m\u1ed9t v\u00e0i \u00fd ni\u1ec7m m\u01a1 h\u1ed3 cho c\u00e1c l\u1eddi gi\u1ea3i th\u00edch b\u1eaft \u0111\u1ea7u xu\u1ea5t hi\u1ec7n. C\u00e1c l\u1eddi gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c t\u1eadp trung v\u00e0o c\u00e1c tr\u01b0\u1eddng h\u1ee3p c\u1ee5 th\u1ec3, 116","ch\u1eb3ng h\u1ea1n nh\u01b0 \u0111\u1ecbnh lu\u1eadt Pareto, sau khi nh\u00e0 kinh t\u1ebf h\u1ecdc Vilfredo Pareto c\u00f4ng b\u1ed1 ph\u00e1t minh c\u00f4ng th\u1ee9c to\u00e1n h\u1ecdc c\u00f3 th\u1ec3 qu\u1ea3n l\u00fd s\u1ef1 ph\u00e2n b\u1ed5 gi\u00e0u ngh\u00e8o. \u0110\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn v\u1ec1 ph\u01b0\u01a1ng di\u1ec7n k\u0129 thu\u1eadt nh\u01b0 l\u00e0 \u201cm\u1ed1i t\u01b0\u01a1ng quan \u0111\u1ecbnh lu\u1eadt l\u0169y th\u1eeba ng\u01b0\u1ee3c\u201d, c\u00f4ng th\u1ee9c bao g\u1ed3m m\u1ed9t con s\u1ed1 d\u1eabn \u0111\u1ebfn l\u0169y th\u1eeba hi\u1ec3n nhi\u00ean n\u1eb1m gi\u1eefa 1 v\u00e0 2. S\u1eed d\u1ee5ng c\u00e1c d\u1eef li\u1ec7u v\u1ec1 kinh t\u1ebf h\u1ecdc cho ch\u00ednh \u0111\u1ea5t n\u01b0\u1edbc m\u00ecnh, \u00f4ng Pareto nh\u1eadn th\u1ea5y c\u00f4ng th\u1ee9c tr\u00ean cho ra k\u1ebft qu\u1ea3 20% ng\u01b0\u1eddi d\u00e2n \u00dd chi\u1ebfm h\u1eefu 80% t\u1ed5ng t\u00e0i s\u1ea3n c\u1ee7a qu\u1ed1c gia. V\u00e0 c\u00e0ng ng\u1ea1c nhi\u00ean h\u01a1n, khi \u00f4ng Pareto nh\u1eadn th\u1ea5y r\u1eb1ng t\u1ec9 l\u1ec7 n\u00e0y c\u0169ng \u00e1p d\u1ee5ng \u0111\u00fang cho c\u00e1c n\u1ec1n kinh t\u1ebf c\u1ee7a c\u00e1c qu\u1ed1c gia kh\u00e1c nh\u01b0 n\u1ec1n kinh t\u1ebf c\u00f4ng nghi\u1ec7p h\u00f3a c\u1ee7a Anh, n\u00f4ng nghi\u1ec7p h\u00f3a c\u1ee7a Nga, v\u00e0 qua nhi\u1ec1u th\u1ebf k\u1ec9 t\u1eeb x\u00e3 h\u1ed9i thu\u1ed9c tri\u1ec1u \u0111\u1ea1i Victoria ng\u01b0\u1ee3c v\u1ec1 \u0110\u1ebf ch\u1ebf La M\u00e3. V\u00e0 kh\u00f4ng c\u00f3 g\u00ec ng\u1ea1c nhi\u00ean khi c\u00f4ng b\u1ed1 \u0111\u00e3 t\u00ecm ra \u201c\u0111\u1ecbnh lu\u1eadt chung\u201d c\u1ee7a Pareto \u0111\u00e3 b\u1ecb m\u1ecdi ng\u01b0\u1eddi c\u01b0\u1eddi nh\u1ea1o l\u00fac b\u1ea5y gi\u1edd, nh\u01b0ng b\u00e2y gi\u1edd l\u1ea1i \u0111ang \u0111\u01b0\u1ee3c \u1ee7ng h\u1ed9. Nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y cho th\u1ea5y r\u1eb1ng c\u00e1c \u0111\u1ecbnh lu\u1eadt t\u01b0\u01a1ng t\u1ef1 nh\u01b0 \u0111\u1ecbnh lu\u1eadt c\u1ee7a Pareto \u0111\u00e3 hi\u1ec7n r\u00f5 m\u1ed9t c\u00e1ch t\u1ef1 nhi\u00ean \u0111\u1ed1i v\u1edbi c\u00e1c n\u1ec1n kinh t\u1ebf tu\u00e2n th\u1ee7 theo c\u00e1c y\u00eau c\u1ea7u - \u0111\u00e1ng k\u1ec3 nh\u01b0 t\u00e0i s\u1ea3n l\u00e0 h\u1ec7 qu\u1ea3 c\u1ee7a vi\u1ec7c lu\u00e2n chuy\u1ec3n ti\u1ec1n t\u1ec7 v\u00e0 h\u00e0ng h\u00f3a gi\u1eefa c\u00e1c th\u00e0nh ph\u1ea7n tham gia v\u00e0o n\u1ec1n kinh t\u1ebf, c\u1ed9ng th\u00eam nh\u1eefng thu nh\u1eadp hay chi ti\u00eau kh\u00f4ng th\u01b0\u1eddng xuy\u00ean nh\u01b0 \u0111\u1ea7u c\u01a1 t\u00edch tr\u1eef, \u0111\u1ea7u t\u01b0 b\u1ea5t \u0111\u1ed9ng s\u1ea3n,... \u0110i\u1ec1u n\u00e0y cho th\u1ea5y s\u1ef1 dao \u0111\u1ed9ng v\u1ec1 t\u00e0i s\u1ea3n qua c\u00e1c n\u1ec1n kinh t\u1ebf tr\u00ean d\u1eabn \u0111\u1ebfn c\u00e1c \u0111i\u1ec1u t\u01b0\u01a1ng t\u1ef1 nh\u01b0 \u201c\u0110\u1ecbnh lu\u1eadt 117","l\u0169y th\u1eeba\u201d c\u1ee7a Pareto. Tuy nhi\u00ean, c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t \u0111\u00e1ng quan t\u00e2m l\u00e0, kh\u00e1c v\u1edbi nh\u1eadn \u0111\u1ecbnh c\u1ee7a Pareto, gi\u00e1 tr\u1ecb l\u0169y th\u1eeba kh\u00f4ng c\u1ed1 \u0111\u1ecbnh trong kho\u1ea3ng 1 v\u00e0 2. V\u00e0 \u0111i\u1ec1u n\u00e0y c\u0169ng c\u00f3 ngh\u0129a l\u00e0 n\u1ec1n kinh t\u1ebf kh\u00f4ng nh\u1ea5t thi\u1ebft ph\u1ea3i lu\u00f4n \u0111\u00fang nh\u01b0 t\u1ec9 l\u1ec7 80\/20 b\u1ea5t h\u1ee3p l\u00fd trong vi\u1ec7c ph\u00e2n b\u1ed5 t\u00e0i s\u1ea3n. C\u00e1c nghi\u00ean c\u1ee9u c\u0169ng ch\u1ec9 ra r\u1eb1ng c\u1ea7n c\u00f3 s\u1ef1 ph\u00e2n b\u1ed5 t\u00e0i s\u1ea3n c\u00f4ng b\u1eb1ng h\u01a1n b\u1eb1ng c\u00e1ch khuy\u1ebfn kh\u00edch v\u00e0 n\u00e2ng cao m\u1eadu d\u1ecbch qua to\u00e0n b\u1ed9 chu\u1ed7i l\u1ee3i t\u1ee9c, t\u1eeb ng\u01b0\u1eddi ngh\u00e8o nh\u1ea5t \u0111\u1ebfn gi\u00e0u nh\u1ea5t. 103 C\u00f3 \u0111\u00fang l\u00e0 kh\u00f4ng th\u1ec3 ch\u1ee9ng minh m\u1ed9t m\u1ec7nh \u0111\u1ec1 ph\u1ee7 \u0111\u1ecbnh kh\u00f4ng? \u00dd ki\u1ebfn tr\u00ean th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u0111\u01b0a ra b\u1edfi nh\u1eefng ng\u01b0\u1eddi \u0111ang \u0111u\u1ed1i l\u00fd trong vi\u1ec7c b\u1ea3o v\u1ec7 m\u1ed9t l\u1eadp lu\u1eadn nh\u01b0ng th\u1eadt ra n\u00f3 kh\u00f4ng \u0111\u00fang, \u00edt nh\u1ea5t, kh\u00f4ng \u0111\u00fang trong kh\u00eda c\u1ea1nh logic. Th\u1eadt v\u1eady, b\u1eb1ng ch\u1ee9ng c\u1ee7a c\u00e1c m\u1ec7nh \u0111\u1ec1 ph\u1ee7 \u0111\u1ecbnh v\u1eabn th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng, c\u1ea3 trong logic h\u1ecdc c\u0169ng nh\u01b0 trong to\u00e1n h\u1ecdc nh\u1eb1m t\u1ea1o n\u00ean s\u1ef1 nh\u1ea5n m\u1ea1nh. Ph\u01b0\u01a1ng ph\u00e1p d\u00f9ng \u0111\u1ec3 ch\u1ee9ng minh m\u1ed9t m\u1ec7nh \u0111\u1ec1 ph\u1ee7 \u0111\u1ecbnh \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 ph\u01b0\u01a1ng ph\u00e1p ph\u1ea3n ch\u1ee9ng v\u00e0 \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n b\u1eb1ng c\u00e1ch gi\u1ea3 \u0111\u1ecbnh m\u1ed9t \u0111i\u1ec1u ng\u01b0\u1ee3c l\u1ea1i v\u1edbi m\u1ec7nh \u0111\u1ec1 ban \u0111\u1ea7u l\u00e0 \u0111\u00fang v\u00e0 sau \u0111\u00f3 ch\u1ee9ng minh r\u1eb1ng \u0111i\u1ec1u \u0111\u00f3 d\u1eabn t\u1edbi \u0111i\u1ec1u ng\u01b0\u1ee3c l\u1ea1i. M\u1ed9t trong nh\u1eefng v\u00ed d\u1ee5 c\u1ee5 th\u1ec3 nh\u1ea5t ch\u1ee9ng minh hi\u1ec7u qu\u1ea3 c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p tr\u00ean l\u00e0 ph\u1ea3n ch\u1ee9ng c\u1ee7a Euclid cho 118","r\u1eb1ng c\u00f3 v\u00f4 s\u1ed1 c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1. \u0110\u1ea7u ti\u00ean, \u00f4ng gi\u1ea3 \u0111\u1ecbnh m\u1ed9t \u0111i\u1ec1u ng\u01b0\u1ee3c l\u1ea1i, t\u1ee9c l\u00e0 s\u1ed1 nguy\u00ean t\u1ed1 s\u1ebd d\u1eebng l\u1ea1i \u1edf m\u1ed9t gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i n\u00e0o \u0111\u00f3 (t\u1ee9c l\u00e0 gi\u1ea3 \u0111\u1ecbnh r\u1eb1ng s\u1ed1 nguy\u00ean t\u1ed1 l\u00e0 h\u1eefu h\u1ea1n) - v\u00e0 ch\u1ec9 ra r\u1eb1ng \u0111i\u1ec1u \u0111\u00f3 c\u00f3 \u00e1m ch\u1ec9 r\u1eb1ng v\u1eabn ph\u1ea3i c\u00f2n nh\u1eefng s\u1ed1 nguy\u00ean t\u1ed1 l\u1edbn h\u01a1n. \u0110\u00e2y l\u00e0 m\u1ed9t \u0111i\u1ec1u m\u00e2u thu\u1eabn v\u1edbi gi\u1ea3 thi\u1ebft ban \u0111\u1ea7u v\u00e0 v\u00ec v\u1eady ch\u1ee9ng minh \u0111\u01b0\u1ee3c r\u1eb1ng c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1 l\u00e0 kh\u00f4ng c\u00f3 gi\u1edbi h\u1ea1n. B\u00ean ngo\u00e0i th\u1ebf gi\u1edbi quy t\u1eafc c\u1ee7a logic v\u00e0 to\u00e1n h\u1ecdc, vi\u1ec7c ch\u1ee9ng minh m\u1ed9t m\u1ec7nh \u0111\u1ec1 ph\u1ee7 \u0111\u1ecbnh l\u00e0 \u00edt r\u00f5 r\u00e0ng nh\u01b0ng l\u1ea1i th\u00fa v\u1ecb h\u01a1n. Gi\u1eefa c\u00e1c nh\u00e0 khoa h\u1ecdc, \u0111i\u1ec1u \u0111\u00f3 g\u1ea7n gi\u1ed1ng nh\u01b0 m\u1ed9t l\u1eddi cam \u0111oan r\u1eb1ng m\u1ed9t ng\u01b0\u1eddi kh\u00f4ng bao gi\u1edd c\u00f3 th\u1ec3 l\u00e0m m\u1ed9t \u0111i\u1ec1u g\u00ec kh\u00e1c m\u00e0 kh\u00f4ng c\u1ea7n ch\u1ee9ng minh \u0111i\u1ec1u ph\u1ee7 \u0111\u1ecbnh - c\u0169ng gi\u1ed1ng nh\u01b0 vi\u1ec7c t\u00ecm m\u1ed9t minh ch\u1ee9ng v\u1eefng ch\u1eafc cho gi\u00e1 tr\u1ecb c\u1ee7a n\u00f3 \u1edf t\u1ea5t c\u1ea3 m\u1ecdi n\u01a1i v\u00e0o m\u1ecdi th\u1eddi \u0111i\u1ec3m l\u00e0 ho\u00e0n to\u00e0n kh\u00f4ng th\u1ec3. \u0110i\u1ec1u \u0111\u00f3 \u0111\u01b0\u1ee3c ch\u1ec9 ra \u0111\u1ea7u ti\u00ean b\u1edfi nh\u00e0 tri\u1ebft h\u1ecdc th\u1ebf k\u1ec9 18 Davia Hume (nh\u01b0ng tr\u1edf n\u00ean n\u1ed5i ti\u1ebfng nh\u1edd v\u00e0o c\u00f4ng c\u1ee7a nh\u00e0 tri\u1ebft h\u1ecdc khoa h\u1ecdc th\u1ebf k\u1ec9 20, Karl Popper). Nh\u1eefng l\u1eadp lu\u1eadn c\u1ee7a \u00f4ng th\u01b0\u1eddng \u0111\u01b0\u1ee3c mi\u00eau t\u1ea3 nh\u01b0 l\u00e0 m\u1ed9t kh\u1eb3ng \u0111\u1ecbnh cho ni\u1ec1m tin r\u1eb1ng c\u00e1c h\u1ecdc thuy\u1ebft khoa h\u1ecdc l\u00e0 kh\u00f4ng th\u1ec3 ch\u1ee9ng minh nh\u01b0ng \u0111i\u1ec1u \u0111\u00f3 kh\u00f4ng \u0111\u00fang: c\u00e1c nh\u00e0 khoa h\u1ecdc v\u1eabn th\u01b0\u1eddng xuy\u00ean b\u1ecf qua nh\u1eefng th\u00e1ch th\u1ee9c \u0111\u1ed1i v\u1edbi nh\u1eefng h\u1ecdc thuy\u1ebft y\u00eau qu\u00fd c\u1ee7a m\u00ecnh b\u1eb1ng c\u00e1ch d\u1ef1a v\u00e0o nh\u1eefng l\u1eddi gi\u1ea3i th\u00edch kh\u00e1c, t\u1eeb nh\u1eefng k\u0129 thu\u1eadt th\u1ef1c nghi\u1ec7m \u0111\u00e1ng nghi ng\u1edd \u0111\u1ebfn nh\u1eefng gian l\u1eadn c\u00f4ng khai. C\u00e1c nh\u00e0 khoa h\u1ecdc th\u01b0\u1eddng t\u1eeb b\u1ecf nh\u1eefng \u00fd t\u01b0\u1edfng c\u1ee7a h\u1ecd kh\u00f4ng ph\u1ea3i v\u00ec nh\u1eefng \u00fd t\u01b0\u1edfng \u0111\u00f3 \u0111\u01b0\u1ee3c ch\u1ee9ng minh r\u1eb1ng kh\u00f4ng \u0111\u00fang 119","m\u1ed9t c\u00e1ch r\u00f5 r\u00e0ng m\u00e0 l\u00e0 do s\u1ef1 xu\u1ea5t hi\u1ec7n c\u1ee7a nh\u1eefng h\u1ecdc thuy\u1ebft kh\u00e1c c\u00f3 kh\u1ea3 n\u0103ng gi\u1ea3i th\u00edch t\u1ed1t h\u01a1n. 104 S\u1ed1 l\u1edbn nh\u1ea5t c\u00f3 th\u1ec3 l\u00e0 s\u1ed1 n\u00e0o? C\u00e2u tr\u1ea3 l\u1eddi \u0111\u01a1n gi\u1ea3n ch\u00ednh l\u00e0 v\u00f4 c\u1ef1c nh\u01b0ng trong nh\u1eefng n\u0103m 1870, nh\u00e0 to\u00e1n h\u1ecdc Georg Cantor \u0111\u00e3 \u0111\u01b0a ra m\u1ed9t l\u00fd lu\u1eadn xu\u1ea5t s\u1eafc cho th\u1ea5y s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a nhi\u1ec1u lo\u1ea1i v\u00f4 c\u1ef1c kh\u00e1c nhau - m\u00e0 trong \u0111\u00f3 m\u1ed9t v\u00e0i s\u1ed1 v\u00f4 c\u1ef1c l\u1edbn h\u01a1n nh\u1eefng s\u1ed1 v\u00f4 c\u1ef1c kh\u00e1c r\u1ea5t nhi\u1ec1u. S\u1ed1 v\u00f4 c\u1ef1c \u201cnh\u1ecf nh\u1ea5t\u201d ch\u00ednh l\u00e0 lo\u1ea1i v\u00f4 c\u1ef1c \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n b\u1eb1ng vi\u1ec7c \u0111\u1ebfm m\u00e3i m\u00e3i: 0,1,2,3... T\u00ean c\u1ee7a lo\u1ea1i v\u00f4 c\u1ef1c n\u00e0y l\u00e0 Aleph-null (\u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean sau k\u00ed hi\u1ec7u \u0111\u1ea7u ti\u00ean trong h\u1ec7 th\u1ed1ng ch\u1eef c\u00e1i Hebrew) v\u00e0 ch\u00ednh l\u00e0 t\u00ean g\u1ecdi ban \u0111\u1ea7u c\u1ee7a c\u1ee7a c\u00e1i m\u00e0 Cantor g\u1ecdi l\u00e0 nh\u1eefng s\u1ed1 h\u1eefu h\u1ea1n chuy\u1ec3n \u0111\u1ed5i. Nh\u1eefng s\u1ed1 n\u00e0y c\u00f3 m\u1ed9t s\u1ed1 \u0111\u1eb7c t\u00ednh th\u1eadt s\u1ef1 k\u00ec l\u1ea1. V\u00ed d\u1ee5, c\u1ed9ng th\u00eam m\u1ed9t Aleph-null v\u00e0o ch\u00ednh n\u00f3 (t\u1ee9c l\u00e0 nh\u00e2n \u0111\u00f4i m\u1ed9t Aleph-null) ch\u1ec9 \u0111\u01a1n gi\u1ea3n l\u00e0 l\u1ea1i sinh ra m\u1ed9t Aleph-null, cho n\u00ean vi\u1ec7c nh\u00e2n Aleph-null v\u1edbi ch\u00ednh n\u00f3 (t\u1ee9c l\u00e0 b\u00ecnh ph\u01b0\u01a1ng Aleph-null) c\u0169ng gi\u1ed1ng nh\u01b0 v\u1eady. Nh\u01b0ng \u0111\u00f3 ch\u1ec9 m\u1edbi l\u00e0 b\u1eaft \u0111\u1ea7u, Cantor c\u00f2n ch\u1ec9 ra r\u1eb1ng c\u00f3 nh\u1eefng s\u1ed1 v\u00f4 c\u1ef1c kh\u00e1c l\u1edbn h\u01a1n, b\u1eaft \u0111\u1ea7u b\u1edfi m\u1ed9t Aleph-null - m\u1ed9t con s\u1ed1 l\u1edbn \u0111\u1ebfn n\u1ed7i n\u00f3 kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ea1t \u0111\u1ebfn b\u1eb1ng vi\u1ec7c \u0111\u1ebfm trong m\u1ed9t l\u01b0\u1ee3ng th\u1eddi gian v\u00f4 h\u1ea1n. \u0110i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a r\u1eb1ng c\u00f3 m\u1ed9t s\u1ed1 v\u00f4 c\u1ef1c c\u1ee7a nh\u1eefng s\u1ed1 v\u00f4 c\u1ef1c h\u01a1n, m\u00e0 s\u1ed1 v\u00f4 c\u1ef1c n\u00e0y s\u1ebd l\u1edbn h\u01a1n s\u1ed1 v\u00f4 c\u1ef1c k\u1ebf n\u00f3, cho t\u1edbi cu\u1ed1i c\u00f9ng khi c\u00f3 m\u1ed9t s\u1ed1 v\u00f4 c\u1ef1c \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ee9c \u0111\u1ed9 l\u1edbn 120","nh\u1ea5t, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 V\u00f4 c\u1ef1c tuy\u1ec7t \u0111\u1ed1i, k\u00ed hi\u1ec7u l\u00e0 Omega. Con s\u1ed1 n\u00e0y l\u1edbn \u0111\u1ebfn n\u1ed7i n\u00f3 kh\u00f4ng th\u1ec3 m\u00f4 t\u1ea3 theo ngh\u0129a \u0111en. Th\u1eadt v\u1eady, \u0111\u1ecbnh ngh\u0129a c\u1ee7a n\u00f3 d\u1ef1a tr\u00ean \u00fd t\u01b0\u1edfng r\u1eb1ng b\u1ea5t k\u00ec s\u1ef1 c\u1ed1 g\u1eafng n\u00e0o \u0111\u1ec3 m\u00f4 t\u1ea3 n\u00f3 ch\u1ec9 c\u00f3 th\u1ec3 l\u00e0 \u0111ang m\u00f4 t\u1ea3 nh\u1eefng s\u1ed1 nh\u1ecf h\u01a1n th\u00f4i. 105 Khi c\u00e1c \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung l\u00ean, t\u1ec9 l\u1ec7 c\u00f9ng xu\u1ea5t hi\u1ec7n m\u1eb7t ng\u1eeda l\u00e0 bao nhi\u00eau? T\u1ec9 l\u1ec7 12 \u0111\u1ed3ng xu c\u00f9ng ng\u1eeda khi tung l\u00ean m\u1ed9t c\u00e1ch ng\u1eabu nhi\u00ean l\u00e0 1\/4096 - th\u1eadt s\u1ef1 l\u00e0 m\u1ed9t t\u1ec9 l\u1ec7 nh\u1ecf nh\u01b0ng c\u0169ng \u0111\u1ee7 \u0111\u1ec3 bi\u1ec7n h\u1ed9 cho nh\u1eefng m\u1ed1i nghi ng\u1edd cho r\u1eb1ng c\u00f3 s\u1ef1 l\u1eeba b\u1ecbp. \u0110\u01b0\u01a1ng \u0111\u1ea7u v\u1edbi c\u00e2u h\u1ecfi n\u00e0y, c\u00e1c nh\u00e0 khoa h\u1ecdc trong m\u1ed9t kho\u1ea3ng th\u1eddi gian d\u00e0i \u0111\u00e3 d\u1ef1a v\u00e0o m\u1ed9t quy t\u1eafc. Quy t\u1eafc \u0111\u00f3 cho r\u1eb1ng nh\u1eefng hi\u1ec7n t\u01b0\u1ee3ng c\u00f3 v\u1ebb nh\u01b0 l\u00e0 l\u1eeba b\u1ecbp (n\u00f3i theo t\u1eeb chuy\u00ean m\u00f4n l\u00e0 \u201cc\u00f3 t\u00ednh ch\u1ea5t x\u00e1c su\u1ea5t\u201d) x\u1ea3y ra n\u1ebfu t\u1ec9 l\u1ec7 c\u1ee7a vi\u1ec7c thu th\u1eadp c\u00e1c k\u1ebft qu\u1ea3 quan s\u00e1t \u0111\u01b0\u1ee3c m\u1ed9t c\u00e1ch ng\u1eabu nhi\u00ean l\u00e0 nh\u1ecf h\u01a1n 1\/20. \u0110\u1ed1i v\u1edbi vi\u1ec7c tung m\u1ed9t \u0111\u1ed3ng xu, quy t\u1eafc \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 n\u1ebfu \u0111\u1ea1t \u0111\u01b0\u1ee3c 5 ho\u1eb7c nhi\u1ec1u h\u01a1n m\u1eb7t ng\u1eeda (ho\u1eb7c \u00fap) \u1edf c\u00e1c l\u1ea7n tung li\u00ean t\u1ee5c s\u1ebd g\u00e2y ra m\u1ed1i nghi ng\u1edd v\u1ec1 s\u1ef1 ch\u00ednh x\u00e1c c\u1ee7a c\u00e1c \u0111\u1ed3ng 121","xu. T\u1ea5t nhi\u00ean, s\u1ef1 sai l\u1ec7ch s\u1ebd kh\u00f4ng b\u1ed9c l\u1ed9 d\u01b0\u1edbi d\u1ea1ng m\u1ed9t d\u00e3y li\u00ean t\u1ee5c c\u00e1c m\u1eb7t ng\u1eeda: 100 \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung l\u00ean s\u1ebd c\u00f3 \u00edt nh\u1ea5t 64 m\u1eb7t ng\u1eeda theo th\u1ee9 t\u1ef1 b\u1ea5t k\u1ef3, \u0111i\u1ec1u \u0111\u00f3 \u0111\u01b0\u1ee3c ngh\u0129 r\u1eb1ng theo \u0111\u00fang t\u00ednh ch\u1ea5t x\u00e1c su\u1ea5t. T\u1ec9 l\u1ec7 c\u1ea7n cho vi\u1ec7c g\u00e2y ra c\u00e1c m\u1ed1i nghi ng\u1edd s\u1ebd ti\u1ebfn g\u1ea7n t\u1edbi 50% khi s\u1ed1 l\u01b0\u1ee3ng \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung t\u0103ng l\u00ean (ph\u1ea3n \u00e1nh m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng r\u1eb1ng, n\u1ebfu \u0111\u1ed3ng xu ho\u00e0n to\u00e0n c\u00e2n b\u1eb1ng, t\u1ec9 l\u1ec7 c\u00f3 m\u1eb7t ng\u1eeda c\u0169ng s\u1ebd ti\u1ebfn \u0111\u1ebfn r\u1ea5t g\u1ea7n con s\u1ed1 50%). V\u1edbi 1.000 \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung, t\u1ec9 l\u1ec7 c\u00f3 m\u1eb7t ng\u1eeda l\u00e0 52,7% trong khi 10.000 \u0111\u1ed3ng xu \u0111\u1ef1\u01a1c tung th\u00ec t\u1ec9 l\u1ec7 l\u00e0 50,83%. \u0110i\u1ec1u \u0111\u00f3 gi\u1ea3i t\u1ecfa c\u00e1c m\u1ed1i nghi ng\u1edd b\u00ean trong c\u00e1c quy t\u1eafc khoa h\u1ecdc th\u00f4ng th\u01b0\u1eddng. 106 C\u00f3 th\u1ec3 d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c m\u1ed9t \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung l\u00ean s\u1ebd r\u1edbt xu\u1ed1ng \u0111\u1ea5t v\u1edbi m\u1eb7t n\u00e0o kh\u00f4ng? Theo nguy\u00ean t\u1eafc, th\u1eadt s\u1ef1 c\u00f3 th\u1ec3 d\u1ef1 \u0111o\u00e1n \u0111\u1ed3ng xu s\u1ebd r\u1edbt xu\u1ed1ng \u0111\u1ea5t v\u1edbi m\u1eb7t x\u1ea5p hay ng\u1eeda. C\u01a1 h\u1ecdc c\u01a1 b\u1ea3n c\u1ee7a vi\u1ec7c tung \u0111\u1ed3ng ti\u1ec1n th\u00ec kh\u00e1 \u0111\u01a1n gi\u1ea3n v\u00e0 c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh t\u00ecm k\u1ebft qu\u1ea3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c gi\u1ea3i b\u1eb1ng m\u00e1y vi t\u00ednh. Tuy nhi\u00ean, m\u1ed9t nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y c\u1ee7a gi\u00e1o s\u01b0 J.P.Cusumano v\u00e0 ti\u1ebfn s\u0129 N.K.Hecht c\u1ee7a \u0111\u1ea1i h\u1ecdc bang Pennsylvania \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng tr\u1ea1ng th\u00e1i cu\u1ed1i c\u00f9ng c\u1ee7a \u0111\u1ed3ng xu khi \u0111\u00e1p xu\u1ed1ng \u0111\u1ea5t ch\u1ec9 c\u00f3 th\u1ec3 d\u1ef1 \u0111o\u00e1n khi m\u00e0 \u0111\u1ed3ng xu \u0111\u01b0\u1ee3c tung y\u1ebfu \u0111\u1ebfn n\u1ed7i n\u00f3 h\u1ea7u nh\u01b0 kh\u00f4ng l\u00ean \u0111\u1ee7 cao \u0111\u1ec3 ho\u00e0n t\u1ea5t m\u1ed9t v\u00f2ng quay \u0111\u1ea7y \u0111\u1ee7. \u0110\u00f3 l\u00e0 do vi\u1ec7c tung \u0111\u1ed3ng xu c\u00f3 t\u00ednh 122","ch\u1ea5t \u201ch\u1ed7n lo\u1ea1n\u201d - ngh\u0129a l\u00e0, ch\u1ec9 m\u1ed9t sai s\u00f3t r\u1ea5t nh\u1ecf trong vi\u1ec7c m\u00f4 t\u1ea3 tr\u1ea1ng th\u00e1i ban \u0111\u1ea7u c\u1ee7a \u0111\u1ed3ng xu s\u1ebd t\u0103ng l\u00ean r\u1ea5t nhanh theo th\u1eddi gian v\u00e0 c\u00f3 th\u1ec3 l\u00e0m ti\u00eau tan m\u1ecdi hy v\u1ecdng d\u1ef1 \u0111o\u00e1n ch\u00ednh x\u00e1c \u0111\u1ed3ng xu s\u1ebd \u0111\u00e1p xu\u1ed1ng \u0111\u1ea5t nh\u01b0 th\u1ebf n\u00e0o. N\u00ean, \u0111\u1ed1i v\u1edbi nh\u1eefng m\u1ee5c \u0111\u00edch th\u1ef1c t\u1ebf, vi\u1ec7c tung \u0111\u1ed3ng xu l\u00e0 ho\u00e0n to\u00e0n ng\u1eabu nhi\u00ean. Nh\u1eefng th\u00ed nghi\u1ec7m ch\u1ee9ng minh cho nh\u1eadn \u0111\u1ecbnh tr\u00ean \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n b\u1edfi John Kerrich, m\u1ed9t nh\u00e0 to\u00e1n h\u1ecdc g\u1ed1c Copenhagen, \u0111\u00e3 t\u1eebng b\u1ecb giam gi\u1eef trong cu\u1ed9c x\u00e2m l\u01b0\u1ee3c c\u1ee7a \u0110an M\u1ea1ch v\u00e0o Anh n\u0103m 1940. Trong su\u1ed1t th\u1eddi gian b\u1ecb b\u1ecf t\u00f9, ti\u1ebfn s\u0129 Kerrich \u0111\u00e3 gi\u1ebft th\u1eddi gian b\u1eb1ng c\u00e1ch tung \u0111\u1ed3ng ti\u1ec1n 10.000 l\u1ea7n v\u00e0 ghi l\u1ea1i c\u00e1c k\u1ebft qu\u1ea3. \u00d4ng ph\u00e1t hi\u1ec7n ra r\u1eb1ng t\u1ec9 l\u1ec7 t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a m\u1eb7t x\u1ea5p v\u00e0 ng\u1eeda l\u00e0 ho\u00e0n to\u00e0n kh\u00f4ng thay \u0111\u1ed5i v\u1edbi s\u1ef1 tung ng\u1eabu nhi\u00ean, kho\u1ea3ng 5,067 m\u1eb7t ng\u1eeda v\u00e0 4,933 m\u1eb7t x\u1ea5p. 107 L\u00e0m c\u00e1ch n\u00e0o \u0111\u1ec3 m\u1ed9t ng\u01b0\u1eddi c\u00f3 th\u1ec3 m\u01b0\u1eddng t\u01b0\u1ee3ng ra con s\u1ed1 m\u1ed9t tri\u1ec7u? M\u1ed9t trong nh\u1eefng th\u00e1ch th\u1ee9c th\u00fa v\u1ecb nh\u1ea5t c\u1ee7a vi\u1ec7c vi\u1ebft b\u00e0i trong khoa h\u1ecdc ch\u00ednh l\u00e0 vi\u1ec7c \u0111\u01b0a ra c\u00e1c c\u00e1ch \u0111\u1ec3 m\u01b0\u1eddng t\u01b0\u1ee3ng nh\u1eefng th\u1ee9 n\u1eb1m ngo\u00e0i nh\u1eefng d\u00e3y s\u1ed1 th\u00f4ng th\u01b0\u1eddng ta g\u1eb7p. L\u00e0m t\u1ed1t \u0111i\u1ec1u \u0111\u00f3, c\u00e1c k\u1ebft qu\u1ea3 c\u00f3 th\u1ec3 t\u1ea1o n\u00ean m\u1ed9t \u1ea5n t\u01b0\u1ee3ng r\u1ea5t l\u00e2u d\u00e0i. M\u1ed9t cu\u1ed1n s\u00e1ch v\u1ec1 thi\u00ean v\u0103n h\u1ecdc \u0111\u00e3 \u0111\u01b0a ra m\u1ed9t h\u00ecnh t\u01b0\u1ee3ng c\u00f3 th\u1ec3 nh\u1edb \u0111\u01b0\u1ee3c m\u1ed9t c\u00e1ch chi ti\u1ebft 123","v\u1ec1 s\u1ef1 kh\u1ed5ng l\u1ed3 c\u1ee7a h\u1ec7 m\u1eb7t tr\u1eddi. Theo t\u00e1c gi\u1ea3 quy\u1ec3n s\u00e1ch, n\u1ebfu m\u1eb7t tr\u1eddi \u0111\u01b0\u1ee3c t\u01b0\u1ee3ng tr\u01b0ng b\u1edfi m\u1ed9t qu\u1ea3 banh ch\u01a1i tr\u00ean b\u1edd bi\u1ec3n, th\u00ec tr\u00e1i \u0111\u1ea5t gi\u1ed1ng nh\u01b0 m\u1ed9t ng\u01b0\u1eddi ch\u01a1i \u1edf c\u00e1ch \u0111\u00f3 30 b\u01b0\u1edbc ch\u00e2n v\u00e0 sao Di\u00eam V\u01b0\u01a1ng l\u00e0 \u0111i\u1ec3m d\u1eebng c\u00e1ch \u0111\u01b0\u1eddng xu\u1ed1ng b\u1edd bi\u1ec3n 1,2 km. Ch\u01b0a h\u1ebft, n\u1ebfu theo c\u00e1ch chia nh\u01b0 \u00fd t\u01b0\u1edfng k\u00ec qu\u1eb7c tr\u00ean, th\u00ec ng\u00f4i sao g\u1ea7n nh\u1ea5t s\u1ebd n\u1eb1m c\u00e1ch xa m\u1eb7t tr\u1eddi kho\u1ea3ng h\u01a1n 8.000 km. Vi\u1ec7c minh h\u1ecda nh\u1eefng con s\u1ed1 thu\u1ea7n t\u00fay th\u00ec kh\u00e1 kh\u00f3 nh\u01b0ng m\u1ed9t c\u00e1ch hay \u0111\u1ec3 m\u01b0\u1eddng t\u01b0\u1ee3ng m\u1ed9t tri\u1ec7u l\u00e0 s\u1eed d\u1ee5ng gi\u1ea5y d\u00f9ng \u0111\u1ec3 v\u1ebd \u0111\u1ed3 th\u1ecb (gi\u1ea5y c\u00f3 k\u1ebb s\u1eb5n nh\u1eefng \u00f4 vu\u00f4ng): m\u1ed9t t\u1edd gi\u1ea5y A4 v\u1edbi nh\u1eefng \u00f4 vu\u00f4ng c\u00f3 k\u00edch th\u01b0\u1edbc 2mm2 th\u00ec ch\u1ee9a kho\u1ea3ng 15.540 \u00f4 vu\u00f4ng. V\u1edbi c\u00e1ch t\u00ednh nh\u01b0 tr\u00ean, 65 t\u1edd gi\u1ea5y ch\u1ec9 ch\u1ee9a h\u01a1n m\u1ed9t tri\u1ec7u \u00f4 vu\u00f4ng. M\u1ed9t c\u00e1ch kh\u00e1c l\u00e0 s\u1eed d\u1ee5ng \u0111\u01b0\u1eddng: m\u1ed9t tri\u1ec7u h\u1ea1t \u0111\u01b0\u1eddng n\u1eb7ng kho\u1ea3ng 700g, trong khi m\u1ed9t t\u1ec9 h\u1ea1t \u0111\u01b0\u1eddng ch\u1ec9 n\u1eb7ng h\u01a1n 0.75 t\u1ea5n m\u1ed9t ch\u00fat. Nh\u1eefng c\u00e1ch ph\u00e2n t\u00edch tr\u00ean c\u00f3 th\u1ec3 tr\u1edf n\u00ean \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch khi c\u1ed1 g\u1eafng l\u00e0m r\u00f5 s\u1ef1 kh\u1ed5ng l\u1ed3 c\u1ee7a nh\u1eefng con s\u1ed1 n\u00e0o \u0111\u00f3. V\u00ed d\u1ee5, c\u01a1 h\u1ed9i tr\u00fang s\u1ed1 \u1edf Anh l\u00e0 m\u1ed9t ph\u1ea7n 13.983.816, m\u1ed9t con s\u1ed1 m\u00e0 th\u1eadt s\u1ef1 kh\u00f4ng th\u1ec3 m\u01b0\u1eddng t\u01b0\u1ee3ng th\u1ea5y. S\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p gi\u1ea5y v\u1ebd \u0111\u1ed3 th\u1ecb, m\u1ecdi th\u1ee9 tr\u1edf n\u00ean r\u00f5 h\u01a1n m\u1ed9t ch\u00fat: vi\u1ec7c l\u1ea5y \u0111\u01b0\u1ee3c ch\u00ednh x\u00e1c s\u00e1u con s\u1ed1 gi\u1ed1ng nh\u01b0 vi\u1ec7c ch\u1ecdn m\u1ed9t \u00f4 vu\u00f4ng 2mm2 gi\u1eefa m\u1ed9t ch\u1ed3ng 900 t\u1edd gi\u1ea5y. T\u01b0\u01a1ng t\u1ef1, s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p \u0111\u01b0\u1eddng, vi\u1ec7c l\u1ea5y \u0111\u01b0\u1ee3c ch\u00ednh x\u00e1c s\u00e1u con s\u1ed1 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng vi\u1ec7c t\u00ecm m\u1ed9t h\u1ea1t \u0111\u01b0\u1eddng m\u00e0u \u0111en gi\u1eefa 10 kg \u0111\u01b0\u1eddng. 124","108 S\u1ed1 l\u1edbn nh\u1ea5t v\u00e0 nh\u1ecf nh\u1ea5t \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong khoa h\u1ecdc l\u00e0 g\u00ec? C\u00f3 r\u1ea5t nhi\u1ec1u tranh c\u00e3i trong c\u1ea3 hai \u0111\u1ec1 t\u00e0i tr\u00ean. Trong th\u1eadp ni\u00ean 1930, nh\u00e0 v\u1eadt l\u00fd \u0111o\u1ea1t gi\u1ea3i Nobel Paul Dirac \u0111\u00e3 ph\u00e1t tri\u1ec3n m\u1ed9t h\u1ecdc thuy\u1ebft m\u00e0 ng\u00e0y nay \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn v\u1edbi t\u00ean g\u1ecdi l\u00e0 \u201cGi\u1ea3 thi\u1ebft nh\u1eefng con s\u1ed1 l\u1edbn\u201d, d\u1ef1a v\u00e0o s\u1ef1 t\u01b0\u01a1ng \u0111\u1ed3ng k\u00ec l\u1ea1 c\u1ee7a ba con s\u1ed1: c\u01b0\u1eddng \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb v\u00e0 l\u1ef1c h\u1ea5p d\u1eabn trong nguy\u00ean t\u1eed hydro (1039), tu\u1ed5i c\u1ee7a v\u0169 tr\u1ee5 \u0111\u01b0\u1ee3c chia theo kho\u1ea3ng th\u1eddi gian \u0111\u1ec3 \u00e1nh s\u00e1ng \u0111i qua m\u1ed9t nguy\u00ean t\u1eed hydro (c\u0169ng l\u00e0 1039), v\u00e0 c\u0103n b\u1eadc hai c\u1ee7a s\u1ed1 l\u01b0\u1ee3ng c\u00e1c h\u1ea1t c\u00f3 trong v\u0169 tr\u1ee5 (ch\u00ednh l\u00e0 c\u0103n b\u1eadc hai c\u1ee7a 1078, b\u1eb1ng 1039). Vi\u1ec7c Dirac ti\u1ebfn t\u1edbi so s\u00e1nh ba s\u1ed1 \u0111\u00f3 nh\u01b0 th\u1ebf n\u00e0o hay t\u1ea1i sao c\u00e1c s\u1ed1 \u0111\u00f3 l\u1ea1i gi\u1ed1ng nhau nh\u01b0 v\u1eady v\u1eabn l\u00e0 \u0111i\u1ec1u ch\u01b0a ch\u1eafc ch\u1eafn. Tuy nhi\u00ean, nghi\u00ean c\u1ee9u c\u1ee7a \u00f4ng \u0111\u00e3 d\u1eabn \u0111\u1ebfn con s\u1ed1 1078 (s\u1ed1 g\u1ed3m c\u00f3 m\u1ed9t s\u1ed1 1 v\u00e0 78 s\u1ed1 0 theo sau) tr\u1edf th\u00e0nh m\u1ed9t \u1ee9ng c\u1eed vi\u00ean s\u00e1ng gi\u00e1 cho con s\u1ed1 l\u1edbn nh\u1ea5t ph\u00f9 h\u1ee3p v\u1edbi th\u1ef1c t\u1ebf trong khoa h\u1ecdc. Con s\u1ed1 nh\u1ecf nh\u1ea5t chi\u1ebfm v\u1ecb tr\u00ed quan tr\u1ecdng trung t\u00e2m trong khoa h\u1ecdc c\u00f3 \u0111\u1eb7c t\u00ednh kh\u00f4ng r\u00f5 r\u00e0ng, l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a m\u1ed9t \u01b0\u1edbc t\u00ednh t\u1ec7 h\u1ea1i ch\u01b0a t\u1eebng c\u00f3. Nh\u1eefng nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y v\u1ec1 v\u0169 tr\u1ee5 \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng v\u0169 tr\u1ee5 \u0111ang gi\u00e3n n\u1edf v\u1edbi m\u1ed9t t\u1ed1c \u0111\u1ed9 t\u0103ng li\u00ean t\u1ee5c, \u0111\u01b0\u1ee3c th\u00fac \u0111\u1ea9y b\u1edfi m\u1ed9t l\u1ef1c \u201ckh\u00e1ng l\u1ef1c h\u1ea5p d\u1eabn\u201d b\u00ed \u1ea9n. Gi\u1ea3 thi\u1ebft t\u1ed1t nh\u1ea5t v\u1ec1 ngu\u1ed3n c\u1ee7a l\u1ef1c n\u00e0y ch\u00ednh l\u00e0 b\u1ea3n th\u00e2n kh\u00f4ng gian tr\u1ed1ng r\u1ed7ng, kh\u00f4ng gian m\u00e0 theo c\u00e1c \u0111\u1ecbnh lu\u1eadt c\u1ee7a th\u1ebf gi\u1edbi h\u1ea1 nguy\u00ean t\u1eed \u0111\u01b0\u1ee3c xem x\u00e9t t\u1ec9 125","m\u1ec9 v\u1edbi th\u1ee9 \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 n\u0103ng l\u01b0\u1ee3ng l\u01b0\u1ee3ng t\u1eed ch\u00e2n kh\u00f4ng. C\u00f3 th\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng \u0111\u1ed9 l\u1edbn c\u1ee7a n\u0103ng l\u01b0\u1ee3ng n\u00e0y nh\u01b0ng k\u1ebft qu\u1ea3 l\u1ea1i kh\u00f4ng theo th\u1ee9 t\u1ef1 v\u1edbi gi\u00e1 tr\u1ecb \u0111\u01b0\u1ee3c \u0111o m\u00e0 nh\u1ecf h\u01a1n kho\u1ea3ng 10120 l\u1ea7n. Gi\u1ea3i th\u00edch t\u1ea1i sao gi\u00e1 tr\u1ecb \u0111\u00fang l\u1ea1i r\u1ea5t nh\u1ecf (v\u00e0 v\u1eabn kh\u00f4ng ph\u1ea3i l\u00e0 s\u1ed1 0) v\u00e0 \u0111\u01b0\u1ee3c xem nh\u01b0 l\u00e0 m\u1ed9t trong nh\u1eefng b\u00ed \u1ea9n l\u1edbn nh\u1ea5t c\u1ee7a khoa h\u1ecdc \u0111\u01b0\u01a1ng th\u1eddi. 109 T\u1ea1i sao c\u00e1c nh\u00e0 to\u00e1n h\u1ecdc l\u1ea1i r\u1ea5t h\u1ee9ng th\u00fa v\u1edbi c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1? C\u00e1c s\u1ed1 nguy\u00ean t\u1ed1 l\u00e0 c\u00e1c \u201ckh\u1ed1i nh\u00e0\u201d c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 l\u1edbn h\u01a1n 1. Ngh\u0129a l\u00e0 t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1, t\u1ef1 b\u1ea3n th\u00e2n c\u1ee7a n\u00f3 \u0111\u00e3 l\u00e0 m\u1ed9t s\u1ed1 nguy\u00ean t\u1ed1, nh\u01b0 s\u1ed1 2, 17, 53 ho\u1eb7c 673, ho\u1eb7c l\u00e0 s\u1ea3n ph\u1ea9m c\u1ee7a c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1, nh\u01b0 s\u1ed1 17.119 (17x19x53). H\u01a1n n\u1eefa, m\u1ed7i c\u00e1c con s\u1ed1 \u0111\u1ec1u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1 c\u1ee7a m\u00ecnh b\u1eb1ng m\u1ed9t c\u00e1ch duy nh\u1ea5t. \u0110\u00f3 kh\u00f4ng ch\u1ec9 l\u00e0 gi\u1ea3 thi\u1ebft: n\u0103m 1801 nh\u00e0 to\u00e1n ho\u1ea1c Carl Gauss \u0111\u00e3 \u0111\u01b0a ra m\u1ed9t b\u1eb1ng ch\u1ee9ng cho \u201c\u0110\u1ecbnh lu\u1eadt c\u01a1 b\u1ea3n c\u1ee7a s\u1ed1 h\u1ecdc\u201d (m\u1eb7c d\u00f9 c\u00f3 v\u1ebb nh\u01b0 Euclid \u0111\u00e3 ch\u1ee9ng minh tr\u01b0\u1edbc \u0111\u00f3 2.000 n\u0103m). Ngo\u1ea1i tr\u1eeb t\u00ednh ch\u1ea5t c\u01a1 b\u1ea3n c\u1ee7a m\u00ecnh, c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1 c\u00f2n tr\u00eau ng\u01b0\u01a1i c\u00e1c nh\u00e0 to\u00e1n h\u1ecdc b\u1eb1ng c\u00e1c t\u00ednh ch\u1ea5t c\u00f3 v\u1ebb nh\u01b0 \u0111\u00fang nh\u01b0ng l\u1ea1i kh\u00f4ng c\u00f3 b\u1eb1ng ch\u1ee9ng ch\u1ee9ng minh. V\u00ed d\u1ee5, b\u1ea3n th\u00e2n Eu- clid \u0111\u00e3 \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ed9t ch\u1ee9ng c\u1ee9 r\u00f5 r\u00e0ng l\u00e0 c\u00f3 v\u00f4 s\u1ed1 c\u00e1c s\u1ed1 nguy\u00ean t\u1ed1, nh\u01b0ng cho \u0111\u1ebfn ng\u00e0y nay v\u1eabn kh\u00f4ng c\u00f3 126","ai ch\u1ee9ng minh \u0111\u01b0\u1ee3c r\u1eb1ng c\u00f3 v\u00f4 s\u1ed1 \u201cc\u00e1c c\u1eb7p s\u1ed1 nguy\u00ean t\u1ed1\u201d, nh\u01b0 5 v\u00e0 7, hay 59 v\u00e0 61, trong \u0111\u00f3 hai s\u1ed1 l\u1ebb k\u1ebf ti\u1ebfp nhau l\u00e0 nh\u1eefng s\u1ed1 nguy\u00ean t\u1ed1. Sau \u0111\u00f3 c\u00f3 \u01af\u1edbc \u0111o\u00e1n c\u1ee7a Goldbach\u2019s, l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c n\u00eau ra v\u00e0o n\u0103m 1742, ph\u00e1t bi\u1ec3u r\u1eb1ng t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 l\u1edbn h\u01a1n 5 \u0111\u1ec1u l\u00e0 m\u1ed9t t\u1ed5ng duy nh\u1ea5t c\u1ee7a \u0111\u00fang ba s\u1ed1 nguy\u00ean t\u1ed1. M\u1ed9t l\u1ea7n n\u1eefa, trong khi \u0111i\u1ec1u \u0111\u00f3 \u0111\u01b0\u1ee3c tin r\u1eb1ng \u0111\u00fang m\u1ed9t c\u00e1ch r\u1ed9ng r\u00e3i, v\u1eabn kh\u00f4ng c\u00f3 ai th\u00e0nh c\u00f4ng trong vi\u1ec7c ch\u1ee9ng minh n\u00f3. 110 T\u1ea1i sao ng\u01b0\u1eddi ta l\u1ea1i nh\u1ea5n m\u1ea1nh \u0111\u1ebfn con s\u1ed1 \u201ctrung gian\u201d (median) thay v\u00ec d\u00f9ng s\u1ed1 trung b\u00ecnh (average)? C\u00f3 nhi\u1ec1u ng\u01b0\u1eddi cho r\u1eb1ng trung gian ch\u00ednh l\u00e0 t\u1eeb \u0111\u1ed3ng ngh\u0129a c\u1ee7a trung b\u00ecnh, nh\u01b0ng c\u00f3 m\u1ed9t s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai ngh\u0129a c\u1ee7a ch\u00fang v\u00e0 s\u1ef1 kh\u00e1c bi\u1ec7t \u0111\u00f3 kh\u00f4ng ch\u1ec9 \u0111\u01b0\u1ee3c quan t\u00e2m \u0111\u1ebfn v\u1ec1 m\u1eb7t l\u00fd thuy\u1ebft. Trung b\u00ecnh th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u00e1m ch\u1ec9 m\u1ed9t gi\u00e1 tr\u1ecb \u201c\u0111i\u1ec3n h\u00ecnh\u201d, v\u00ed d\u1ee5 nh\u01b0 chi\u1ec1u cao, tu\u1ed5i hay l\u01b0\u01a1ng. T\u1eeb n\u00e0y th\u1ec3 hi\u1ec7n kh\u00e1 \u0111\u1ee7 \u00fd ngh\u0129a, \u0111\u1eb7c bi\u1ec7t n\u1ebfu c\u00e1c gi\u00e1 tr\u1ecb kh\u00f4ng kh\u00e1c nhau nhi\u1ec1u. Tuy nhi\u00ean, n\u1ebfu c\u00e1c gi\u00e1 tr\u1ecb c\u00f3 khuynh h\u01b0\u1edbng kh\u00e1c nhau nhi\u1ec1u, vi\u1ec7c s\u1eed d\u1ee5ng gi\u00e1 tr\u1ecb trung b\u00ecnh s\u1ebd g\u00e2y hi\u1ec3u l\u1ea7m gh\u00ea g\u1edbm. V\u00ed d\u1ee5, m\u1ed9t c\u00f4ng ty nh\u1ecf v\u1edbi s\u00e1u nh\u00e2n vi\u00ean ki\u1ebfm \u0111\u01b0\u1ee3c 5.000$ m\u1ed9t n\u0103m v\u00e0 s\u1ebfp l\u1edbn \u0111\u01b0\u1ee3c tr\u1ea3 l\u01b0\u01a1ng 110.000$ c\u00f3 th\u1ec3 tuy\u00ean b\u1ed1 m\u1ed9t c\u00e1ch \u0111\u00fang \u0111\u1eafn l\u00e0 m\u1ee9c 127","l\u01b0\u01a1ng trung b\u00ecnh m\u00e0 c\u00f4ng ty tr\u1ea3 l\u00e0 20.000$. T\u1eeb trung gian l\u1ea1i h\u01a1i kh\u00e1c \u0111i trong \u0111\u00e1nh gi\u00e1 c\u00e1c v\u1ea5n \u0111\u1ec1 b\u1eb1ng c\u00e1ch \u0111\u1eb7t ra gi\u00e1 tr\u1ecb \u201cch\u00ednh gi\u1eefa\u201d - t\u1ee9c l\u00e0 gi\u00e1 tr\u1ecb m\u00e0 t\u1ea1i \u0111\u00f3 s\u1ed1 ng\u01b0\u1eddi l\u00e0m vi\u1ec7c t\u1ec7 h\u01a1n nhi\u1ec1u b\u1eb1ng s\u1ed1 ng\u01b0\u1eddi l\u00e0m vi\u1ec7c t\u1ed1t h\u01a1n. Trong tr\u01b0\u1eddng h\u1ee3p nh\u01b0 v\u00ed d\u1ee5 tr\u00ean, m\u1ee9c l\u01b0\u01a1ng trung gian l\u00e0 5.000$ - m\u1ee9c l\u01b0\u01a1ng m\u00e0 t\u1ea5t c\u1ea3 nh\u00e2n vi\u00ean, ngo\u1ea1i tr\u1eeb s\u1ebfp l\u1edbn, c\u00f3 th\u1ec3 mong \u0111\u1ee3i nh\u1eadn \u0111\u01b0\u1ee3c. 111 C\u00f3 \u0111\u00fang r\u1eb1ng ch\u1ec9 c\u1ea7n c\u00f3 23 ng\u01b0\u1eddi trong m\u1ed9t c\u0103n ph\u00f2ng, ch\u1eafc ch\u1eafn s\u1ebd c\u00f3 hai ng\u01b0\u1eddi c\u00f3 c\u00f9ng ng\u00e0y sinh? M\u1ed9t \u0111\u00e1m \u0111\u00f4ng 367 ng\u01b0\u1eddi th\u00ec ho\u00e0n to\u00e0n ch\u1eafc ch\u1eafn r\u1eb1ng c\u00f3 \u00edt nh\u1ea5t hai ng\u01b0\u1eddi c\u00f3 c\u00f9ng ng\u00e0y sinh nh\u1eadt, v\u1edbi gi\u1ea3 thi\u1ebft l\u00e0 trong m\u1ed9t \u0111\u00e1m \u0111\u00f4ng g\u1ed3m 366 ng\u01b0\u1eddi, ng\u00e0y sinh \u0111\u01b0\u1ee3c tr\u1ea3i \u0111\u1ec1u trong c\u1ea3 366 ng\u00e0y c\u1ee7a n\u0103m nhu\u1eadn. Nh\u01b0ng \u201cNgh\u1ecbch l\u00fd ng\u00e0y sinh\u201d th\u1eadt s\u1ef1 ph\u00e1t bi\u1ec3u r\u1eb1ng ch\u1ec9 c\u1ea7n 23 ng\u01b0\u1eddi l\u00e0 \u0111\u00e3 cho ra m\u1ed9t t\u1ec9 l\u1ec7 nhi\u1ec1u h\u01a1n 50:50 v\u1ec1 kh\u1ea3 n\u0103ng c\u00f3 hai ng\u01b0\u1eddi c\u00f3 c\u00f9ng ng\u00e0y sinh. S\u1ed1 l\u01b0\u1ee3ng ng\u01b0\u1eddi c\u1ea7n thi\u1ebft nh\u1ecf nh\u01b0 v\u1eady th\u1eadt s\u1ef1 g\u00e2y kinh ng\u1ea1c (b\u00ecnh th\u01b0\u1eddng s\u1ed1 ng\u01b0\u1eddi c\u1ea7n thi\u1ebft \u0111\u01b0\u1ee3c \u01b0\u1edbc \u0111o\u00e1n l\u00e0 kho\u1ea3ng 180 ng\u01b0\u1eddi). Hai nguy\u00ean nh\u00e2n ch\u00ednh khi\u1ebfn s\u1ed1 l\u01b0\u1ee3ng \u0111\u00f3 nh\u1ecf h\u01a1n nhi\u1ec1u so v\u1edbi con s\u1ed1 \u01b0\u1edbc \u0111o\u00e1n l\u00e0 do ch\u00fang ta b\u1ecb l\u1eeba ph\u1ec9nh b\u1edfi nh\u1eefng s\u1ef1 tr\u00f9ng h\u1ee3p \u201c\u0111\u00e1ng kinh ng\u1ea1c\u201d. Th\u1ee9 nh\u1ea5t, c\u1ea7n ch\u00fa \u00fd r\u1eb1ng kh\u00f4ng c\u00f3 ng\u00e0y \u0111\u1eb7c bi\u1ec7t 128","n\u00e0o \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp \u0111\u1ebfn; ch\u1ec9 c\u1ea7n m\u1ed9t s\u1ef1 tr\u00f9ng kh\u1edbp c\u1ee7a hai ng\u00e0y sinh b\u1ea5t k\u1ef3, n\u00f3 b\u1eaft \u0111\u01b0\u1ee3c sai s\u00f3t c\u1ee7a m\u1ed9t nh\u00e0 to\u00e1n h\u1ecdc kh\u00e1ch m\u1eddi trong bu\u1ed5i bi\u1ec3u di\u1ec5n c\u1ee7a Johnny Carson v\u00e0i n\u0103m tr\u01b0\u1edbc \u0111\u00e2y. Ch\u00fa \u00fd r\u1eb1ng c\u00f3 kho\u1ea3ng 120 kh\u00e1n gi\u1ea3 trong bu\u1ed5i bi\u1ec5u di\u1ec5n \u0111\u00f3 - nhi\u1ec1u h\u01a1n nhi\u1ec1u so v\u1edbi s\u1ed1 ng\u01b0\u1eddi m\u00e0 ngh\u1ecbch l\u00fd y\u00eau c\u1ea7u. Carson quy\u1ebft \u0111\u1ecbnh y\u00eau c\u1ea7u kh\u00e1ch m\u1eddi m\u00ecnh l\u00e0m m\u1ed9t cu\u1ed9c ki\u1ec3m tra v\u00e0 h\u1ecfi xem c\u00f3 b\u1ea5t k\u00ec ai trong kh\u00e1n ph\u00f2ng c\u00f3 c\u00f9ng ng\u00e0y sinh v\u1edbi \u00f4ng, ng\u00e0y 23 th\u00e1ng 10 kh\u00f4ng? Kh\u00f4ng c\u00f3. \u00d4ng \u0111\u00e3 khi\u1ebfn ng\u01b0\u1eddi kh\u00e1ch m\u1eddi c\u1ee7a m\u00ecnh h\u01a1i \u0111\u1ecf m\u1eb7t v\u00ec qu\u00ea. B\u1eb1ng c\u00e1ch \u0111\u01b0a ra m\u1ed9t ng\u00e0y \u0111\u1eb7c bi\u1ec7t, Carson \u0111\u00e3 l\u00e0m gi\u1ea3m m\u1ea1nh kh\u1ea3 n\u0103ng c\u00f3 s\u1ef1 tr\u00f9ng kh\u1edbp v\u1ec1 ng\u00e0y sinh (c\u1ea7n m\u1ed9t \u0111\u00e1m \u0111\u00f4ng g\u1ed3m h\u01a1n 250 ng\u01b0\u1eddi m\u1edbi \u0111\u1ea1t \u0111\u1ef1\u01a1c t\u1ec9 l\u1ec7 50:50 c\u00f3 ng\u00e0y sinh tr\u00f9ng kh\u1edbp v\u00e0o m\u1ed9t ng\u00e0y \u0111\u1eb7c bi\u1ec7t). Trong khi \u0111\u00f3 Ngh\u1ecbch l\u00fd \u0111\u00e3 cho ph\u00e9p t\u00ednh to\u00e1n s\u1ef1 tr\u00f9ng kh\u1edbp ng\u00e0y sinh b\u1ea5t k\u1ef3, m\u1ed9t m\u1ee5c ti\u00eau \u00edt kh\u1eaft khe h\u01a1n nhi\u1ec1u. Nguy\u00ean nh\u00e2n quan tr\u1ecdng th\u1ee9 hai l\u00e0 s\u1ed1 c\u1eb7p ng\u01b0\u1eddi c\u00f3 th\u1ec3 gh\u00e9p \u0111\u00f4i v\u1edbi nhau t\u1eeb nh\u1eefng ng\u01b0\u1eddi trong \u0111\u00e1m \u0111\u00f4ng l\u00e0 l\u1edbn h\u01a1n nhi\u1ec1u so v\u1edbi b\u1ea1n c\u00f3 th\u1ec3 ngh\u0129. V\u00ed d\u1ee5, m\u1ed9t nh\u00f3m b\u1ed1n ng\u01b0\u1eddi c\u00f3 th\u1ec3 c\u00f3 t\u1edbi s\u00e1u c\u00e1ch \u0111\u1ec3 gh\u00e9p \u0111\u00f4i, trong khi 10 ng\u01b0\u1eddi cho ta t\u1edbi 45 c\u00e1ch gh\u00e9p \u0111\u00f4i. \u0110\u1ed1i v\u1edbi m\u1ed9t \u0111\u00e1m \u0111\u00f4ng 23 ng\u01b0\u1eddi, c\u00f3 kh\u00f4ng \u00edt h\u01a1n 256 c\u00e1ch gh\u00e9p \u0111\u00f4i. V\u1edbi kh\u1ea3 n\u0103ng l\u00e0 ch\u1ec9 c\u00f3 366 ng\u00e0y sinh trong m\u1ed9t n\u0103m, d\u01b0\u1eddng nh\u01b0 kh\u00f4ng c\u00f3 g\u00ec \u0111\u00e1ng ng\u1ea1c nhi\u00ean khi 23 ng\u01b0\u1eddi l\u00e0 \u0111\u1ee7 \u0111\u1ec3 c\u00f3 m\u1ed9t c\u01a1 h\u1ed9i \u0111\u1ec3 c\u00f3 \u00edt nh\u1ea5t m\u1ed9t c\u1eb7p c\u00f3 ng\u00e0y sinh tr\u00f9ng nhau. Vi\u1ec7c kh\u00f4ng c\u1ea7n ng\u00e0y \u0111\u1eb7c bi\u1ec7t, c\u00f9ng v\u1edbi hi\u1ec7u qu\u1ea3 c\u1ee7a 129","vi\u1ec7c gh\u00e9p \u0111\u00f4i, gi\u00fap gi\u1ea3i th\u00edch t\u1ea1i sao ch\u00fang ta th\u01b0\u1eddng ng\u1ea1c nhi\u00ean b\u1edfi \u201cnh\u1eefng tr\u00f9ng h\u1ee3p\u201d k\u00ec l\u1ea1. Ch\u00fang ta \u00edt khi ch\u1ec9 ra tr\u01b0\u1edbc m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c t\u00ednh ch\u1ea5t c\u1ee7a s\u1ef1 tr\u00f9ng h\u1ee3p c\u00f3 th\u1ec3 s\u1ebd l\u00e0m ch\u00fang ta ng\u1ea1c nhi\u00ean. V\u00e0 ch\u00fang ta th\u01b0\u1eddng \u0111\u00e1nh gi\u00e1 th\u1ea5p vi\u1ec7c c\u00f3 bao nhi\u00eau c\u01a1 h\u1ed9i \u0111\u1ec3 c\u00f3 th\u1ec3 c\u00f3 s\u1ef1 tr\u00f9ng h\u1ee3p t\u1eeb b\u1ea5t k\u00ec m\u1ed9t t\u1eadp h\u1ee3p c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng - ng\u01b0\u1eddi ho\u1eb7c hi\u1ec7n t\u01b0\u1ee3ng. 112 L\u00e0m c\u00e1ch n\u00e0o c\u00e1c nh\u00e0 to\u00e1n h\u1ecdc c\u00f3 th\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c s\u1ed1 pi \u0111\u1ebfn h\u00e0ng t\u1ec9 ch\u1eef s\u1ed1 sau d\u1ea5u th\u1eadp ph\u00e2n? Qua nhi\u1ec1u th\u1ebf k\u1ef7, nhi\u1ec1u nh\u00e0 to\u00e1n h\u1ecdc, k\u1ec3 c\u1ea3 Isaac Newton, \u0111\u00e3 l\u00e3ng ph\u00ed th\u1eddi gian c\u1ee7a m\u00ecnh \u0111\u1ec3 t\u00ednh to\u00e1n c\u00e1c con s\u1ed1 c\u1ee7a ch\u1eef s\u1ed1 pi - m\u1eb7c d\u00f9 kh\u00f4ng ph\u1ea3i h\u1ecd lu\u00f4n lu\u00f4n th\u00e0nh c\u00f4ng. N\u0103m 1983, nh\u00e0 to\u00e1n h\u1ecdc William Shanks \u0111\u00e3 l\u1eadp m\u1ed9t k\u1ec9 l\u1ee5c th\u1ebf gi\u1edbi v\u1ec1 vi\u1ec7c t\u00ednh to\u00e1n b\u1eb1ng tay gi\u00e1 tr\u1ecb c\u1ee7a 707 con s\u1ed1 sau d\u1ea5u th\u1eadp ph\u00e2n, m\u1ed9t c\u1ed1 g\u1eafng phi th\u01b0\u1eddng ti\u00eau t\u1ed1n c\u1ee7a \u00f4ng 15 n\u0103m l\u00e0m vi\u1ec7c: trung b\u00ecnh m\u1ed9t tu\u1ea7n cho m\u1ed9t con s\u1ed1. V\u00e0 kh\u00f4ng c\u00f3 g\u00ec \u0111\u00e1ng ng\u1ea1c nhi\u00ean, khi \u00edt c\u00f3 ai h\u1ee9ng th\u00fa v\u1edbi vi\u1ec7c ki\u1ec3m tra l\u1ea1i c\u00e1c con s\u1ed1 m\u00e0 Shanks t\u00ednh ra b\u1eb1ng c\u00e1ch th\u1ef1c hi\u1ec7n l\u1ea1i vi\u1ec7c t\u00ednh to\u00e1n \u0111\u00f3. Tuy nhi\u00ean, c\u00f3 m\u1ed9t c\u00e1ch ki\u1ec3m tra \u0111\u01a1n gi\u1ea3n, d\u1ef1a tr\u00ean m\u1ed9t gi\u1ea3 thi\u1ebft r\u1ea5t ph\u1ed5 bi\u1ebfn l\u00e0 c\u00e1c con s\u1ed1 c\u1ee7a s\u1ed1 pi l\u00e0 ho\u00e0n to\u00e0n ng\u1eabu nhi\u00ean, n\u00ean m\u1ed7i con s\u1ed1, t\u1eeb 0 \u0111\u1ebfn 9, s\u1ebd c\u00f3 x\u00e1c 130","su\u1ea5t xu\u1ea5t hi\u1ec7n l\u00e0 1 ph\u1ea7n 10 trong vi\u1ec7c t\u00ednh to\u00e1n gi\u00e1 tr\u1ecb c\u1ee7a s\u1ed1 pi. V\u00ed d\u1ee5 nh\u01b0, trong 707 gi\u00e1 tr\u1ecb m\u00e0 Shanks t\u00ednh ra, ph\u1ea3i c\u00f3 70 ho\u1eb7c 71 con s\u1ed1 7. Tuy nhi\u00ean, ng\u01b0\u1eddi ta s\u1edbm nh\u1eadn ra l\u00e0 trong k\u1ebft qu\u1ea3 cu\u1ed1i c\u00f9ng m\u00e0 Shanks t\u00ednh ra, b\u1ecb thi\u1ebfu \u0111i m\u1ed9t con s\u1ed1 7 m\u00e0 kh\u00f4ng hi\u1ec3u nguy\u00ean nh\u00e2n. Cho \u0111\u1ebfn t\u1eadn n\u0103m 1945, nguy\u00ean nh\u00e2n c\u1ee7a n\u00f3 m\u1edbi \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n: do Shank \u0111\u00e3 c\u00f3 m\u1ed9t sai s\u00f3t, khi\u1ebfn cho t\u1ea5t c\u1ea3 c\u00e1c con s\u1ed1 t\u1eeb sau con s\u1ed1 th\u1ee9 527 tr\u1edf n\u00ean kh\u00f4ng \u0111\u00fang (ho\u1eb7c, n\u00f3i th\u1eb3ng ra th\u00ec Shanks \u0111\u00e3 ph\u00ed h\u01a1n ba n\u0103m l\u00e0m vi\u1ec7c). C\u00e1c c\u1ed1 g\u1eafng nh\u1eb1m t\u00ednh to\u00e1n s\u1ed1 pi \u0111\u00e3 ti\u1ebfp t\u1ee5c ti\u1ebfn nhanh k\u1ec3 t\u1eeb sau \u0111\u00f3; trong n\u0103m 2002, gi\u00e1o s\u01b0 Yasumasa Kanada v\u00e0 c\u00e1c c\u1ed9ng t\u00e1c vi\u00ean c\u1ee7a \u00f4ng t\u1ea1i \u0111\u1ea1i h\u1ecdc C\u00f4ng ngh\u1ec7 Th\u00f4ng tin Tokyo (University of Tokyo Information Technology Centre) tuy\u00ean b\u1ed1 r\u1eb1ng h\u1ecd \u0111\u00e3 th\u00e0nh c\u00f4ng trong vi\u1ec7c t\u00ednh to\u00e1n m\u1ed9t ng\u00e0n t\u1ec9 con s\u1ed1 sau d\u1ea5u th\u1eadp ph\u00e2n c\u1ee7a s\u1ed1 pi. H\u1ecd \u0111\u00e3 s\u1eed d\u1ee5ng si\u00eau m\u00e1y t\u00ednh Hitachi SR8000 c\u00f3 kh\u1ea3 n\u0103ng th\u1ef1c hi\u1ec7n m\u1ed9t ng\u00e0n t\u1ec9 ph\u00e9p t\u00ednh trong v\u00f2ng m\u1ed9t gi\u00e2y. D\u00f9 v\u1eady, chi\u1ebfc m\u00e1y t\u00ednh n\u00e0y c\u0169ng ph\u1ea3i t\u1ed1n h\u1ebft 25 ng\u00e0y \u0111\u1ec3 t\u00ecm ra 1.200 t\u1ec9 con s\u1ed1. \u0110\u1ec3 ki\u1ec3m tra t\u00ednh ch\u00ednh x\u00e1c c\u1ee7a k\u1ebft qu\u1ea3 \u0111\u00f3, Kanada v\u00e0 c\u00e1c \u0111\u1ed3ng s\u1ef1 c\u1ee7a \u00f4ng \u0111\u00e3 th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh kh\u1ed5ng l\u1ed3 \u0111\u00f3 t\u1edbi hai l\u1ea7n, \u0111\u1ed3ng th\u1eddi h\u1ecd c\u0169ng th\u1ef1c hi\u1ec7n ph\u00e9p ki\u1ec3m tra t\u1eebng d\u00f9ng \u0111\u1ec3 ph\u00e1t hi\u1ec7n ra sai l\u1ea7m c\u1ee7a Shanks v\u00e0 \u0111\u00e3 ki\u1ec3m tra t\u1ea7n su\u1ea5t xu\u1ea5t hi\u1ec7n t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a c\u00e1c con s\u1ed1 trong k\u1ebft qu\u1ea3. M\u1ed9t l\u1ea7n n\u1eefa, c\u00e1c k\u1ebft qu\u1ea3 \u0111\u00e3 \u0111\u00fang v\u1edbi s\u1ef1 mong \u0111\u1ee3i: s\u1ed1 l\u01b0\u1ee3ng s\u1ed1 7 l\u00e0 119.999.740.505 - g\u1ea7n b\u1eb1ng m\u1ed9t ph\u1ea7n m\u01b0\u1eddi c\u1ee7a 1.200 t\u1ec9. 131","113 T\u1ea1i sao c\u00e1c \u0111\u1ed3ng h\u1ed3 \u0111\u01b0\u1ee3c quay l\u00f9i 1 gi\u1edd v\u00e0o th\u1eddi \u0111i\u1ec3m tr\u01b0\u1edbc ng\u00e0y h\u1ea1 ch\u00ed (ng\u00e0y ng\u1eafn nh\u1ea5t) trong n\u0103m v\u00e0 quay nhanh 1 gi\u1edd v\u00e0o ba th\u00e1ng sau ng\u00e0y h\u1ea1 ch\u00ed \u0111\u00f3? C\u00e2u chuy\u1ec7n d\u00e0i d\u00f2ng v\u1ec1 S\u1ef1 k\u00e9o d\u00e0i ng\u00e0y l\u00e0m vi\u1ec7c m\u00f9a h\u1ea1 (\u0111\u1ec3 ti\u1ebft ki\u1ec7m \u0111i\u1ec7n) th\u01b0\u1eddng \u0111\u01b0\u1ee3c ngh\u0129 l\u00e0 do t\u00e1c \u0111\u1ed9ng \u0111\u1ed9c nh\u1ea5t c\u1ee7a m\u1ee9c \u0111\u1ed9 \u00e1nh s\u00e1ng. Nh\u01b0ng n\u1ebfu \u0111i\u1ec1u \u0111\u00f3 l\u00e0 \u0111\u00fang, th\u00ec s\u1ef1 thay \u0111\u1ed5i h\u1ec7 th\u1ed1ng ng\u00e0y th\u00e1ng s\u1ebd kh\u00f4ng c\u00f2n \u0111\u1ed1i x\u1ee9ng v\u1edbi ng\u00e0y \u201c\u0111\u00f4ng ch\u00ed\u201d, v\u00e0o kho\u1ea3ng ng\u00e0y 21 th\u00e1ng 12. Vi\u1ec7c thi\u1ebfu \u0111\u1ed1i x\u1ee9ng \u0111\u00f3 ti\u1ebft l\u1ed9 cho ta nguy\u00ean nh\u00e2n m\u00e0 c\u00e1c ch\u00ednh ph\u1ee7 ph\u1ea3i t\u00e1c \u0111\u1ed9ng v\u00e0o s\u1ef1 thay \u0111\u1ed5i h\u1ec7 th\u1ed1ng ng\u00e0y th\u00e1ng: s\u1ef1 c\u1ea7n ph\u1ea3i c\u1eaft gi\u1ea3m n\u0103ng l\u01b0\u1ee3ng b\u1eb1ng c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh th\u1eddi gian ch\u00fang ta th\u1ee9c d\u1eady v\u00e0 nhu c\u1ea7u s\u1eed d\u1ee5ng n\u0103ng l\u01b0\u1ee3ng. B\u1eb1ng c\u00e1ch v\u1eb7n cho c\u00e1c \u0111\u1ed3ng h\u1ed3 \u201cm\u00f9a xu\u00e2n\u201d \u0111i nhanh h\u01a1n m\u1ed9t gi\u1edd trong m\u00f9a xu\u00e2n, m\u1eb7t tr\u1eddi s\u1ebd l\u1eb7n ch\u1eadm h\u01a1n m\u1ed9t gi\u1edd v\u00e0 l\u00e0m kho\u1ea3ng th\u1eddi gian t\u1eeb l\u00fac m\u1eb7t tr\u1eddi l\u1eb7n t\u1edbi l\u00fac \u0111i ng\u1ee7 \u0111\u01b0\u1ee3c r\u00fat ng\u1eafn \u0111i m\u1ed9t gi\u1edd, c\u1eaft gi\u1ea3m th\u1eddi gian m\u00e0 ch\u00fang ta \u1edf trong nh\u00e0, th\u1ee9c d\u1eady v\u00e0 s\u1eed d\u1ee5ng n\u0103ng l\u01b0\u1ee3ng. Khi m\u1ed9t qu\u1ed1c gia \u0111ang \u1edf trong Th\u1eddi gian m\u00f9a h\u00e8, ch\u00ednh ph\u1ee7 c\u1ee7a h\u1ecd s\u1ebd b\u00e1m v\u00e0o n\u00f3 c\u00e0ng l\u00e2u c\u00e0ng t\u1ed1t v\u00e0 th\u00eam v\u00e0o \u201cs\u1ef1 k\u00e9o d\u00e0i ng\u00e0y l\u00e0m vi\u1ec7c m\u00f9a h\u1ea1\u201d cho \u0111\u1ebfn cu\u1ed1i th\u00e1ng 10. T\u1eeb n\u0103m 1996, to\u00e0n th\u1ec3 kh\u1ed1i ki\u00ean minh ch\u00e2u \u00c2u \u0111\u00e3 \u0111\u1eb7t \u0111\u1ed3ng h\u1ed3 c\u1ee7a m\u00ecnh ch\u1ea1y nhanh h\u01a1n m\u1ed9t ti\u1ebfng v\u00e0o 132","ng\u00e0y ch\u1ee7 nh\u1eadt cu\u1ed1i c\u00f9ng c\u1ee7a th\u00e1ng 3 v\u00e0 v\u1eb7n ng\u01b0\u1ee3c l\u1ea1i m\u1ed9t gi\u1edd v\u00e0o ng\u00e0y ch\u1ee7 nh\u1eadt cu\u1ed1i c\u00f9ng c\u1ee7a th\u00e1ng 10. Do s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 kh\u00ed h\u1eadu v\u00e0 v\u0129 \u0111\u1ed9, n\u01b0\u1edbc M\u1ef9 b\u1eaft \u0111\u1ea7u \u201cs\u1ef1 k\u00e9o d\u00e0i ng\u00e0y l\u00e0m vi\u1ec7c m\u00f9a h\u1ea1\u201d tr\u1ec5 h\u01a1n m\u1ed9t tu\u1ea7n, v\u00e0o ch\u1ee7 nh\u1eadt \u0111\u1ea7u ti\u00ean c\u1ee7a th\u00e1ng 4. Trong su\u1ed1t cu\u1ed9c kh\u1ee7ng ho\u1ea3ng n\u0103ng l\u01b0\u1ee3ng gi\u1eefa th\u1eadp ni\u00ean 1970, n\u01b0\u1edbc M\u1ef9 tr\u1edf n\u00ean c\u1ef1c k\u00ec li\u1ec1u l\u0129nh trong vi\u1ec7c ti\u1ebft ki\u1ec7m n\u0103ng l\u01b0\u1ee3ng b\u1eb1ng c\u00e1ch \u201ck\u00e9o d\u00e0i ng\u00e0y l\u00e0m vi\u1ec7c m\u00f9a h\u1ea1\u201d \u0111\u1ebfn n\u1ed7i Qu\u1ed1c H\u1ed9i \u0111\u1ec1 ngh\u1ecb b\u1eaft \u0111\u1ea7u \u201cs\u1ef1 k\u00e9o d\u00e0i ng\u00e0y l\u00e0m vi\u1ec7c m\u00f9a h\u1ea1\u201d v\u00e0o ng\u00e0y 6 th\u00e1ng 1. 114 T\u1ea1i sao kho\u1ea3ng c\u00e1ch ng\u1eafn nh\u1ea5t gi\u1eefa hai \u0111i\u1ec3m l\u1ea1i l\u00e0 m\u1ed9t \u0111o\u1ea1n th\u1eb3ng? B\u1ea5t k\u00ec ai c\u00f3 m\u1ed9t \u00edt hi\u1ec3u bi\u1ebft v\u1ec1 h\u00e0ng h\u1ea3i \u0111\u1ec1u bi\u1ebft r\u1eb1ng \u0111i\u1ec1u tr\u00ean kh\u00f4ng ph\u1ea3i lu\u00f4n lu\u00f4n \u0111\u00fang: kho\u1ea3ng c\u00e1ch ng\u1eafn nh\u1ea5t gi\u1eefa hai \u0111i\u1ec3m b\u1ea5t k\u00ec tr\u00ean \u0111\u1ecba c\u1ea7u (ho\u1eb7c b\u1ea5t c\u1ee9 qu\u1ea3 c\u1ea7u n\u00e0o) l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a m\u1ed9t \u201c\u0111\u01b0\u1eddng tr\u00f2n kh\u1ed5ng l\u1ed3\u201d c\u00f3 \u0111\u01b0\u1eddng k\u00ednh b\u1eb1ng v\u1edbi \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a \u0111\u01b0\u1eddng x\u00edch \u0111\u1ea1o. Tuy nhi\u00ean, \u0111i\u1ec1u \u0111\u00f3 l\u1ea1i lu\u00f4n \u0111\u00fang tr\u00ean nh\u1eefng t\u1edd gi\u1ea5y ph\u1eb3ng, v\u00e0 m\u1ed9t b\u1eb1ng ch\u1ee9ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c r\u00fat ra t\u1eeb c\u00e1c \u0111\u1ecbnh l\u00fd v\u1ec1 tam gi\u00e1c c\u1ee7a Euclid trong th\u1ebf k\u1ec9 th\u1ee9 t\u01b0 tr\u01b0\u1edbc C\u00f4ng nguy\u00ean. V\u1ebd hai \u0111i\u1ec3m A v\u00e0 B v\u1edbi m\u1ed9t \u0111o\u1ea1n th\u1eb3ng n\u1ed1i gi\u1eefa ch\u00fang, sau \u0111\u00f3 h\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng r\u1eb1ng c\u00f3 m\u1ed9t \u0111\u01b0\u1eddng kh\u00e1c c\u00f3 th\u1ec3 n\u1ed1i hai \u0111i\u1ec3m \u0111\u00f3, \u0111\u01b0\u1eddng \u0111i \u0111\u00f3 khi\u1ebfn b\u1ea1n c\u00f3 th\u1ec3 133","nh\u1ea3y qua \u0111o\u1ea1n th\u1eb3ng kia, ngang qua m\u1ed9t \u0111i\u1ec3m C. C\u00e1c \u0110\u1ecbnh lu\u1eadt c\u1ee7a Euclid ch\u1ec9 ra r\u1eb1ng d\u00f9 \u0111i\u1ec3m C c\u00f3 g\u1ea7n nh\u01b0 n\u1eb1m tr\u00ean \u0111o\u1ea1n th\u1eb3ng ban \u0111\u1ea7u, kho\u1ea3ng c\u00e1ch t\u1eeb n\u00f3 \u0111\u1ebfn \u0111i\u1ec3m A c\u1ed9ng v\u1edbi kho\u1ea3ng c\u00e1ch t\u1eeb n\u00f3 \u0111\u1ebfn \u0111i\u1ec3m B th\u00ec lu\u00f4n lu\u00f4n l\u1edbn h\u01a1n kho\u1ea3ng c\u00e1ch ban \u0111\u1ea7u gi\u1eefa \u0111i\u1ec3m A v\u00e0 B. N\u00ean, ch\u1ec9 m\u1ed9t g\u00f3c l\u1ec7ch r\u1ea5t nh\u1ecf so v\u1edbi \u0111\u01b0\u1eddng th\u1eb3ng ban \u0111\u1ea7u c\u0169ng lu\u00f4n lu\u00f4n l\u00e0m t\u0103ng th\u00eam kho\u1ea3ng c\u00e1ch. C\u00f3 th\u1ec3 kh\u00e1i qu\u00e1t h\u00f3a \u00fd t\u01b0\u1edfng bi\u1ebfn m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00e0nh m\u1ed9t m\u1eb7t cong. Vi\u1ec7c t\u00ednh to\u00e1n h\u00ecnh d\u1ea1ng c\u1ee7a n\u00f3 g\u00e2y ra kh\u00e1 nhi\u1ec1u kh\u00f3 kh\u0103n cho c\u00e1c nh\u00e0 to\u00e1n h\u1ecdc cho \u0111\u1ebfn t\u1eadn n\u0103m 1915, khi Einstein \u0111\u01b0a ra Thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i. Thuy\u1ebft n\u00e0y n\u00f3i r\u1eb1ng c\u00e1c tia s\u00e1ng \u0111i theo d\u1ea1ng s\u00f3ng, h\u00ecnh d\u1ea1ng gi\u00fap \u0111\u01b0a ra c\u00e1ch \u0111o \u0111\u1ea1c c\u01b0\u1eddng \u0111\u1ed9 tr\u1ecdng l\u1ef1c. 115 T\u1ea1i sao v\u00f2ng tr\u00f2n l\u1ea1i \u0111\u01b0\u1ee3c chia th\u00e0nh 360 \u0111\u1ed9? M\u1eb7c d\u00f9 trong th\u1ebf k\u1ec9 21, th\u1eddi gian v\u00e0 g\u00f3c v\u1eabn ti\u1ebfp t\u1ee5c \u0111\u01b0\u1ee3c t\u00ednh b\u1edfi c\u00f9ng m\u1ed9t h\u1ec7 \u0111\u01a1n v\u1ecb kh\u00f3 hi\u1ec3u \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng b\u1edfi ng\u01b0\u1eddi Sumeri c\u00e1ch \u0111\u00e2y h\u01a1n 4.000 n\u0103m. Ch\u00ednh x\u00e1c n\u00f3 \u0111\u01b0\u1ee3c b\u1eaft \u0111\u1ea7u nh\u01b0 th\u1ebf n\u00e0o th\u00ec v\u1eabn c\u00f2n b\u1ecb tranh lu\u1eadn b\u1edfi c\u00e1c nh\u00e0 s\u1eed h\u1ecdc nh\u01b0ng m\u1ed9t h\u1ecdc thuy\u1ebft, \u0111\u01b0\u1ee3c \u0111\u01b0a ra l\u1ea7n \u0111\u1ea7u ti\u00ean v\u00e0o 200 n\u0103m tr\u01b0\u1edbc, \u0111\u00e3 li\u00ean h\u1ec7 n\u00f3 v\u1edbi \u201cchu k\u1ef3\u201d l\u1ecbch c\u1ee7a m\u1ed9t n\u0103m. C\u00e1c nh\u00e0 to\u00e1n h\u1ecdc ng\u01b0\u1eddi Sumeri \u0111\u00e3 ph\u00e1t hi\u1ec7n r\u1eb1ng s\u1ed1 ng\u00e0y trong m\u1ed9t n\u0103m g\u1ea7n b\u1eb1ng 360, m\u1ed9t s\u1ed1 d\u01b0\u01a1ng c\u00f3 r\u1ea5t nhi\u1ebfu th\u1eeba s\u1ed1 khi\u1ebfn n\u00f3 c\u00f3 134","th\u1ec3 \u0111\u01b0\u1ee3c chia nh\u1ecf th\u00e0nh nh\u1eefng ph\u1ea7n nh\u1ecf h\u01a1n. N\u0103m ng\u00e0y c\u00f2n l\u1ea1i trong n\u0103m b\u1ecb b\u1ecf qua ch\u00ednh l\u00e0 nh\u1eefng ng\u00e0y ngh\u1ec9 l\u1ec5. M\u1ed9t h\u1ecdc thuy\u1ebft kh\u00e1c l\u1ea1i l\u00fd lu\u1eadn r\u1eb1ng vi\u1ec7c chia v\u00f2ng tr\u00f2n th\u00e0nh 360 \u0111\u1ed9 b\u1eaft ngu\u1ed3n t\u1eeb n\u1ec1n t\u1ea3ng l\u00e0 con s\u1ed1 60 trong s\u1ed1 h\u1ecdc \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng b\u1edfi ng\u01b0\u1eddi Sumeri. M\u1ed9t v\u00f2ng tr\u00f2n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh s\u00e1u ph\u1ea7n b\u1eb1ng nhau m\u1ed9t c\u00e1ch d\u1ec5 d\u00e0ng b\u1eb1ng c\u00e1ch \u0111\u00e1nh d\u1ea5u c\u00e1c \u0111i\u1ec3m d\u1ecdc theo chu vi c\u1ee7a n\u00f3, \u0111i\u1ec3m n\u00e0y c\u00e1ch \u0111i\u1ec3m kia m\u1ed9t kho\u1ea3ng b\u1eb1ng b\u00e1n k\u00ednh v\u00f2ng tr\u00f2n \u0111\u00f3. N\u1ebfu m\u1ed7i ph\u1ea7n \u0111\u00f3 \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 60 \u0111\u01a1n v\u1ecb, th\u00ec m\u1ed9t v\u00f2ng tr\u00f2n s\u1ebd l\u00e0 360 \u0111\u01a1n v\u1ecb - hi\u1ec7n nay \u0111\u01b0\u1ee3c ch\u00fang ta g\u1ecdi l\u00e0 \u0111\u1ed9. 116 Li\u1ec7u c\u00e1c th\u1ee7 m\u00f4n c\u00f3 c\u01a1 h\u1ed9i n\u00e0o \u0111\u1ec3 b\u1eaft \u0111\u01b0\u1ee3c c\u00e1c qu\u1ea3 ph\u1ea1t \u0111\u1ec1n hay kh\u00f4ng? Nh\u1eefng ng\u01b0\u1eddi t\u1eebng quy \u0111\u1ecbnh \u0111\u1eb7t \u0111i\u1ec3m s\u00fat ph\u1ea1t \u0111\u1ec1n c\u00e1ch v\u1ea1ch khung th\u00e0nh 11 m\u00e9t khi vi\u1ec7c s\u00fat ph\u1ea1t \u0111\u1ec1n \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng l\u1ea7n \u0111\u1ea7u ti\u00ean trong b\u00f3ng \u0111\u00e1 v\u00e0o n\u0103m 1891 ch\u1eafc c\u0169ng bi\u1ebft kh\u00e1 r\u00f5 v\u1ec1 kh\u1ea3 n\u0103ng ph\u1ea3n x\u1ea1 c\u1ee7a con ng\u01b0\u1eddi. C\u1ea7n kho\u1ea3ng n\u1eeda gi\u00e2y \u0111\u1ec3 cho m\u1ed9t c\u00fa s\u00fat ph\u1ea1t \u0111\u1ec1n th\u00f4ng th\u01b0\u1eddng \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng 11m \u0111\u00f3. \u0110\u1ec3 c\u00f3 th\u1ec3 hi\u1ec3u \u0111\u01b0\u1ee3c m\u1ee9c \u0111\u1ed9 kh\u00f3 kh\u0103n m\u00e0 m\u1ed9t th\u1ee7 m\u00f4n ph\u1ea3i \u0111\u1ed1i 135","\u0111\u1ea7u khi c\u1ed1 g\u1eafng ch\u1ed1ng l\u1ea1i qu\u1ea3 ph\u1ea1t \u0111\u1ec1n, h\u00e3y c\u1ea7m m\u1ed9t \u0111\u1ed3ng xu v\u00e0 gi\u1eef n\u00f3 \u1edf \u0111\u1ed9 cao b\u1eb1ng vai c\u1ee7a b\u1ea1n r\u1ed3i th\u1ea3 xu\u1ed1ng \u0111\u1ea5t. Trong kho\u1ea3ng th\u1eddi gian b\u1eb1ng th\u1eddi gian \u0111\u1ed3ng xu r\u01a1i xu\u1ed1ng \u0111\u1ea5t, ng\u01b0\u1eddi th\u1ee7 m\u00f4n ph\u1ea3i ph\u00e1n \u0111o\u00e1n \u0111\u01b0\u1ee3c h\u01b0\u1edbng bay c\u1ee7a tr\u00e1i banh, nh\u1ea3y t\u1edbi v\u00e0 b\u1eaft tr\u00e1i banh \u0111\u00f3. K\u1ebft qu\u1ea3 l\u00e0 c\u00e1c th\u1ee7 m\u00f4n kh\u00f4ng c\u00f3 nhi\u1ec1u c\u01a1 h\u1ed9i \u0111\u1ec3 c\u1ee9u c\u00e1c qu\u1ea3 ph\u1ea1t \u0111\u1ec1n tr\u1eeb khi h\u1ecd c\u00f3 th\u1ec3 t\u00ecm ra m\u1ed9t c\u00e1ch \u0111\u1ec3 \u0111o\u00e1n tr\u01b0\u1edbc tr\u00e1i banh s\u1ebd bay \u0111i \u0111\u00e2u. C\u00e1c s\u1ed1 li\u1ec7u th\u1ed1ng k\u00ea cho th\u1ea5y c\u00e1c th\u1ee7 m\u00f4n ch\u1ec9 c\u00f3 th\u1ec3 b\u1eaft \u0111\u01b0\u1ee3c m\u1ed9t tr\u00ean n\u0103m tr\u00e1i ph\u1ea1t \u0111\u1ec1n trong su\u1ed1t c\u00e1c gi\u1ea3i v\u00f4 \u0111\u1ecbch c\u1ee7a UEFA - kho\u1ea3ng 30 ph\u1ea7n tr\u0103m c\u00e1c qu\u1ea3 ph\u1ea1t \u0111\u1ec1n. C\u00e1c nghi\u00ean c\u1ee9u v\u1ec1 nh\u1eefng th\u1ee7 m\u00f4n xu\u1ea5t s\u1eafc nh\u1ea5t ch\u1ec9 ra r\u1eb1ng h\u1ecd th\u01b0\u1eddng b\u1eaft \u0111\u1ea7u di chuy\u1ec3n trong kho\u1ea3ng 0,1 gi\u00e2y tr\u01b0\u1edbc khi tr\u00e1i banh b\u1ecb s\u00fat v\u00e0 ph\u1ea3n \u1ee9ng n\u00e0y c\u1ee7a h\u1ecd l\u00e0 d\u1ef1a tr\u00ean v\u1ecb tr\u00ed c\u1ee7a ch\u00e2n v\u00e0 b\u00e0n ch\u00e2n c\u1ee7a ng\u01b0\u1eddi s\u00fat. C\u00f2n c\u00e1c nghi\u00ean c\u1ee9u b\u1edfi nh\u1eefng nh\u00e0 khoa h\u1ecdc v\u1ec1 th\u1ec3 thao th\u00ec ch\u1ec9 ra r\u1eb1ng m\u1ea5u ch\u1ed1t quan tr\u1ecdng nh\u1ea5t l\u00e0 ph\u00e1t hi\u1ec7n ra h\u01b0\u1edbng c\u1ee7a h\u00f4ng v\u00e0 b\u00e0n ch\u00e2n. C\u00e1c ph\u00e2n t\u00edch cho th\u1ea5y ngay tr\u01b0\u1edbc s\u00fat, nh\u1eefng ng\u01b0\u1eddi s\u00fat th\u01b0\u1eddng \u0111\u1eb7t b\u00e0n ch\u00e2n tr\u1ee5 (kh\u00f4ng s\u00fat b\u00f3ng) theo h\u01b0\u1edbng c\u1ee7a c\u00fa s\u00fat cu\u1ed1i c\u00f9ng. Theo gi\u00e1o s\u01b0 Ian Frank v\u00e0 c\u00e1c \u0111\u1ed3ng s\u1ef1 c\u1ee7a \u00f4ng t\u1ea1i \u0110\u1ea1i h\u1ecdc British Columbia, quy t\u1eafc \u201ctheo d\u00f5i b\u00e0n ch\u00e2n tr\u1ee5\u201d \u0111\u00fang trong kho\u1ea3ng 80-85% l\u1ea7n b\u1eaft. T\u1ed1t h\u01a1n n\u1eefa, quy t\u1eafc \u0111\u00f3 c\u00f2n mang l\u1ea1i 136","cho th\u1ee7 m\u00f4n kho\u1ea3ng 0,2 gi\u00e2y \u0111\u1ec3 chu\u1ea9n b\u1ecb tr\u01b0\u1edbc khi qu\u1ea3 b\u00f3ng \u0111\u01b0\u1ee3c s\u00fat. \u0110\u1ed1i v\u1edbi m\u1ed9t tr\u00e1i banh \u0111\u01b0\u1ee3c s\u00fat v\u1edbi v\u1eadn t\u1ed1c l\u1edbn h\u01a1n 80 km\/gi\u1edd, 0,2 gi\u00e2y l\u00e0 kho\u1ea3ng th\u1eddi gian m\u00e0 qu\u1ea3 b\u00f3ng \u0111i \u0111\u01b0\u1ee3c m\u1ed9t n\u1eeda \u0111o\u1ea1n \u0111\u01b0\u1eddng \u0111\u1ebfn khung th\u00e0nh - v\u00e0 0,2 gi\u00e2y ch\u00ednh l\u00e0 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa chi\u1ebfn th\u1eafng v\u00e0 th\u1ea5t b\u1ea1i. 117 T\u1ea1i sao nh\u1eefng l\u1ed7 nh\u1ecf tr\u00ean c\u00e1c tr\u00e1i banh golf gi\u00fap cho ch\u00fang bay xa h\u01a1n? C\u00e1c qu\u1ea3 banh golf c\u00f3 \u0111\u01b0\u1ee3c h\u00ecnh d\u1ea1ng c\u00f3 nhi\u1ec1u l\u1ed7 \u0111\u1eb7c bi\u1ec7t nh\u01b0 v\u1eady c\u00e1ch \u0111\u00e2y kho\u1ea3ng m\u1ed9t th\u1ebf k\u1ef7, khi c\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t n\u1eafm b\u1eaft \u0111\u01b0\u1ee3c c\u00e1c l\u1ee3i \u00edch c\u1ee7a m\u1ed9t ph\u00e1t hi\u1ec7n r\u1eb1ng m\u1ed9t tr\u00e1i banh v\u1edbi b\u1ec1 m\u1eb7t l\u1ed7 ch\u1ed7 s\u1ebd bay xa h\u01a1n v\u00e0 cao h\u01a1n so v\u1edbi nh\u1eefng qu\u1ea3 banh ho\u00e0n to\u00e0n tr\u01a1n nh\u1eb5n. \u0110i\u1ec1u n\u00e0y r\u00f5 l\u00e0 tr\u00e1i v\u1edbi tr\u1ef1c gi\u00e1c: ch\u1eafc ch\u1eafn m\u1ed9t th\u1ee9 v\u1edbi b\u1ec1 m\u1eb7t l\u1edfm ch\u1edfm s\u1ebd g\u1eb7p ph\u1ea3i nhi\u1ec1u ma s\u00e1t h\u01a1n khi n\u00f3 bay xuy\u00ean qua kh\u00f4ng kh\u00ed? L\u1eddi gi\u1ea3i th\u00edch n\u1eb1m \u1edf t\u00e1c \u0111\u1ed9ng c\u1ee7a c\u00e1c l\u1ed7 v\u00e0o d\u00f2ng kh\u00f4ng kh\u00ed xung quanh qu\u1ea3 banh. Khi \u0111ang bay, m\u1ed9t v\u1ec7t kh\u00f4ng kh\u00ed h\u1ed7n lo\u1ea1n \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh ph\u00eda sau tr\u00e1i banh, h\u00fat n\u0103ng l\u01b0\u1ee3ng t\u1eeb qu\u1ea3 banh, c\u00f3 ngh\u0129a l\u00e0 qu\u1ea3 banh s\u1ebd kh\u00f4ng th\u1ec3 bay xa nh\u01b0 mong \u0111\u1ee3i. C\u00e1c l\u1ed7 tr\u00ean qu\u1ea3 banh cho kh\u00f4ng kh\u00ed t\u01b0\u01a1ng \u0111\u1ed1i \u201cnh\u1edbt\u201d th\u1ed5i xung quanh qu\u1ea3 banh c\u00e1c \u0111i\u1ec3m t\u1ef1a \u0111\u1ec3 n\u00f3 b\u00e1m v\u00e0o v\u00e0 137","k\u1ebft qu\u1ea3 l\u00e0 qu\u1ea3 banh t\u1ef1 bao b\u1ecdc b\u1ec1 m\u1eb7t c\u1ee7a m\u00ecnh m\u1ed9t c\u00e1ch tr\u01a1n nh\u1eb5n h\u01a1n, l\u00e0m gi\u1ea3m k\u00edch th\u01b0\u1edbc c\u1ee7a c\u00e1c v\u1ec7t kh\u00f4ng kh\u00ed h\u1ed7n lo\u1ea1n. Nh\u1edd \u0111\u00f3, gi\u1ea3m n\u0103ng l\u01b0\u1ee3ng m\u1ea5t do s\u1ef1 k\u00e9o v\u00e0 cho ph\u00e9p tr\u00e1i banh bay xa h\u01a1n \u0111\u1ed1i v\u1edbi m\u1ed9t c\u00fa \u0111\u00e1nh m\u1ea1nh. Nh\u1eefng nh\u00e0 s\u1ea3n xu\u1ea5t banh \u0111\u00e1nh golf \u0111\u00e3 t\u1ed1n r\u1ea5t nhi\u1ec1u th\u1eddi gian trong vi\u1ec7c c\u1ed1 g\u1eafng t\u00ecm ki\u1ebfm s\u1ef1 k\u1ebft h\u1ee3p t\u1ed1i \u01b0u k\u00edch th\u01b0\u1edbc, h\u00ecnh d\u1ea1ng v\u00e0 s\u1ef1 s\u1eafp x\u1ebfp c\u1ee7a c\u00e1c l\u1ed7 nh\u1ecf tr\u00ean qu\u1ea3 banh. Trong r\u1ea5t nhi\u1ec1u n\u0103m, h\u00ecnh d\u1ea1ng t\u01b0\u01a1ng \u0111\u1ed1i \u0111\u01a1n gi\u1ea3n c\u1ee7a kho\u1ea3ng 300 l\u1ed7 nh\u1ecf \u0111\u00e3 \u0111\u01b0\u1ee3c ngh\u0129 l\u00e0 t\u1ed1i \u01b0u. N\u0103m 1995, nh\u00e0 s\u1ea3n xu\u1ea5t ng\u01b0\u1eddi M\u1ef9 Wilson \u0111\u00e3 gi\u1edbi thi\u1ec7u qu\u1ea3 banh c\u00f3 500 l\u1ed7 c\u1ee7a m\u00ecnh ra th\u1ecb tr\u01b0\u1eddng, qu\u1ea3 banh n\u00e0y \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf b\u1edfi m\u1ed9t chuy\u00ean gia kh\u00ed \u0111\u1ed9ng h\u1ecdc c\u1ee7a NASA, bao g\u1ed3m 500 l\u1ed7 v\u1edbi nhi\u1ec1u k\u00edch th\u01b0\u1edbc kh\u00e1c nhau \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp th\u00e0nh d\u1ea1ng c\u1ee7a 60 tam gi\u00e1c c\u1ea7u. C\u00e1c l\u1ed7 l\u1edbn \u0111\u01b0\u1ee3c cho r\u1eb1ng c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m t\u00e1c \u0111\u1ed9ng c\u1ee7a s\u1ef1 chuy\u1ec3n \u0111\u1ed9ng h\u1ed7n lo\u1ea1n c\u1ee7a kh\u00f4ng kh\u00ed, l\u00e0m t\u0103ng l\u1ef1c n\u00e2ng v\u00e0 duy tr\u00ec \u0111\u1ed9 xo\u00e1y truy\u1ec1n v\u00e0o qu\u1ea3 b\u00f3ng, trong khi c\u00e1c l\u1ed7 nh\u1ecf gi\u00fap ki\u1ec3m so\u00e1t l\u1ef1c n\u00e2ng. D\u00f9 sao, c\u00e1c qu\u1ea3 b\u00f3ng n\u00e0y c\u0169ng kh\u00f4ng th\u1ec3 bi\u1ebfn m\u1ed9t v\u1eadn \u0111\u1ed9ng vi\u00ean 20 tu\u1ed5i ch\u01a1i k\u00e9m th\u00e0nh nh\u00e0 v\u00f4 \u0111\u1ecbch th\u1ebf gi\u1edbi Tiger Woods. 118 L\u00e0m th\u1ebf n\u00e0o m\u00e0 tr\u00e1i banh c\u00f3 th\u1ec3 \u0111i l\u1ec7ch h\u01b0\u1edbng khi \u0111ang bay? V\u00e0i n\u0103m tr\u01b0\u1edbc, c\u00f3 r\u1ea5t nhi\u1ec1u cu\u1ed9c tranh c\u00e3i gi\u1eefa nh\u1eefng ng\u01b0\u1eddi say m\u00ea m\u00f4n th\u1ec3 thao cricket v\u1ec1 vi\u1ec7c li\u1ec7u th\u1eadt s\u1ef1 138","tr\u00e1i banh c\u00f3 th\u1ec3 \u0111i l\u1ec7ch h\u01b0\u1edbng khi \u0111ang bay v\u1ec1 ph\u00eda c\u00e1c v\u1eadn \u0111\u1ed9ng vi\u00ean cricket kh\u00f4ng. Cu\u1ed9c tranh lu\u1eadn cu\u1ed1i c\u00f9ng \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft b\u1eb1ng vi\u1ec7c xem l\u1ea1i c\u00e1c b\u0103ng ghi h\u00ecnh chi\u1ebfu ch\u1eadm. Cho th\u1ea5y m\u1ed9t \u0111i\u1ec1u \u0111\u00e1ng ng\u1ea1c nhi\u00ean l\u00e0 s\u1ef1 \u0111i ch\u1ec7ch \u0111\u00f3 l\u00e0 ho\u00e0n to\u00e0n th\u1eadt. C\u00f3 l\u1ebd c\u00e1c c\u1ed5 \u0111\u1ed9ng vi\u00ean c\u1ee7a m\u00f4n b\u00f3ng \u0111\u00e1 c\u0169ng t\u1eebng chia s\u1ebb s\u1ef1 nghi ng\u1edd n\u00e0y, khi m\u00e0 hi\u1ec7u \u1ee9ng \u0111i ch\u1ec7ch \u0111\u00f3 th\u01b0\u1eddng xuy\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u1ea1o ra nh\u1eefng \u201cc\u00fa s\u00fat cong h\u00ecnh tr\u00e1i chu\u1ed1i\u201d ngo\u1ea1n m\u1ee5c, bay v\u00f2ng qua h\u00e0ng h\u1eadu v\u1ec7. Hi\u1ec7n t\u01b0\u1ee3ng c\u01a1 b\u1ea3n ch\u00ednh l\u00e0 Hi\u1ec7u \u1ee9ng Magnus, \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean theo nh\u00e0 v\u1eadt l\u00fd \u0111\u00e3 nghi\u00ean c\u1ee9u ra n\u00f3 c\u00e1ch \u0111\u00e2y h\u01a1n 150 n\u0103m. Tr\u1eeb phi m\u1ed9t tr\u00e1i banh b\u1ecb s\u00fat \u0111\u00fang ngay v\u00e0o t\u00e2m c\u1ee7a n\u00f3, c\u00f2n kh\u00f4ng c\u00e1c qu\u1ea3 banh lu\u00f4n lu\u00f4n t\u1ef1 xoay khi n\u00f3 bay xuy\u00ean qua kh\u00f4ng kh\u00ed d\u1eabn t\u1edbi t\u1ed1c \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a kh\u00f4ng kh\u00ed ngang qua m\u1ed9t b\u00ean c\u1ee7a qu\u1ea3 banh tr\u1edf n\u00ean cao h\u01a1n so v\u1edbi c\u00e1c m\u1eb7t kh\u00e1c. H\u1ea7u h\u1ebft c\u00e1c s\u00e1ch gi\u00e1o khoa ch\u1ee9ng t\u1ecf r\u1eb1ng, do \u00e1p su\u1ea5t sinh ra b\u1edfi b\u1ea5t k\u00ec m\u1ed9t lo\u1ea1i kh\u00ed n\u00e0o c\u0169ng c\u00f3 m\u1ed1i li\u00ean h\u1ec7 \u0111\u1ebfn t\u1ed1c \u0111\u1ed9 c\u1ee7a d\u00f2ng kh\u00ed \u0111\u00f3, s\u1ef1 kh\u00e1c bi\u1ec7t trong t\u1ed1c 139","\u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a kh\u00f4ng kh\u00ed \u1edf c\u00e1c b\u00ean c\u1ee7a qu\u1ea3 b\u00f3ng s\u1ebd g\u00e2y n\u00ean s\u1ef1 gi\u1ea3m \u00e1p su\u1ea5t \u1edf m\u1ed9t b\u00ean c\u1ee7a qu\u1ea3 b\u00f3ng, b\u00ean n\u00e0y c\u1ee7a qu\u1ea3 b\u00f3ng sau \u0111\u00f3 s\u1ebd b\u1ecb \u0111\u1ea9y ch\u1ec7ch kh\u1ecfi h\u01b0\u1edbng bay m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3 nh\u1edd t\u00e1c \u0111\u1ed9ng c\u1ee7a \u00e1p su\u1ea5t cao h\u01a1n \u1edf m\u1eb7t b\u00ean kia. Tuy th\u1ebf, nh\u01b0 ti\u1ebfn s\u0129 John Wesson ch\u1ec9 ra trong nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y c\u1ee7a \u00f4ng v\u1ec1 hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y, c\u00e1c tranh c\u00e3i tr\u00ean l\u00e0m n\u00ean r\u1ea5t nhi\u1ec1u gi\u1ea3 \u0111\u1ecbnh m\u00e0 t\u00ednh ch\u1eafc ch\u1eafn c\u1ee7a c\u00e1c gi\u1ea3 \u0111\u1ecbnh n\u00e0y kh\u00f3 m\u00e0 \u0111\u00e1nh gi\u00e1 \u0111\u01b0\u1ee3c. \u00d4ng cho r\u1eb1ng c\u00e2u gi\u1ea3i th\u00edch h\u1ee3p l\u00fd h\u01a1n c\u1ea3 ch\u00ednh l\u00e0 hi\u1ec7u \u1ee9ng l\u1ec7ch h\u01b0\u1edbng \u0111\u00e3 khai th\u00e1c \u0111\u1ed9 nh\u1edbt hay c\u00f2n g\u1ecdi l\u00e0 \u201c\u0111\u1ed9 d\u00ednh c\u1ee7a kh\u00f4ng kh\u00ed\u201d, c\u1ed9ng v\u1edbi s\u1ef1 hi\u1ec7n di\u1ec7n c\u1ee7a c\u00e1c g\u00f3c v\u00e0 r\u00e3nh tr\u00ean b\u1ec1 m\u1eb7t tr\u00e1i b\u00f3ng. D\u1eabn t\u1edbi qu\u1ea3 b\u00f3ng chuy\u1ec3n \u0111\u1ed9ng h\u01a1i gi\u1ed1ng v\u1edbi m\u1ed9t b\u00e1nh xe n\u01b0\u1edbc, v\u1edbi c\u00e1c ph\u00e2n t\u1eed kh\u00f4ng kh\u00ed b\u00e1m s\u00e1t v\u00e0o qu\u1ea3 banh tr\u01b0\u1edbc khi b\u1ecb l\u1eadt sang m\u1ed9t b\u00ean v\u1edbi t\u1ed1c \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i cao. Ch\u00ednh l\u1ef1c \u0111\u1ea9y \u0111\u00f3 g\u00e2y n\u00ean ph\u1ea3n \u1ee9ng bay ch\u1ec7ch c\u1ee7a tr\u00e1i b\u00f3ng. Hi\u1ec7u \u1ee9ng bay l\u1ec7ch h\u01b0\u1edbng c\u00f3 th\u1ec3 tr\u00f4ng r\u1ea5t ngo\u1ea1n m\u1ee5c, khi c\u1ea7u th\u1ee7 b\u00f3ng \u0111\u00e1 ng\u01b0\u1eddi Brasil Roberto Carlos tr\u00ecnh di\u1ec5n trong m\u1ed9t tr\u1eadn \u0111\u1ea5u v\u1edbi \u0111\u1ed9i tuy\u1ec3n Ph\u00e1p v\u00e0o th\u00e1ng 6 n\u0103m 1997. Anh \u201cc\u1eaft\u201d qu\u1ea3 b\u00f3ng b\u1eb1ng m\u00e1 ngo\u00e0i b\u00e0n ch\u00e2n tr\u00e1i t\u1eeb v\u1ecb tr\u00ed c\u00e1ch khung th\u00e0nh 35m, khi\u1ebfn tr\u00e1i b\u00f3ng bay xo\u00e1y v\u1edbi t\u1ed1c \u0111\u1ed9 137 km\/gi\u1edd v\u1ec1 ph\u00eda b\u00ean ph\u1ea3i c\u1ee7a h\u00e0ng h\u1eadu v\u1ec7. Qu\u1ef9 \u0111\u1ea1o c\u1ee7a qu\u1ea3 b\u00f3ng mang n\u00f3 \u0111i ra xa so v\u1edbi khu v\u1ef1c tr\u01b0\u1edbc khung th\u00e0nh khi\u1ebfn cho m\u1ed9t ng\u01b0\u1eddi nh\u1eb7t banh \u0111ang \u0111\u1ee9ng \u1edf v\u1ea1ch khung th\u00e0nh h\u1ee5p xu\u1ed1ng \u0111\u1ec3 tr\u00e1nh c\u00e1i m\u00e0 anh ta ngh\u0129 r\u1eb1ng s\u1ebd th\u1eadt s\u1ef1 bay \u0111\u1ebfn. 140","Nh\u01b0ng kh\u00f4ng, khi qu\u1ea3 b\u00f3ng bay ch\u1eadm l\u1ea1i, s\u1ef1 k\u00ec di\u1ec7u c\u1ee7a \u201cc\u00fa s\u00fat cong h\u00ecnh qu\u1ea3 chu\u1ed1i\u201d m\u1edbi b\u1eaft \u0111\u1ea7u hi\u1ec7n ra, \u0111\u1ea9y tr\u00e1i banh bay theo m\u1ed9t \u0111\u01b0\u1eddng cong kh\u00edt khao v\u00e0 bay v\u00e0o l\u01b0\u1edbi. 119 V\u00ec sao c\u00e1c m\u1ea3nh v\u00e1 tr\u00ean b\u1ec1 m\u1eb7t tr\u00e1i banh l\u1ea1i c\u00f3 d\u1ea1ng ng\u0169 gi\u00e1c v\u00e0 l\u1ee5c gi\u00e1c? M\u1ecdi ng\u01b0\u1eddi th\u01b0\u1eddng kh\u00f4ng li\u00ean t\u01b0\u1edfng b\u00f3ng \u0111\u00e1 v\u1edbi to\u00e1n h\u1ecdc cao c\u1ea5p nh\u01b0ng vi\u1ec7c ch\u1ea5p v\u00e1 m\u01b0\u1eddi hai h\u00ecnh ng\u0169 gi\u00e1c m\u00e0u \u0111en v\u00e0 hai m\u01b0\u01a1i h\u00ecnh l\u1ee5c gi\u00e1c m\u00e0u tr\u1eafng bao quanh tr\u00e1i banh truy\u1ec1n th\u1ed1ng l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a hai \u0111\u1ecbnh l\u00fd s\u00e2u s\u1eafc. \u0110\u1ecbnh l\u00fd th\u1ee9 nh\u1ea5t, \u0111\u01b0\u1ee3c ch\u1ee9ng minh b\u1edfi nh\u00e0 to\u00e1n h\u1ecdc v\u0129 \u0111\u1ea1i Carl Gauss n\u0103m 1828, ch\u1ec9 ra r\u1eb1ng kh\u00f4ng th\u1ec3 l\u00e0m ra m\u1ed9t h\u00ecnh c\u1ea7u ho\u00e0n h\u1ea3o t\u1eeb b\u1ea5t k\u00ec v\u1eadt g\u00ec h\u00ecnh ph\u1eb3ng: s\u1ebd lu\u00f4n lu\u00f4n c\u00f3 c\u00e1c n\u1ebfp nh\u0103n ho\u1eb7c b\u1ecb m\u00e9o m\u00f3. Nh\u1eefng chuy\u00ean gia l\u00e0m b\u1ea3n \u0111\u1ed3 \u0111\u00e3 bi\u1ebft v\u1ec1 \u0111i\u1ec1u \u0111\u00f3 r\u1ea5t l\u00e2u tr\u01b0\u1edbc khi Carl Gauss ch\u1ee9ng minh n\u00f3 m\u1ed9t c\u00e1ch ch\u00ednh quy v\u00e0 ti\u1ebfn t\u1edbi th\u1ef1c hi\u1ec7n m\u1ed9t d\u00e3y \u0111\u1ea7y \u0111\u1ee7 c\u00e1c \u201c\u0111\u1ec1 \u00e1n\u201d b\u1ea3n \u0111\u1ed3, m\u00f4 t\u1ea3 b\u1ec1 m\u1eb7t cong c\u1ee7a tr\u00e1i \u0111\u1ea5t tr\u00ean c\u00e1c m\u1ea3nh gi\u1ea5y ph\u1eb3ng nh\u01b0ng lu\u00f4n lu\u00f4n c\u00f3 c\u00e1c sai l\u1ec7ch \u1edf m\u1ed9t trong c\u00e1c m\u1ea3nh gi\u1ea5y. 141","\u0110\u1ed1i v\u1edbi c\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t, v\u1ea5n \u0111\u1ec1 l\u00e0 l\u00e0m sao \u0111\u1ec3 ch\u1ebf t\u1ea1o m\u1ed9t qu\u1ea3 banh ch\u1eafc ch\u1eafn v\u00e0 c\u00f3 th\u1ec3 b\u01a1m ph\u1ed3ng sao cho n\u00f3 c\u00e0ng gi\u1ed1ng h\u00ecnh c\u1ea7u c\u00e0ng t\u1ed1t. Vi\u1ec7c ch\u1ea5p v\u00e1 c\u00e1c m\u1ea3nh da t\u01b0\u01a1ng \u0111\u1ed1i l\u1edbn l\u00e0 m\u1ed9t gi\u1ea3i ph\u00e1p hay, do n\u00f3 l\u00e0m h\u1ea1n ch\u1ebf vi\u1ec7c ph\u1ea3i kh\u00e2u v\u00e1 nhi\u1ec1u, \u0111\u1ed1i ph\u00f3 t\u00e1c \u0111\u1ed9ng c\u1ee7a c\u00e1c c\u00fa s\u00fat v\u00e0 s\u1ef1 n\u1ea3y c\u1ee7a qu\u1ea3 b\u00f3ng. H\u00ecnh d\u1ea1ng c\u1ee7a c\u00e1c mi\u1ebfng da c\u00f2n li\u00ean quan \u0111\u1ebfn m\u1ed9t \u0111\u1ecbnh lu\u1eadt do Rene Descartes t\u00ecm ra n\u0103m 1935 (nh\u01b0ng \u0111\u01b0\u1ee3c \u0111\u1eb7t t\u00ean l\u00e0 c\u00f4ng th\u1ee9c Euler, sau khi nh\u00e0 to\u00e1n h\u1ecdc t\u00eann Euler ph\u00e1t hi\u1ec7n l\u1ea1i n\u00f3 v\u00e0o m\u1ed9t th\u1ebf k\u1ec9 sau \u0111\u00f3). \u0110\u1ecbnh l\u00fd n\u00e0y kh\u1eb3ng \u0111\u1ecbnh r\u1eb1ng, \u0111\u1ed1i v\u1edbi b\u1ea5t k\u00ec v\u1eadt r\u1eafn n\u00e0o c\u00f3 d\u1ea1ng ng\u0169 gi\u00e1c, t\u1ed5ng s\u1ed1 c\u00e1c m\u1eb7t v\u00e0 c\u00e1c g\u00f3c b\u1eb1ng v\u1edbi t\u1ed5ng s\u1ed1 c\u1ea1nh c\u1ed9ng v\u1edbi 2. V\u00ed d\u1ee5 nh\u01b0, \u0111\u1ed1i v\u1edbi c\u00e1c h\u00ecnh l\u1eadp ph\u01b0\u01a1ng, ch\u00fang ta c\u00f3 6 m\u1eb7t v\u00e0 8 g\u00f3c, t\u1ed5ng c\u1ed9ng l\u00e0 14, b\u1eb1ng v\u1edbi t\u1ed5ng s\u1ed1 c\u1ea1nh l\u00e0 12 c\u1ed9ng v\u1edbi 2. S\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c n\u00e0y, ch\u00fang ta \u0111\u00e3 ph\u00e1t hi\u1ec7n ra s\u1ef1 k\u1ebft h\u1ee3p c\u1ee7a 12 h\u00ecnh ng\u0169 gi\u00e1c v\u00e0 20 h\u00ecnh l\u1ee5c gi\u00e1c l\u00e0 c\u1ea7n thi\u1ebft \u0111\u1ec3 t\u1ea1o n\u00ean m\u1ed9t v\u1eadt r\u1eafn h\u00ecnh c\u1ea7u t\u01b0\u01a1ng \u0111\u1ed1i m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n nh\u1ea5t. N\u00f3 \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn nh\u01b0 m\u1ed9t kh\u1ed1i 20 m\u1eb7t b\u1ecb c\u1eaft x\u00e9n v\u00e0 c\u00f3 th\u1ec3 th\u1ea5y ch\u00fang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i kh\u1eafp th\u1ebf gi\u1edbi. 120 \u0110\u00e2u l\u00e0 nguy\u00ean nh\u00e2n c\u1ee7a \u201cl\u1ee3i th\u1ebf s\u00e2n nh\u00e0\u201d trong b\u00f3ng \u0111\u00e1? M\u1ed9t \u0111i\u1ec1u ch\u1eafc ch\u1eafn l\u00e0 l\u1ee3i th\u1ebf s\u00e2n nh\u00e0 th\u1eadt s\u1ef1 r\u1ea5t l\u1edbn trong b\u00f3ng \u0111\u00e1. M\u1ed9t nghi\u00ean c\u1ee9u \u0111\u1ed3 s\u1ed9 c\u1ee7a h\u01a1n 4000 tr\u1eadn \u0111\u1ea5u t\u1ea1i gi\u1ea3i Ngo\u1ea1i h\u1ea1ng Anh su\u1ed1t nh\u1eefng n\u0103m 1990, th\u1ef1c 142","hi\u1ec7n b\u1edfi ti\u1ebfn s\u0129 Mark Dixon v\u00e0 ti\u1ebfn s\u0129 Michale Robinson c\u1ee7a \u0111\u1ea1i h\u1ecdc City, Lu\u00e2n \u0110\u00f4n \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng g\u1ea7n m\u1ed9t n\u1eeda c\u00e1c tr\u1eadn \u0111\u1ea5u t\u1ea1i s\u00e2n nh\u00e0 l\u00e0 mang l\u1ea1i chi\u1ebfn th\u1eafng cho \u0111\u1ed9i nh\u00e0 so v\u1edbi con s\u1ed1 1\/4 khi \u0111\u1ea5u \u1edf s\u00e2n kh\u00e1ch. Kh\u00f4ng c\u00f3 g\u00ec \u0111\u00e1ng ng\u1ea1c nhi\u00ean, \u0111\u00e3 c\u00f3 m\u1ed9t nghi\u00ean c\u1ee9u r\u1ed9ng r\u00e3i v\u1ec1 nguy\u00ean nh\u00e2n c\u1ee7a l\u1ee3i th\u1ebf s\u00e2n nh\u00e0, v\u1edbi t\u1ea5t c\u1ea3 m\u1ecdi th\u1ee9 t\u1eeb vi\u1ec7c c\u0103ng th\u1eb3ng do di chuy\u1ec3n cho \u0111\u1ebfn s\u1ef1 thi\u00ean v\u1ecb c\u1ee7a tr\u1ecdng t\u00e0i. Trong t\u1ea5t c\u1ea3, c\u00e1c y\u1ebfu t\u1ed1 t\u00e2m l\u00fd d\u01b0\u1eddng nh\u01b0 l\u00e0 nguy\u00ean nh\u00e2n ch\u00ednh. M\u1ed9t nghi\u00ean c\u1ee9u v\u1ec1 m\u1ee9c \u0111\u1ed9 l\u1ee3i th\u1ebf trong nh\u1eefng lo\u1ea1i tr\u1eadn \u0111\u1ea5u kh\u00e1c nhau c\u1ee7a ti\u1ebfn s\u0129 Richard Pollard c\u1ee7a \u0111\u1ea1i h\u1ecdc South Pacific, \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng c\u00e1c y\u1ebfu t\u1ed1 t\u00e2m l\u00fd l\u00e0 t\u01b0\u01a1ng \u0111\u1ed1i nh\u1ecf trong c\u00e1c tr\u1eadn \u0111\u1ea5u \u0111\u1ecba ph\u01b0\u01a1ng v\u00e0 t\u01b0\u01a1ng \u0111\u1ed1i l\u1edbn trong c\u00e1c tr\u1eadn \u0111\u1ea5u qu\u1ed1c t\u1ebf - do \u0111\u00f3 m\u1ed9t ng\u01b0\u1eddi c\u00f3 th\u1ec3 ngh\u0129 r\u1eb1ng c\u00e1c c\u1ea7u th\u1ee7 thi \u0111\u1ea5u \u1edf xa b\u1ecb t\u00e1c \u0111\u1ed9ng b\u1edfi c\u1ea3m gi\u00e1c say t\u00e0u xe. C\u00e1c nghi\u00ean c\u1ee9u v\u1ec1 \u0111i\u1ec1u \u0111\u00f3 ch\u1ec9 ra r\u1eb1ng c\u00e1c m\u00f4n thi \u0111\u1ea5u nh\u01b0 b\u00f3ng ch\u00e0y, trong \u0111\u00f3 ng\u01b0\u1eddi qu\u1ea3n l\u00fd \u0111\u1ed9i c\u00f3 r\u1ea5t nhi\u1ec1u c\u01a1 h\u1ed9i \u0111\u1ec3 l\u00e0m tr\u1ea5n t\u0129nh c\u00e1c v\u1eadn \u0111\u1ed9ng vi\u00ean b\u1ecb m\u1ea5t b\u00ecnh t\u0129nh c\u00f3 r\u1ea5t \u00edt l\u1ee3i th\u1ebf s\u00e2n nh\u00e0 so v\u1edbi m\u00f4n b\u00f3ng \u0111\u00e1, m\u00f4n m\u00e0 c\u00e1c c\u1ea7u th\u1ee7 thi \u0111\u1ea5u xa b\u1ecb bu\u1ed9c ph\u1ea3i ch\u1ecbu \u0111\u1ef1ng ti\u1ebfng g\u00e0o th\u00e9t t\u1eeb c\u1ed5 \u0111\u1ed9ng vi\u00ean \u0111\u1ed9i nh\u00e0 trong su\u1ed1t 45 ph\u00fat m\u1ed9t c\u00e1ch c\u0103ng th\u1eb3ng. Tr\u01b0\u1edbc khi m\u1ed9t ai \u0111\u00f3 ch\u1ec9 tr\u00edch r\u1eb1ng c\u00e1c c\u1ea7u th\u1ee7 n\u00e0y thi\u1ebfu tinh th\u1ea7n th\u00e9p th\u00ec n\u00ean ghi nh\u1edb r\u1eb1ng ngay c\u1ea3 ban t\u1ed5 ch\u1ee9c v\u00e0 tr\u1ecdng 143","t\u00e0i c\u1ee7a tr\u1eadn \u0111\u1ea5u c\u0169ng b\u1ecb \u0111e d\u1ecda b\u1edfi ti\u1ebfng \u1ed3n c\u1ee7a h\u00e0ng ch\u1ee5c ng\u00e0n kh\u00e1n gi\u1ea3 h\u00e2m m\u1ed9. N\u0103m 1999, t\u1ea1p ch\u00ed The Lancet \u0111\u00e3 \u0111\u0103ng c\u00e1c k\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u c\u1ee7a ti\u1ebfn s\u0129 Alan Nevill v\u00e0 c\u00e1c c\u1ed9ng s\u1ef1 c\u1ee7a m\u00ecnh t\u1ea1i \u0111\u1ea1i h\u1ecdc Liverpool John Moores. Nghi\u00ean c\u1ee9u \u0111\u00f3 y\u00eau c\u1ea7u xem x\u00e9t c\u00e1c b\u0103ng video gian l\u1eadn trong m\u1ed9t tr\u1eadn \u0111\u1ea5u th\u1eadt s\u1ef1. H\u1ecd ph\u00e1t hi\u1ec7n ra r\u1eb1ng n\u1ebfu c\u00e1c \u00e2m thanh \u0111\u1ef1\u01a1c b\u1eadt l\u00ean, nh\u1eefng ng\u01b0\u1eddi theo d\u00f5i c\u00f3 khuynh h\u01b0\u1edbng b\u1eaft l\u1ed7i nh\u1eefng c\u1ea7u th\u1ee7 \u0111\u1ed9i kh\u00e1ch ch\u01a1i x\u1ea5u, n\u1ebfu \u00e2m thanh b\u1ecb t\u1eaft \u0111i, d\u1ef1 thi\u00ean v\u1ecb gi\u1ea3m h\u1eb3n: \u0111\u00e2y l\u00e0 b\u1eb1ng ch\u1ee9ng r\u00f5 r\u00e0ng cho vi\u1ec7c, trong b\u00f3ng \u0111\u00e1, nh\u1eefng ng\u01b0\u1eddi la h\u00e9t chi\u1ebfn th\u1eafng. C\u00f3 l\u00fd do n\u00e0o \u0111\u1ec3 gi\u1ea3i th\u00edch cho 121 vi\u1ec7c t\u1ea1i sao l\u1ea1i c\u00f3 r\u1ea5t nhi\u1ec1u quy\u1ebft \u0111\u1ecbnh sai v\u1ec1 l\u1ed7i vi\u1ec7t v\u1ecb trong b\u00f3ng \u0111\u00e1 kh\u00f4ng? Quy t\u1eafc vi\u1ec7t v\u1ecb g\u00e2y ra nhi\u1ec1u tranh c\u00e3i h\u01a1n so v\u1edbi b\u1ea5t k\u00ec quy t\u1eafc n\u00e0o kh\u00e1c trong b\u00f3ng \u0111\u00e1. \u0110\u01a1n gi\u1ea3n nh\u1ea5t, quy t\u1eafc n\u00e0y x\u00e1c \u0111\u1ecbnh r\u1eb1ng m\u1ed9t c\u1ea7u th\u1ee7 \u1edf v\u1ecb tr\u00ed vi\u1ec7t v\u1ecb n\u1ebfu: t\u1ea1i th\u1eddi \u0111i\u1ec3m tr\u00e1i banh \u0111\u01b0\u1ee3c chuy\u1ec1n b\u1edfi m\u1ed9t ng\u01b0\u1eddi \u0111\u1ed3ng \u0111\u1ed9i, ch\u1ec9 c\u00f3 th\u1ee7 m\u00f4n \u1edf gi\u1eefa c\u1ea7u th\u1ee7 \u0111\u00f3 v\u00e0 v\u1ea1ch khung th\u00e0nh. C\u00f3 r\u1ea5t nhi\u1ec1u \u0111\u1ecbnh ngh\u0129a v\u1ec1 vi\u1ec7c r\u01a1i v\u00e0o b\u1eaby vi\u1ec7t v\u1ecb v\u00e0 nh\u1eefng \u0111i\u1ec1u t\u01b0\u01a1ng t\u1ef1 nh\u1eefng quy t\u1eafc tr\u00ean l\u00e0 c\u01a1 b\u1ea3n. Quy t\u1eafc \u0111\u00f3 c\u0169ng n\u1eafm gi\u1eef m\u1ea5u ch\u1ed1t c\u1ee7a v\u1ea5n \u0111\u1ec1: c\u00e1c tr\u1ecdng t\u00e0i c\u1ee7a tr\u1eadn \u0111\u1ea5u s\u1ebd ph\u00e1n \u0111o\u00e1n v\u1ecb tr\u00ed t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a qu\u1ea3 banh, ng\u01b0\u1eddi t\u1ea5n c\u00f4ng v\u00e0 h\u1eadu v\u1ec7 \u0111\u1ee9ng sau c\u00f9ng, 144","t\u1ea5t c\u1ea3 \u0111\u1ec1u trong nh\u1eefng v\u1ecb tr\u00ed kh\u00e1c nhau v\u00e0 \u1edf c\u00f9ng m\u1ed9t th\u1eddi \u0111i\u1ec3m. \u0110i\u1ec1u \u0111\u00f3 kh\u00f4ng d\u1ec5, v\u00e0 c\u00e1c nghi\u00ean c\u1ee9u ch\u1ec9 ra r\u1eb1ng c\u00f3 kho\u1ea3ng 20 ph\u1ea7n tr\u0103m quy\u1ebft \u0111\u1ecbnh c\u1ee7a tr\u1ecdng t\u00e0i v\u1ec1 l\u1ed7i vi\u1ec7t v\u1ecb l\u00e0 sai. C\u00f3 l\u1ebd c\u00e2u tr\u1ea3 l\u1eddi r\u00f5 r\u00e0ng cho nh\u1eefng sai l\u1ea7m tr\u00ean l\u00e0 c\u00e1c tr\u1ecdng t\u00e0i c\u1ea7n \u0111\u01b0\u1ee3c t\u1eadp hu\u1ea5n nhi\u1ec1u h\u01a1n. Nh\u01b0ng nh\u1eefng nghi\u00ean c\u1ee9u g\u1ea7n \u0111\u00e2y b\u1edfi c\u00e1c nh\u00e0 khoa h\u1ecdc \u1edf tr\u01b0\u1eddng \u0111\u1ea1i h\u1ecdc Free c\u1ee7a Amsterdam, H\u00e0 Lan \u0111\u00e3 \u0111\u1eb7t tr\u00e1ch nhi\u1ec7m v\u00e0o m\u1ed9t \u1ea3o gi\u00e1c quang h\u1ecdc d\u1eabn \u0111\u1ebfn c\u00e1c c\u1ea7u th\u1ee7 t\u1ea5n c\u00f4ng c\u00f3 v\u1ebb nh\u01b0 r\u01a1i v\u00e0o l\u1ed7i vi\u1ec7t v\u1ecb nhi\u1ec1u h\u01a1n l\u00e0 h\u1ecd th\u1eadt s\u1ef1 r\u01a1i v\u00e0o l\u1ed7i \u0111\u00f3. \u0110\u1ec3 hi\u1ec3u r\u00f5 \u1ea3o gi\u00e1c \u0111\u00f3 nh\u01b0 th\u1ebf n\u00e0o, h\u00e3y gi\u1eef trong m\u1ed7i b\u00e0n tay m\u1ed9t c\u00e2y b\u00fat th\u1eb3ng \u0111\u1ee9ng, \u0111\u01b0a ch\u00fang l\u00ean theo chi\u1ec1u d\u00e0i c\u00e1nh tay, sao cho c\u00e2y b\u00fat n\u00e0y s\u1ebd b\u1ecb che ph\u00eda sau c\u1ee7a c\u00e2y b\u00fat kia. N\u1ebfu c\u00e2y b\u00fat n\u1eb1m xa nh\u1ea5t l\u00e0 m\u1ed9t c\u1ea7u th\u1ee7 t\u1ea5n c\u00f4ng v\u1eeba chuy\u1ec1n banh \u0111i, h\u1ecd s\u1ebd kh\u00f4ng b\u1ecb l\u1ed7i vi\u1ec7t v\u1ecb. B\u00e2y gi\u1edd h\u00e3y d\u1ecbch chuy\u1ec3n \u0111\u1ea7u c\u1ee7a b\u1ea1n sang ph\u1ea3i v\u00e0 nh\u00ecn l\u1ea1i l\u1ea7n n\u1eefa: \u201cc\u1ea7u th\u1ee7 t\u1ea5n c\u00f4ng\u201d b\u00e2y gi\u1edd c\u00f3 v\u1ebb nh\u01b0 \u0111\u1ee9ng tr\u01b0\u1edbc ng\u01b0\u1eddi h\u1eadu v\u1ec7 v\u00e0 b\u1ecb l\u1ed7i vi\u1ec7t v\u1ecb. Do \u0111\u00f3, b\u1ea5t k\u00ec tr\u1ee3 l\u00fd tr\u1ecdng t\u00e0i n\u00e0o nh\u00ecn ng\u01b0\u1ee3c v\u1ec1 sau theo h\u01b0\u1edbng c\u00e1c c\u1ea7u th\u1ee7, v\u1edbi c\u1ea7u th\u1ee7 t\u1ea5n c\u00f4ng \u0111\u1ee9ng xa nh\u1ea5t, \u0111\u1ec1u c\u00f3 nguy c\u01a1 ph\u1ea5t c\u1edd vi\u1ec7t v\u1ecb sai. Ch\u1eafc ch\u1eafn c\u00e1c nh\u00e0 khoa h\u1ecdc c\u0169ng ph\u00e1t hi\u1ec7n ra r\u1eb1ng c\u00f3 \u0111\u1ebfn kho\u1ea3ng 90% tr\u01b0\u1eddng h\u1ee3p c\u00e1c tr\u1ee3 l\u00fd tr\u1ecdng t\u00e0i nh\u00ecn ng\u01b0\u1ee3c v\u1ec1 ph\u00eda sau. 145","KH\u00cd T\u01af\u1ee2NG H\u1eccC 122 Khi b\u1ecb m\u1eafc m\u01b0a, b\u1ea1n n\u00ean \u0111i b\u1ed9 hay ch\u1ea1y? C\u00f3 v\u1ebb nh\u01b0 c\u00e2u tr\u1ea3 l\u1eddi d\u01b0\u1eddng nh\u01b0 r\u1ea5t r\u00f5 r\u00e0ng: ch\u1ea1y lu\u00f4n lu\u00f4n \u0111\u01b0\u1ee3c ch\u1ecdn l\u1ef1a nhi\u1ec1u h\u01a1n v\u00ec n\u00f3 gi\u1ea3m thi\u1ec3u th\u1eddi gian ch\u00fang ta \u1edf trong tr\u1eddi m\u01b0a. Nh\u01b0ng sau \u0111\u00f3 c\u00e1c m\u1ed1i nghi ng\u1edd b\u1eaft \u0111\u1ea7u xu\u1ea5t hi\u1ec7n. T\u1ea5t c\u1ea3 c\u00e1c t\u00e0i x\u1ebf xe \u0111\u1ec1u hi\u1ec3u m\u1ed9t ng\u01b0\u1eddi l\u00e1i xe trong m\u01b0a c\u00e0ng nhanh th\u00ec l\u01b0\u1ee3ng n\u01b0\u1edbc m\u01b0a \u0111\u1eadp v\u00e0o k\u00ednh ch\u1eafn gi\u00f3 c\u1ee7a xe trong th\u1eddi gian m\u1ed9t gi\u00e2y (l\u01b0u l\u01b0\u1ee3ng n\u01b0\u1edbc m\u01b0a) l\u1ea1i c\u00e0ng l\u1edbn, v\u00e0 c\u00e1c thanh g\u1ea1t n\u01b0\u1edbc m\u01b0a c\u0169ng ph\u1ea3i ho\u1ea1t \u0111\u1ed9ng nhanh h\u01a1n \u0111\u1ec3 l\u00e0m s\u1ea1ch k\u00ednh. Cho n\u00ean, li\u1ec7u c\u00f3 ph\u1ea3i l\u00e0 n\u1ebfu ch\u00fang ta \u0111i b\u1ed9 xuy\u00ean qua tr\u1eddi m\u01b0a, l\u01b0\u1ee3ng n\u01b0\u1edbc m\u01b0a tr\u00ean m\u1ed9t \u0111\u01a1n v\u1ecb th\u1eddi gian (l\u01b0u l\u01b0\u1ee3ng m\u01b0a) m\u00e0 ch\u00fang ta nh\u1eadn ph\u1ea3i s\u1ebd nh\u1ecf h\u01a1n v\u00ec v\u1eady ta c\u0169ng s\u1ebd \u00edt b\u1ecb \u01b0\u1edbt h\u01a1n? N\u1ebfu b\u1ecf qua c\u00e1c t\u00ednh to\u00e1n to\u00e1n h\u1ecdc, ta th\u1ea5y ngay r\u1eb1ng th\u1ef1c t\u1ebf l\u00e0: b\u1ea1n lu\u00f4n lu\u00f4n u\u1edbt \u00edt h\u01a1n n\u1ebfu b\u1ea1n ch\u1ea1y. Ti\u1ebfp theo, ch\u00fang ta \u0111i \u0111\u1ebfn m\u1ed9t kh\u00fac m\u1eafc cu\u1ed1i: s\u1eed d\u1ee5ng c\u00e1c bi\u1ec3u \u0111\u1ed3 th\u1ef1c t\u1ebf v\u1ec1 c\u01b0\u1eddng \u0111\u1ed9 m\u01b0a, t\u1ed1c \u0111\u1ed9 gi\u00f3 v\u00e0 t\u1ed1c \u0111\u1ed9 ch\u1ea1y, 146","th\u00ec h\u00f3a ra l\u1ee3i \u00edch c\u1ee7a vi\u1ec7c ch\u1ea1y r\u00f5 r\u00e0ng l\u00e0 r\u1ea5t nh\u1ecf. Do \u0111\u00f3, n\u1ebfu b\u1ecb m\u1eafc v\u00e0o m\u1ed9t c\u01a1n m\u01b0a nh\u1eb9, vi\u1ec7c ch\u1ea1y nhanh \u0111\u1ec3 t\u00ecm ch\u1ed7 tr\u00fa m\u01b0a kh\u00f4ng mang l\u1ea1i nhi\u1ec1u l\u1ee3i \u00edch h\u01a1n tr\u1eeb khi c\u00f3 v\u1ebb nh\u01b0 s\u1eafp c\u00f3 m\u1ed9t tr\u1eadn m\u01b0a r\u1ea5t l\u1edbn x\u1ea3y ra. 123 Th\u1eddi \u0111i\u1ec3m n\u00e0o l\u00e0 n\u00f3ng nh\u1ea5t trong ng\u00e0y? V\u00e0o ngay gi\u1eefa tr\u01b0a, trong khi m\u1eb7t tr\u1eddi \u1edf v\u1ecb tr\u00ed cao nh\u1ea5t tr\u00ean tr\u1eddi v\u00e0 tia \u201cc\u1ef1c t\u00edm\u201d c\u00f3 c\u01b0\u1eddng \u0111\u1ed9 m\u1ea1nh nh\u1ea5t, th\u00ec nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed l\u1ea1i kh\u00f4ng h\u1eb3n l\u00e0 n\u00f3ng nh\u1ea5t. Do m\u1eb7t \u0111\u1ea5t ti\u1ebfp t\u1ee5c h\u1ea5p thu s\u1ee9c n\u00f3ng c\u1ee7a m\u1eb7t tr\u1eddi, khi\u1ebfn nhi\u1ec7t \u0111\u1ed9 c\u1ee7a kh\u00f4ng kh\u00ed ph\u00eda tr\u00ean n\u00f3 t\u0103ng l\u00ean \u0111\u1ec1u \u0111\u1eb7n trong nhi\u1ec1u gi\u1edd li\u1ec1n sau bu\u1ed5i tr\u01b0a. Trong nh\u1eefng ng\u00e0y h\u00e8 quang \u0111\u00e3ng, kh\u00f4ng gi\u00f3, nhi\u1ec7t \u0111\u1ed9 cao nh\u1ea5t trong ng\u00e0y th\u01b0\u1eddng v\u00e0o kho\u1ea3ng 4 gi\u1edd chi\u1ec1u (v\u00e0 th\u1ec9nh tho\u1ea3ng tr\u1ec5 h\u01a1n). Sau \u0111\u00f3, \u0111\u1ed9 cao c\u1ee7a m\u1eb7t tr\u1eddi tr\u00ean b\u1ea7u tr\u1eddi s\u1ebd gi\u1ea3m xu\u1ed1ng, khi\u1ebfn m\u1ecdi v\u1eadt b\u1eaft \u0111\u1ea7u l\u1ea1nh \u0111i. 124 T\u1ea1i sao \u0111\u00f4i khi b\u1ea1n th\u1ea5y \u0111\u01b0\u1ee3c nhi\u1ec1u h\u01a1n m\u1ed9t c\u1ea7u v\u1ed3ng? C\u1ea7u v\u1ed3ng l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a vi\u1ec7c nh\u1eefng gi\u1ecdt m\u01b0a \u1edf tr\u00ean \u0111\u1ea7u ch\u00fang ta b\u1ecb chi\u1ebfu b\u1edfi \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi t\u1eeb ph\u00eda sau 147","ch\u00fang ta, sau \u0111\u00f3 c\u00e1c tia s\u00e1ng n\u00e0y s\u1ebd b\u1ecb b\u1ebb cong v\u00e0 ph\u00e2n t\u00e1ch ra th\u00e0nh c\u00e1c m\u00e0u th\u00e0nh ph\u1ea7n c\u1ee7a n\u00f3. C\u00e1c tia c\u1ee7a \u00e1nh s\u00e1ng c\u00f3 m\u00e0u \u0111\u01b0\u1ee3c sinh ra t\u1eeb m\u1ed7i gi\u1ecdt m\u01b0a sau khi va ch\u1ea1m s\u1ebd \u0111\u01b0\u1ee3c b\u1ebb cong kho\u1ea3ng 420, do \u0111\u00f3 ch\u00fang ta ch\u1ec9 th\u1ea5y \u0111\u01b0\u1ee3c c\u00e1c tia t\u1eeb c\u00e1c gi\u1ecdt m\u01b0a m\u00e0 s\u1ef1 b\u1ebb cong 420 l\u00e0m cho ch\u00fang chi\u1ebfu th\u1eb3ng t\u1edbi m\u1eaft ch\u00fang ta. T\u1ea5t c\u1ea3 c\u00e1c tia \u0111\u00e1p \u1ee9ng \u0111\u01b0\u1ee3c ti\u00eau chu\u1ea9n n\u00e0y th\u00ec n\u1eb1m tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n; ph\u1ea7n \u0111\u01b0\u1eddng tr\u00f2n m\u00e0 kh\u00f4ng b\u1ecb che khu\u1ea5t b\u1edfi \u0111\u01b0\u1eddng ch\u00e2n tr\u1eddi v\u00e0 m\u1eb7t \u0111\u1ea5t ch\u00ednh l\u00e0 c\u00e1i m\u00e0 ch\u00fang ta g\u1ecdi l\u00e0 c\u1ea7u v\u1ed3ng. N\u1ebfu \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi \u0111\u1ee7 m\u1ea1nh, ta c\u00f2n c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c m\u1ed9t c\u1ea7u v\u1ed3ng th\u1ee9 hai, nh\u1ea1t h\u01a1n b\u00ean ngo\u00e0i c\u00e1i th\u1ee9 nh\u1ea5t, l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a vi\u1ec7c \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi b\u1ecb d\u1ed9i l\u1ea1i l\u1ea7n th\u1ee9 hai b\u00ean trong gi\u1ecdt n\u01b0\u1edbc tr\u01b0\u1edbc khi ph\u00e1t ra. V\u00e0 c\u00f3 m\u1ed9t c\u1ea7u v\u1ed3ng th\u1ee9 ba, th\u1eadm ch\u00ed c\u00f2n l\u1edbn h\u01a1n kh\u00f4ng? \u0110\u01b0\u01a1ng nhi\u00ean \u0111i\u1ec1u n\u00e0y c\u0169ng l\u00e0 h\u1ee3p l\u00fd, v\u1ea3 l\u1ea1i n\u00f3 \u0111\u00e3 \u0111\u01b0\u1ee3c ch\u1ee9ng minh l\u1ea7n \u0111\u1ea7u ti\u00ean b\u1edfi nh\u00e0 khoa h\u1ecdc th\u1ebf k\u1ec9 17 Edmond Halley. C\u1ea7u v\u1ed3ng th\u1ee9 ba n\u00e0y s\u1ebd xu\u1ea5t hi\u1ec7n xung quanh ch\u00ednh m\u1eb7t tr\u1eddi. V\u00e0 n\u00f3 c\u0169ng s\u1ebd y\u1ebfu h\u01a1n c\u1ea7u v\u1ed3ng th\u1ee9 hai, \u0111i\u1ec1u n\u00e0y \u0111\u00e3 gi\u1ea3i th\u00edch r\u1ea5t r\u00f5 t\u1ea1i sao ch\u01b0a c\u00f3 ai \u0111\u00e3 th\u1ef1c s\u1ef1 t\u1eebng nh\u00ecn th\u1ea5y n\u00f3. C\u00e1c m\u00e0u s\u1eafc m\u00e0 c\u1ea7u v\u1ed3ng bi\u1ec3u l\u1ed9 l\u00e0 do khi m\u1ed9t tia s\u00e1ng \u0111i qua gi\u1ecdt m\u01b0a, m\u1ed7i m\u00e0u s\u1eafc b\u00ean trong tia s\u00e1ng 148","b\u1ecb cong (b\u1ecb kh\u00fac x\u1ea1) \u1edf m\u1ee9c \u0111\u1ed9 h\u01a1i kh\u00e1c nhau, ph\u1ee5 thu\u1ed9c v\u00e0o b\u01b0\u1edbc s\u00f3ng c\u1ee7a n\u00f3 (m\u00e0u \u0111\u1ecf \u00edt b\u1ecb kh\u00fac x\u1ea1 h\u01a1n m\u00e0u t\u00edm), k\u1ebft qu\u1ea3 l\u00e0 \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi m\u00e0u tr\u1eafng ban \u0111\u1ea7u b\u1ecb chia th\u00e0nh t\u1ea5t c\u1ea3 c\u00e1c m\u00e0u c\u1ee7a c\u1ea7u v\u1ed3ng. Nh\u01b0ng t\u1ea1i sao ch\u00fang ta ch\u1ec9 th\u1ea5y m\u1ed9t c\u1ea7u v\u1ed3ng thay v\u00ec h\u00e0ng tri\u1ec7u c\u00e1i nh\u1ecf h\u01a1n t\u1eeb m\u1ed7i gi\u1ecdt m\u01b0a ri\u00eang bi\u1ec7t? \u0110i\u1ec1u n\u00e0y l\u00e0 b\u1edfi v\u00ec ch\u00fang ta ch\u1ec9 th\u1ea5y \u0111\u01b0\u1ee3c c\u00e1c c\u1ea7u v\u1ed3ng t\u1ea1o ra t\u1eeb c\u00e1c gi\u1ecdt n\u1eb1m \u1edf m\u1ed9t v\u1ecb tr\u00ed ch\u00ednh x\u00e1c m\u00e0 t\u1eeb \u0111\u00f3 \u00e1nh s\u00e1ng ph\u00e1t ra t\u1eeb n\u00f3 c\u00f3 th\u1ec3 \u0111i v\u00e0o m\u1eaft ch\u00fang ta - n\u00f3i ng\u1eafn g\u1ecdn, m\u1ed7i ch\u00fang ta th\u1ea5y \u0111\u01b0\u1ee3c m\u1ed9t c\u1ea7u v\u1ed3ng \u0111\u01b0\u1ee3c c\u00e1 nh\u00e2n h\u00f3a cho ri\u00eang ta. N\u1ebfu c\u1ea7u v\u1ed3ng th\u1ee9 hai l\u1edbn h\u01a1n c\u0169ng \u0111\u01b0\u1ee3c th\u1ea5y, h\u00e3y ch\u00fa \u00fd c\u00e1c m\u00e0u s\u1eafc \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp ng\u01b0\u1ee3c so v\u1edbi c\u1ea7u v\u1ed3ng ch\u00ednh - s\u1ef1 ph\u1ea3n x\u1ea1 \u00e1nh s\u00e1ng l\u1ea7n th\u1ee9 hai \u0111\u00e3 d\u1eabn t\u1edbi tr\u1eadt t\u1ef1 xu\u1ea5t hi\u1ec7n c\u1ee7a c\u00e1c m\u00e0u b\u1ecb \u0111\u1ea3o l\u1ed9n. 125 C\u00f3 th\u1ec3 l\u00e1i xe xuy\u00ean qua qua ph\u1ea7n cu\u1ed1i c\u1ee7a c\u1ea7u v\u1ed3ng kh\u00f4ng? C\u1ea7u v\u1ed3ng l\u00e0 v\u1eadt th\u1ec3 c\u00f3 li\u00ean quan nhi\u1ec1u \u0111\u1ebfn v\u1ecb tr\u00ed c\u1ee7a m\u1eb7t tr\u1eddi, c\u00e1c \u0111\u00e1m m\u00e2y g\u00e2y m\u01b0a v\u00e0 ch\u00ednh ch\u00fang ta. Ch\u00fang ch\u1ec9 xu\u1ea5t hi\u1ec7n khi m\u1eaft c\u1ee7a b\u1ea1n \u1edf v\u00e0o v\u1ecb tr\u00ed ch\u1eafn c\u00e1c ch\u00f9m \u00e1nh s\u00e1ng m\u00e0u sinh ra khi c\u00e1c tia m\u1eb7t tr\u1eddi g\u1eb7p n\u01b0\u1edbc m\u01b0a b\u1ecb kh\u00fac x\u1ea1 v\u00e0 ph\u1ea3n x\u1ea1 l\u1ea1i. Tuy nhi\u00ean, s\u1ebd c\u00f3 m\u1ed9t v\u1ecb tr\u00ed m\u00e0 \u1edf \u0111\u00f3 c\u00e1c tia s\u00e1ng kh\u00f4ng th\u1ec3 \u0111i v\u00e0o m\u1eaft c\u1ee7a ch\u00fang ta nhi\u1ec1u h\u01a1n n\u1eefa v\u00e0 c\u1ea7u v\u1ed3ng c\u1ee7a ch\u00fang ta s\u1ebd bi\u1ebfn m\u1ea5t, m\u1eb7c d\u00f9 n\u00f3 c\u00f3 th\u1ec3 v\u1eabn \u0111\u01b0\u1ee3c nh\u00ecn th\u1ea5y b\u1edfi nh\u1eefng ng\u01b0\u1eddi kh\u00e1c. M\u1ed9t trong nh\u1eefng 149"]