Hãy Trả Lời Em Tại Sao_ - Tập 12 (Arkady Leokum) thuviensach.vn

["kho\u1ea3ng c\u00e1ch n\u1eb1m ngang m\u00e0 ch\u00fang l\u01b0\u1ee3n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng b\u1eb1ng c\u00e1ch nh\u00e2n t\u1ec9 s\u1ed1 n\u00e0y v\u1edbi \u0111\u1ed9 cao c\u1ee7a m\u00e1y bay khi \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3 t\u1eaft. V\u00ed d\u1ee5, n\u1ebfu r\u01a1i t\u1eeb \u0111\u1ed9 cao kho\u1ea3ng g\u1ea7n 10km - m\u1ed9t ph\u1ea3n l\u1ef1c c\u01a1 h\u00e0nh kh\u00e1ch c\u00f3 th\u1ec3 \u0111\u1ebfn \u0111\u01b0\u1ee3c m\u1ed9t \u0111\u1ecba \u0111i\u1ec3m kh\u00e1c c\u00e1ch xa kho\u1ea3ng 160 km. Th\u00e1ng 8 n\u0103m 2001, m\u1ed9t m\u00e1y bay Airbus 330 bay t\u1eeb Toronto t\u1edbi Lisbon \u0111\u00e3 b\u1ecb thi\u1ebfu h\u1ee5t nhi\u00ean li\u1ec7u tr\u1ea7m tr\u1ecdng. Sau khi nh\u1eadn th\u1ea5y sai l\u1ea7m, c\u00e1c phi c\u00f4ng \u0111\u00e3 chuy\u1ec3n h\u01b0\u1edbng t\u1edbi m\u1ed9t b\u00e3i \u0111\u00e1p m\u00e1y bay \u1edf Azores nh\u01b0ng c\u1ea3 hai \u0111\u1ed9ng c\u01a1 \u0111\u1ec1u t\u1eaft khi h\u1ecd c\u00f2n c\u00e1ch \u0111\u00f3 137 km. May sao, m\u00e1y bay c\u1ee7a h\u1ecd c\u00f3 t\u1ec9 s\u1ed1 n\u00e2ng-k\u00e9o v\u00e0o kho\u1ea3ng 16 v\u00e0 m\u00e1y bay \u1edf \u0111\u1ed9 cao h\u01a1n 10km, ngh\u0129a l\u00e0 m\u00e1y bay c\u00f3 th\u1ec3 l\u01b0\u1ee3n h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng. C\u00e1c phi c\u00f4ng \u0111\u00e3 th\u1ef1c hi\u1ec7n m\u1ed9t chuy\u1ebfn h\u1ea1 c\u00e1nh t\u1ed1c \u0111\u1ed9 cao r\u1ea5t th\u00e0nh c\u00f4ng v\u00e0 ch\u1ec9 c\u00f3 kho\u1ea3ng m\u1ed9t ch\u1ee5c h\u00e0nh kh\u00e1ch b\u1ecb th\u01b0\u01a1ng nh\u1eb9. 115 Chu\u1ed7i xo\u1eafn \u0111\u00f4i DNA l\u1edbn nh\u01b0 th\u1ebf n\u00e0o? L\u1edbn \u0111\u1ebfn kinh ng\u1ea1c: ph\u00e2n t\u1eed DNA \u0111\u01b0\u1ee3c n\u1eb1m g\u1ecdn trong m\u1ed7i t\u1ebf b\u00e0o c\u1ee7a ch\u00fang ta c\u00f3 chi\u1ec1u ngang ch\u1ec9 kho\u1ea3ng 20 nguy\u00ean t\u1eed nh\u01b0ng d\u00e0i kho\u1ea3ng 1,2 m. B\u1ecb qu\u1ea5n ch\u1eb7t l\u1ea1i th\u00e0nh nhi\u1ec5m s\u1eafc th\u1ec3, n\u00f3 ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u1ea5y d\u01b0\u1edbi k\u00ednh hi\u1ec3n vi \u0111i\u1ec7n t\u1eed nh\u01b0ng n\u1ebfu t\u1ea5t c\u1ea3 DNA trong c\u01a1 th\u1ec3 m\u1ed9t ng\u01b0\u1eddi \u0111\u01b0\u1ee3c n\u1ed1i \u0111\u1ea7u v\u1edbi nhau, ch\u00fang s\u1ebd k\u00e9o d\u00e0i g\u1ea5p m\u01b0\u1eddi l\u1ea7n t\u1eeb kho\u1ea3ng c\u00e1ch tr\u00e1i \u0111\u1ea5t t\u1edbi sao Di\u00eam V\u01b0\u01a1ng. 150 https:\/\/thuviensach.vn","Greenwich \u0111\u00e3 tr\u1edf th\u00e0nh 116 trung t\u00e2m c\u1ee7a b\u1ea3n \u0111\u1ed3 th\u1ebf gi\u1edbi t\u1eeb khi n\u00e0o? H\u1ea7u h\u1ebft c\u00e1c b\u1ea3n \u0111\u1ed3 \u0111\u1eb7t n\u01b0\u1edbc Anh \u1edf trung t\u00e2m c\u1ee7a th\u1ebf gi\u1edbi, v\u1edbi kinh tuy\u1ebfn g\u1ed1c Greenwich ch\u1ea1y qua v\u00f9ng \u0111\u1ea5t c\u1ee7a Tr\u1ea1m quan s\u00e1t ho\u00e0ng gia (Royal Observatory) \u1edf ph\u00eda nam London, ph\u00e2n chia ph\u00eda \u0111\u00f4ng v\u00e0 ph\u00eda t\u00e2y. Tuy nhi\u00ean c\u00e1c b\u1ea3n \u0111\u1ed3 th\u1eddi trung c\u1ed5 v\u00ed d\u1ee5 nh\u01b0 b\u1ea3n \u0111\u1ed3 th\u1ebf gi\u1edbi Mappa Mundi \u1edf th\u1ebf k\u1ef7 13 th\u01b0\u1eddng \u0111\u1eb7t trung t\u00e2m \u1edf th\u00e0nh ph\u1ed1 Jerusalem, b\u1edfi v\u00ec theo quy\u1ec3n s\u00e1ch Book of Ezekiel n\u00f3i r\u1eb1ng ch\u00ednh Ch\u00faa \u201c\u0111\u00e3 \u0111\u1eb7t th\u00e0nh ph\u1ed1 \u1edf trung t\u00e2m qu\u1ed1c gia\u201d. Kinh tuy\u1ebfn g\u1ed1c Greenwich ch\u1ec9 tr\u1edf th\u00e0nh trung t\u00e2m ch\u00ednh th\u1ee9c c\u1ee7a th\u1ebf gi\u1edbi v\u00e0o g\u1ea7n \u0111\u00e2y, n\u0103m 1884, khi m\u1ed9t h\u1ed9i ngh\u1ecb qu\u1ed1c t\u1ebf nh\u1eadn th\u1ea5y c\u00e1c h\u1ea3i \u0111\u1ed3 c\u1ee7a H\u1ea3i qu\u00e2n ho\u00e0ng gia, v\u1edbi trung t\u00e2m \u1edf Greenwich, \u0111\u01b0\u1ee3c t\u00f4n tr\u1ecdng v\u00e0 s\u1eed d\u1ee5ng qu\u00e1 r\u1ed9ng r\u00e3i n\u00ean th\u1eadt c\u00f3 \u00fd ngh\u0129a khi \u0111i\u1ec1u ch\u1ec9nh c\u00e1c b\u1ea3n \u0111\u1ed3 kh\u00e1c cho ph\u00f9 h\u1ee3p v\u1edbi c\u00f9ng kinh tuy\u1ebfn g\u1ed1c \u0111\u00f3. T\u1ea1i sao nh\u1eefng ng\u01b0\u1eddi x\u00e2y \u0111\u01b0\u1eddng 117 h\u1ea7m \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ed9t \u0111\u1ed9 ch\u00ednh x\u00e1c cao nh\u01b0 th\u1ebf b\u00ean d\u01b0\u1edbi m\u1eb7t \u0111\u1ea5t? Ph\u01b0\u01a1ng ph\u00e1p ti\u00eau chu\u1ea9n l\u00e0 \u0111\u1ea7u ti\u00ean ph\u1ea3i t\u00ecm ra h\u01b0\u1edbng b\u1eb1ng c\u00e1c ph\u01b0\u01a1ng ph\u00e1p kh\u1ea3o s\u00e1t \u0111\u1ecba h\u00ecnh b\u00ecnh th\u01b0\u1eddng t\u1eeb tr\u00ean b\u1ec1 m\u1eb7t. Sau \u0111\u00f3 \u0111\u1eb7t c\u00e1c tr\u1ee5c th\u1eb3ng xu\u1ed1ng v\u00e0o 151 https:\/\/thuviensach.vn","trong ng\u1ecdn \u0111\u1ed3i t\u1edbi m\u1ed9t \u0111\u1ed9 s\u00e2u c\u1ea7n thi\u1ebft. Ch\u1ec9 sau \u0111\u00f3 vi\u1ec7c \u0111\u00e0o b\u1edbi m\u1edbi b\u1eaft \u0111\u1ea7u t\u1eeb c\u1ea3 hai \u0111\u1ea7u, \u0111i theo c\u00e1c tr\u1ee5c \u0111\u00f3 c\u00f9ng v\u1edbi c\u00e1c ch\u1ec9 d\u1eabn v\u1ec1 ph\u01b0\u01a1ng h\u01b0\u1edbng t\u1eeb tr\u00ean b\u1ec1 m\u1eb7t. C\u00e1ch n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n kh\u00e1 t\u1ed1t nh\u01b0ng kh\u00f4ng ph\u1ea3i l\u00e0 kh\u00f4ng th\u1ec3 sai l\u1ea7m. Nh\u1eefng ng\u01b0\u1eddi x\u00e2y d\u1ef1ng c\u1ee7a \u0111\u01b0\u1eddng h\u1ea7m d\u00e0i 400m Salt- ersford, \u1edf tr\u00ean k\u00eanh Trent v\u00e0 Mersey c\u1ea1nh Northwich, Chesire, \u0111\u00e3 kh\u00f4ng th\u1ef1c s\u1ef1 th\u00e0nh c\u00f4ng trong vi\u1ec7c l\u00e0m hai \u0111\u1ea7u \u0111\u01b0\u1eddng h\u1ea7m g\u1eb7p nhau \u1edf gi\u1eefa, k\u1ebft qu\u1ea3 l\u00e0 c\u00f3 m\u1ed9t ch\u1ed7 g\u1ea5p kh\u00fac l\u1edbn trong \u0111\u01b0\u1eddng h\u1ea7m. C\u00e1i g\u00ec g\u00e2y ra \u1ea3o \u1ea3nh nh\u01b0 118 g\u01b0\u01a1ng soi tr\u00ean c\u00e1c con \u0111\u01b0\u1eddng v\u00e0o m\u00f9a h\u00e8? V\u00e0o ban ng\u00e0y, b\u1ec1 m\u1eb7t \u0111\u01b0\u1eddng nh\u1eadn l\u1ea5y nhi\u1ec7t l\u01b0\u1ee3ng t\u1eeb \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi v\u00e0 th\u1ebf l\u00e0 n\u00f3 n\u00f3ng h\u01a1n nhi\u1ec1u so v\u1edbi kh\u00f4ng kh\u00ed b\u00ean tr\u00ean n\u00f3. K\u1ebft qu\u1ea3 t\u1ea1o ra m\u1ed9t l\u1edbp ph\u1ea3n chi\u1ebfu m\u00e0 \u1edf \u0111\u00f3 kh\u00f4ng kh\u00ed ti\u1ebfp x\u00fac v\u1edbi m\u1eb7t \u0111\u01b0\u1eddng nh\u1eb9 h\u01a1n kh\u00f4ng kh\u00ed b\u00ean tr\u00ean - ng\u01b0\u1ee3c v\u1edbi t\u00ecnh tr\u1ea1ng b\u00ecnh th\u01b0\u1eddng. T\u00ednh ch\u1ea5t quang h\u1ecdc c\u1ee7a kh\u00f4ng kh\u00ed c\u0169ng b\u1ecb t\u00e1c \u0111\u1ed9ng b\u1edfi s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9, l\u00e0m cho c\u00e1c tia s\u00e1ng t\u1eeb m\u1eb7t tr\u1eddi m\u00e0 b\u00ecnh th\u01b0\u1eddng s\u1ebd \u0111i th\u1eb3ng xu\u1ed1ng m\u1eb7t \u0111\u01b0\u1eddng l\u1ea1i cong nh\u00e0o xu\u1ed1ng r\u1ed3i b\u1ebb ng\u01b0\u1ee3c l\u00ean v\u00e0 \u0111i th\u1eb3ng v\u00e0o m\u1eaft 152 https:\/\/thuviensach.vn","ch\u00fang ta. Do \u0111\u00f3 l\u1edbp ph\u1ea3n chi\u1ebfu n\u00e0y cho ph\u00e9p ch\u00fang ta nh\u00ecn th\u1ea5y m\u1eb7t tr\u1eddi m\u00e0 kh\u00f4ng c\u1ea7n ph\u1ea3i nh\u00ecn l\u00ean, m\u1ed9t tr\u1ea1ng th\u00e1i k\u00ec d\u1ecb v\u00e0 \u0111\u01b0\u1ee3c b\u1ed9 n\u00e3o ch\u00fang ta di\u1ec5n gi\u1ea3i th\u00e0nh b\u1eb1ng nh\u1eefng l\u1eddi quen thu\u1ed9c h\u01a1n: gi\u1ed1ng nh\u01b0 s\u1ef1 ph\u1ea3n chi\u1ebfu c\u1ee7a b\u1ea7u tr\u1eddi \u1edf trong n\u01b0\u1edbc \u0111ang n\u1eb1m r\u00f5 r\u00e0ng tr\u00ean m\u1eb7t \u0111\u01b0\u1eddng. N\u1ebfu m\u1ed9t v\u1eadt b\u1ecb r\u01a1i kh\u1ecfi m\u1ed9t 119 chi\u1ebfc xe \u0111ang ch\u1ea1y, t\u1ea1i sao n\u00f3 kh\u00f4ng l\u0103n ra ra sau? D\u01b0\u1eddng nh\u01b0 m\u1ed9t tr\u00e1i t\u00e1o b\u1ecb r\u01a1i kh\u1ecfi m\u1ed9t chi\u1ebfc xe ch\u1eafc ch\u1eafn s\u1ebd v\u0103ng l\u00f9i l\u1ea1i. Nh\u01b0ng x\u00e9t cho c\u00f9ng, trong kho\u1ea3ng 0,5 gi\u00e2y m\u00e0 n\u00f3 r\u01a1i xu\u1ed1ng s\u00e0n, m\u1ed9t chi\u1ebfc xe \u0111ang ch\u1ea1y v\u1edbi v\u1eadn t\u1ed1c 100 km\/gi\u1edd c\u00f3 th\u1ec3 \u0111i \u0111\u01b0\u1ee3c t\u1edbi 14 m. L\u00fd do m\u00e0 tr\u00e1i t\u00e1o kh\u00f4ng di chuy\u1ec3n l\u00f9i l\u00e0 v\u00ec: kh\u00f4ng ch\u1ec9 c\u00f3 m\u1ed7i chi\u1ebfc xe \u0111ang di chuy\u1ec3n 100 km\/gi\u1edd m\u00e0 l\u00e0 t\u1ea5t c\u1ea3 m\u1ecdi th\u1ee9 \u0111ang li\u00ean k\u1ebft v\u1edbi chi\u1ebfc xe \u0111\u00f3, bao g\u1ed3m c\u1ea3 tr\u00e1i t\u00e1o c\u0169ng di chuy\u1ec3n 100 km\/gi\u1edd. Cho n\u00ean khi tr\u00e1i t\u00e1o r\u01a1i, n\u00f3 v\u1eabn \u0111ang \u0111i t\u1edbi \u1edf v\u1eadn t\u1ed1c 100 km\/gi\u1edd, \u0111\u1ea3m b\u1ea3o cho n\u00f3 kh\u00f4ng bay th\u1eb3ng ra ph\u00eda sau v\u00e0 gi\u1ebft ch\u1ebft c\u00e1c h\u00e0nh kh\u00e1ch kh\u00f4ng k\u1ecbp c\u00fai xu\u1ed1ng. M\u1ecdi vi\u1ec7c s\u1ebd tr\u1edf n\u00ean c\u00e0ng th\u00fa v\u1ecb h\u01a1n n\u1ebfu v\u1eadn t\u1ed1c c\u1ee7a chi\u1ebfc xe thay \u0111\u1ed5i khi tr\u00e1i t\u00e1o \u0111ang r\u01a1i: tr\u00e1i t\u00e1o s\u1ebd th\u1eadt s\u1ef1 \u0111i l\u00f9i l\u1ea1i, b\u1edfi v\u00ec m\u1ed9t khi n\u00f3 \u0111\u00e3 b\u1eaft \u0111\u1ea7u r\u01a1i, n\u00f3 ch\u1eb3ng c\u00f2n c\u00e1ch n\u00e0o \u0111\u1ec3 t\u0103ng v\u1eadn t\u1ed1c c\u1ee7a n\u00f3 cho b\u1eb1ng v\u1edbi chi\u1ebfc xe \u0111ang gia t\u1ed1c. N\u1ebfu b\u1ea1n kh\u00f4ng bi\u1ebft r\u1eb1ng chi\u1ebfc xe \u0111ang gia t\u1ed1c, b\u1ea1n c\u00f2n c\u00f3 th\u1ec3 b\u1ecb d\u1eabn d\u1eaft t\u1edbi \u00fd ngh\u0129 r\u1eb1ng c\u00f3 m\u1ed9t l\u1ef1c b\u00ed \u1ea9n \u0111\u00e3 t\u00f3m l\u1ea5y tr\u00e1i t\u00e1o v\u00e0 k\u00e9o l\u00f9i n\u00f3. 153 https:\/\/thuviensach.vn","120 C\u00f4ng ngh\u1ec7 \u201ct\u00e0ng h\u00ecnh\u201d ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o? K\u1ef9 thu\u1eadt s\u1eed d\u1ee5ng c\u00e1c v\u1eadt li\u1ec7u \u0111\u1eb7c bi\u1ec7t trong cu\u1ed9c chi\u1ebfn ch\u1ed1ng l\u1ea1i m\u00e1y d\u00f2 rada \u0111\u00e3 \u0111\u01b0\u1ee3c m\u1edf \u0111\u1ea7u b\u1edfi c\u00e1c nh\u00e0 thi\u1ebft k\u1ebf t\u00e0u ng\u1ea7m \u0110\u1ee9c trong Th\u1ebf chi\u1ebfn th\u1ee9 hai. Trong n\u0103m 1944, m\u1ed1i quan t\u00e2m \u0111\u1ebfn th\u1ea5t b\u1ea1i c\u1ee7a c\u00e1c t\u00e0u U (t\u00e0u ph\u1ea3i n\u1ed5i l\u00ean) \u0111\u00e3 d\u1eabn \u0111\u1ebfn vi\u1ec7c ph\u00e1t tri\u1ec3n \u1ed1ng th\u00f4ng h\u01a1i c\u1ee7a t\u00e0u ng\u1ea7m, cho ph\u00e9p c\u00e1c t\u00e0u ng\u1ea7m ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1c \u0111\u1ed9ng c\u01a1 diesel trong khi v\u1eabn \u0111ang ch\u00ecm. C\u00e1c s\u0129 quan ch\u1ec9 huy h\u1ea3i qu\u00e2n \u0110\u1ee9c tin r\u1eb1ng c\u00e1c phi c\u01a1 c\u1ee7a Phe \u0110\u1ed3ng Minh v\u1edbi rada c\u1ef1c nh\u1ea1y c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n ra \u1ed1ng th\u00f4ng h\u01a1i v\u00e0 do \u0111\u00f3 h\u1ecd ph\u00e1t tri\u1ec3n m\u1ed9t h\u1ee3p ch\u1ea5t cao su \u0111\u1eb7c bi\u1ec7t, \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 h\u1ea5p thu n\u0103ng l\u01b0\u1ee3ng c\u1ee7a rada v\u00e0 gi\u1ea3m t\u1ed1i thi\u1ec3u s\u1ef1 ph\u1ea3n x\u1ea1. H\u1ecd \u0111\u00e3 kh\u00f4ng th\u00e0nh c\u00f4ng v\u00ec l\u1edbp v\u1ecf b\u1ecdc nhanh ch\u00f3ng b\u1ecb n\u01b0\u1edbc bi\u1ec3n cu\u1ed1n \u0111i. C\u00f4ng ngh\u1ec7 t\u00e0ng h\u00ecnh hi\u1ec7n \u0111\u1ea1i \u0111\u01b0\u1ee3c m\u1edf \u0111\u1ea7u b\u1edfi Kh\u00f4ng l\u1ef1c Hoa K\u1ef3, v\u00e0o n\u0103m 1989, khi h\u1ecd s\u1eed d\u1ee5ng phi c\u01a1 t\u00e0ng h\u00ecnh F-117A Nighthawk trong tr\u1eadn chi\u1ebfn x\u00e2m l\u01b0\u1ee3c Pan- ama. V\u1edbi c\u00e1c phi c\u01a1 b\u00ecnh th\u01b0\u1eddng, khi b\u1ecb va ph\u1ea3i c\u00e1c tia rada ch\u00fang s\u1ebd l\u00e0m d\u1ed9i l\u1ea1i h\u1ea7u h\u1ebft n\u0103ng l\u01b0\u1ee3ng s\u00f3ng radio, l\u00e0m cho ch\u00fang d\u1ec5 b\u1ecb ph\u00e1t hi\u1ec7n b\u1edfi c\u00e1c l\u1ef1c l\u01b0\u1ee3ng ph\u00f2ng kh\u00f4ng. Phi c\u01a1 F-117A gi\u1ea3m kh\u1ea3 n\u0103ng b\u1ecb ph\u00e1t hi\u1ec7n b\u1eb1ng hai c\u00e1ch. 154 https:\/\/thuviensach.vn","Th\u1ee9 nh\u1ea5t, n\u00f3 \u0111\u01b0\u1ee3c bao b\u1ecdc b\u1edfi m\u1ed9t l\u1edbp h\u1ea1t s\u1eaft hay carbon, h\u1ea5p th\u1ee5 h\u1ea7u h\u1ebft n\u0103ng l\u01b0\u1ee3ng rada v\u00e0 chuy\u1ec3n ch\u00fang th\u00e0nh nhi\u1ec7t. Ngay c\u1ea3 v\u00f2m k\u00ednh che bu\u1ed3ng l\u00e1i c\u0169ng \u0111\u01b0\u1ee3c bao b\u1ecdc b\u1edfi m\u1ed9t ch\u1ea5t trong su\u1ed1t v\u00e0 h\u1ea5p th\u1ee5 tia rada l\u00e0 idium-thi\u1ebfc oxide, \u0111\u1ec3 ng\u0103n m\u0169 b\u1ea3o hi\u1ec3m c\u1ee7a phi c\u00f4ng t\u1ea1o ra n\u0103ng l\u01b0\u1ee3ng ph\u1ea3n x\u1ea1. Th\u1ee9 hai, ph\u1ea7n n\u0103ng l\u01b0\u1ee3ng rada b\u1ecb ph\u1ea3n x\u1ea1 l\u1ea1i \u0111\u01b0\u1ee3c gi\u1ea3m t\u1ed1i \u0111a b\u1edfi h\u00ecnh d\u1ea1ng g\u00f3c c\u1ea1nh c\u1ee7a th\u00e2n m\u00e1y bay F-117A. H\u00ecnh d\u1ea1ng n\u00e0y gi\u00fap tr\u00e1nh \u0111\u01b0\u1ee3c c\u00e1c tia th\u1eb3ng g\u00f3c t\u1ea1o ra s\u1ef1 ph\u1ea3n x\u1ea1 m\u1ea1nh. K\u1ebft qu\u1ea3 l\u00e0 h\u00ecnh \u1ea3nh rada ch\u1ec9 m\u00f4 t\u1ea3 m\u1ed9t v\u1eadt th\u1ec3 c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ee7a m\u1ed9t con chim nh\u1ecf. T\u1ea1i sao c\u00e1c b\u1ecdt kh\u00ed do t\u00e0u 121 thuy\u1ec1n t\u1ea1o ra lu\u00f4n lu\u00f4n c\u00f3 m\u00e0u tr\u1eafng b\u1ea5t k\u1ec3 m\u00e0u c\u1ee7a n\u01b0\u1edbc bi\u1ec3n l\u00e0 g\u00ec? D\u00f2ng n\u01b0\u1edbc xo\u00e1y t\u1ea1o ra b\u1edfi h\u1ec7 th\u1ed1ng \u0111\u1ea9y c\u1ee7a con t\u00e0u v\u00e0 s\u1ef1 di chuy\u1ec3n c\u1ee7a con t\u00e0u trong n\u01b0\u1edbc bi\u1ec3n t\u1ea1o ra v\u00f4 s\u1ed1 b\u1ecdt kh\u00ed. C\u00e1c b\u1ecdt kh\u00ed n\u00e0y ch\u1ee9a c\u00e1c t\u00fai kh\u00f4ng kh\u00ed nh\u1ecf bao b\u1ecdc b\u1edfi m\u1ed9t l\u1edbp ph\u00e2n t\u1eed n\u01b0\u1edbc h\u00ecnh c\u1ea7u, l\u00e0m ph\u00e1t t\u00e1n c\u00e1c tia s\u00e1ng chi\u1ebfu v\u00e0o ch\u00fang. V\u00e0 v\u00ec \u00e1nh s\u00e1ng chi\u1ebfu v\u00e0o ch\u00fang l\u00e0 \u00e1nh s\u00e1ng tr\u1eafng, k\u1ebft qu\u1ea3 s\u1ebd l\u00e0 m\u1ed9t kh\u1ed1i m\u00e0u tr\u1eafng cu\u1ed3n cu\u1ed9n, c\u00f3 th\u1ec3 tr\u00f4ng th\u1ea5y t\u1eeb m\u1ecdi h\u01b0\u1edbng. 155 https:\/\/thuviensach.vn","122 T\u1ea1i sao c\u00e1c b\u00e1nh xe quay l\u00f9i trong c\u00e1c cu\u1ed1n phim? \u0110\u00f3 ch\u00ednh l\u00e0 m\u1ed9t d\u1ea5u hi\u1ec7u c\u1ee7a hi\u1ec7n t\u01b0\u1ee3ng c\u00e1c cu\u1ed1n phim \u0111\u01b0\u1ee3c thu h\u00ecnh \u1edf v\u1eadn t\u1ed1c 24 h\u00ecnh\/gi\u00e2y. N\u1ebfu c\u00e1c b\u00e1nh xe c\u0169ng quay \u1edf v\u1eadn t\u1ed1c 24 c\u00e2y c\u0103m\/gi\u00e2y, v\u1ecb tr\u00ed c\u1ee7a m\u1ed9t c\u00e2y c\u0103m trong h\u00ecnh n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c chi\u1ebfm l\u1ea5y b\u1edfi m\u1ed9t c\u00e2y c\u0103m kh\u00e1c trong h\u00ecnh k\u1ebf ti\u1ebfp, cho ta m\u1ed9t h\u00ecnh \u1ea3nh kh\u00f4ng c\u00f3 g\u00ec thay \u0111\u1ed5i v\u00e0 c\u00e1c b\u00e1nh xe d\u01b0\u1eddng nh\u01b0 kh\u00f4ng chuy\u1ec3n \u0111\u1ed9ng. Nh\u01b0ng n\u1ebfu b\u00e1nh xe chuy\u1ec3n \u0111\u1ed9ng \u1edf v\u1eadn t\u1ed1c ch\u1eadm h\u01a1n 24 c\u00e2y c\u0103m\/gi\u00e2y m\u1ed9t ch\u00fat, m\u1ed7i c\u00e2y c\u0103m s\u1ebd kh\u00f4ng c\u00f3 \u0111\u1ee7 th\u1eddi gian \u0111\u1ec3 \u0111i t\u1edbi v\u1ecb tr\u00ed v\u00e0o l\u00fac m\u00e0 h\u00ecnh k\u1ebf ti\u1ebfp \u0111\u01b0\u1ee3c quay v\u00e0 v\u00ec th\u1ebf ch\u1ec9 t\u1edbi \u0111\u01b0\u1ee3c ph\u00eda sau c\u00e2y c\u0103m trong \u1ea3nh tr\u01b0\u1edbc. K\u1ebft qu\u1ea3 l\u00e0 c\u00e1c b\u00e1nh xe tr\u00f4ng nh\u01b0 \u0111ang xoay l\u00f9i. 123 T\u1ea1i sao kh\u00ed helium l\u00e0m cho gi\u1ecdng n\u00f3i tr\u1edf n\u00ean gi\u1ed1ng nh\u01b0 ti\u1ebfng k\u00eau ch\u00edt ch\u00edt? H\u00edt kh\u00ed helium v\u00e0o cho ph\u00e9p b\u1ea5t c\u1ee9 ai c\u0169ng g\u00e2y \u0111\u01b0\u1ee3c \u1ea5n t\u01b0\u1ee3ng m\u1ea1nh nh\u01b0 v\u1ecbt Donald trong m\u1ed9t v\u00e0i gi\u00e2y. Helium c\u00f3 t\u1ec9 tr\u1ecdng nh\u1eb9 h\u01a1n kh\u00f4ng kh\u00ed kho\u1ea3ng b\u1ea3y l\u1ea7n v\u00e0 v\u00ec l\u00e0 kh\u00ed tr\u01a1, n\u00f3 \u0111\u01b0\u1ee3c c\u1ea5u t\u1ea1o t\u1eeb c\u00e1c nguy\u00ean t\u1eed \u0111\u1ed9c l\u1eadp ch\u1ee9 kh\u00f4ng ph\u1ea3i ph\u00e2n t\u1eed. \u0110i\u1ec1u n\u00e0y l\u00e0m cho \u00e2m thanh di chuy\u1ec3n qua 156 https:\/\/thuviensach.vn","helium nhanh h\u01a1n qua kh\u00f4ng kh\u00ed g\u1ea5p ba l\u1ea7n, l\u00e0m t\u0103ng t\u1ea7n s\u1ed1 c\u1ed9ng h\u01b0\u1edfng m\u00e0 c\u1ed5 h\u1ecdng c\u1ee7a ch\u00fang ta c\u00f3 th\u1ec3 t\u1ea1o ra khi n\u00f3i, k\u1ebft qu\u1ea3 l\u00e0 m\u1ed9t ti\u1ebfng n\u00f3i ch\u00edt ch\u00edt. Tuy nhi\u00ean, c\u00f3 m\u1ed9t l\u1eddi c\u1ea3nh b\u00e1o: helium kh\u00f4ng ph\u1ea3i kh\u00f4ng kh\u00ed v\u00e0 m\u1eb7c d\u00f9 n\u00f3 r\u1ea5t nh\u1eb9, n\u00f3 v\u1eabn c\u00f3 th\u1ec3 g\u00e2y ra cho\u00e1ng v\u00e1ng v\u00e0 ng\u1ea1t th\u1edf n\u1ebfu b\u1ecb ng\u0103n c\u1ea3n tho\u00e1t ra kh\u1ecfi ph\u1ed5i. T\u1ea1i sao r\u00e3nh xo\u1eafn trong 124 n\u00f2ng s\u00fang cho ph\u00e9p vi\u00ean \u0111\u1ea1n \u0111i xa h\u01a1n? \u0110\u01b0\u1ee3c ph\u00e1t minh v\u00e0o \u0111\u1ea7u th\u1ebf k\u1ef7 16 b\u1edfi c\u00e1c th\u1ee3 l\u00e0m s\u00fang Ch\u00e2u \u00c2u, c\u00e1c r\u00e3nh xo\u1eafn b\u00ean trong n\u00f2ng s\u00fang l\u00e0m cho vi\u00ean \u0111\u1ea1n t\u1ef1 xoay quanh khi n\u00f3 b\u1ecb b\u1eafn ra d\u01b0\u1edbi l\u1ef1c n\u1ed5, \u0111\u1ea1t \u0111\u01b0\u1ee3c v\u1eadn t\u1ed1c quay h\u01a1n 150.000 v\u00f2ng\/ph\u00fat. Gi\u1ed1ng y nh\u01b0 c\u00e1ch m\u00e0 con quay ch\u1ed1ng l\u1ea1i s\u1ef1 nghi\u00eang c\u1ee7a tr\u1ee5c xoay, vi\u00ean \u0111\u1ea1n t\u1ef1 xoay c\u00f2n \u1ed5n \u0111\u1ecbnh h\u01a1n nhi\u1ec1u trong khi bay v\u00e0 \u00edt c\u00f3 khuynh h\u01b0\u1edbng r\u01a1i xu\u1ed1ng. K\u1ebft qu\u1ea3 l\u00e0 \u0111\u1ed9 ch\u00ednh x\u00e1c t\u0103ng l\u00ean, s\u1ee9c c\u1ea3n kh\u00f4ng kh\u00ed gi\u1ea3m xu\u1ed1ng v\u00e0 t\u1ea7m b\u1eafn t\u0103ng l\u00ean. Hi\u1ec7u \u1ee9ng t\u01b0\u01a1ng t\u1ef1 c\u0169ng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ph\u00e1o hoa th\u0103ng thi\u00ean, v\u1edbi b\u1ed9 th\u0103ng b\u1eb1ng b\u1eb1ng nh\u1ef1a xo\u1eafn nh\u1eb9 l\u1ea1i, t\u1ea1o ra s\u1ef1 xoay khi ch\u00fang bay l\u00ean. C\u00e1c ti\u1ec1n v\u1ec7 trong m\u00f4n b\u00f3ng b\u1ea7u d\u1ee5c c\u0169ng khai th\u00e1c hi\u1ec7u \u1ee9ng \u201c\u1ed5n \u0111\u1ecbnh nh\u1edd xoay\u201d b\u1eb1ng c\u00e1ch th\u1eadn 157 https:\/\/thuviensach.vn","tr\u1ecdng xoay qu\u1ea3 b\u00f3ng khi n\u00f3 r\u1eddi tay h\u1ecd, bay th\u1eb3ng t\u1edbi m\u1ee5c ti\u00ean v\u00e0 th\u01b0\u1eddng xuy\u00ean c\u00f3 m\u1ed9t \u0111\u1ed9 ch\u00ednh x\u00e1c t\u1edbi kinh ng\u1ea1c. 125 Ng\u01b0\u1eddi m\u00f9 c\u00f3 n\u1eb1m m\u01a1 kh\u00f4ng? C\u00f3 - tuy nhi\u00ean b\u1ea3n ch\u1ea5t ch\u00ednh x\u00e1c c\u1ee7a n\u00f3 th\u00ec c\u00f2n ph\u1ee5 thu\u1ed9c v\u00e0o h\u1ecd b\u1ecb m\u00f9 t\u1eeb khi n\u00e0o. Nh\u1eefng ng\u01b0\u1eddi b\u1ecb m\u00f9 t\u1eeb nh\u1ecf tr\u1ea3i qua c\u00e1c gi\u1ea5c m\u01a1 ch\u1ee7 y\u1ebfu xoay quanh c\u1ea3m gi\u00e1c c\u01a1 th\u1ec3, trong khi nh\u1eefng ng\u01b0\u1eddi b\u1ecb m\u00f9 sau n\u00e0y trong cu\u1ed9c s\u1ed1ng th\u00ec s\u1eed d\u1ee5ng kho h\u00ecnh \u1ea3nh \u0111\u00e3 \u0111\u01b0\u1ee3c t\u1ea1o ra trong th\u1eddi gian h\u1ecd c\u00f2n s\u00e1ng m\u1eaft l\u00e0m n\u1ec1n t\u1ea3ng cho nh\u1eefng gi\u1ea5c m\u01a1 m\u00e0 th\u01b0\u1eddng r\u1ea5t sinh \u0111\u1ed9ng. Theo gi\u00e1o s\u01b0 J. Allan Hobson c\u1ee7a tr\u01b0\u1eddng y khoa Harvard, t\u00e1c gi\u1ea3 c\u1ee7a quy\u1ec3n s\u00e1ch N\u1eb1m m\u01a1: gi\u1edbi thi\u1ec7u v\u1ec1 khoa h\u1ecdc c\u1ee7a gi\u1ea5c ng\u1ee7 (Dreaming: a introduction to the science of sleep, Oxford University Express, 2003), m\u1ed9t s\u1ed1 ng\u01b0\u1eddi c\u00f2n c\u00f3 th\u1ec3 t\u00f9y \u00fd s\u1eed d\u1ee5ng gi\u1ea5c m\u01a1 \u0111\u1ec3 l\u00e0m s\u1ed1ng l\u1ea1i c\u00e1c k\u1ef7 ni\u1ec7m \u0111\u1eb7c bi\u1ec7t ch\u1eb3ng h\u1ea1n nh\u01b0 s\u1ef1 h\u1ed9i t\u1ee5 gia \u0111\u00ecnh. 126 Con ng\u01b0\u1eddi \u0111\u00e3 x\u00e1c \u0111\u1ecbnh n\u0103m nh\u01b0 th\u1ebf n\u00e0o tr\u01b0\u1edbc khi ph\u00e1t minh ra BC v\u00e0 AD? Thu\u1eadt ng\u1eef BC (tr\u01b0\u1edbc c\u00f4ng nguy\u00ean TCN) v\u00e0 AD (sau c\u00f4ng nguy\u00ean SCN) trong v\u0103n b\u1ea3n hi\u1ec7n \u0111\u1ea1i th\u01b0\u1eddng \u0111\u01b0\u1ee3c 158 https:\/\/thuviensach.vn","ghi l\u00e0 BCE (before the common era) v\u00e0 CE (common era), b\u1eaft ngu\u1ed3n t\u1eeb c\u00f4ng tr\u00ecnh c\u1ee7a Dionysius Exiguus (Denis the Lesser), m\u1ed9t tu s\u0129 l\u00e0m vi\u1ec7c t\u1ea1i La M\u00e3 c\u00e1ch \u0111\u00e2y h\u01a1n 1400 n\u0103m. N\u0103m 532 SCN, Dionysius \u0111\u00e3 \u0111\u1ec1 ngh\u1ecb m\u1ed9t lo\u1ea1i l\u1ecbch C\u01a1 \u0111\u1ed1c gi\u00e1o v\u1edbi ng\u00e0y b\u1eaft \u0111\u1ea7u \u0111\u01b0\u1ee3c \u0111\u1eb7t v\u00e0o m\u1ed9t s\u1ef1 ki\u1ec7n t\u00f4n gi\u00e1o c\u1ef1c k\u1ef3 quan tr\u1ecdng. T\u1ea5t c\u1ea3 \u0111\u1ec1u r\u1ea5t d\u1ec5 hi\u1ec3u nh\u01b0ng sau \u0111\u00f3 ng\u01b0\u1eddi ta l\u1ea1i g\u1eb7p ph\u1ea3i nh\u1eefng v\u1ea5n \u0111\u1ec1 c\u1ef1c k\u1ef3 r\u1eafc r\u1ed1i v\u1ec1 l\u1ecbch. Nh\u1eefng v\u1ea5n \u0111\u1ec1 \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y b\u00ean d\u01b0\u1edbi l\u00e0 d\u1ef1a tr\u00ean nghi\u00ean c\u1ee9u c\u1ee7a ti\u1ebfn s\u0129 Duncan Steel trong cu\u1ed1n Making Time (Wiley, 2000). \u0110\u1ea7u ti\u00ean, Dionysius \u0111\u00e3 kh\u00f4ng l\u00e0m m\u1ed9t vi\u1ec7c hi\u1ec3n nhi\u00ean l\u00e0 b\u1eaft \u0111\u1ea7u lo\u1ea1i l\u1ecbch m\u1edbi t\u1eeb ng\u00e0y sinh c\u1ee7a ch\u00faa Jesus m\u00e0 l\u1ea1i b\u1eaft \u0111\u1ea7u b\u1eb1ng Ng\u00e0y hi\u1ec7n th\u00e2n c\u1ee7a Ch\u00faa - t\u1ee9c l\u00e0, th\u1eddi \u0111i\u1ec3m b\u1eaft \u0111\u1ea7u c\u00f3 nh\u1eadn th\u1ee9c v\u1ec1 Ch\u00faa c\u1ee9u th\u1ebf - v\u00e0 s\u1eed d\u1ee5ng ng\u00e0y \u0111\u00f3 l\u00e0m n\u0103m th\u1ee9 nh\u1ea5t C\u00f4ng Nguy\u00ean. C\u00e1c nh\u00e0 s\u1eed h\u1ecdc hi\u1ec7n nay tin r\u1eb1ng s\u1ef1 l\u1ef1a ch\u1ecdn n\u00e0y l\u00e0 sai, do nh\u1eadn th\u1ee9c v\u1ec1 Ch\u00faa c\u1ee9u th\u1ebf \u0111\u00e3 x\u1ea3y ra t\u1eeb nhi\u1ec1u n\u0103m tr\u01b0\u1edbc. D\u00f9 g\u00ec \u0111i n\u1eefa, Dionysius v\u1eabn ti\u1ebfp t\u1ee5c h\u01b0\u1edbng \u0111i c\u1ee7a m\u00ecnh, g\u1ecdi t\u1ea5t c\u1ea3 c\u00e1c n\u0103m sau \u0111\u00f3 l\u00e0 anno ab Incarnatione, c\u00f3 ngh\u0129a l\u00e0 n\u0103m c\u1ee7a s\u1ef1 hi\u1ec7n th\u00e2n. Thu\u1eadt ng\u1eef Anno Domini (N\u0103m c\u1ee7a Ch\u00faa, the year of Lord) v\u1eabn c\u00f2n ch\u01b0a xu\u1ea5t hi\u1ec7n cho t\u1edbi 200 n\u0103m sau (d\u01b0\u1eddng nh\u01b0 n\u00f3 \u0111\u01b0\u1ee3c \u0111\u1eb7t ra l\u1ea7n \u0111\u1ea7u ti\u00ean b\u1edfi Venerable Bede) trong khi thu\u1eadt ng\u1eef BC th\u00ec \u0111\u01b0\u1ee3c \u0111\u1eb7t ra g\u1ea7n \u0111\u00e2y h\u01a1n, \u0111\u00e2u \u0111\u00f3 trong th\u1ebf k\u1ef7 17. B\u1ea5t ch\u1ea5p nh\u1eefng n\u1ed7 l\u1ef1c c\u1ee7a m\u00ecnh, Dionysius \u0111\u00e3 kh\u00f4ng s\u1ed1ng \u0111\u01b0\u1ee3c \u0111\u1ec3 th\u1ea5y h\u1ec7 th\u1ed1ng \u0111\u00f3 \u0111\u01b0\u1ee3c ch\u1ea5p nh\u1eadn r\u1ed9ng r\u00e3i, v\u00e0 trong nhi\u1ec1u n\u0103m sau khi \u00f4ng ch\u1ebft, ng\u00e0y th\u00e1ng 159 https:\/\/thuviensach.vn","v\u1eabn \u0111\u01b0\u1ee3c t\u00ednh theo h\u1ec7 La M\u00e3, v\u1edbi ng\u00e0y b\u1eaft \u0111\u1ea7u \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh v\u00e0o ng\u00e0y th\u00e0nh l\u1eadp th\u00e0nh La M\u00e3. Theo h\u1ecdc gi\u1ea3 La M\u00e3 Marcus Terentius, s\u1ef1 ki\u1ec7n n\u00e0y x\u1ea3y ra v\u00e0o n\u0103m 753 TCN cho n\u00ean nh\u1eefng n\u0103m sau \u0111\u00f3 \u0111\u01b0\u1ee3c m\u1edf \u0111\u1ea7u b\u1eb1ng thu\u1eadt ng\u1eef anno urbis conditae (AUC - n\u0103m th\u00e0nh l\u1eadp c\u1ee7a th\u00e0nh ph\u1ed1, \u201cin the year of the foundation of the city\u201d). 127 T\u1ea1i sao con ng\u01b0\u1eddi ng\u1ee7 qu\u00e1 g\u1ea7n c\u1ea1nh gi\u01b0\u1eddng m\u00e0 l\u1ea1i kh\u00f4ng r\u1edbt xu\u1ed1ng? T\u1ea5t c\u1ea3 c\u00e1c b\u1eadc cha m\u1eb9 \u0111\u1ec1u bi\u1ebft s\u1ef1 nguy hi\u1ec3m c\u1ee7a vi\u1ec7c \u0111\u1ee9a con nh\u1ecf b\u1ecb r\u01a1i ra kh\u1ecfi gi\u01b0\u1eddng v\u00e0 th\u1ef1c v\u1eady, kh\u1ea3 n\u0103ng n\u1eb1m trong gi\u01b0\u1eddng d\u01b0\u1eddng nh\u01b0 \u0111\u1ea1t \u0111\u01b0\u1ee3c d\u1ea7n d\u1ea7n theo th\u1eddi gian. C\u00e1c c\u1ea3nh phim chi\u1ebfu nh\u1eefng \u0111\u1ee9a b\u00e9 \u1edf tu\u1ed5i t\u1eadp \u0111i \u0111ang n\u1eb1m ng\u1ee7 cho th\u1ea5y r\u1eb1ng ch\u00fang v\u1eabn ng\u1ee7 tho\u1ea3i m\u00e1i theo b\u1ea5t c\u1ee9 h\u01b0\u1edbng n\u00e0o, ngay c\u1ea3 c\u00fai m\u1eb7t xu\u1ed1ng, cho n\u00ean ch\u00fang c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng xoay tr\u00f2n m\u1ed9t v\u00f2ng sau m\u1ed9t gi\u1ea5c ng\u1ee7 \u0111\u00eam v\u00e0 k\u1ebft th\u00fac \u1edf tr\u00ean s\u00e0n nh\u00e0. M\u1eb7c kh\u00e1c, \u1edf nh\u1eefng \u0111\u1ee9a tr\u1ebb l\u1edbn h\u01a1n v\u00e0 \u1edf ng\u01b0\u1eddi l\u1edbn, h\u1ecd d\u01b0\u1eddng nh\u01b0 \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c c\u00e1ch tr\u00e1nh c\u1ea3 t\u01b0 th\u1ebf c\u00fai m\u1eb7t xu\u1ed1ng v\u00e0 gi\u1eef m\u1ed9t c\u1ea3m gi\u00e1c v\u1ec1 v\u1ecb tr\u00ed c\u1ee7a h\u1ecd tr\u00ean gi\u01b0\u1eddng, gi\u00fap cho h\u1ecd v\u1eabn n\u1eb1m tr\u00ean gi\u01b0\u1eddng (c\u00f3 th\u1ec3 l\u00e0 su\u1ed1t ng\u00e0y n\u1ebfu h\u1ecd l\u00e0 d\u00e2n ng\u1ee7 ng\u00e0y l\u01b0\u1eddi bi\u1ebfng). 160 https:\/\/thuviensach.vn","C\u00f3 ph\u1ea3i c\u00e1c c\u1eb7p sinh \u0111\u00f4i 128 b\u1ecb d\u00ednh li\u1ec1n \u0111\u1ec1u nh\u1ea5t thi\u1ebft c\u00f3 c\u00f9ng gi\u1edbi t\u00ednh? Tr\u01b0\u1edbc \u0111\u00e2y \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 sinh \u0111\u00f4i Siam (sau khi c\u00f3 m\u1ed9t \u0111\u00f4i song sinh n\u1ed5i ti\u1ebfng Chang v\u00e0 Eng, sinh t\u1ea1i Siam, Th\u00e1i Lan, n\u0103m 1811), song sinh d\u00ednh li\u1ec1n l\u00e0 c\u1eb7p song sinh gi\u1ed1ng h\u1ec7t nhau \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh t\u1eeb duy nh\u1ea5t m\u1ed9t qu\u1ea3 tr\u1ee9ng \u0111\u00e3 th\u1ee5 tinh v\u00e0 \u0111\u00e3 tr\u1ea3i qua s\u1ef1 ph\u00e2n t\u00e1ch kh\u00f4ng ho\u00e0n to\u00e0n. Do \u0111\u00f3 ch\u00fang c\u00f3 DNA gi\u1ed1ng h\u1ec7t nhau v\u00e0 lu\u00f4n lu\u00f4n c\u00f3 c\u00f9ng gi\u1edbi t\u00ednh. V\u00ec nh\u1eefng l\u00fd do ch\u01b0a r\u00f5, sinh \u0111\u00f4i d\u00ednh li\u1ec1n th\u01b0\u1eddng g\u1eb7p \u1edf b\u00e9 g\u00e1i g\u1ea5p \u0111\u00f4i so v\u1edbi b\u00e9 trai. B\u1eb1ng c\u00e1ch n\u00e0o 129 thuy\u1ec1n bu\u1ed3m th\u1ec3 thao c\u00f3 th\u1ec3 \u0111i nhanh h\u01a1n gi\u00f3? C\u00f3 m\u1ed9t \u0111i\u1ec1u k\u00ec l\u1ea1 kh\u00f4ng th\u1ec3 ch\u1ed1i c\u00e3i r\u1eb1ng m\u1ed9t chi\u1ebfc thuy\u1ec1n bu\u1ed3m c\u00f3 th\u1ec3 \u0111i 25 h\u1ea3i l\u00ed trong m\u1ed9t c\u01a1n gi\u00f3 ch\u1ec9 c\u00f3 15 h\u1ea3i l\u00ed. R\u00f5 r\u00e0ng, m\u1ed9t chi\u1ebfc thuy\u1ec1n bu\u1ed3m v\u1edbi ng\u1ecdn gi\u00f3 \u1edf ngay sau l\u01b0ng v\u00e0 kh\u00f4ng c\u00f3 d\u00f2ng n\u01b0\u1edbc \u0111\u1ea9y t\u1edbi th\u00ec kh\u00f4ng th\u1ec3 di chuy\u1ec3n nhanh h\u01a1n gi\u00f3, n\u1ebfu n\u00f3 x\u1ea3y ra, c\u00e1nh bu\u1ed3m c\u1ee7a n\u00f3 s\u1ebd \u0111i nhanh h\u01a1n ch\u00ednh th\u1ee9 \u0111\u01b0\u1ee3c cho l\u00e0 \u0111ang \u0111\u1ea9y n\u00f3 t\u1edbi. 161 https:\/\/thuviensach.vn","B\u00ed m\u1eadt c\u1ee7a vi\u1ec7c \u0111i nhanh h\u01a1n gi\u00f3 l\u00e0 nh\u1edd \u0111i\u1ec1u ch\u1ec9nh h\u01b0\u1edbng c\u1ee7a thuy\u1ec1n sao cho bu\u1ed3m c\u1ee7a n\u00f3 lu\u00f4n \u0111\u01b0\u1ee3c \u0111\u1eb7t nghi\u00eang so v\u1edbi ng\u1ecdn gi\u00f3 \u0111ang th\u1ed5i t\u1edbi. B\u1eb1ng c\u00e1ch \u0111i \u201cs\u00e1t v\u1edbi gi\u00f3\u201d, c\u00e1nh bu\u1ed3m s\u1ebd l\u00e0m l\u1ec7ch h\u01b0\u1edbng gi\u00f3 khi gi\u00f3 th\u1ed5i qua. Theo \u0111\u1ecbnh lu\u1eadt Newton, s\u1ef1 thay \u0111\u1ed5i h\u01b0\u1edbng c\u1ee7a kh\u1ed1i kh\u00f4ng kh\u00ed \u0111ang chuy\u1ec3n \u0111\u1ed9ng s\u1ebd sinh ra m\u1ed9t l\u1ef1c l\u00ean c\u00e1nh bu\u1ed3m, t\u1ea1o ra gia t\u1ed1c cho n\u00f3. \u0110i\u1ec1u n\u00e0y s\u1ebd ti\u1ebfp t\u1ee5c di\u1ec5n ra cho t\u1edbi khi l\u1ef1c \u0111\u1ea9y t\u1edbi c\u1ee7a c\u00e1nh bu\u1ed3m b\u1eb1ng v\u1edbi l\u1ef1c k\u00e9o l\u00f9i n\u00f3 (m\u00e0 ch\u1ee7 y\u1ebfu l\u00e0 do n\u01b0\u1edbc bi\u1ec3n b\u00ean d\u01b0\u1edbi), t\u1ea1i \u0111i\u1ec3m \u0111\u00f3 n\u00f3 s\u1ebd \u1ed5n \u0111\u1ecbnh l\u1ea1i v\u1edbi \u201ct\u1ed1c \u0111\u1ed9 gi\u1edbi h\u1ea1n\u201d. T\u1ed1c \u0111\u1ed9 n\u00e0y \u1edf c\u00e1c thuy\u1ec1n \u0111\u00f4i (catamaran) k\u1ef9 thu\u1eadt cao c\u00f3 th\u1ec3 g\u1ea5p \u0111\u00f4i t\u1ed1c \u0111\u1ed9 gi\u00f3. T\u1ed1c \u0111\u1ed9 cao h\u01a1n v\u1eabn c\u00f2n c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c n\u1ebfu l\u1ef1c k\u00e9o l\u00f9i b\u1ecb gi\u1ea3m \u0111i, v\u00ed d\u1ee5 b\u1eb1ng c\u00e1ch t\u00e1ch thuy\u1ec1n bu\u1ed3m ra kh\u1ecfi m\u1eb7t n\u01b0\u1edbc v\u00e0 \u0111\u1eb7t n\u00f3 l\u00ean m\u1ed9t t\u1ea5m v\u00e1n tr\u01b0\u1ee3t tuy\u1ebft. Ng\u01b0\u1eddi ta n\u00f3i r\u1eb1ng thuy\u1ec1n bu\u1ed3m tr\u01b0\u1ee3t b\u0103ng n\u00e0y l\u01b0\u1edbt tr\u00ean c\u00e1c m\u1eb7t h\u1ed3 \u0111\u00f3ng b\u0103ng v\u1edbi l\u1ef1c c\u1ea3n t\u1ed1i thi\u1ec3u \u0111\u00e3 di chuy\u1ec3n nhanh g\u1ea5p t\u00e1m l\u1ea7n gi\u00f3. 130 T\u1ea1i sao con ng\u01b0\u1eddi n\u00f3i nhi\u1ec1u th\u1ebf? \u0110i\u1ec1u n\u00e0y c\u00f3 \u0111em l\u1ea1i l\u1ee3i th\u1ebf ti\u1ebfn h\u00f3a n\u00e0o kh\u00f4ng? S\u1ef1 ph\u1ed5 bi\u1ebfn \u0111\u00e1ng s\u1ee3 c\u1ee7a t\u1eadt ng\u1ed3i l\u00ea \u0111\u00f4i m\u00e1ch \u0111\u00e3 k\u00edch th\u00edch m\u1ed9t s\u1ed1 h\u1ecdc gi\u1ea3 t\u1ef1 h\u1ecfi r\u1eb1ng li\u1ec7u kh\u1ea3 n\u0103ng n\u00f3i c\u00f3 v\u01b0\u1ee3t tr\u1ed9i h\u01a1n c\u1ea3 kh\u1ea3 n\u0103ng nghe c\u1ee7a l\u1ed7 tai kh\u00f4ng. Gi\u00e1o 162 https:\/\/thuviensach.vn","s\u01b0 Robin Dunbar, m\u1ed9t nh\u00e0 t\u00e2m l\u00fd h\u1ecdc ti\u1ebfn h\u00f3a \u1edf \u0111\u1ea1i h\u1ecdc Liverpool, l\u00fd lu\u1eadn r\u1eb1ng c\u00f4ng d\u1ee5ng c\u1ee7a vi\u1ec7c \u201cb\u00e0 t\u00e1m\u201d c\u1ee7a con ng\u01b0\u1eddi c\u0169ng gi\u1ed1ng c\u00f4ng d\u1ee5ng c\u1ee7a vi\u1ec7c b\u1eaft ch\u00e1y r\u1eadn c\u1ee7a linh tr\u01b0\u1edfng - t\u1ee9c l\u00e0, n\u00f3 cung c\u1ea5p m\u1ed9t s\u1ef1 li\u00ean k\u1ebft x\u00e3 h\u1ed9i. Trong quy\u1ec3n s\u00e1ch c\u1ee7a m\u00ecnh, Ch\u1ea3i l\u00f4ng, n\u00f3i nhi\u1ec1u v\u00e0 s\u1ef1 ti\u1ebfn h\u00f3a c\u1ee7a ng\u00f4n ng\u1eef (Grooming, gossip and the evolution of language, Faber, 1996), Dunbar ch\u1ec9 ra r\u1eb1ng kh\u1ec9 \u0111\u00e3 t\u1ed1n nhi\u1ec1u gi\u1edd \u0111\u1ec3 ch\u1ea3i l\u00f4ng cho nhau. B\u1ea5t k\u1ec3 s\u1ef1 tho\u1ea3i m\u00e1i r\u00f5 r\u00e0ng \u0111\u00f3, c\u00e1c lo\u00e0i linh tr\u01b0\u1edfng l\u1ea1i tr\u1edf n\u00ean kh\u00f3 t\u00ednh trong vi\u1ec7c ch\u1ecdn b\u1ea1n \u0111\u1ec3 ch\u1ea3i l\u00f4ng. Ch\u00fang tu\u00e2n theo h\u1ec7 th\u1ee9 b\u1eadc nghi\u00eam ng\u1eb7t; b\u1ea1n b\u00e8 v\u00e0 h\u1ecd h\u00e0ng th\u00e2n thu\u1ed9c s\u1ebd \u0111\u01b0\u1ee3c \u0111\u1ed1i \u0111\u00e3i \u201cn\u0103m sao\u201d, trong khi c\u00e1c \u0111\u00f4i b\u1ea1n t\u00ecnh c\u1edd ch\u1ec9 \u0111\u01b0\u1ee3c c\u00e0o c\u00e0o qua loa. C\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u h\u00e0nh vi \u0111\u1ed9ng v\u1eadt \u0111\u00e3 ph\u00e1t hi\u1ec7n r\u1eb1ng h\u1ecd c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c c\u1ea5u tr\u00fac x\u00e3 h\u1ed9i c\u1ee7a qu\u1ea7n th\u1ec3 kh\u1ec9 b\u1eb1ng c\u00e1ch quan s\u00e1t con n\u00e0o \u0111ang ch\u1ea3i l\u00f4ng cho con n\u00e0o. Gi\u00e1o s\u01b0 Dunbar \u0111\u00e3 c\u00f3 m\u1ed9t s\u1ef1 so s\u00e1nh h\u1ee3p l\u00fd \u0111\u1ed1i v\u1edbi vi\u1ec7c con ng\u01b0\u1eddi s\u1eed d\u1ee5ng vi\u1ec7c ng\u1ed3i l\u00ea \u0111\u00f4i m\u00e1ch \u0111\u1ec3 h\u00ecnh th\u00e0nh v\u00e0 duy tr\u00ec c\u1ea5u tr\u00fac x\u00e3 h\u1ed9i. \u00d4ng l\u00fd lu\u1eadn r\u1eb1ng ch\u00fang ta g\u1ea7n nh\u01b0 \u0111\u00e3 ph\u00e1t tri\u1ec3n ng\u00f4n ng\u1eef b\u1eb1ng c\u00e1ch l\u1ea3i nh\u1ea3i nh\u1eefng chuy\u1ec7n v\u1edb v\u1ea9n, cho ph\u00e9p ch\u00fang ta duy tr\u00ec s\u1ef1 li\u00ean k\u1ebft x\u00e3 h\u1ed9i hi\u1ec7u qu\u1ea3 h\u01a1n nhi\u1ec1u so v\u1edbi vi\u1ec7c ch\u1ea3i l\u00f4ng. Thay v\u00ec ng\u1ed3i h\u00e0ng gi\u1edd ch\u1ea3i l\u00f4ng cho nhau, con ng\u01b0\u1eddi c\u00f3 th\u1ec3 v\u1eeba n\u00f3i chuy\u1ec7n v\u1eeba l\u00e0m nh\u1eefng vi\u1ec7c kh\u00e1c v\u00e0 h\u01a1n n\u1eefa, ta c\u00f3 th\u1ec3 n\u00f3i chuy\u1ec7n v\u1edbi nh\u1eefng nh\u00f3m l\u1edbn h\u01a1n nhi\u1ec1u. \u00dd t\u01b0\u1edfng r\u1eb1ng ch\u00fang ta \u0111\u00e3 phung ph\u00ed m\u1ed9t n\u0103ng l\u1ef1c qu\u00fd gi\u00e1 nh\u01b0 v\u1eady v\u00e0o nh\u1eefng chuy\u1ec7n nh\u1ea3m nh\u00ed th\u00ec c\u00f3 v\u1ebb v\u00f4 163 https:\/\/thuviensach.vn","l\u00fd; h\u1ea7u h\u1ebft c\u00e1c l\u00fd thuy\u1ebft ch\u00ednh \u0111\u1ec1u cho r\u1eb1ng ng\u00f4n ng\u1eef \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n \u0111\u1ec3 truy\u1ec1n \u0111\u1ea1t c\u00e1c th\u00f4ng tin ph\u1ee9c t\u1ea1p, v\u00ed d\u1ee5 c\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 gi\u1ebft ch\u1ebft m\u1ed9t con voi mammouth l\u00e0 g\u00ec? Tuy nhi\u00ean Dunbar ch\u1ec9 ra r\u1eb1ng m\u1ed1i li\u00ean k\u1ebft x\u00e3 h\u1ed9i l\u00e0 \u0111\u1eb7c bi\u1ec7t quan tr\u1ecdng v\u00e0 vi\u1ec7c ph\u00e2n t\u00edch c\u00e1c cu\u1ed9c \u0111\u1ed1i tho\u1ea1i c\u1ee7a con ng\u01b0\u1eddi cho th\u1ea5y r\u1eb1ng 2\/3 th\u1eddi gian \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 huy\u00ean thuy\u00ean v\u1ec1 c\u00e1c v\u1ea5n \u0111\u1ec1 x\u00e3 h\u1ed9i. Tuy nhi\u00ean c\u00e1c k\u1ebft lu\u1eadn d\u1ef1a v\u00e0o nh\u1eefng g\u00ec ch\u00fang ta \u0111ang l\u00e0m hi\u1ec7n nay th\u1eadt kh\u00f3 l\u00e0 m\u1ed9t l\u00fd l\u1ebd thuy\u1ebft ph\u1ee5c \u0111\u1ed1i v\u1edbi nh\u1eefng g\u00ec ch\u00fang ta \u0111\u00e3 l\u00e0m trong qu\u00e1 tr\u00ecnh ti\u1ebfn h\u00f3a. Ch\u00fang ta, nh\u1eefng con ng\u01b0\u1eddi hi\u1ec7n \u0111\u1ea1i, c\u00f3 nhi\u1ec1u th\u1eddi gian \u0111\u1ec3 t\u00e1n d\u00f3c h\u01a1n t\u1ed5 ti\u00ean th\u1eddi ti\u1ec1n s\u1eed c\u1ee7a ch\u00fang ta. Nh\u01b0ng \u00fd t\u01b0\u1edfng ch\u00fang ta t\u00e1n d\u00f3c \u0111\u1ec3 duy tr\u00ec nh\u00f3m l\u00e0 ho\u00e0n to\u00e0n h\u1ee3p l\u00fd. N\u00f3 c\u00f2n c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch t\u1ea1i sao nh\u1eefng t\u1edd t\u1ea1p ch\u00ed l\u00e1 c\u1ea3i l\u1ea1i d\u00e0nh qu\u00e1 nhi\u1ec1u kh\u00f4ng gian cho m\u1ee5c bu\u00f4n chuy\u1ec7n. 131 B\u1eb1ng c\u00e1ch n\u00e0o ch\u00fang ta bi\u1ebft \u0111\u01b0\u1ee3c t\u1ea5t c\u1ea3 c\u00e1c d\u1ea5u v\u00e2n tay \u0111\u1ec1u l\u00e0 duy nh\u1ea5t? \u00dd t\u01b0\u1edfng r\u1eb1ng d\u1ea5u v\u00e2n tay l\u00e0 duy nh\u1ea5t \u0111\u00e3 c\u00f3 t\u1eeb nhi\u1ec1u th\u1ebf k\u1ef7 v\u00e0 d\u01b0\u1eddng nh\u01b0 n\u00f3 ch\u1eb3ng d\u1ef1a tr\u00ean c\u01a1 s\u1edf n\u00e0o ngo\u00e0i m\u1ed9t s\u1ef1 gi\u1ea3 \u0111\u1ecbnh r\u1eb1ng n\u00f3 qu\u00e1 ph\u1ee9c t\u1ea1p \u0111\u1ec3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c l\u1eb7p l\u1ea1i \u1edf m\u1ecdi chi ti\u1ebft. Vi\u1ec7c s\u1eed d\u1ee5ng d\u1ea5u v\u00e2n tay nh\u01b0 m\u1ed9t k\u1ef9 thu\u1eadt ph\u00e1p y b\u1eaft ngu\u1ed3n t\u1eeb m\u1ed9t 164 https:\/\/thuviensach.vn","chuy\u00ean kh\u1ea3o ph\u00e1t h\u00e0nh v\u00e0o n\u0103m 1892 b\u1edfi nh\u00e0 th\u00f4ng th\u00e1i Francis Galton. V\u1edbi t\u00ednh c\u00e1ch h\u1ebft s\u1ee9c k\u1ef9 l\u01b0\u1ee1ng, Galton \u0111\u00e3 xem x\u00e9t m\u1ecdi kh\u00eda c\u1ea1nh c\u1ea7n thi\u1ebft c\u1ee7a m\u1ed9t d\u1ea5u v\u00e2n tay \u0111\u1ec3 chuy\u1ec3n n\u00f3 th\u00e0nh m\u1ed9t m\u00f4n khoa h\u1ecdc, bao g\u1ed3m c\u1ea3 vi\u1ec7c \u01b0\u1edbc l\u01b0\u1ee3ng x\u00e1c su\u1ea5t hai ng\u01b0\u1eddi c\u00f3 c\u00f9ng m\u1ed9t d\u1ea5u v\u00e2n tay. \u0110\u1ec3 l\u00e0m vi\u1ec7c n\u00e0y, \u00f4ng \u0111\u00e3 t\u00ednh to\u00e1n k\u00edch th\u01b0\u1edbc c\u1ee7a m\u1ed9t m\u1ea3nh v\u00e2n tay \u0111\u1ec3 h\u00ecnh d\u1ea1ng c\u1ee7a n\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c l\u1eb7p l\u1ea1i ch\u00ednh x\u00e1c \u1edf 50% tr\u01b0\u1eddng h\u1ee3p so s\u00e1nh v\u1edbi ng\u01b0\u1eddi. K\u1ebft h\u1ee3p v\u1edbi s\u1ed1 l\u01b0\u1ee3ng c\u1ee7a nh\u1eefng m\u1ea3nh nh\u01b0 v\u1eady c\u1ea7n thi\u1ebft \u0111\u1ec3 t\u1ea1o th\u00e0nh m\u1ed9t d\u1ea5u v\u00e2n tay \u0111i\u1ec3n h\u00ecnh, \u00f4ng \u01b0\u1edbc l\u01b0\u1ee3ng r\u1eb1ng c\u00e1c d\u1ea5u v\u00e2n tay kh\u00e1c nhau \u0111\u1ee7 nhi\u1ec1u \u0111\u1ec3 ch\u1ec9 c\u00f3 th\u1ec3 may m\u1eafn t\u00ecm \u0111\u01b0\u1ee3c m\u1ed9t d\u1ea5u v\u00e2n tay \u0111\u1ed3ng d\u1ea1ng trong 1\/64 t\u1ec9 tr\u01b0\u1eddng h\u1ee3p. V\u00ec con s\u1ed1 n\u00e0y d\u1ec5 d\u00e0ng v\u01b0\u1ee3t xa d\u00e2n s\u1ed1 th\u1ebf gi\u1edbi, Galton k\u1ebft lu\u1eadn r\u1eb1ng c\u00e1c d\u1ea5u v\u00e2n tay th\u1ef1c ch\u1ea5t l\u00e0 duy nh\u1ea5t. \u0110i\u1ec1u \u0111\u00e1ng lo l\u00e0, c\u00e1c nghi\u00ean c\u1ee9u c\u1ee7a Galton ch\u1ec9 s\u1eed d\u1ee5ng \u00edt h\u01a1n 100 d\u1ea5u v\u00e2n tay v\u00e0 l\u00fd lu\u1eadn v\u1ec1 s\u1ef1 tr\u00f9ng h\u1ee3p c\u1ee7a \u00f4ng c\u0169ng r\u1ea5t l\u1ecfng l\u1ebbo. Theo nh\u01b0 gi\u00e1o s\u01b0 Stephen Stigler \u0111\u00e3 ch\u1ec9 ra trong quy\u1ec3n s\u00e1ch l\u1ecbch s\u1eed v\u1ec1 c\u00e1c kh\u00e1i ni\u1ec7m th\u1ed1ng k\u00ea Statistics on the Table (Harvard University Press, 1999) c\u1ee7a \u00f4ng, tri\u1ec3n v\u1ecdng x\u00e1c \u0111\u1ecbnh m\u1ed9t t\u00ean nghi ph\u1ea1m qua d\u1ea5u v\u00e2n tay l\u00e0 qu\u00e1 h\u1ea5p d\u1eabn v\u00e0 cho t\u1edbi nh\u1eefng n\u0103m 1920, c\u00e1c v\u0103n b\u1ea3n ch\u00ednh quy \u0111\u00e3 kh\u1eb3ng \u0111\u1ecbnh t\u00ednh duy nh\u1ea5t c\u1ee7a d\u1ea5u v\u00e2n tay l\u00e0 m\u1ed9t s\u1ef1 th\u1eadt. Trong nhi\u1ec1u th\u1eadp k\u1ef7, gi\u1ea3 \u0111\u1ecbnh c\u1ee7a Galton \u0111\u00e3 lan r\u1ed9ng m\u00e0 h\u1ea7u nh\u01b0 kh\u00f4ng c\u00f3 m\u1ed9t s\u1ef1 th\u00e1ch th\u1ee9c n\u00e0o, c\u00e0ng l\u00e0m t\u0103ng th\u00eam danh ti\u1ebfng cho n\u00f3. Tuy nhi\u00ean, vi\u1ec7c thi\u1ebfu \u0111i s\u1ef1 165 https:\/\/thuviensach.vn","th\u00e1ch th\u1ee9c th\u00ec kh\u00f3 c\u00f3 th\u1ec3 l\u00e0 b\u1eb1ng ch\u1ee9ng cho s\u1ef1 ch\u00ednh x\u00e1c tuy\u1ec7t \u0111\u1ed1i - ch\u1ec9 c\u00f3 c\u00e1c b\u1eb1ng ch\u1ee9ng \u201cmang t\u00ednh khoa h\u1ecdc\u201d m\u1edbi c\u00f3 th\u1ec3 khu\u1ea5t ph\u1ee5c \u0111\u01b0\u1ee3c nh\u1eefng k\u1ebb \u0111a nghi to m\u1ed3m. Nh\u01b0ng t\u1eeb cu\u1ed1i nh\u1eefng n\u0103m 1990 \u0111\u00e3 c\u00f3 nhi\u1ec1u th\u00e1ch th\u1ee9c th\u00e0nh c\u00f4ng \u0111\u1ed1i v\u1edbi ch\u1ee9ng c\u1ee9 v\u1ec1 v\u00e2n tay, m\u1eb7c d\u00f9 ch\u00fang ch\u1ee7 y\u1ebfu ch\u1ec9 t\u1eadp trung v\u00e0o sai ph\u1ea1m trong nh\u1eadn di\u1ec7n v\u00e0 x\u1eed l\u00fd. V\u00e0 d\u1ea5u v\u00e2n tay v\u1eabn \u0111\u01b0\u1ee3c nh\u1ea5t tr\u00ed l\u00e0 duy nh\u1ea5t v\u1ec1 b\u1ea3n ch\u1ea5t, b\u1ea5t ch\u1ea5p m\u1ed9t th\u1ef1c t\u1ebf r\u1eb1ng kh\u00f4ng c\u00f3 hi v\u1ecdng n\u00e0o \u0111\u1ec3 gi\u00fap n\u00f3 tho\u00e1t kh\u1ecfi s\u1ef1 ng\u1edd v\u1ef1c. M\u1ed9t v\u00e0i b\u1eb1ng ch\u1ee9ng c\u00f3 t\u00ednh g\u1ee3i \u00fd kh\u00e1c \u0111\u00e3 h\u00ecnh th\u00e0nh trong khi nghi\u00ean c\u1ee9u qu\u00e1 tr\u00ecnh sinh h\u00f3a c\u1ee7a vi\u1ec7c t\u1ea1o d\u1ea5u v\u00e2n tay. Gi\u00e1o s\u01b0 James Murray c\u1ee7a \u0111\u1ea1i h\u1ecdc Washington v\u00e0 c\u00e1c \u0111\u1ed3ng nghi\u1ec7p \u0111\u00e3 t\u00ednh to\u00e1n c\u00e1c qu\u00e1 tr\u00ecnh n\u00e0y tr\u00ean m\u00e1y t\u00ednh \u0111\u1ec3 thi\u1ebft l\u1eadp l\u1ea1i c\u00e1c d\u1ea1ng \u0111\u1eb7c \u0111i\u1ec3m c\u1ee7a v\u00e2n tay. C\u00e1c t\u00ednh to\u00e1n n\u00e0y c\u0169ng cho th\u1ea5y ngay c\u1ea3 m\u1ed9t s\u1ef1 kh\u00e1c bi\u1ec7t nh\u1ecf nh\u1ea5t c\u0169ng l\u00e0m thay \u0111\u1ed5i ho\u00e0n to\u00e0n k\u1ebft qu\u1ea3 cu\u1ed1i c\u00f9ng. B\u1edfi v\u00ec lu\u00f4n lu\u00f4n c\u00f3 y\u1ebfu t\u1ed1 ng\u1eabu nhi\u00ean trong qu\u00e1 tr\u00ecnh s\u1ed1ng, \u0111i\u1ec1u n\u00e0y g\u1ee3i \u00fd m\u1ea1nh m\u1ebd r\u1eb1ng kh\u00f4ng c\u00f3 hai ng\u01b0\u1eddi n\u00e0o c\u00f3 d\u1ea5u v\u00e2n tay gi\u1ed1ng nhau ch\u00ednh x\u00e1c. Cho n\u00ean sau h\u1ebft c\u00f3 l\u1ebd Galton \u0111\u00e3 \u0111\u00fang - nh\u01b0ng nh\u1edd may m\u1eafn nhi\u1ec1u h\u01a1n l\u00e0 khoa h\u1ecdc thu\u1ea7n t\u00fay. 132 T\u1ea1i sao b\u1ea1c h\u00e0 l\u00e0m h\u01a1i th\u1edf c\u00f3 c\u1ea3m gi\u00e1c l\u1ea1nh? Ch\u00fang ta c\u1ea3m nh\u1eadn n\u00f3ng v\u00e0 l\u1ea1nh th\u00f4ng qua ph\u1ea3n \u1ee9ng m\u00e0 ch\u00fang k\u00edch th\u00edch \u1edf \u0111\u1ea7u d\u00e2y th\u1ea7n kinh c\u1ea3m gi\u00e1c 166 https:\/\/thuviensach.vn","c\u1ee7a ch\u00fang ta. T\u1ea1i \u0111\u00e2y c\u00f3 c\u00e1c protein m\u00e0 c\u00f3 th\u1ec3 thay \u0111\u1ed5i d\u00f2ng ion v\u00e0o v\u00e0 ra kh\u1ecfi t\u1ebf b\u00e0o t\u00f9y theo nhi\u1ec7t \u0111\u1ed9. C\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u \u1edf \u0111\u1ea1i h\u1ecdc California t\u1ea1i San Francisco, M\u1ef9 g\u1ea7n \u0111\u00e2y \u0111\u00e3 ph\u00e1t hi\u1ec7n m\u1ed9t lo\u1ea1i protein nh\u01b0 th\u1ebf c\u0169ng b\u1ecb t\u00e1c \u0111\u1ed9ng b\u1edfi menthol, ch\u1ea5t ch\u1ee9a trong b\u1ea1c h\u00e0. Ng\u1eadm b\u1ea1c h\u00e0 trong mi\u1ec7ng s\u1ebd gi\u00fap gi\u1ea3i ph\u00f3ng \u0111\u1ee7 menthol l\u00ean c\u00e1c \u0111\u1ea7u d\u00e2y th\u1ea7n kinh c\u1ea3m gi\u00e1c \u0111\u1ec3 k\u00edch th\u00edch m\u1ed9t ph\u1ea3n \u1ee9ng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 khi u\u1ed1ng n\u01b0\u1edbc l\u1ea1nh v\u00e0 s\u1ebd t\u1ea1o ra m\u1ed9t \u1ea3o gi\u00e1c nh\u01b0 \u0111ang h\u00edt v\u00e0o m\u1ed9t l\u00e0n h\u01a1i l\u1ea1nh. 133 \u0110\u1ed9ng t\u00e1c h\u00fat th\u1ef1c s\u1ef1 l\u00e0 nh\u01b0 th\u1ebf n\u00e0o? C\u00e1c gi\u00e1o vi\u00ean v\u1eadt l\u00fd th\u01b0\u1eddng cho r\u1eb1ng h\u00fat l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng th\u1ea7n b\u00ed. \u0110i\u1ec1u n\u00e0y th\u1eadt kh\u00f3 \u0111\u1ec3 tin v\u00ec th\u1ef1c t\u1ebf th\u00ec ta v\u1eabn d\u00f9ng \u1ed1ng h\u00fat \u0111\u1ec3 h\u00fat n\u01b0\u1edbc ng\u1ecdt. Tuy nhi\u00ean, c\u00e1c gi\u00e1o vi\u00ean \u0111\u00e3 n\u00f3i \u0111\u00fang: s\u1ef1 h\u00fat kh\u00f4ng th\u1ef1c s\u1ef1 t\u1ed3n t\u1ea1i. Ch\u00fang ta kh\u00f4ng ph\u1ea3i \u0111ang h\u00fat n\u01b0\u1edbc b\u1eb1ng c\u00e1i \u1ed1ng h\u00fat, thay v\u00ec th\u1ebf ta ch\u1ec9 t\u1ea1o \u0111i\u1ec1u ki\u1ec7n \u0111\u1ec3 kh\u00ed quy\u1ec3n xung quanh \u0111\u1ea9y n\u01b0\u1edbc l\u00ean m\u00e0 th\u00f4i. \u0110\u1ec3 l\u00e0m \u0111i\u1ec1u n\u00e0y ch\u00fang ta c\u1ea7n ph\u1ea3i gi\u1ea3m \u00e1p su\u1ea5t \u1edf n\u01a1i m\u00e0 ta mu\u1ed1n ch\u1ea5t l\u1ecfng \u0111i t\u1edbi, b\u1eb1ng c\u00e1ch r\u00fat kh\u00f4ng kh\u00ed ra kh\u1ecfi \u0111\u1ea7u tr\u00ean c\u1ee7a c\u00e1i \u1ed1ng h\u00fat. M\u1eb7c d\u00f9 vi\u1ec7c n\u00e0y ch\u1ec9 gi\u00fap h\u00fat kh\u00f4ng kh\u00ed trong \u1ed1ng ra, s\u1ef1 di chuy\u1ec3n l\u00ean tr\u00ean c\u1ee7a 167 https:\/\/thuviensach.vn","ch\u1ea5t l\u1ecfng l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a vi\u1ec7c n\u00f3 c\u00f3 \u00e1p su\u1ea5t \u1edf \u0111\u00e1y \u1ed1ng cao h\u01a1n \u00e1p su\u1ea5t \u1edf \u0111\u1ec9nh \u1ed1ng. M\u1eb7c d\u00f9 kh\u00f4ng th\u1ef1c s\u1ef1 t\u1ed3n t\u1ea1i, s\u1ef1 h\u00fat l\u1ea1i c\u00f3 \u0111\u01b0\u1ee3c m\u1ed9t s\u1ee9c m\u1ea1nh h\u1ebft s\u1ee9c \u1ea5n t\u01b0\u1ee3ng, nh\u1edd v\u00e0o m\u1ed9t \u0111i\u1ec1u r\u1eb1ng, \u1edf m\u1ef1c n\u01b0\u1edbc bi\u1ec3n, \u00e1p su\u1ea5t kh\u00ed quy\u1ec3n t\u1ea1o ra m\u1ed9t \u00e1p l\u1ef1c kho\u1ea3ng 700 kg\/m2. Ch\u1ec9 c\u1ea7n t\u1ea1o ra \u00e1p su\u1ea5t ch\u00e2n kh\u00f4ng m\u1ed9t ph\u1ea7n c\u0169ng c\u00f3 th\u1ec3 t\u1ea1o n\u00ean m\u1ed9t l\u1ef1c h\u00fat m\u1ea1nh m\u1ebd. Ta s\u1ebd th\u1ea5y \u0111\u01b0\u1ee3c \u0111i\u1ec1u n\u00e0y qua th\u00ed nghi\u1ec7m c\u1ee7a Otto von Guericke v\u00e0o gi\u1eefa nh\u1eefng n\u0103m 1650: s\u1eed d\u1ee5ng m\u1ed9t m\u00e1y b\u01a1m kh\u00f4ng kh\u00ed, \u00f4ng t\u1ea1o ra m\u1ed9t kho\u1ea3ng ch\u00e2n kh\u00f4ng \u1edf gi\u1eefa hai b\u00e1n c\u1ea7u kim lo\u1ea1i c\u00f3 \u0111\u01b0\u1eddng k\u00ednh kho\u1ea3ng 30cm ho\u1eb7c l\u1edbn h\u01a1n, g\u1eafn v\u1edbi nhau ch\u1ec9 b\u1eb1ng m\u1ed9t \u00edt d\u1ea7u. Sau \u0111\u00f3 \u00f4ng c\u1ed9t hai nh\u00f3m ng\u1ef1a v\u00e0o m\u1ed7i b\u00ean b\u00e1n c\u1ea7u v\u00e0 cho ch\u00fang k\u00e9o theo hai h\u01b0\u1edbng ng\u01b0\u1ee3c nhau. Ch\u00fang \u0111\u00e3 kh\u00f4ng th\u1ec3 t\u00e1ch \u0111\u00f4i hai b\u00e1n c\u1ea7u. M\u1eb7c d\u00f9 b\u00ean trong hai b\u00e1n c\u1ea7u ch\u1eb3ng c\u00f3 g\u00ec ngo\u00e0i ch\u00e2n kh\u00f4ng, \u00e1p l\u1ef1c c\u1ee7a c\u1ea3 kh\u00ed quy\u1ec3n tr\u00e1i \u0111\u1ea5t l\u1ea1i \u0111ang \u0111\u1ea9y v\u00e0o m\u1eb7t ngo\u00e0i c\u1ee7a ch\u00fang, k\u1eb9p ch\u1eb7t ch\u00fang v\u00e0o nhau v\u1edbi s\u1ee9c n\u1eb7ng h\u00e0ng t\u1ea5n. 134 B\u1eb1ng c\u00e1ch n\u00e0o m\u1ed9t \u1ed1ng truy\u1ec1n n\u01b0\u1edbc siphon d\u1ef1a theo n\u01b0\u1edbc \u0111\u1ec3 t\u1ef1 \u0111\u1ea9y ch\u00fang \u0111i l\u00ean? B\u1ea1n c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng hi\u1ec7u \u1ee9ng siphon \u0111\u1ec3 bi\u1ec3u di\u1ec5n khi \u0111i u\u1ed1ng n\u01b0\u1edbc v\u1edbi b\u1ea1n b\u00e8. \u0110\u01a1n gi\u1ea3n th\u00f4i\u00a0: d\u00f9ng m\u1ed9t chi\u1ebfc \u1ed1ng h\u00fat cong, n\u1eb1m n\u1ed1i li\u1ec1n gi\u1eefa hai c\u00e1i ly, m\u1ed9t c\u00e1i ly \u1edf cao 168 https:\/\/thuviensach.vn","h\u01a1n v\u00e0 m\u1ed9t c\u00e1i ly \u1edf th\u1ea5p h\u01a1n; nhanh ch\u00f3ng h\u00fat nh\u1eb9 \u0111\u1ea7u th\u1ea5p c\u1ee7a chi\u1ebfc \u1ed1ng h\u00fat s\u1ebd cho ph\u00e9p chuy\u1ec3n ch\u1ea5t l\u1ecfng trong c\u00e1i ly cao v\u01b0\u1ee3t qua c\u1ea1nh c\u1ee7a n\u00f3 v\u00e0 ch\u1ea3y xu\u1ed1ng ly th\u1ea5p h\u01a1n. \u0110i\u1ec1u l\u00e0m cho hi\u1ec7u \u1ee9ng n\u00e0y th\u00fa v\u1ecb l\u00e0 ch\u1ea5t l\u1ecfng v\u1eabn ti\u1ebfp t\u1ee5c ch\u1ea3y m\u00e0 kh\u00f4ng c\u1ea7n m\u1ed9t s\u1ef1 h\u1ed7 tr\u1ee3 c\u01a1 h\u1ecdc n\u00e0o, ngay c\u1ea3 khi ta \u0111\u00e3 ng\u1eebng h\u00fat. L\u1eddi gi\u1ea3i th\u00edch l\u00e0 \u0111\u00e2y: t\u01b0\u1edfng t\u01b0\u1ee3ng c\u1ed9t n\u01b0\u1edbc \u1ed1ng nh\u01b0 l\u00e0 m\u1ed9t s\u1ee3i d\u00e2y m\u1ea3nh qu\u1ea5n qua m\u1ed9t c\u00e1i c\u1ed9t: n\u1ebfu m\u1ed9t \u0111\u1ea7u d\u00e2y th\u1ea5p h\u01a1n \u0111\u1ea7u kia, l\u1ef1c h\u00fat tr\u00e1i \u0111\u1ea5t s\u1ebd k\u00e9o s\u1ee3i d\u00e2y qua c\u1ed9t. Trong siphon vi\u1ec7c h\u00fat ban \u0111\u1ea7u \u1edf b\u00ean th\u1ea5p h\u01a1n \u0111\u00e3 gi\u00fap k\u00e9o n\u01b0\u1edbc l\u00ean kh\u1ecfi c\u1ea1nh c\u1ee7a ly (m\u1eb7c d\u00f9, khi h\u00fat t\u1ea1o m\u1ed9t ch\u00e2n kh\u00f4ng, ch\u1ea5t l\u1ecfng th\u1eadt s\u1ef1 \u0111\u1ea9y \u1ed1ng h\u00fat l\u00ean b\u1edfi \u00e1p su\u1ea5t kh\u00ed quy\u1ec3n \u1edf \u0111\u1ea7u b\u00ean kia). R\u1ed3i tr\u1ecdng l\u1ef1c s\u1ebd gi\u1ea3i quy\u1ebft ph\u1ea7n c\u00f2n l\u1ea1i l\u00e0 k\u00e9o n\u00f3 xu\u1ed1ng d\u01b0\u1edbi. Ch\u1ea5t l\u1ecfng th\u1eadt ra kh\u00f4ng ph\u1ea3i l\u00e0 m\u1ed9t s\u01a1i d\u1eady, v\u1eady t\u1ea1i sao c\u1ed9t ch\u1ea5t l\u1ecfng kh\u00f4ng b\u1ecb \u0111\u1ee9t ra \u1edf \u0111\u1ec9nh \u0111\u01b0\u1eddng cong, khi m\u00e0 m\u1ed7i b\u00ean b\u1ecb tr\u1ecdng l\u1ef1c k\u00e9o v\u1ec1 m\u1ed9t h\u01b0\u1edbng kh\u00e1c nhau? \u0110\u00f3 l\u00e0 do \u00e1p su\u1ea5t kh\u00f4ng kh\u00ed: n\u1ebfu th\u1ef1c s\u1ef1 c\u00f3 m\u1ed9t ch\u1ed7 \u0111\u1ee9t \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh gi\u1eefa c\u1ed9t ch\u1ea5t l\u1ecfng, kh\u00f4ng gian \u1edf gi\u1eefa s\u1ebd ch\u1ec9 c\u00f2n ch\u00e2n kh\u00f4ng, v\u00e0 n\u00f3 s\u1ebd nhanh ch\u00f3ng \u0111\u01b0\u1ee3c l\u1ea5p \u0111\u1ea7y n\u01b0\u1edbc \u0111\u01b0\u1ee3c \u00e1p l\u1ef1c kh\u00ed quy\u1ec3n \u0111\u1ea9y t\u1edbi. Th\u1eadt \u0111\u00e1ng ng\u1ea1c nhi\u00ean, c\u1ed9t ch\u1ea5t l\u1ecfng \u0111\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c gi\u1eef nguy\u00ean v\u1eb9n v\u00e0 ch\u1ea3y l\u00ean cao t\u1edbi 10m tr\u01b0\u1edbc khi tu\u1ed9t xu\u1ed1ng l\u1ea1i. 169 https:\/\/thuviensach.vn","135 T\u1ea1i sao h\u1ea7u h\u1ebft c\u00e1c turbine n\u0103ng l\u01b0\u1ee3ng gi\u00f3 \u0111\u1ec1u c\u00f3 ba c\u00e1nh thay v\u00ec b\u1ed1n? M\u1ed9t l\u00fd do c\u1ee7a vi\u1ec7c \u01b0u ti\u00ean cho ba c\u00e1nh qu\u1ea1t thay v\u00ec b\u1ed1n l\u00e0 chi ph\u00ed: v\u1edbi b\u1ea5t k\u1ef3 k\u00edch th\u01b0\u1edbc turbine n\u00e0o, s\u1ebd r\u1ebb h\u01a1n n\u1ebfu c\u00f3 \u00edt c\u00e1nh qu\u1ea1t h\u01a1n. Th\u1ea9m m\u1ef9 c\u0169ng l\u00e0 m\u1ed9t v\u1ea5n \u0111\u1ec1; ng\u01b0\u1eddi ta th\u1ea5y c\u00e1c v\u1eadt th\u1ec3 ba c\u00e1nh qu\u1ea1t \u0111\u1eb9p m\u1eaft h\u01a1n l\u00e0 b\u1ed1n c\u00e1nh qu\u1ea1t. Tuy nhi\u00ean, v\u1eabn c\u00f2n m\u1ed9t v\u1ea5n \u0111\u1ec1 nghi\u00eam tr\u1ecdng h\u01a1n v\u1edbi b\u1ea5t k\u1ef3 turbine n\u00e0o c\u00f3 s\u1ed1 l\u01b0\u1ee3ng c\u00e1nh qu\u1ea1t l\u00e0 s\u1ed1 ch\u1eb5n. Khi m\u1ed9t c\u00e1nh qu\u1ea1t \u0111ang h\u01b0\u1edbng th\u1eb3ng l\u00ean v\u00e0 ch\u1ecbu to\u00e0n b\u1ed9 s\u1ee9c gi\u00f3 ph\u00eda sau n\u00f3 th\u00ec c\u00e1nh qu\u1ea1t \u0111\u1ed1i di\u1ec7n \u1edf ngay b\u00ean d\u01b0\u1edbi n\u00f3 l\u1ea1i \u0111\u01b0\u1ee3c che ch\u1eafn b\u1edfi tr\u1ee5c \u0111\u1ee9ng - g\u00e2y ra s\u1ef1 m\u1ea5t c\u00e2n b\u1eb1ng r\u1ea5t l\u1edbn, \u1ea3nh h\u01b0\u1edfng nghi\u00eam tr\u1ecdng t\u1edbi t\u00ednh \u1ed5n \u0111\u1ecbnh. C\u00f3 m\u1ed9t c\u00e1ch \u0111\u1ecbnh ngh\u0129a 136 chung n\u00e0o cho b\u00ean ph\u1ea3i v\u00e0 b\u00ean tr\u00e1i kh\u00f4ng? Kh\u00f4ng ch\u1ec9 c\u00f3 m\u1ed7i tri\u1ebft gia Immanuel Kant c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c chi\u1ec1u s\u00e2u b\u00ed \u1ea9n c\u1ee7a c\u00e2u h\u1ecfi n\u00e0y, m\u1eb7c d\u00f9 ngay c\u1ea3 \u00f4ng c\u0169ng s\u1ebd b\u1ecb b\u1ea5t ng\u1edd b\u1edfi c\u00e2u tr\u1ea3 l\u1eddi cu\u1ed1i c\u00f9ng. Trong m\u1ed9t 170 https:\/\/thuviensach.vn","b\u00e0i lu\u1eadn ng\u1eafn \u0111\u01b0\u1ee3c xu\u1ea5t b\u1ea3n v\u00e0o n\u0103m 1768, Concerning the Ultimate Ground of the Differentiation of Direction in Space (B\u00e0n v\u1ec1 n\u1ec1n t\u1ea3ng cu\u1ed1i c\u00f9ng c\u1ee7a vi\u1ec7c ph\u00e2n bi\u1ec7t ph\u01b0\u01a1ng h\u01b0\u1edbng trong kh\u00f4ng gian), Kant \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng c\u00f3 \u0111\u00f4i \u0111i\u1ec1u k\u00ec l\u1ea1 v\u1ec1 vi\u1ec7c thu\u1eadn tay tr\u00e1i hay tay ph\u1ea3i. Th\u00f4ng th\u01b0\u1eddng, khi ch\u00fang ta n\u00f3i hai v\u1eadt th\u1ec3 l\u00e0 \u201ckh\u00e1c nhau\u201d, ta h\u00e0m \u00fd r\u1eb1ng vi\u1ec7c \u0111o l\u01b0\u1eddng c\u00e1c \u0111\u1eb7c \u0111i\u1ec3m c\u1ee7a ch\u00fang s\u1ebd cho c\u00e1c gi\u00e1 tr\u1ecb kh\u00e1c nhau, v\u00ed d\u1ee5 nh\u01b0 r\u1ed9ng l\u1edbn h\u01a1n hay n\u1eb7ng h\u01a1n. Do \u0111\u00f3 vi\u1ec7c ch\u1ee9ng t\u1ecf hai v\u1eadt l\u00e0 kh\u00e1c nhau th\u00ec kh\u00e1 d\u1ec5 d\u00e0ng. Tuy nhi\u00ean l\u00e0m sao ch\u00fang ta m\u00f4 t\u1ea3 s\u1ef1 kh\u00e1c bi\u1ec7t trong vi\u1ec7c thu\u1eadn tay tr\u00e1i hay tay ph\u1ea3i? Ch\u00fang ta \u0111\u1ec1u bi\u1ebft r\u1eb1ng tay tr\u00e1i l\u00e0 kh\u00e1c tay ph\u1ea3i nh\u01b0ng l\u00e0m sao b\u1ea1n gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c s\u1ef1 kh\u00e1c bi\u1ec7t n\u00e0y cho m\u1ed9t d\u00e2n t\u1ed9c xa l\u1ea1, nh\u1eefng ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 nh\u00ecn th\u1ea5y ch\u00fang? S\u1ef1 thu\u1eadn b\u00ean tr\u00e1i hay ph\u1ea3i r\u00f5 r\u00e0ng l\u00e0 nh\u1eefng t\u00ednh ch\u1ea5t c\u01a1 b\u1ea3n c\u1ee7a v\u1eadt th\u1ec3 (th\u1eadt v\u1eady, ngay c\u1ea3 b\u1ea3n th\u00e2n s\u1ef1 s\u1ed1ng c\u0169ng ph\u1ee5 thu\u1ed9c v\u00e0o t\u00ednh thu\u1eadn chi\u1ec1u c\u1ee7a DNA v\u00e0 amino acid) cho n\u00ean ch\u1eafc ch\u1eafn ph\u1ea3i c\u00f3 m\u1ed9t ti\u00eau chu\u1ea9n chung \u0111\u1ec3 d\u1ef1a v\u00e0o \u0111\u00f3 ch\u00fang ta c\u00f3 th\u1ec3 \u0111\u1ecbnh ngh\u0129a b\u00ean ph\u1ea3i v\u00e0 b\u00ean tr\u00e1i? C\u00f3 m\u1ed9t ti\u00eau chu\u1ea9n nh\u01b0 th\u1ebf, v\u00e0 n\u00f3 \u0111\u01b0\u1ee3c ch\u00f4n d\u1ea5u trong ch\u00ednh c\u1ea5u tr\u00fac c\u1ee7a v\u0169 tr\u1ee5. Kh\u00e1i ni\u1ec7m m\u01a1 h\u1ed3 v\u1ec1 s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a n\u00f3 \u0111\u00e3 n\u1ed5i l\u00ean l\u1ea7n \u0111\u1ea7u ti\u00ean n\u0103m 1918 khi nh\u00e0 to\u00e1n h\u1ecdc Emmy Noether minh h\u1ecda m\u1ed9t s\u1ef1 li\u00ean k\u1ebft s\u00e2u s\u1eafc gi\u1eefa kh\u00e1i ni\u1ec7m to\u00e1n h\u1ecdc v\u1ec1 t\u00ednh \u0111\u1ed1i x\u1ee9ng v\u00e0 c\u00e1c \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n, ch\u1eb3ng h\u1ea1n nh\u01b0 s\u1ef1 b\u1ea3o to\u00e0n n\u0103ng l\u01b0\u1ee3ng trong v\u1eadt l\u00fd. \u0110\u1ecbnh l\u00fd Noether t\u1ea1o m\u1ed9t c\u1ea7u n\u1ed1i gi\u1eefa t\u00ednh ch\u1ea5t to\u00e1n 171 https:\/\/thuviensach.vn","h\u1ecdc kh\u00f4ng thay \u0111\u1ed5i - v\u00ed d\u1ee5, s\u1ef1 \u0111\u1ed1i x\u1ee9ng gi\u1eef cho m\u1ecdi v\u1eadt gi\u1ed1ng h\u1ec7t nhau khi nh\u00ecn qua m\u1ed9t t\u1ea5m g\u01b0\u01a1ng - v\u1edbi t\u00ednh ch\u1ea5t v\u1eadt l\u00fd kh\u00f4ng \u0111\u1ed5i. N\u00f3 c\u0169ng cho ta manh m\u1ed1i v\u1ec1 n\u01a1i c\u00f3 th\u1ec3 t\u00ecm th\u1ea5y m\u1ed9t ti\u00eau chu\u1ea9n ph\u1ed5 qu\u00e1t cho s\u1ef1 thu\u1eadn tay. V\u00ec n\u1ebfu kh\u00f4ng c\u00f3 m\u1ed9t c\u00e1ch tuy\u1ec7t \u0111\u1ed1i \u0111\u1ec3 ph\u00e2n bi\u1ec7t b\u00ean tr\u00e1i v\u00e0 ph\u1ea3i, v\u0169 tr\u1ee5 c\u1ee7a ch\u00fang ta s\u1ebd c\u00f3 m\u1ed9t s\u1ef1 \u0111\u1ed1i x\u1ee9ng c\u0103n b\u1ea3n gi\u1eefa b\u00ean tr\u00e1i v\u00e0 b\u00ean ph\u1ea3i; v\u00e0 theo \u0111\u1ecbnh l\u00fd Noether, c\u00e1c \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n trong v\u1eadt l\u00fd lu\u00f4n lu\u00f4n \u0111\u00fang. V\u00e0o gi\u1eefa nh\u1eefng n\u0103m 1950, c\u00e1c nh\u00e0 v\u1eadt l\u00fd \u0111\u00e3 ph\u00e1t hi\u1ec7n r\u1eb1ng \u0111i\u1ec1u n\u00e0y kh\u00f4ng ph\u1ea3i nh\u01b0 v\u1eady: c\u00e1c h\u1ea1t \u0111\u01b0\u1ee3c sinh ra t\u1eeb m\u1ed9t h\u1ea1t nh\u00e2n ph\u00f3ng x\u1ea1 vi ph\u1ea1m v\u00e0o \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n c\u00f3 li\u00ean quan t\u1edbi s\u1ef1 \u0111\u1ed1i x\u1ee9ng tr\u00e1i ph\u1ea3i. Do \u0111\u00f3, ch\u00fang ta \u0111\u1ebfn \u0111\u01b0\u1ee3c m\u1ed9t k\u1ebft lu\u1eadn kh\u00e1 l\u1ea1 l\u00f9ng r\u1eb1ng th\u1ef1c s\u1ef1 c\u00f3 m\u1ed9t ti\u00eau chu\u1ea9n ph\u1ed5 qu\u00e1t cho b\u00ean tr\u00e1i v\u00e0 b\u00ean ph\u1ea3i nh\u01b0ng n\u00f3 ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n b\u1eb1ng c\u00e1ch nghi\u00ean c\u1ee9u chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a m\u1ed9t s\u1ed1 h\u1ea1t nh\u00e2n nguy\u00ean t\u1eed n\u00e0o \u0111\u00f3. V\u00e0 vi\u1ec7c Kant c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng ri\u00eang l\u00fd l\u1ebd \u0111\u1ec3 hi\u1ec3u \u0111\u01b0\u1ee3c r\u1eb1ng c\u00e2u tr\u1ea3 l\u1eddi cho c\u00e2u h\u1ecfi \u0111\u01a1n gi\u1ea3n n\u00e0y l\u00e0 r\u1ea5t c\u0103n b\u1ea3n, ch\u1eafc ch\u1eafn l\u00e0 m\u1ed9t s\u1ef1 ch\u1ee9ng th\u1ef1c cho thi\u00ean t\u00e0i c\u1ee7a m\u1ed9t nh\u00e0 tri\u1ebft h\u1ecdc. 137 T\u1ea1i sao carbon monoxide (CO) g\u00e2y ch\u1ebft ng\u01b0\u1eddi, trong khi m\u1ed9t n\u1eeda c\u1ee7a n\u00f3 l\u00e0 oxygen? M\u1ed9t ngh\u1ecbch l\u00fd hi\u1ec3n nhi\u00ean nh\u01b0 th\u1ebf, ch\u1eb3ng l\u1ebd m\u00f4n h\u00f3a h\u1ecdc \u0111\u00e3 kh\u00f4ng gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c g\u00ec? Tuy nhi\u00ean, trong m\u1ed9t m\u00f4n h\u1ecdc ch\u1eafc ch\u1eafn ph\u1ea3i c\u00f3 \u0111i\u1ec1u g\u00ec \u0111\u00f3 tuy\u1ec7t di\u1ec7u 172 https:\/\/thuviensach.vn","\u0111\u1ec3 gi\u1ea3i th\u00edch c\u00e1c ngh\u1ecbch l\u00fd nh\u01b0 t\u1ea1i sao CO gi\u00e0u oxygen l\u1ea1i g\u00e2y ch\u1ebft ng\u01b0\u1eddi - hay t\u1ea1i sao mu\u1ed1i \u0103n l\u1ea1i kh\u00f4ng \u0111\u1ed9c, m\u1eb7c d\u00f9 n\u00f3 \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb chlorine, ch\u1ea5t \u0111\u00e3 gi\u1ebft h\u00e0ng ng\u00e0n \u0111\u1ed9i qu\u00e2n trong th\u1ebf chi\u1ebfn th\u1ee9 nh\u1ea5t. C\u00e1ch \u0111\u1ec3 l\u00fd gi\u1ea3i ngh\u1ecbch l\u00fd \u0111\u00f3 n\u1eb1m trong li\u00ean k\u1ebft h\u00f3a h\u1ecdc t\u1ea1o ra b\u1edfi c\u00e1c \u0111\u00e1m m\u00e2y electron bao quanh m\u1ed7i nguy\u00ean t\u1eed. Trong tr\u01b0\u1eddng h\u1ee3p c\u1ee7a mu\u1ed1i, li\u00ean k\u1ebft m\u1ea1nh gi\u1eefa c\u00e1c nguy\u00ean t\u1eed Na v\u1edbi Cl \u0111\u1ea3m b\u1ea3o cho Cl kh\u00f4ng h\u00ecnh th\u00e0nh n\u00ean c\u00e1c ph\u00e2n t\u1eed Cl2 \u0111\u1ec3 r\u1ed3i li\u00ean k\u1ebft v\u1edbi n\u01b0\u1edbc v\u00e0 t\u1ea1o th\u00e0nh acid HCl, nh\u1eefng ch\u1ea5t g\u00e2y ra hi\u1ec7u \u1ee9ng ch\u1ebft ng\u01b0\u1eddi c\u1ee7a chlorine. S\u1ef1 nguy hi\u1ec3m c\u1ee7a CO b\u1eaft ngu\u1ed3n t\u1eeb s\u1ef1 t\u01b0\u01a1ng t\u00e1c c\u1ee7a n\u00f3 v\u1edbi haemoglobin, lo\u1ea1i protein ch\u1ecbu tr\u00e1ch nhi\u1ec7m trong vi\u1ec7c v\u1eadn chuy\u1ec3n O2 \u0111i kh\u1eafp c\u01a1 th\u1ec3. Haemoglobin c\u00f3 c\u00e1c \u0111i\u1ec3m tr\u00ean b\u1ec1 m\u1eb7t c\u1ee7a n\u00f3 d\u00f9ng \u0111\u1ec3 mang c\u00e1c ph\u00e2n t\u1eed O2; nh\u01b0ng th\u1eadt kh\u00f4ng may l\u00e0 c\u00e1c \u0111i\u1ec3m \u0111\u00f3 l\u1ea1i \u201cm\u00ea m\u1ea9n\u201d ph\u00e2n t\u1eed CO h\u01a1n O2. H\u1eadu qu\u1ea3 l\u00e0 ng\u01b0\u1eddi h\u00edt ph\u1ea3i b\u1ecb ng\u1ea1t th\u1edf \u1edf m\u1ee9c \u0111\u1ed9 ph\u00e2n t\u1eed: ch\u1ec9 c\u1ea7n n\u1ed3ng \u0111\u1ed9 CO b\u1eb1ng 1\/1.000 so v\u1edbi kh\u00f4ng kh\u00ed c\u0169ng c\u00f3 th\u1ec3 g\u00e2y t\u1eed vong. Ng\u1eabu nhi\u00ean, c\u1ea3 CO2 c\u0169ng c\u00f3 th\u1ec3 g\u00e2y t\u1eed vong, nh\u01b0 s\u1ef1 ki\u1ec7n n\u0103m 1986 \u0111\u00e3 ch\u1ee9ng t\u1ecf, khi 1.700 ng\u01b0\u1eddi ch\u1ebft t\u1ea1i Cameroon do s\u1ef1 ph\u00f3ng th\u00edch CO2 t\u1eeb h\u1ed3 Nyos. V\u00ec CO2 kh\u00f4ng c\u00f3 \u00e1i l\u1ef1c c\u1ef1c cao v\u1edbi haemoglobon nh\u01b0 h\u1ecd h\u00e0ng CO c\u1ee7a n\u00f3, n\u1ed3ng \u0111\u1ed9 t\u1eed vong c\u1ee7a n\u00f3 ph\u1ea3i cao h\u01a1n kho\u1ea3ng 173 https:\/\/thuviensach.vn","100 l\u1ea7n, t\u1ee9c l\u00e0 n\u1ebfu n\u1ed3ng \u0111\u1ed9 CO2 chi\u1ebfm t\u1edbi 1\/10 trong kh\u00f4ng kh\u00ed th\u00ec m\u1edbi c\u00f3 th\u1ec3 g\u00e2y t\u1eed vong \u0111\u01b0\u1ee3c. 138 T\u1ea1i sao ch\u00fang ta kh\u00f4ng th\u1ec3 nh\u00ecn r\u00f5 d\u01b0\u1edbi n\u01b0\u1edbc n\u1ebfu kh\u00f4ng c\u00f3 m\u1eb7t n\u1ea1 hay hay k\u00ednh b\u01a1i? Hi\u1ec7u \u1ee9ng che m\u1edd b\u1ecb g\u00e2y ra b\u1edfi v\u00ec m\u1eaft ch\u00fang ta kh\u00f4ng c\u00f2n kh\u1ea3 n\u0103ng t\u1eadp trung c\u00e1c tia s\u00e1ng t\u1edbi \u0111\u00fang ngay v\u00f5ng m\u1ea1c. B\u1ea5t c\u1ee9 khi n\u00e0o \u00e1nh s\u00e1ng chuy\u1ec3n t\u1eeb m\u1ed9t m\u00f4i tr\u01b0\u1eddng n\u00e0y sang m\u00f4i tr\u01b0\u1eddng kh\u00e1c, v\u1eadn t\u1ed1c v\u00e0 h\u01b0\u1edbng c\u1ee7a n\u00f3 \u0111\u1ec1u thay \u0111\u1ed5i nh\u1eb9. M\u1eaft c\u1ee7a ch\u00fang ta \u0111\u01b0\u1ee3c \u0111i\u1ec1u ti\u1ebft \u0111\u1ec3 ph\u00f9 h\u1ee3p v\u1edbi \u00e1nh s\u00e1ng chi\u1ebfu t\u1edbi sau khi \u0111i qua kh\u00f4ng kh\u00ed, \u0111\u1ea3m b\u1ea3o cho s\u1ef1 kh\u00fac x\u1ea1 \u00e1nh s\u00e1ng t\u1ea1o \u0111\u01b0\u1ee3c m\u1ed9t h\u00ecnh \u1ea3nh t\u1eadp trung r\u00f5 n\u00e9t. N\u1ebfu c\u00f3 n\u01b0\u1edbc \u0111ang bao quanh m\u1eaft ch\u00fang ta, m\u1ee9c \u0111\u1ed9 kh\u00fac x\u1ea1 s\u1ebd b\u1ecb thay \u0111\u1ed5i v\u00e0 m\u1eaft c\u1ee7a ch\u00fang ta s\u1ebd kh\u00f4ng th\u1ec3 b\u1ebb cong \u00e1nh s\u00e1ng \u0111\u1ee7 m\u1ee9c \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c h\u00ecnh \u1ea3nh r\u00f5 n\u00e9t. 139 \u00c1nh s\u00e1ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o ra kh\u00f4ng c\u1ea7n nhi\u1ec7t hay kh\u00f4ng? Ch\u00fang ta th\u01b0\u1eddng li\u00ean k\u1ebft \u00e1nh s\u00e1ng v\u00e0 nhi\u1ec7t: l\u1eeda, n\u1ebfn, m\u1eb7t tr\u1eddi. C\u00e1c b\u00f3ng \u0111\u00e8n tr\u00f2n s\u00e1ng ti\u00eau chu\u1ea9n n\u00ean \u0111\u01b0\u1ee3c 174 https:\/\/thuviensach.vn","g\u1ecdi l\u00e0 c\u00e1c \u201cb\u00f3ng \u0111\u00e8n nhi\u1ec7t\u201d th\u00ec th\u00edch h\u1ee3p h\u01a1n, b\u1edfi v\u00ec 90% \u0111i\u1ec7n n\u0103ng chuy\u1ec3n cho ch\u00fang \u0111\u01b0\u1ee3c bi\u1ebfn th\u00e0nh nhi\u1ec7t. Tuy nhi\u00ean, c\u00f3 r\u1ea5t nhi\u1ec1u c\u00e1ch \u0111\u1ec3 sinh ra \u00e1nh s\u00e1ng m\u00e0 kh\u00f4ng c\u1ea7n nhi\u1ec7t, v\u00e0 ch\u00fang ho\u1ea1t \u0111\u1ed9ng d\u1ef1a v\u00e0o c\u00e1c ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c h\u01a1n l\u00e0 nhi\u1ec7t \u0111\u1ec3 bu\u1ed9c c\u00e1c electron nh\u1ea3y l\u00ean c\u00e1c m\u1ee9c n\u0103ng l\u01b0\u1ee3ng cao h\u01a1n \u1edf trong nguy\u00ean t\u1eed, t\u1eeb \u0111\u00f3 ch\u00fang r\u01a1i xu\u1ed1ng tr\u1edf l\u1ea1i, ph\u00e1t ra n\u0103ng l\u01b0\u1ee3ng c\u1ee7a ch\u00fang d\u01b0\u1edbi d\u1ea1ng \u00e1nh s\u00e1ng. N\u00f3i chung, c\u00e1c qu\u00e1 tr\u00ecnh nh\u01b0 v\u1eady \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 s\u1ef1 ph\u00e1t quang, v\u00e0 trong \u0111\u1ecbnh ngh\u0129a r\u1ed9ng \u0111\u00f3 c\u00f3 r\u1ea5t nhi\u1ec1u c\u00e1ch \u0111\u1ec3 sinh ra \u00e1nh s\u00e1ng l\u1ea1nh. V\u00ed d\u1ee5, c\u00e1c h\u1ee3p ch\u1ea5t hu\u1ef3nh quang s\u1ebd b\u00f9ng ph\u00e1t \u00e1nh s\u00e1ng m\u1ed9t l\u00e1t n\u1ebfu \u0111\u01b0\u1ee3c k\u00edch th\u00edch th\u00edch h\u1ee3p nh\u01b0ng ph\u1ea3i c\u1ea7n c\u00f3 s\u1ef1 k\u00edch th\u00edch li\u00ean t\u1ee5c \u0111\u1ec3 ti\u1ebfp t\u1ee5c s\u00e1ng. Nh\u1eefng con s\u1ed1 ph\u00e1t s\u00e1ng tr\u00ean \u0111\u1ed3ng h\u1ed3 \u0111eo tay tr\u01b0\u1edbc \u0111\u00e2y c\u0169ng v\u1eady: ch\u00fang s\u1eed d\u1ee5ng c\u00e1c h\u1ee3p ch\u1ea5t nh\u01b0 k\u1ebdm sulphide, ch\u1ea5t m\u00e0 s\u1ef1 hu\u1ef3nh quang t\u01b0\u01a1ng \u0111\u1ed1i ng\u1eafn c\u1ee7a n\u00f3 \u0111\u01b0\u1ee3c sinh ra b\u1edfi s\u1ef1 ph\u00e2n r\u00e3 ph\u00f3ng x\u1ea1 c\u1ee7a radium (ch\u1ea5t n\u00e0y \u0111\u00e3 d\u1eabn t\u1edbi c\u00e1i ch\u1ebft c\u1ee7a nhi\u1ec1u ng\u01b0\u1eddi th\u1ee3 l\u00e0m con s\u1ed1). C\u00e1c \u0111\u1ed3ng h\u1ed3 ph\u00e1t s\u00e1ng ng\u00e0y nay s\u1eed d\u1ee5ng c\u00e1c h\u1ee3p ch\u1ea5t \u201c\u0111\u1ea5t hi\u1ebfm\u201d nh\u01b0 europium, c\u00e1c electron trong europium ph\u1ea3n \u1ee9ng l\u1ea1i v\u1edbi \u00e1nh s\u00e1ng ban ng\u00e0y th\u00f4ng th\u01b0\u1eddng r\u1ed3i ph\u00e1t ra \u00e1nh s\u00e1ng l\u1ea1nh s\u00e1ng m\u1ed9t c\u00e1ch k\u00ec l\u1ea1 trong su\u1ed1t \u0111\u00eam d\u00e0i. C\u0169ng nh\u01b0 b\u00ecnh th\u01b0\u1eddng, thi\u00ean nhi\u00ean l\u1ea1i chi\u1ebfn th\u1eafng: c\u00f3 r\u1ea5t nhi\u1ec1u sinh v\u1eadt nh\u01b0 c\u00e1 v\u00e0 \u0111om \u0111\u00f3m \u0111\u00e3 ph\u00e1t tri\u1ec3n c\u00e1c h\u00f3a ch\u1ea5t m\u00e0 c\u00f3 th\u1ec3 ph\u00e1t ra \u00e1nh s\u00e1ng l\u1ea1nh v\u1edbi hi\u1ec7u qu\u1ea3 th\u1eadt \u1ea5n t\u01b0\u1ee3ng. Ngay c\u1ea3 m\u1ed9t v\u00e0i lo\u1ea1i n\u1ea5m c\u0169ng l\u00e0m \u0111\u01b0\u1ee3c \u0111i\u1ec1u n\u00e0y, t\u1ea1o ra m\u00e0u s\u1eafc r\u1ef1c r\u1ee1 \u0111\u00e1ng s\u1ee3 khi ch\u00fang \u0111ang ph\u00e2n h\u1ee7y \u1edf trong r\u1eebng, ngay gi\u1eefa \u0111\u00eam khuya. 175 https:\/\/thuviensach.vn","140 T\u1ea1i sao phun n\u01b0\u1edbc b\u1ecdt v\u00e0o m\u1eb7t n\u1ea1 l\u1eb7n l\u00e0m cho n\u00f3 h\u1ebft m\u1edd? \u0110\u00e2y l\u00e0 hi\u1ec7u \u1ee9ng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 khi b\u1ea1n qu\u1ec7t nh\u1eb9 ng\u00f3n tay v\u00e0o m\u1ed9t m\u1ea9u x\u00e0 ph\u00f2ng v\u00e0 lau n\u00f3 tr\u00ean m\u1ed9t t\u1ea5m g\u01b0\u01a1ng b\u1ecb b\u00e1m h\u01a1i n\u01b0\u1edbc. N\u01b0\u1edbc b\u1ecdt gi\u00fap ph\u00e1 v\u1ee1 s\u1ee9c c\u0103ng b\u1ec1 m\u1eb7t c\u1ee7a n\u01b0\u1edbc \u0111\u1ecdng b\u00ean trong m\u1eb7t n\u1ea1, nh\u1edd \u0111\u00f3 n\u00f3 lan ra th\u00e0nh m\u1ed9t l\u1edbp ph\u1eb3ng t\u01b0\u01a1ng \u0111\u1ed1i \u00edt b\u1ecb b\u00f3p m\u00e9o m\u00e0 b\u1ea1n c\u00f3 th\u1ec3 nh\u00ecn xuy\u00ean qua, thay v\u00ec v\u00f4 s\u1ed1 nh\u1eefng gi\u1ecdt n\u01b0\u1edbc nh\u1ecf v\u00e0 tr\u00f2n. C\u00e1i g\u00ec \u0111\u00e3 g\u00e2y ra c\u00e1c d\u00f2ng 141 b\u1ecdt kh\u00ed nh\u1ecf b\u1ed1c l\u00ean trong m\u1ed9t ly s\u00e2m-panh? \u0110\u00e2y l\u00e0 m\u1ed9t trong s\u1ed1 nh\u1eefng c\u00e2u h\u1ecfi t\u1ea7m th\u01b0\u1eddng m\u00e0 l\u1ea1i d\u1eabn \u0111\u1ebfn gi\u1ea3i Nobel. C\u00e1c b\u1ecdt kh\u00ed trong s\u00e2m-panh v\u00e0 n\u01b0\u1edbc u\u1ed1ng c\u00f3 ga l\u00e0 carbon dioxide. Kh\u00ed n\u00e0y \u0111\u01b0\u1ee3c n\u00e9n \u00e9p v\u00e0o n\u01b0\u1edbc d\u01b0\u1edbi \u00e1p su\u1ea5t cao, khi m\u1edf chai, \u00e1p su\u1ea5t gi\u1ea3m, kh\u00ed \u0111\u00e3 tho\u00e1t ra kh\u1ecfi ch\u1ea5t l\u1ecfng. Khi c\u00e1c ph\u00e2n t\u1eed carbon dioxide tho\u00e1t ra, m\u1ed9t s\u1ed1 va ch\u1ea1m v\u00e0o th\u00e0nh ly v\u00e0 b\u1ecb m\u1eafc v\u00e0o trong c\u00e1c khe h\u1edf nh\u1ecf hay b\u00e1m v\u00e0o c\u00e1c h\u1ea1t b\u1ee5i. N\u1ebfu c\u00f3 \u0111\u1ee7 kh\u00ed \u0111\u01b0\u1ee3c t\u00edch t\u1ee5 \u1edf \u201c\u0111i\u1ec3m t\u1ea1o nh\u00e2n\u201d n\u00e0y, n\u00f3 176 https:\/\/thuviensach.vn","s\u1ebd t\u1ea1o th\u00e0nh m\u1ed9t b\u1ecdt kh\u00ed l\u1edbn d\u1ea7n l\u00ean cho t\u1edbi khi n\u00f3 v\u1ee1 ra v\u00e0 n\u1ed5i l\u00ean b\u1ec1 m\u1eb7t. K\u1ebft qu\u1ea3: m\u1ed9t d\u00f2ng li\u00ean t\u1ee5c c\u00e1c b\u1ecdt kh\u00ed n\u1ed5i l\u00ean d\u01b0\u1eddng nh\u01b0 ch\u1eb3ng t\u1eeb n\u01a1i n\u00e0o c\u1ea3. N\u0103m 1952, khi nh\u00e0 v\u1eadt l\u00fd Donald Glaser \u0111ang suy ngh\u0129 v\u1ec1 c\u00e1c b\u1ecdt kh\u00ed n\u1ed5i l\u00ean trong ly bia c\u1ee7a m\u00ecnh, \u00f4ng nh\u1eadn ra r\u1eb1ng m\u1ed9t qu\u00e1 tr\u00ecnh t\u01b0\u01a1ng t\u1ef1 c\u00f3 th\u1ec3 ti\u1ebft l\u1ed9 s\u1ef1 hi\u1ec7n di\u1ec7n c\u1ee7a c\u00e1c h\u1ea1t h\u1ea1 nguy\u00ean t\u1eed, th\u1ee9 c\u00f3 th\u1ec3 t\u1ea1o ra m\u1ed9t v\u1ec7t bong b\u00f3ng khi b\u1ecb ph\u00f3ng qua hydrogen l\u1ecfng. \u0110i\u1ec1u n\u00e0y \u0111\u00e3 d\u1eabn \u00f4ng t\u1edbi s\u1ef1 ph\u00e1t minh \u201cbu\u1ed3ng bong b\u00f3ng\u201d (bubble chamber) v\u00e0 \u0111\u1ea1t \u0111\u01b0\u1ee3c gi\u1ea3i Nobel v\u1eadt l\u00fd n\u0103m 1960. 142 Acid m\u1ea1nh nh\u1ea5t l\u00e0 ch\u1ea5t n\u00e0o? Acid \u0111\u00e1ng s\u1ee3 nh\u1ea5t th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng trong c\u00e1c ph\u00f2ng th\u00ed nghi\u1ec7m l\u00e0 hydrofluoric acid (HF), d\u00f9ng \u0111\u1ec3 l\u00e0m s\u1ea1ch kim lo\u1ea1i. M\u1ed9t ch\u1ea5t l\u1ecfng kh\u00f4ng m\u00e0u, m\u1edd gi\u1ed1ng kh\u00f3i, HF c\u00f3 t\u00ednh \u0103n m\u00f2n kh\u1ee7ng khi\u1ebfp, nh\u01b0 nhi\u1ec1u c\u00e2u chuy\u1ec7n kinh d\u1ecb \u0111\u00e3 ch\u1ee9ng th\u1ef1c. M\u1ed9t k\u1ef9 thu\u1eadt vi\u00ean trong m\u1ed9t ph\u00f2ng th\u00ed nghi\u1ec7m t\u00ecnh c\u1edd \u0111\u00e3 l\u00e0m tr\u00e0n m\u1ed9t ly \u0111\u1ea7y HF l\u00ean \u0111\u00f9i m\u00ecnh; d\u00f9 \u0111\u00e3 nh\u00fang m\u00ecnh ngay l\u1eadp t\u1ee9c v\u00e0o n\u01b0\u1edbc v\u00e0 \u0111\u01b0\u1ee3c chuy\u1ec3n g\u1ea5p \u0111\u1ebfn b\u1ec7nh vi\u1ec7n, anh v\u1eabn b\u1ecb m\u1ea5t c\u00e1i ch\u00e2n \u0111\u00f3. Ngay c\u1ea3 sau \u0111\u00f3, ph\u1ea3n \u1ee9ng gi\u1eefa HF v\u00e0 calcium trong x\u01b0\u01a1ng c\u1ee7a anh v\u1eabn kh\u00f4ng d\u1eebng l\u1ea1i v\u00e0 anh \u0111\u00e3 ch\u1ebft sau 15 ng\u00e0y \u0111au \u0111\u1edbn. M\u1ed9t \u0111i\u1ec1u l\u1ea1 l\u00e0, b\u1ea5t k\u1ec3 t\u00ednh ho\u1ea1t 177 https:\/\/thuviensach.vn","\u0111\u1ed9ng c\u1ef1c m\u1ea1nh c\u1ee7a n\u00f3 tr\u00ean kim lo\u1ea1i v\u00e0 m\u00f4 s\u1ed1ng, HF c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ch\u1ee9a trong c\u00e1c chai \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb m\u1ed9t s\u1ed1 lo\u1ea1i ch\u1ea5t d\u1ebbo. Tuy nhi\u00ean, v\u1eabn c\u00f2n c\u00f3 m\u1ed9t acid \u0103n m\u00f2n m\u1ea1nh h\u01a1n n\u1eefa. B\u1eb1ng c\u00e1ch h\u00f2a tr\u1ed9n v\u1edbi nhau nhi\u1ec1u h\u00f3a ch\u1ea5t kh\u1ee7ng khi\u1ebfp, c\u00e1c nh\u00e0 h\u00f3a h\u1ecdc \u0111\u00e3 \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ed9t h\u1ed7n h\u1ee3p c\u1ee7a antimony pentafuoride, fluorosulphonic acid v\u00e0 sulfur tri- oxide, v\u1edbi t\u00ednh acid l\u1edbn h\u01a1n nhi\u1ec1u so v\u1edbi b\u1ea5t k\u1ef3 h\u1ee3p ch\u1ea5t n\u00e0o kh\u00e1c; l\u1edbn \u0111\u1ebfn n\u1ed7i, ch\u1eb3ng ai bi\u1ebft ch\u1eafc \u0111\u01b0\u1ee3c t\u00ednh acid c\u1ee7a n\u00f3 th\u1ef1c s\u1ef1 m\u1ea1nh t\u1edbi m\u1ee9c n\u00e0o. 143 T\u1ea1i sao m\u1ed9t s\u1ed1 ch\u1ea5t r\u1eafn nh\u01b0 th\u1ee7y tinh v\u00e0 perpex (ch\u1ea5t d\u1ebbo l\u00e0m k\u00ednh m\u00e1y bay) l\u1ea1i trong su\u1ed1t? B\u1ea5t c\u1ee9 v\u1eadt n\u00e0o trong su\u1ed1t \u0111\u1ec1u cho ph\u00e9p c\u00e1c tia s\u00e1ng \u0111i xuy\u00ean qua c\u00e1c l\u1edbp nguy\u00ean t\u1eed d\u00e0y \u0111\u1eb7c c\u1ee7a n\u00f3 m\u1ed9t c\u00e1ch g\u1ea7n nh\u01b0 to\u00e0n v\u1eb9n. V\u00ec ch\u1ec9 m\u1ed9t h\u1ea1t mu\u1ed1i nh\u1ecf c\u0169ng ch\u1ee9a c\u0169ng ch\u1ee9a kho\u1ea3ng 20 t\u1ec9 nguy\u00ean t\u1eed, kh\u00f4ng c\u00f3 g\u00ec ng\u1ea1c nhi\u00ean khi \u00e1nh s\u00e1ng kh\u00f4ng th\u1ec3 t\u00ecm \u0111\u01b0\u1ee3c \u0111\u01b0\u1eddng \u0111i qua h\u1ea7u h\u1ebft ch\u1ea5t r\u1eafn v\u00e0 b\u1ecb gi\u1eef l\u1ea1i, b\u1ecb ph\u1ea3n x\u1ea1 hay ph\u00e2n t\u00e1n b\u1edfi c\u00e1c \u0111\u00e1m m\u00e2y electron bao quanh m\u1ed7i nguy\u00ean t\u1eed. L\u00fd do m\u00e0 \u00e1nh s\u00e1ng c\u00f3 th\u1ec3 \u0111i xuy\u00ean qua c\u00e1c ch\u1ea5t nh\u01b0 th\u1ee7y tinh l\u00e0 b\u1edfi v\u00ec c\u00e1c ph\u00e2n t\u1eed c\u1ee7a ch\u00fang ch\u1ec9 gi\u1eef \u0111\u01b0\u1ee3c c\u00e1c tia s\u00e1ng v\u1edbi b\u01b0\u1edbc s\u00f3ng ng\u1eafn h\u01a1n \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c (n\u00f3 bao g\u1ed3m c\u1ea3 c\u00e1c tia s\u00e1ng t\u1eed ngo\u1ea1i sinh ung th\u01b0, may 178 https:\/\/thuviensach.vn","gh\u00ea). K\u00ednh c\u00f2n c\u00f3 t\u00ednh ch\u1ea5t tr\u01a1n nh\u1eb5n v\u00e0 v\u00f4 \u0111\u1ecbnh h\u00ecnh v\u00e0 do \u0111\u00f3 c\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a n\u00f3 kh\u00f4ng c\u00f3 b\u1ea5t c\u1ee9 th\u1ee9 g\u00ec c\u00f3 k\u00edch th\u01b0\u1edbc t\u01b0\u01a1ng t\u1ef1 v\u1edbi \u0111\u1ed9 d\u00e0i b\u01b0\u1edbc s\u00f3ng c\u1ee7a \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c. Do \u0111\u00f3 c\u00e1c tia n\u00e0y c\u00f3 th\u1ec3 \u0111i xuy\u00ean qua v\u1edbi s\u1ef1 ph\u00e2n t\u00e1n v\u00e0 m\u1ea5t m\u00e1t n\u0103ng l\u01b0\u1ee3ng t\u1ed1i thi\u1ec3u, cho ph\u00e9p ch\u00fang ta nh\u00ecn c\u00e1c v\u1eadt th\u1ec3 xuy\u00ean qua ch\u00fang m\u1ed9t c\u00e1ch r\u00f5 r\u00e0ng. V\u1edbi nhi\u1ec1u ch\u1ea5t r\u1eafn, ch\u1eb3ng c\u00f3 c\u00e1ch n\u00e0o \u0111\u1ec3 thay \u0111\u1ed5i c\u1ea5u tr\u00fac b\u00ean trong hay ph\u00e2n t\u1eed c\u1ee7a ch\u00fang \u0111\u1ec3 l\u00e0m cho ch\u00fang trong su\u1ed1t. M\u1ed9t ph\u01b0\u01a1ng ph\u00e1p thay th\u1ebf l\u00e0 chuy\u1ec3n sang d\u00f9ng \u00e1nh s\u00e1ng v\u1edbi b\u01b0\u1edbc s\u00f3ng ng\u1eafn h\u01a1n v\u00e0 kh\u1ea3 n\u0103ng xuy\u00ean th\u1ea5u cao h\u01a1n, ch\u1eb3ng h\u1ea1n nh\u01b0 tia X. T\u1ea1i sao c\u00e1c v\u1eadt th\u1ec3 kim lo\u1ea1i 144 c\u00f3 c\u1ea3m gi\u00e1c l\u1ea1nh h\u01a1n c\u00e1c v\u1eadt th\u1ec3 b\u1eb1ng g\u1ed7, khi c\u1ea3 hai \u0111\u1ec1u \u1edf c\u00f9ng nhi\u1ec7t \u0111\u1ed9? Khi ch\u00fang ta ch\u1ea1m v\u00e0o m\u1ed9t v\u1eadt th\u1ec3, ch\u00fang ta kh\u00f4ng th\u1ef1c s\u1ef1 c\u1ea3m nh\u1eadn nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u00f3 m\u00e0 ch\u1ec9 c\u1ea3m nh\u1eadn chi\u1ec1u v\u00e0 t\u1ed1c \u0111\u1ed9 c\u1ee7a d\u00f2ng nhi\u1ec7t l\u01b0\u1ee3ng gi\u1eefa ng\u00f3n tay c\u1ee7a ch\u00fang ta v\u00e0 v\u1eadt th\u1ec3. V\u00ed d\u1ee5, trong m\u1ed9t c\u0103n ph\u00f2ng 210C, b\u1ea5t c\u1ee9 v\u1eadt n\u00e0o c\u0169ng l\u1ea1nh h\u01a1n ng\u00f3n tay c\u1ee7a ch\u00fang ta (ng\u00f3n tay c\u00f3 nhi\u1ec7t \u0111\u1ed9 g\u1ea7n v\u1edbi th\u00e2n nhi\u1ec7t, kho\u1ea3ng 370C). B\u1ea5t ch\u1ea5p r\u1eb1ng t\u1ea5t c\u1ea3 v\u1eadt th\u1ec3 \u0111\u1ec1u \u1edf c\u00f9ng nhi\u1ec7t \u0111\u1ed9, 179 https:\/\/thuviensach.vn","c\u00e1c v\u1eadt b\u1eb1ng g\u1ed7 v\u1eabn c\u00f3 th\u1ec3 l\u00e0m cho ta c\u00f3 c\u1ea3m gi\u00e1c \u1ea5m h\u01a1n, b\u1edfi v\u00ec g\u1ed7 d\u1eabn truy\u1ec1n nhi\u1ec7t \u00edt h\u01a1n 100 l\u1ea7n so v\u1edbi kim lo\u1ea1i v\u00e0 do \u0111\u00f3 s\u1ef1 m\u1ea5t m\u00e1t nhi\u1ec7t t\u1eeb ng\u00f3n tay ch\u00fang ta sang v\u1eadt \u0111\u00f3 c\u0169ng ch\u1eadm h\u01a1n nhi\u1ec1u. V\u1edbi nh\u1eefng v\u1eadt n\u00f3ng h\u01a1n ch\u00fang ta, hi\u1ec7u \u1ee9ng n\u00e0y s\u1ebd ho\u1ea1t \u0111\u1ed9ng ng\u01b0\u1ee3c l\u1ea1i, l\u00e0m cho c\u00e1c v\u1eadt b\u1eb1ng g\u1ed7 c\u00f3 c\u1ea3m gi\u00e1c t\u01b0\u01a1ng \u0111\u1ed1i l\u1ea1nh. Do \u0111\u00f3, v\u00ed d\u1ee5, m\u1ed9t c\u00e1i gh\u1ebf d\u00e0i b\u1eb1ng g\u1ed7 m\u00e0 \u0111\u00e3 \u1edf d\u01b0\u1edbi m\u1eb7t tr\u1eddi c\u1ea3 m\u1ed9t ng\u00e0y s\u1ebd kh\u00f4ng l\u00e0m ch\u00fang ta c\u1ea3m th\u1ea5y n\u00f3ng b\u1eb1ng tay v\u1ecbn b\u1eb1ng s\u1eaft c\u1ee7a n\u00f3, ngay c\u1ea3 khi ch\u00fang c\u00f3 c\u00f9ng nhi\u1ec7t \u0111\u1ed9, b\u1edfi v\u00ec v\u1eadn t\u1ed1c m\u00e0 ch\u00fang ta nh\u1eadn nhi\u1ec7t l\u01b0\u1ee3ng t\u1eeb chi\u1ebfc gh\u1ebf g\u1ed7 ch\u1eadm h\u01a1n nhi\u1ec1u so v\u1edbi v\u1eadn t\u1ed1c t\u1eeb thanh kim lo\u1ea1i c\u1ee7a tay v\u1ecbn gh\u1ebf. 180 https:\/\/thuviensach.vn","M\u1ee5c l\u1ee5c TH\u1ebe GI\u1edaI T\u1ef0 NHI\u00caN 1.\t \u0110\u1ed9ng v\u1eadt th\u1eadt s\u1ef1 c\u00f3 th\u1ec3 c\u1ea3m nh\u1eadn m\u1ed9t c\u01a1n \u0111\u1ed9ng \u0111\u1ea5t \t\t \t s\u1eafp \u0111\u1ebfn kh\u00f4ng?\t 5 2.\t T\u1ea1i sao nam gi\u1edbi c\u00f3 nhi\u1ec1u g\u1ea7n b\u1eb1ng n\u1eef gi\u1edbi?\t 7 3.\t T\u1ea1i sao con ng\u01b0\u1eddi \u0111i th\u1eb3ng tr\u00ean hai ch\u00e2n?\t 8 4.\t B\u1ea1n c\u00f3 bi\u1ebft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa alligator (c\u00e1 s\u1ea5u M\u1ef9) \t\t \t v\u00e0 crocodile (c\u00e1 s\u1ea5u) kh\u00f4ng?\t 10 5.\t Thuy\u1ec1n c\u00f3 th\u1ec3 b\u1ecb \u0111\u00e1nh ch\u00ecm b\u1edfi m\u1ef1c \u1ed1ng \t\t \t kh\u1ed5ng l\u1ed3 kh\u00f4ng?\t 11 6.\t N\u1ebfu hi\u1ec7n t\u01b0\u1ee3ng th\u1ea7n giao c\u00e1ch c\u1ea3m c\u00f3 th\u1eadt, \t\t \t t\u1ea1i sao lu\u1eadt ti\u1ebfn h\u00f3a l\u1ea1i kh\u00f4ng l\u00e0m cho n\u00f3 ph\u1ed5 bi\u1ebfn?\t 12 7.\t X\u00e9t theo c\u00e1c t\u1ebf b\u00e0o trong c\u01a1 th\u1ec3, c\u00f3 ph\u1ea3i ch\u00fang ta \t\t \t kh\u00f4ng c\u00f2n l\u00e0 ch\u00fang ta c\u00e1ch \u0111\u00e2y 10 n\u0103m?\t 14 8.\t T\u1ea1i sao nam gi\u1edbi c\u00f3 n\u00fam v\u00fa?\t 16 9.\t Dung l\u01b0\u1ee3ng tr\u00ed nh\u1edb c\u1ee7a b\u1ed9 n\u00e3o con ng\u01b0\u1eddi l\u00e0 bao nhi\u00eau?\t17 10.\tT\u1ea1i sao chim \u0111\u1ee9ng tr\u00ean d\u00e2y \u0111i\u1ec7n m\u00e0 kh\u00f4ng b\u1ecb gi\u1eadt \u0111i\u1ec7n?\t 19 11.\tC\u00f3 ph\u1ea3i b\u00e1nh m\u00ec kh\u00f4ng t\u1ed1t cho v\u1ecbt - v\u00e0 n\u1ebfu v\u1eady, \t\t \t ch\u00fang ta n\u00ean cho ch\u00fang \u0103n c\u00e1i g\u00ec?\t 20 12.\tN\u1ebfu ti\u1ebfn h\u00f3a l\u00e0 ng\u1eabu nhi\u00ean th\u00ec l\u00e0m sao ta gi\u1ea3i th\u00edch \t\t \t \u0111\u01b0\u1ee3c nh\u1eefng thi\u1ebft k\u1ebf hi\u1ec7n c\u00f3 trong t\u1ef1 nhi\u00ean?\t 21 13.\tL\u00e0m sao m\u00e8o s\u1ed1ng s\u00f3t qua nh\u1eefng c\u00fa r\u01a1i c\u00f3 th\u1ec3 \t\t \t gi\u1ebft ch\u1ebft con ng\u01b0\u1eddi?\t 22 14.\tT\u1ea1i sao ti\u1ebfng k\u00eau c\u1ee7a v\u1ecbt l\u1ea1i kh\u00f4ng t\u1ea1o ti\u1ebfng v\u1ecdng?\t 23 181 https:\/\/thuviensach.vn","15.\t C\u00f3 th\u1eadt l\u00e0 r\u00eau c\u00f3 khuynh h\u01b0\u1edbng m\u1ecdc \u1edf ph\u00eda b\u1eafc \t\t \t c\u1ee7a th\u00e2n c\u00e2y?\t 24 16.\tT\u1ea1i sao nh\u1eefng \u0111\u1ed9ng v\u1eadt c\u00f3 v\u00fa \u1edf bi\u1ec3n nh\u01b0 c\u00e1 heo \t\t \t ch\u1ec9 s\u1ed1ng \u0111\u01b0\u1ee3c trong n\u01b0\u1edbc mu\u1ed1i?\t 25 17.\tB\u1eb1ng c\u00e1ch n\u00e0o h\u01a1i \u1ea9m trong \u0111\u1ea5t \u0111\u1ebfn \u0111\u01b0\u1ee3c ng\u1ecdn \t\t \t nh\u1eefng c\u00e2y cao?\t 26 18.\tC\u00f3 ph\u1ea3i t\u1ea5t c\u1ea3 \u0111\u1ed9ng v\u1eadt th\u01b0\u1eddng thu\u1eadn tay ph\u1ea3i?\t 27 19.\tT\u1ea1i sao ch\u00fang ta kh\u00f4ng th\u1ec3 t\u1ef1 c\u00f9 l\u00e9c?\t 28 20.\tT\u1ea1i sao n\u1eef gi\u1edbi nh\u1ecf h\u01a1n nam gi\u1edbi?\t 29 21.\tKh\u1ee7ng long kh\u1ed5ng l\u1ed3 c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u1ef1ng \u0111\u01b0\u1ee3c \t\t \t ch\u1ebf \u0111\u1ed9 \u0103n rau c\u1ecf th\u00f4i kh\u00f4ng?\t 30 22.\tT\u1ea1i sao nh\u1ec7n kh\u00f4ng b\u1ecb d\u00ednh v\u00e0o m\u1ea1ng c\u1ee7a ch\u00fang?\t 31 23.\tT\u1ea1i sao b\u1ea1n kh\u00f4ng th\u1ec3 hu\u1ea5n luy\u1ec7n m\u00e8o?\t 32 24.\tT\u1ea1i sao qu\u1ea3 tr\u1ee9ng c\u00f3 h\u00ecnh qu\u1ea3 tr\u1ee9ng?\t 32 25.\tLo\u00e0i nh\u1ec7n gi\u0103ng t\u01a1 nh\u01b0 th\u1ebf n\u00e0o?\t 34 26.\tC\u00f3 th\u1eadt l\u00e0 m\u1ed9t v\u00e0i con tinh tinh \u0111\u00e3 \u0111\u01b0\u1ee3c d\u1ea1y \t\t \t cho n\u00f3i kh\u00f4ng ?\t 35 27.\tV\u00ec sao c\u00e1 voi l\u1eb7n \u0111\u01b0\u1ee3c r\u1ea5t s\u00e2u m\u00e0 kh\u00f4ng c\u00f3 \t\t \t bi\u1ec3u hi\u1ec7n kh\u00f3 ch\u1ecbu n\u00e0o?\t 36 28.\tT\u1ea1i sao m\u1ed9t s\u1ed1 ng\u01b0\u1eddi h\u1eaft h\u01a1i khi nh\u00ecn v\u00e0o m\u1eb7t tr\u1eddi?\t 37 29.\tT\u1ea1i sao ng\u01b0\u1eddi \u1edf nh\u1eefng n\u01b0\u1edbc n\u00f3ng l\u1ea1i da \u0111en?\t 38 TR\u00caN TR\u1edcI - D\u01af\u1edaI \u0110\u1ea4T 30.\tB\u1eb1ng c\u00e1ch n\u00e0o ng\u01b0\u1eddi Hi L\u1ea1p c\u1ed5 bi\u1ebft \u0111\u01b0\u1ee3c tr\u00e1i \u0111\u1ea5t tr\u00f2n?\t41 31.\tS\u1ef1 tr\u00f4i c\u1ee7a c\u00e1c l\u1ee5c \u0111\u1ecba s\u1ebd t\u00e1c \u0111\u1ed9ng t\u1edbi b\u1ea3n \u0111\u1ed3 tr\u00e1i \u0111\u1ea5t \t\t \t t\u01b0\u01a1ng lai nh\u01b0 th\u1ebf n\u00e0o?\t 42 32.\tBao gi\u1edd th\u00ec nhi\u00ean li\u1ec7u h\u00f3a th\u1ea1ch c\u1ea1n ki\u1ec7t?\t 43 182 https:\/\/thuviensach.vn","33.\tT\u1ea5t c\u1ea3 l\u01b0\u1ee3ng n\u01b0\u1edbc trong c\u00e1c \u0111\u1ea1i d\u01b0\u01a1ng \t\t \t c\u1ee7a th\u1ebf gi\u1edbi b\u1eaft ngu\u1ed3n t\u1eeb \u0111\u00e2u?\t 45 34.\tLi\u1ec7u c\u00f3 bao gi\u1edd tr\u00e1i \u0111\u1ea5t s\u1ebd ng\u1eebng xoay kh\u00f4ng?\t 46 35.\tNam c\u1ef1c \u0111\u00e3 b\u1ecb \u0111\u00f3ng b\u0103ng t\u1eeb bao gi\u1edd?\t 48 36.\tB\u1eb1ng c\u00e1ch n\u00e0o Scott v\u00e0 Amundsen t\u00ecm ra Nam C\u1ef1c \t\t \t m\u00e0 kh\u00f4ng c\u1ea7n s\u1ef1 h\u1ed7 tr\u1ee3 c\u1ee7a c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n h\u00e0ng h\u1ea3i \t\t \t hi\u1ec7n \u0111\u1ea1i?\t 49 37.\tLi\u1ec7u cu\u1ed1i c\u00f9ng s\u1ef1 ph\u00e1 r\u1eebng c\u00f3 khi\u1ebfn ch\u00fang ta \t\t \t c\u1ea1n ki\u1ec7t kh\u00ed oxy?\t 51 38.\tC\u00f3 bao nhi\u00eau n\u01b0\u1edbc trong kh\u00ed quy\u1ec3n n\u1ebfu so s\u00e1nh \t\t \t v\u1edbi c\u00e1c \u0111\u1ea1i d\u01b0\u01a1ng?\t 52 39.\tT\u1ea1i sao s\u1ef1 n\u00f3ng l\u00ean to\u00e0n c\u1ea7u l\u1ea1i l\u00e0m d\u00e2ng \t\t \t m\u1ef1c n\u01b0\u1edbc bi\u1ec3n?\t 52 40.\tLi\u1ec7u s\u1ef1 n\u00f3ng l\u00ean to\u00e0n c\u1ea7u c\u00f3 l\u00e0m cho d\u00f2ng h\u1ea3i l\u01b0u \t\t \t Gulf Stream bi\u1ebfn m\u1ea5t?\t 53 41.\tTr\u00e1i \u0111\u1ea5t c\u00e1ch xa m\u1eb7t tr\u1eddi nh\u1ea5t v\u00e0o th\u00e1ng 7, v\u1eady t\u1ea1i sao \t\t \t \u0111\u00e2y l\u1ea1i l\u00e0 th\u00e1ng n\u00f3ng nh\u1ea5t trong n\u0103m \u1edf b\u1eafc b\u00e1n c\u1ea7u?\t 55 42.\tT\u1ea1i sao m\u1eb7t tr\u1eddi v\u1eabn m\u1ecdc tr\u1ec5 h\u01a1n v\u00e0o bu\u1ed5i s\u00e1ng \t\t \t sau ng\u00e0y ng\u1eafn nh\u1ea5t trong n\u0103m?\t 56 43.\tLi\u1ec7u c\u00e1c t\u1ea3ng b\u0103ng tr\u00f4i \u1edf Nam c\u1ef1c c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \t\t \t k\u00e9o v\u1ec1 nh\u1eefng mi\u1ec1n \u0111\u1ea5t kh\u00f4 c\u1eb1n?\t 58 44.\t\u0110\u1ed9ng \u0111\u1ea5t \u0111\u00e3 bao gi\u1edd \u0111\u01b0\u1ee3c d\u1ef1 \u0111o\u00e1n th\u00e0nh c\u00f4ng ch\u01b0a?\t 59 45.\tT\u1ea1i sao c\u1ef1c b\u1eafc c\u1ee7a t\u1eeb tr\u01b0\u1eddng tr\u00e1i \u0111\u1ea5t kh\u00f4ng n\u1eb1m \t\t \t \u1edf B\u1eafc c\u1ef1c?\t 61 46.\t\u0110i\u1ec1u g\u00ec s\u1ebd x\u1ea3y ra khi c\u00e1c c\u1ef1c t\u1eeb tr\u01b0\u1eddng c\u1ee7a \t\t \t tr\u00e1i \u0111\u1ea5t \u0111\u1ea3o ng\u01b0\u1ee3c \u0111i?\t 63 47.\tLi\u1ec7u m\u1ed9t b\u1edd bi\u1ec3n \u1edf qu\u1ea7n \u0111\u1ea3o Canary c\u00f3 th\u1ec3 t\u1ea1o ra \t\t \t m\u1ed9t c\u01a1n s\u00f3ng th\u1ea7n l\u1edbn kh\u00f4ng?\t 64 183 https:\/\/thuviensach.vn","48.\tT\u1ea1i sao b\u00ean trong tr\u00e1i \u0111\u1ea5t v\u1eabn n\u00f3ng sau nhi\u1ec1u t\u1ec9 n\u0103m?\t 66 49.\tN\u1ebfu b\u00ean trong tr\u00e1i \u0111\u1ea5t b\u1ecb n\u00f3ng ch\u1ea3y, t\u1ea1i sao s\u1ee9c n\u00f3ng \t\t \t ch\u1ec9 l\u00ean t\u1edbi b\u1ec1 m\u1eb7t t\u1ea1i c\u00e1c n\u00fai l\u1eeda?\t 67 50.\tNg\u01b0\u1eddi ta s\u1ebd c\u00e2n nh\u1eb9 \u0111i bao nhi\u00eau khi \u1edf v\u00f9ng x\u00edch \u0111\u1ea1o?\t68 51.\tV\u00ec ozone l\u00e0 kh\u00ed, b\u1eb1ng c\u00e1ch n\u00e0o m\u00e0 m\u1ed9t th\u1ee9 \t\t \t \u0111\u01b0\u1ee3c cho l\u00e0 \u201cl\u1ed7 th\u1ee7ng\u201d c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n?\t 69 52.\tNh\u1eefng \u0111i\u1ec1u ki\u1ec7n tr\u00ean tr\u00e1i \u0111\u1ea5t ph\u1ea3i thay \u0111\u1ed5i \t\t \t t\u1edbi m\u1ee9c n\u00e0o m\u1edbi c\u00f3 th\u1ec3 lo\u1ea1i tr\u1eeb s\u1ef1 s\u1ed1ng?\t 70 53.\tC\u00e1c t\u00e1c \u0111\u1ed9ng c\u1ee7a kh\u00ed quy\u1ec3n c\u00f3 th\u1ec3 cho ph\u00e9p \t\t \t m\u1ed9t ng\u01b0\u1eddi nh\u00ecn qua c\u1ea3 \u0111\u01b0\u1eddng ch\u00e2n tr\u1eddi kh\u00f4ng?\t 72 54.\tMu\u1ed1i \u1edf bi\u1ec3n t\u1eeb \u0111\u00e2u t\u1edbi v\u00e0 n\u00f3 c\u00f3 \u0111ang ti\u1ebfp t\u1ee5c \t\t \t t\u00edch t\u1ee5 l\u1ea1i n\u1eefa kh\u00f4ng?\t 73 55.\tM\u00e1y bay Concorde \u0111\u00e3 bay b\u00ean cao h\u01a1n kh\u00ed quy\u1ec3n \t\t \t bao nhi\u00eau ph\u1ea7n tr\u0103m ?\t 74 TR\u00caN THI\u00caN \u0110\u00c0NG 56.\tKh\u00f4ng gian \u0111\u01b0\u1ee3c t\u00ednh t\u1eeb \u0111\u00e2u?\t 76 57.\tT\u1ea1i sao ch\u00fang ta kh\u00f4ng c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed9ng \t\t \t c\u1ee7a tr\u00e1i \u0111\u1ea5t khi ch\u00fang ta quay quanh m\u1eb7t tr\u1eddi?\t 77 58.\tT\u1ea1i sao m\u1eb7t tr\u0103ng c\u00f3 v\u1ebb l\u1edbn h\u01a1n khi n\u00f3 \u1edf tr\u00ean \t\t \t \u0111\u01b0\u1eddng ch\u00e2n tr\u1eddi?\t 78 59.\tT\u1ea1i sao t\u1ea5t c\u1ea3 c\u00e1c h\u00e0nh tinh \u0111\u1ec1u c\u00f3 h\u00ecnh c\u1ea7u?\t 79 60.\tT\u1ea1i sao t\u1ea5t c\u1ea3 c\u00e1c h\u00e0nh tinh, c\u00e1c ng\u00f4i sao v\u00e0 \t\t \t c\u00e1c thi\u00ean h\u00e0 \u0111\u1ec1u xoay?\t 81 61.\tT\u1ea1i sao \u0111\u00f4i khi b\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y n\u1eeda t\u1ed1i c\u1ee7a \t\t \t m\u1ed9t m\u1eb7t tr\u0103ng l\u01b0\u1ee1i li\u1ec1m?\t 82 62.\tT\u1ea1i sao m\u1eb7t tr\u0103ng lu\u00f4n h\u01b0\u1edbng c\u00f9ng m\u1ed9t m\u1eb7t \t\t \t v\u1ec1 ph\u00eda tr\u00e1i \u0111\u1ea5t?\t 83 184 https:\/\/thuviensach.vn","63.\tKh\u1ea3 n\u0103ng s\u1ef1 s\u1ed1ng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 \u1edf tr\u00e1i \u0111\u1ea5t t\u1ed3n t\u1ea1i \t\t \t \u1edf c\u00e1c n\u01a1i kh\u00e1c trong v\u0169 tr\u1ee5 l\u00e0 bao nhi\u00eau?\t 84 64.\t\u00dd t\u01b0\u1edfng v\u1ec1 tr\u1ecdng l\u1ef1c nh\u00e2n t\u1ea1o trong c\u00e1c t\u00e0u \t\t \t kh\u00f4ng gian \u0111\u00e3 \u0111i v\u1ec1 \u0111\u00e2u?\t 85 65.\tB\u1eb1ng c\u00e1ch n\u00e0o t\u00ecnh tr\u1ea1ng kh\u00f4ng tr\u1ecdng l\u1ef1c \t\t \t \u0111\u01b0\u1ee3c t\u1ea1o ra trong m\u1ed9t m\u00e1y bay?\t 86 66.\tT\u1ea1i sao nh\u1eefng ng\u01b0\u1eddi \u1edf ph\u00eda nam c\u1ee7a \u0111\u01b0\u1eddng x\u00edch \u0111\u1ea1o \t\t \t kh\u00f4ng c\u1ea3m th\u1ea5y h\u1ecd b\u1ecb l\u1ed9n ng\u01b0\u1ee3c?\t 87 67.\tB\u1eb1ng c\u00e1ch n\u00e0o v\u00e0 khi n\u00e0o m\u00e0 tr\u00e1i \u0111\u1ea5t \t\t \t c\u00f3 \u0111\u01b0\u1ee3c m\u1eb7t tr\u0103ng?\t 88 68.\tT\u1ea1i sao m\u1ed7i ng\u00e0y c\u00f3 hai \u0111\u1ee3t th\u1ee7y tri\u1ec1u l\u00ean?\t 89 69.\tTr\u00e1i \u0111\u1ea5t b\u1ecb t\u00e1c \u0111\u1ed9ng b\u1edfi c\u00e1c h\u00e0nh tinh kh\u00e1c \t\t \t t\u1edbi m\u1ee9c \u0111\u1ed9 n\u00e0o?\t 91 70.\tThi\u00ean th\u1ea1ch c\u00f3 g\u00e2y ra ti\u1ebfng \u0111\u1ed9ng khi \t\t \t ch\u00fang r\u01a1i v\u00e0o tr\u00e1i \u0111\u1ea5t kh\u00f4ng?\t 92 71.\tV\u1eadt th\u1ec3 xa nh\u1ea5t c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c b\u1eb1ng m\u1eaft th\u01b0\u1eddng l\u00e0 g\u00ec?\t 93 72.\tKhi m\u1ed9t thi\u00ean th\u1ea1ch \u0111\u1ebfn g\u1ea7n tr\u00e1i \u0111\u1ea5t, t\u1ea1i sao l\u1ef1c \t\t \t h\u1ea5p d\u1eabn kh\u00f4ng k\u00e9o n\u00f3 v\u00e0o v\u00e0 g\u00e2y n\u00ean m\u1ed9t c\u00fa va ch\u1ea1m?\t 94 73.\tTh\u1eddi \u0111i\u1ec3m ch\u00ednh x\u00e1c c\u1ee7a m\u1eb7t tr\u1eddi m\u1ecdc v\u00e0 m\u1eb7t tr\u1eddi l\u1eb7n \t\t \t \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh nh\u01b0 th\u1ebf n\u00e0o?\t 95 74.\tC\u00f3 tr\u01b0\u1eddng h\u1ee3p n\u00e0o phi thuy\u1ec1n b\u1ecb ph\u00e1 h\u1ecfng b\u1edfi \t\t \t \u201cm\u1ea3nh v\u1ee1 kh\u00f4ng gian\u201d kh\u00f4ng?\t 97 75.\tC\u00e1c phi h\u00e0nh gia \u1edf tr\u1ea1m kh\u00f4ng gian t\u00ecm \u0111\u00e2u ra \t\t \t kh\u00f4ng kh\u00ed?\t 99 76.\tC\u00f3 ph\u1ea3i m\u1eb7t tr\u0103ng \u0111ang \u0111i xa ch\u00fang ta?\t 100 77.\tSao Di\u00eam V\u01b0\u01a1ng c\u00f3 th\u1ef1c s\u1ef1 l\u00e0 m\u1ed9t h\u00e0nh tinh kh\u00f4ng?\t101 185 https:\/\/thuviensach.vn","78.\tT\u1ea1i sao nh\u1eefng h\u00e0nh tinh b\u00ean trong l\u00e0 \u0111\u00e1 trong khi \t\t \t c\u00e1c h\u00e0nh tinh b\u00ean ngo\u00e0i l\u00e0 nh\u1eefng qu\u1ea3 c\u1ea7u kh\u00ed?\t 102 79.\tT\u1ea1i sao nh\u1eefng ch\u1ea5t th\u1ea3i h\u1ea1t nh\u00e2n kh\u00f4ng th\u1ec3 \t\t \t \u0111\u01b0\u1ee3c chuy\u1ec3n t\u1edbi m\u1eb7t tr\u1eddi tr\u00ean c\u00e1c t\u00ean l\u1eeda?\t 104 80.\tT\u1ea1i sao t\u1ea5t c\u1ea3 c\u00e1c h\u00e0nh tinh trong h\u1ec7 m\u1eb7t tr\u1eddi \u0111\u1ec1u \t\t \t t\u1ef1 xoay v\u00e0 quay quanh m\u1eb7t tr\u1eddi theo h\u01b0\u1edbng \t\t \t ng\u01b0\u1ee3c chi\u1ec1u kim \u0111\u1ed3ng h\u1ed3?\t 105 81.\tT\u1ea1i sao t\u00e0u kh\u00f4ng gian con thoi kh\u00f4ng th\u1ec3 v\u00e0o l\u1ea1i \t\t \t kh\u00ed quy\u1ec3n tr\u00e1i \u0111\u1ea5t m\u1ed9t c\u00e1ch nh\u1eb9 nh\u00e0ng b\u1eb1ng c\u00e1ch \t\t \t s\u1eed d\u1ee5ng c\u00e1c \u0111\u1ed9ng c\u01a1 t\u00ean l\u1eeda c\u1ee7a n\u00f3 \u0111\u1ec3 l\u00e0m ch\u1eadm l\u1ea1i \t\t \t qu\u00e1 tr\u00ecnh \u0111\u00e1p xu\u1ed1ng?\t 106 82.\tL\u1ef1c h\u1ea5p d\u1eabn c\u1ee7a c\u00e1c h\u00e0nh tinh \u0111\u00e3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \t\t \t nh\u01b0 th\u1ebf n\u00e0o \u0111\u1ec3 t\u0103ng t\u1ed1c c\u00e1c t\u00e0u th\u0103m d\u00f2 kh\u00f4ng gian?\t107 83.\tTh\u1eadt s\u1ef1 c\u00f3 m\u1ed9t h\u00e0nh tinh X b\u00ean ngo\u00e0i nh\u1eefng \t\t \t h\u00e0nh tinh \u0111\u00e3 \u0111\u01b0\u1ee3c bi\u1ebft hay kh\u00f4ng?\t 109 84.\tC\u00f3 ph\u1ea3i b\u1ea5t k\u00ec k\u00ednh vi\u1ec5n v\u1ecdng n\u00e0o c\u0169ng c\u00f3 th\u1ec3 \t\t \t th\u1ea5y \u0111\u01b0\u1ee3c d\u1ea1ng tr\u00f2n c\u1ee7a m\u1ed9t ng\u00f4i sao?\t 110 85.\tT\u1ea1i sao Sao Th\u1ed5 l\u00e0 h\u00e0nh tinh duy nh\u1ea5t c\u00f3 c\u00e1c \t\t \t qu\u1ea7ng s\u00e1ng bao quanh?\t 111 86.\tT\u1ea1i sao ch\u1ec9 c\u00f3 c\u00e1c ng\u00f4i sao m\u1edbi l\u1ea5p l\u00e1nh, \t\t \t c\u00f2n m\u1eb7t tr\u0103ng v\u00e0 c\u00e1c h\u00e0nh tinh th\u00ec kh\u00f4ng?\t 113 V\u0168 TR\u1ee4 87.\tC\u00e1i g\u00ec g\u00e2y ra s\u1ee9c k\u00e9o c\u1ee7a tr\u1ecdng l\u1ef1c?\t 115 88.\tT\u1ed1c \u0111\u1ed9 c\u1ee7a l\u1ef1c h\u1ea5p d\u1eabn l\u00e0 bao nhi\u00eau?\t 116 89.\tCh\u00fang ta di chuy\u1ec3n trong v\u0169 tr\u1ee5 nhanh c\u1ee1 n\u00e0o?\t 118 90.\tC\u00e1c v\u1eadt th\u1ec3 tr\u00f4ng s\u1ebd nh\u01b0 th\u1ebf n\u00e0o n\u1ebfu ch\u00fang ta c\u00f3 th\u1ec3 \t\t \t chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c g\u1ea7n b\u1eb1ng v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng?\t119 186 https:\/\/thuviensach.vn","91.\tL\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 \u201ckh\u00f4ng\u201d c\u00f3 th\u1ec3 t\u1ef1 bi\u1ebfn \u0111\u1ed5i th\u00e0nh \u201cc\u00f3\u201d?\t120 92.\tV\u0169 tr\u1ee5 l\u1edbn c\u1ee1 n\u00e0o, v\u00e0 t\u1ed1c \u0111\u1ed9 gi\u00e3n n\u1edf c\u1ee7a v\u0169 tr\u1ee5?\t 122 93.\tKhi ch\u00fang ta nh\u00ecn v\u00e0o kh\u00f4ng gian, t\u1ea1i sao ch\u00fang ta \t\t \t kh\u00f4ng th\u1ea5y \u0111\u01b0\u1ee3c v\u1ee5 n\u1ed5 Big Bang?\t 124 94.\t N\u1ebfu nh\u01b0 n\u00f3i v\u0169 tr\u1ee5 \u0111ang n\u1edf ra, t\u1ea1i sao Ch\u00f2m sao \t\t \t Ti\u00ean n\u1eef l\u1ea1i d\u1ecbch chuy\u1ec3n v\u1ec1 ph\u00eda ch\u00fang ta?\t 126 95.\t Li\u1ec7u c\u00f3 m\u1ed9t nhi\u1ec7t \u0111\u1ed9 cao t\u1ed1i \u0111a kh\u00f4ng?\t 127 96.\t K\u00edch th\u01b0\u1edbc ban \u0111\u1ea7u c\u1ee7a v\u0169 tr\u1ee5 khi n\u00f3 \u0111\u01b0\u1ee3c sinh ra \t\t \t l\u00e0 bao nhi\u00eau?\t 128 97.\t N\u1ebfu v\u0169 tr\u1ee5 \u0111ang gi\u00e3n n\u1edf, l\u1ef1c th\u00fac \u0111\u1ea9y n\u00f3 gi\u00e3n n\u1edf \t\t \t n\u1eb1m \u1edf \u0111\u00e2u?\t 129 98.\t Trung t\u00e2m c\u1ee7a v\u0169 tr\u1ee5 \u1edf \u0111\u00e2u?\t 129 99.\t V\u0169 tr\u1ee5 \u0111ang gi\u00e3n n\u1edf ra th\u00e0nh c\u00e1i g\u00ec?\t 130 100.\tC\u00f3 bao nhi\u00eau nguy\u00ean t\u1eed trong v\u0169 tr\u1ee5?\t 131 101.\tTa c\u00f3 bi\u1ebft \u0111\u01b0\u1ee3c h\u00ecnh d\u1ea1ng th\u1eadt s\u1ef1 c\u1ee7a nguy\u00ean t\u1eed \t\t \t v\u00e0 ph\u00e2n t\u1eed tr\u00f4ng nh\u01b0 th\u1ebf n\u00e0o kh\u00f4ng?\t 132 102.\tT\u1ea1i sao v\u1eadt ch\u1ea5t c\u00f3 v\u1ebb \u0111\u1eb7c r\u1eafn trong khi nguy\u00ean t\u1eed \t\t \t h\u1ea7u nh\u01b0 l\u00e0 kh\u00f4ng gian r\u1ed7ng?\t 134 103.\t\u0110i\u1ec1u g\u00ec s\u1ebd x\u1ea3y ra n\u1ebfu b\u1ea1n r\u01a1i v\u00e0o m\u1ed9t l\u1ed7 \u0111en?\t 135 104.\tV\u0169 tr\u1ee5 c\u00f3 ch\u1ee9a l\u1ed7 tr\u1eafng kh\u00f4ng?\t 136 105.\tN\u1ebfu m\u1eb7t tr\u1eddi \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb hydrogen, \t\t \t t\u1ea1o sao n\u00f3 kh\u00f4ng b\u00f9ng n\u1ed5?\t 138 106.\tM\u1eb7t tr\u1eddi \u0111ang \u0111\u1ed1t nhi\u00ean li\u1ec7u c\u1ee7a n\u00f3 nhanh \t\t \t t\u1edbi m\u1ee9c n\u00e0o?\t 138 107.\t\u0110i\u1ec1u g\u00ec s\u1ebd x\u1ea3y ra khi m\u1eb7t tr\u1eddi c\u1ea1n ki\u1ec7t n\u0103ng l\u01b0\u1ee3ng?\t 139 108.\t\u0110i\u1ec1u g\u00ec \u0111\u00e3 x\u1ea3y ra v\u1edbi Thuy\u1ebft D\u00e2y (String Theory) \t\t \t nh\u01b0 l\u00e0 m\u1ed9t c\u00e1ch gi\u1ea3i th\u00edch cho s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a v\u0169 tr\u1ee5?\t141 109.\tNh\u01b0ng n\u1ebfu c\u00f3 m\u01b0\u1eddi m\u1ed9t chi\u1ec1u th\u00ec ch\u00fang s\u1ebd \u1edf \u0111\u00e2u?\t 143 187 https:\/\/thuviensach.vn","C\u00c1C V\u1ea4N \u0110\u1ec0 KH\u00c1C 110.\tB\u1eafn ch\u1ec9 thi\u00ean nguy hi\u1ec3m nh\u01b0 th\u1ebf n\u00e0o?\t 145 111.\tCh\u00fang ta th\u1edf ra kh\u00ed CO2, v\u1eady t\u1ea1i sao kh\u00f4ng th\u1ed5i \t\t \t n\u00f3 \u0111\u1ec3 d\u1eadp t\u1eaft l\u1eeda?\t 146 112.\tB\u1eb1ng c\u00e1ch n\u00e0o nh\u1eefng c\u00fa ch\u1eb7t karate \t\t \t l\u1ea1i m\u1ea1nh nh\u01b0 v\u1eady?\t 147 113.\tV\u00e0ng tr\u1eafng l\u00e0 g\u00ec?\t 148 114.\tM\u1ed9t chi\u1ebfc m\u00e1y bay c\u00f3 th\u1ec3 l\u01b0\u1ee3n xa bao nhi\u00eau \t\t \t n\u1ebfu \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3 d\u1eebng l\u1ea1i?\t 149 115.\tChu\u1ed7i xo\u1eafn \u0111\u00f4i DNA l\u1edbn nh\u01b0 th\u1ebf n\u00e0o?\t 150 116.\tGreenwich \u0111\u00e3 tr\u1edf th\u00e0nh trung t\u00e2m c\u1ee7a b\u1ea3n \u0111\u1ed3 \t\t \t th\u1ebf gi\u1edbi t\u1eeb khi n\u00e0o?\t 151 117.\tT\u1ea1i sao nh\u1eefng ng\u01b0\u1eddi x\u00e2y \u0111\u01b0\u1eddng h\u1ea7m \u0111\u1ea1t \u0111\u01b0\u1ee3c \t\t \t m\u1ed9t \u0111\u1ed9 ch\u00ednh x\u00e1c cao nh\u01b0 th\u1ebf b\u00ean d\u01b0\u1edbi m\u1eb7t \u0111\u1ea5t?\t 151 118.\tC\u00e1i g\u00ec g\u00e2y ra \u1ea3o \u1ea3nh nh\u01b0 g\u01b0\u01a1ng soi tr\u00ean c\u00e1c \t\t \t con \u0111\u01b0\u1eddng v\u00e0o m\u00f9a h\u00e8?\t 152 119.\tN\u1ebfu m\u1ed9t v\u1eadt b\u1ecb r\u01a1i kh\u1ecfi m\u1ed9t chi\u1ebfc xe \u0111ang ch\u1ea1y, \t\t \t t\u1ea1i sao n\u00f3 kh\u00f4ng l\u0103n ra ra sau?\t 153 120.\tC\u00f4ng ngh\u1ec7 \u201ct\u00e0ng h\u00ecnh\u201d ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?\t 154 121.\tT\u1ea1i sao c\u00e1c b\u1ecdt kh\u00ed do t\u00e0u thuy\u1ec1n t\u1ea1o ra lu\u00f4n lu\u00f4n \t\t \t c\u00f3 m\u00e0u tr\u1eafng b\u1ea5t k\u1ec3 m\u00e0u c\u1ee7a n\u01b0\u1edbc bi\u1ec3n l\u00e0 g\u00ec?\t 155 122.\tT\u1ea1i sao c\u00e1c b\u00e1nh xe quay l\u00f9i trong c\u00e1c cu\u1ed1n phim?\t 156 123.\t T\u1ea1i sao kh\u00ed helium l\u00e0m cho gi\u1ecdng n\u00f3i tr\u1edf n\u00ean \t\t \t gi\u1ed1ng nh\u01b0 ti\u1ebfng k\u00eau ch\u00edt ch\u00edt?\t 156 124.\tT\u1ea1i sao r\u00e3nh xo\u1eafn trong n\u00f2ng s\u00fang cho ph\u00e9p \t\t \t vi\u00ean \u0111\u1ea1n \u0111i xa h\u01a1n?\t 157 125.\tNg\u01b0\u1eddi m\u00f9 c\u00f3 n\u1eb1m m\u01a1 kh\u00f4ng?\t 158 188 https:\/\/thuviensach.vn","126.\tCon ng\u01b0\u1eddi \u0111\u00e3 x\u00e1c \u0111\u1ecbnh n\u0103m nh\u01b0 th\u1ebf n\u00e0o \t\t \t tr\u01b0\u1edbc khi ph\u00e1t minh ra BC v\u00e0 AD?\t 158 127.\tT\u1ea1i sao con ng\u01b0\u1eddi ng\u1ee7 qu\u00e1 g\u1ea7n c\u1ea1nh gi\u01b0\u1eddng \t\t \t m\u00e0 l\u1ea1i kh\u00f4ng r\u1edbt xu\u1ed1ng?\t 160 128.\tC\u00f3 ph\u1ea3i c\u00e1c c\u1eb7p sinh \u0111\u00f4i b\u1ecb d\u00ednh li\u1ec1n \u0111\u1ec1u \t\t \t nh\u1ea5t thi\u1ebft c\u00f3 c\u00f9ng gi\u1edbi t\u00ednh?\t 161 129.\tB\u1eb1ng c\u00e1ch n\u00e0o thuy\u1ec1n bu\u1ed3m th\u1ec3 thao c\u00f3 th\u1ec3 \t\t \t \u0111i nhanh h\u01a1n gi\u00f3?\t 161 130.\tT\u1ea1i sao con ng\u01b0\u1eddi n\u00f3i nhi\u1ec1u th\u1ebf? \u0110i\u1ec1u n\u00e0y c\u00f3 \t\t \t \u0111em l\u1ea1i l\u1ee3i th\u1ebf ti\u1ebfn h\u00f3a n\u00e0o kh\u00f4ng?\t 162 131.\tB\u1eb1ng c\u00e1ch n\u00e0o ch\u00fang ta bi\u1ebft \u0111\u01b0\u1ee3c t\u1ea5t c\u1ea3 \t\t \t c\u00e1c d\u1ea5u v\u00e2n tay \u0111\u1ec1u l\u00e0 duy nh\u1ea5t?\t 164 132.\tT\u1ea1i sao b\u1ea1c h\u00e0 l\u00e0m h\u01a1i th\u1edf c\u00f3 c\u1ea3m gi\u00e1c l\u1ea1nh?\t 166 133.\t \u0110\u1ed9ng t\u00e1c h\u00fat th\u1ef1c s\u1ef1 l\u00e0 nh\u01b0 th\u1ebf n\u00e0o?\t 167 134.\tB\u1eb1ng c\u00e1ch n\u00e0o m\u1ed9t \u1ed1ng truy\u1ec1n n\u01b0\u1edbc siphon \t\t \t d\u1ef1a theo n\u01b0\u1edbc \u0111\u1ec3 t\u1ef1 \u0111\u1ea9y ch\u00fang \u0111i l\u00ean?\t 168 135.\tT\u1ea1i sao h\u1ea7u h\u1ebft c\u00e1c turbine n\u0103ng l\u01b0\u1ee3ng gi\u00f3 \t\t \t \u0111\u1ec1u c\u00f3 ba c\u00e1nh thay v\u00ec b\u1ed1n?\t 170 136.\tC\u00f3 m\u1ed9t c\u00e1ch \u0111\u1ecbnh ngh\u0129a chung n\u00e0o cho b\u00ean ph\u1ea3i \t\t \t v\u00e0 b\u00ean tr\u00e1i kh\u00f4ng?\t 170 137.\tT\u1ea1i sao carbon monoxide (CO) g\u00e2y ch\u1ebft ng\u01b0\u1eddi, \t\t \t trong khi m\u1ed9t n\u1eeda c\u1ee7a n\u00f3 l\u00e0 oxygen?\t 172 138.\tT\u1ea1i sao ch\u00fang ta kh\u00f4ng th\u1ec3 nh\u00ecn r\u00f5 d\u01b0\u1edbi n\u01b0\u1edbc \t\t \t n\u1ebfu kh\u00f4ng c\u00f3 m\u1eb7t n\u1ea1 hay hay k\u00ednh b\u01a1i?\t 174 139.\t\u00c1nh s\u00e1ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o ra kh\u00f4ng c\u1ea7n nhi\u1ec7t \t\t \t hay kh\u00f4ng?\t 174 140.\tT\u1ea1i sao phun n\u01b0\u1edbc b\u1ecdt v\u00e0o m\u1eb7t n\u1ea1 l\u1eb7n \t\t \t l\u00e0m cho n\u00f3 h\u1ebft m\u1edd?\t 176 189 https:\/\/thuviensach.vn","141.\tC\u00e1i g\u00ec \u0111\u00e3 g\u00e2y ra c\u00e1c d\u00f2ng b\u1ecdt kh\u00ed nh\u1ecf b\u1ed1c l\u00ean \t\t \t trong m\u1ed9t ly s\u00e2m-panh?\t 176 142.\tAcid m\u1ea1nh nh\u1ea5t l\u00e0 ch\u1ea5t n\u00e0o?\t 177 143.\tT\u1ea1i sao m\u1ed9t s\u1ed1 ch\u1ea5t r\u1eafn nh\u01b0 th\u1ee7y tinh v\u00e0 perpex \t\t \t (ch\u1ea5t d\u1ebbo l\u00e0m k\u00ednh m\u00e1y bay) l\u1ea1i trong su\u1ed1t?\t 178 144.\tT\u1ea1i sao c\u00e1c v\u1eadt th\u1ec3 kim lo\u1ea1i c\u00f3 c\u1ea3m gi\u00e1c l\u1ea1nh h\u01a1n \t\t \t c\u00e1c v\u1eadt th\u1ec3 b\u1eb1ng g\u1ed7, khi c\u1ea3 hai \u0111\u1ec1u \u1edf c\u00f9ng nhi\u1ec7t \u0111\u1ed9?\t179 190 https:\/\/thuviensach.vn","191 https:\/\/thuviensach.vn","h\u00e3y tr\u1ea3 l\u1eddi em t\u1ea1i sao? t\u1eadp 12 robert matthews Hu\u1ef3nh Thu H\u01b0\u01a1ng d\u1ecbch Ch\u1ecbu tr\u00e1ch nhi\u1ec7m xu\u1ea5t b\u1ea3n: ts. qu\u00e1ch thu nguy\u1ec7t Bi\u00ean t\u1eadp: thu nhi B\u00eca: b\u00f9i nam S\u1eeda b\u1ea3n in: nh\u1eadt vi K\u0129 thu\u1eadt vi t\u00ednh: v\u0169 ph\u01b0\u1ee3ng NH\u00c0 XU\u1ea4T B\u1ea2N TR\u1eba 161B L\u00fd Ch\u00ednh Th\u1eafng - Qu\u1eadn 3 - Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh \u0110T: 39316289 - 39316211 - 38465595 - 38465596 - 39350973 Fax: 84.8.38437450 - E-mail: nxbtre@ hcm.vnn.vn Website: http:\/\/www.nxbtre.com.vn Chi nh\u00e1nh nh\u00e0 xu\u1ea5t b\u1ea3n tr\u1ebb t\u1ea1i H\u00e0 N\u1ed9i 20 ng\u00f5 91, Nguy\u1ec5n Ch\u00ed Thanh, Qu\u1eadn \u0110\u1ed1ng \u0110a - H\u00e0 N\u1ed9i \u0110T & Fax: (04) 37734544 E-mail: vanphongnxbtre@ hn.vnn.vn 192 https:\/\/thuviensach.vn"]