["PH\u1ee4 L\u1ee4C 276 gian cong. Ch\u00e2n kh\u00f4ng l\u1ea1i c\u00f3 \u0111\u01b0\u1ee3c m\u1ed9t \u201cvai di\u1ec5n\u201d m\u1edbi: l\u1ef1c h\u1ea5p d\u1eabn. \u201cCh\u00e2n kh\u00f4ng l\u01b0\u1ee3ng t\u1eed\u201d \u2013 m\u1ed9t kh\u00f4ng gian tr\u1ed1ng r\u1ed7ng trong c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed nh\u01b0ng ch\u1ee9a \u0111\u1ea7y \u201cn\u0103ng l\u01b0\u1ee3ng\u201d \u2013 c\u00e1c c\u1eb7p h\u1ea1t-ph\u1ea3n h\u1ea1t \u201c\u1ea3o\u201d xu\u1ea5t hi\u1ec7n r\u1ed3i bi\u1ebfn m\u1ea5t r\u1ea5t \u201cn\u00e1o nhi\u1ec7t\u201d v\u00e0 \u201cs\u00f4i \u0111\u1ed9ng\u201d, v\u00e0 m\u1ed9t s\u1ed1 trong ch\u00fang tr\u1edf th\u00e0nh h\u1ea1t-ph\u1ea3n h\u1ea1t th\u1ef1c th\u1ee5, v.v.. Kh\u00e1i ni\u1ec7m n\u0103ng l\u01b0\u1ee3ng trong c\u00f4ng th\u1ee9c E = mc2 \u0111\u01b0\u1ee3c ch\u00ednh Einstein g\u1eafn cho m\u1ed9t \u00fd ngh\u0129a l\u00e0 \u201cs\u1ef1 chuy\u1ec3n h\u00f3a kh\u1ed1i l\u01b0\u1ee3ng th\u00e0nh n\u0103ng l\u01b0\u1ee3ng\u201d m\u00e0 kh\u1ed1i l\u01b0\u1ee3ng v\u1ed1n v\u1eabn \u0111\u01b0\u1ee3c \u00f4ng coi l\u00e0 th\u01b0\u1edbc \u0111o l\u01b0\u1ee3ng v\u1eadt ch\u1ea5t ch\u1ee9a trong v\u1eadt th\u1ec3 (Hawking c\u0169ng th\u1eeba nh\u1eadn quan \u0111i\u1ec3m n\u00e0y). N\u0103ng l\u01b0\u1ee3ng do \u0111\u00f3 \u0111\u00e3 tr\u1edf th\u00e0nh m\u1ed9t substance t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi v\u1eadt ch\u1ea5t, c\u00f3 th\u1ec3 bi\u1ebfn th\u00e0nh v\u1eadt ch\u1ea5t v\u00e0 ng\u01b0\u1ee3c l\u1ea1i, v\u1ea5t ch\u1ea5t c\u00f3 th\u1ec3 bi\u1ebfn th\u00e0nh n\u0103ng l\u01b0\u1ee3ng. L\u00fd thuy\u1ebft \u201cBig bang\u201d c\u0169ng ch\u1ec9 l\u00e0 h\u1ec7 qu\u1ea3 c\u1ee7a quan \u0111i\u1ec3m n\u00e0y. Tuy nhi\u00ean, n\u0103ng l\u01b0\u1ee3ng trong c\u00f4ng th\u1ee9c E = mc2 c\u1ee7a Einstein \u0111\u01b0\u1ee3c \u0111\u1ed3ng nh\u1ea5t v\u1edbi \u201cb\u1ee9c x\u1ea1\u201d \u2013 m\u1ed9t d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng \u0111i\u1ec7n t\u1eeb, hay c\u00f2n g\u1ecdi l\u00e0 photon \u2013 th\u00ec c\u00f3 th\u1ec3 tham gia v\u00e0o qu\u00e1 tr\u00ecnh thu\u1eadn ngh\u1ecbch \u1ea5y. Trong khi \u0111\u00f3, \u201cn\u0103ng l\u01b0\u1ee3ng\u201d \u0111\u1ec3 g\u00e2y ra Big Bang l\u1ea1i l\u00e0 m\u1ed9t d\u1ea1ng ho\u00e0n to\u00e0n kh\u00e1c \u2013 m\u1ed9t d\u1ea1ng \u201cn\u0103ng l\u01b0\u1ee3ng\u201d ch\u1ec9 \u0111\u1ec3 sinh ra \u201cv\u1eadt ch\u1ea5t\u201d v\u00e0o th\u1eddi \u0111i\u1ec3m \u0111\u00f3, \u0111\u1ec3 r\u1ed3i t\u1eeb \u0111\u00f3 \u0111\u1ebfn nay kh\u00f4ng bao gi\u1edd c\u00f2n th\u1ea5y xu\u1ea5t hi\u1ec7n tr\u1edf l\u1ea1i n\u1eefa??? Theo C\u0110M, tr\u01b0\u1edbc h\u1ebft ch\u1eb3ng c\u00f3 \u201cch\u00e2n kh\u00f4ng\u201d n\u00e0o c\u1ea3, sau n\u1eefa l\u00e0 ch\u1eb3ng c\u00f3 n\u0103ng l\u01b0\u1ee3ng n\u00e0o t\u1ed3n t\u1ea1i \u0111\u1ed9c l\u1eadp v\u1edbi v\u1eadt ch\u1ea5t (xem m\u1ee5c 1.2.3) m\u00e0 tr\u00e1i l\u1ea1i, n\u00f3 ch\u1ec9 l\u00e0 m\u1ed9t trong c\u00e1c \u0111\u1eb7c t\u00ednh c\u1ee7a nh\u1eefng d\u1ea1ng t\u1ed3n t\u1ea1i kh\u00e1c nhau c\u1ee7a v\u1eadt ch\u1ea5t m\u00e0 th\u00f4i. Ch\u00ednh vi\u1ec7c \u0111\u1ed3ng nh\u1ea5t photon hay c\u00e1c b\u1ee9c x\u1ea1 nhi\u1ec7t theo l\u00fd thuy\u1ebft nhi\u1ec7t \u0111\u1ed9ng h\u1ecdc (c\u00f4ng th\u1ee9c Planck) v\u1edbi n\u0103ng l\u01b0\u1ee3ng l\u00e0 nguy\u00ean nh\u00e2n g\u00e2y n\u00ean s\u1ef1 nh\u1ea7m l\u1eabn tai h\u1ea1i n\u00e0y. C\u0110M \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng photon hay b\u1ee9c x\u1ea1 nhi\u1ec7t c\u0169ng ch\u1ec9 l\u00e0 m\u1ed9t lo\u1ea1i th\u1ef1c th\u1ec3 v\u1eadt l\u00fd c\u00f3 c\u1ea5u tr\u00fac v\u00e0 b\u1ea3n th\u00e2n ch\u00fang c\u00f3 m\u1ed9t h\u1eefu h\u1ea1n n\u0103ng l\u01b0\u1ee3ng nh\u1ea5t \u0111\u1ecbnh. C\u00f4ng th\u1ee9c W = mc2 + 2U kh\u00f4ng h\u00e0m \u00fd v\u1ec1 s\u1ef1 chuy\u1ec3n h\u00f3a qua l\u1ea1i gi\u1eefa v\u1eadt ch\u1ea5t v\u00e0 n\u0103ng l\u01b0\u1ee3ng n\u00e0o c\u1ea3, m\u00e0 ch\u1ec9 n\u00f3i l\u00ean r\u1eb1ng m\u1ed9t th\u1ef1c th\u1ec3 v\u1eadt l\u00fd c\u00f3 qu\u00e1n t\u00ednh trong tr\u01b0\u1eddng l\u1ef1c th\u1ebf U s\u1ebd h\u00e0m ch\u1ee9a m\u1ed9t n\u0103ng l\u01b0\u1ee3ng W \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh theo c\u00f4ng th\u1ee9c \u0111\u00f3.","PH\u1ee4 L\u1ee4C 277 8. Qu\u00e3ng \u0111\u01b0\u1eddng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng hay v\u00e9c t\u01a1?* Trong v\u1eadt l\u00fd, ng\u01b0\u1eddi ta v\u1eabn coi qu\u00e3ng \u0111\u01b0\u1eddng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 (k\u00fd hi\u1ec7u l\u00e0 dS hay S) khi bi\u1ec3u di\u1ec5n chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a m\u1ed9t v\u1eadt th\u1ec3 t\u1eeb \u0111i\u1ec3m A \u0111\u1ebfn \u0111i\u1ec3m B trong m\u1ed9t kho\u1ea3ng th\u1eddi gian nh\u1ea5t \u0111\u1ecbnh n\u00e0o \u0111\u00f3. Tuy nhi\u00ean, \u0111i\u1ec1u n\u00e0y ch\u1ec9 \u0111\u00fang khi v\u1eadt th\u1ec3 chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng nh\u01b0 H\u00ecnh P1a; n\u1ebfu n\u00f3 chuy\u1ec3n \u0111\u1ed9ng theo m\u1ed9t \u0111\u01b0\u1eddng cong, v\u00ed d\u1ee5 nh\u01b0 \u00bd \u0111\u01b0\u1eddng tr\u00f2n \u0111\u01b0\u1ee3c ch\u1ec9 tra tr\u00ean H\u00ecnh P1b, v\u1ea5n \u0111\u1ec1 s\u1ebd kh\u00e1c: t\u1ed5ng c\u00e1c v\u00e9c t\u01a1 dS l\u00e0 v\u00e9c t\u01a1 S c\u00f3 chi\u1ec1u d\u00e0i b\u1eb1ng 2r kh\u00f4ng ph\u1ea3i l\u00e0 qu\u00e3ng \u0111\u01b0\u1eddng m\u00e0 v\u1eadt th\u1ec3 \u0111i \u0111\u01b0\u1ee3c trong kho\u1ea3ng th\u1eddi gian \u0111\u00f3 \u03c0r. \u0110i\u1ec1u n\u00e0y ch\u1ee9ng t\u1ecf r\u1eb1ng qu\u00e3ng \u0111\u01b0\u1eddng kh\u00f4ng ph\u1ea3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1! dS dS AS B A S B b) a) H\u00ecnh P1. Qu\u00e3ng \u0111\u01b0\u1eddng kh\u00f4ng ph\u1ea3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 Nh\u01b0ng khi \u0111\u00f3, m\u1ed9t v\u1ea5n \u0111\u1ec1 m\u1edbi l\u1ea1i \u0111\u01b0\u1ee3c \u0111\u1eb7t ra li\u00ean quan t\u1edbi kh\u00e1i ni\u1ec7m v\u1eadn t\u1ed1c chuy\u1ec3n \u0111\u1ed9ng v\u1ed1n l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1, theo v\u1eadt l\u00fd hi\u1ec7n h\u00e0nh \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi gi\u1edbi h\u1ea1n: V(t) = lim \u2206t\u21920 \u2206S = dS . (P8.1) \u2206t dt V\u1eady th\u00ec l\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 bi\u1ec3u di\u1ec5n \u0111\u01b0\u1ee3c v\u00e9c t\u01a1 v\u1eadn t\u1ed1c t\u1eeb m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng kh\u00f4ng ph\u1ea3i l\u00e0 v\u00e9c t\u01a1? R\u00fat c\u1ee5c, qu\u00e3ng \u0111\u01b0\u1eddng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng hay v\u00e9c t\u01a1 \u0111\u00e2y? Theo C\u0110M, qu\u00e3ng \u0111\u01b0\u1eddng kh\u00f4ng ph\u1ea3i v\u00e9c t\u01a1 m\u00e0 ch\u1ec9 l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng, v\u00ec v\u1eady, ngh\u1ecbch l\u00fd v\u1edbi qu\u00e3ng \u0111\u01b0\u1eddng \u1edf tr\u00ean s\u1ebd kh\u00f4ng c\u00f2n n\u1eefa; b\u1ea5t c\u1eadp x\u1ea9y ra","PH\u1ee4 L\u1ee4C 278 v\u1edbi v\u1eadn t\u1ed1c trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c gi\u1ea3i t\u1ecfa n\u1ebfu thay bi\u1ec3u th\u1ee9c (P8.1) b\u1eb1ng bi\u1ec3u th\u1ee9c kh\u00e1c c\u00f3 \u00fd ngh\u0129a v\u1eadt l\u00fd h\u01a1n \u0111\u00f3 l\u00e0: V(t) = lim \u2206t\u21920 \u2206S eA = dS eA (P8.2) \u2206t dt \u1edf \u0111\u00e2y eA l\u00e0 v\u00e9c t\u01a1 \u0111\u01a1n v\u1ecb c\u00f3 h\u01b0\u1edbng ti\u1ebfp tuy\u1ebfn v\u1edbi qu\u00e3ng \u0111\u01b0\u1eddng ngay t\u1ea1i \u0111i\u1ec3m A, \u1ee9ng v\u1edbi v\u1ecb tr\u00ed c\u1ee7a v\u1eadt th\u1ec3 t\u1ea1i th\u1eddi \u0111i\u1ec3m t, c\u00f2n S ch\u1ec9 l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng trong kh\u00f4ng gian v\u00e9c t\u01a1 nh\u01b0ng s\u1ef1 bi\u1ebfn thi\u00ean c\u1ee7a n\u00f3 l\u1ea1i c\u00f3 h\u01b0\u1edbng, v\u00e0 h\u01b0\u1edbng n\u00e0y \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edbi ch\u00ednh v\u00e9c t\u01a1 \u0111\u01a1n v\u1ecb eA. 9. N\u0103ng l\u01b0\u1ee3ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng hay v\u00e9c t\u01a1?* N\u0103ng l\u01b0\u1ee3ng cho \u0111\u1ebfn nay v\u1eabn \u0111\u01b0\u1ee3c coi l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng. V\u00ec \u0111\u1ed9ng n\u0103ng c\u0169ng l\u00e0 m\u1ed9t d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng n\u00ean v\u1ec1 nguy\u00ean t\u1eafc n\u00f3 ph\u1ea3i l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng. Nh\u01b0ng \u0111i\u1ec1u n\u00e0y t\u1ecf ra kh\u00f4ng h\u1ee3p l\u00fd b\u1edfi 2 l\u1ebd: + Th\u1ee9 nh\u1ea5t, n\u0103ng l\u01b0\u1ee3ng l\u00e0 kh\u1ea3 n\u0103ng sinh c\u00f4ng m\u00e0 \u0111\u1ed9ng n\u0103ng l\u1ea1i ch\u1ec9 c\u00f3 th\u1ec3 sinh c\u00f4ng theo h\u01b0\u1edbng chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a v\u1eadt th\u1ec3 khi va ch\u1ea1m v\u1edbi c\u00e1c v\u1eadt th\u1ec3 kh\u00e1c c\u00f2n theo c\u00e1c h\u01b0\u1edbng kh\u00e1c th\u00ec kh\u00f4ng th\u1ec3, v\u00ec v\u1eady \u0111\u1ed9ng n\u0103ng kh\u00f4ng th\u1ec3 l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng; + Th\u1ee9 hai, v\u1eadn t\u1ed1c l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 n\u00ean \u0111\u1ed9ng n\u0103ng t\u00ednh theo c\u00f4ng th\u1ee9c: mV 2 2 K = (P9.1) c\u0169ng ch\u1ec9 c\u00f3 th\u1ec3 c\u00f3 ngh\u0129a theo h\u01b0\u1edbng c\u1ee7a v\u1eadn t\u1ed1c c\u00f2n theo c\u00e1c h\u01b0\u1edbng kh\u00e1c th\u00ec ho\u00e0n to\u00e0n kh\u00f4ng th\u1ec3. Th\u1ebf n\u0103ng c\u0169ng l\u00e0 m\u1ed9t d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng v\u00e0 do v\u1eady n\u00f3 c\u0169ng ph\u1ea3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng. Nh\u01b0ng th\u1ebf n\u0103ng c\u0169ng gi\u1ed1ng nh\u01b0 v\u1edbi \u0111\u1ed9ng n\u0103ng, \u0111\u1ebfn l\u01b0\u1ee3t m\u00ecnh, n\u00f3 c\u0169ng ch\u1ec9 c\u00f3 kh\u1ea3 n\u0103ng sinh c\u00f4ng theo h\u01b0\u1edbng \u0111\u01b0\u1eddng s\u1ee9c c\u1ee7a tr\u01b0\u1eddng l\u1ef1c th\u1ebf v\u00e0 v\u00ec v\u1eady,","PH\u1ee4 L\u1ee4C 279 theo l\u00f4g\u00edc, n\u00f3 c\u0169ng ph\u1ea3i l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 m\u00e0 kh\u00f4ng th\u1ec3 l\u00e0 v\u00f4 h\u01b0\u1edbng \u0111\u01b0\u1ee3c. V\u1ea5n \u0111\u1ec1 l\u00e0 \u1edf ch\u1ed7, t\u1ed5ng c\u1ee7a c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng l\u00e0 t\u1ed5ng \u0111\u1ea1i s\u1ed1 c\u00f2n t\u1ed5ng c\u1ee7a c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 l\u00e0 t\u1ed5ng h\u00ecnh h\u1ecdc theo quy t\u1eafc h\u00ecnh b\u00ecnh h\u00e0nh \u2013 trong tr\u01b0\u1eddng h\u1ee3p chung, ch\u00fang c\u00f3 nh\u1eefng k\u1ebft qu\u1ea3 ho\u00e0n to\u00e0n kh\u00e1c nhau. \u0110i\u1ec1u n\u00e0y \u0111\u01b0\u01a1ng nhi\u00ean \u1ea3nh h\u01b0\u1edfng t\u1edbi \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n n\u0103ng l\u01b0\u1ee3ng \u2013 m\u1ed9t \u0111\u1ecbnh lu\u1eadt c\u01a1 b\u1ea3n c\u1ee7a T\u1ef1 nhi\u00ean. Trong khi \u0111\u00f3, kh\u00e1i ni\u1ec7m n\u1ed9i n\u0103ng l\u00e0 n\u0103ng l\u01b0\u1ee3ng h\u00e0m ch\u1ee9a b\u00ean trong v\u1eadt th\u1ec3 th\u00ec kh\u00f3 c\u00f3 th\u1ec3 n\u00f3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 \u0111\u01b0\u1ee3c m\u00e0 l\u00e0 c\u00f3 l\u1ebd ch\u1ec9 c\u00f3 th\u1ec3 l\u00e0 v\u00f4 h\u01b0\u1edbng? V\u00ed d\u1ee5 nh\u01b0 nhi\u1ec7t n\u0103ng ch\u1eb3ng h\u1ea1n? V\u1eady r\u00fat c\u1ee5c n\u0103ng l\u01b0\u1ee3ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng hay v\u00e9c t\u01a1 \u0111\u00e2y? Hay l\u00e0 c\u0169ng c\u00f3 d\u1ea1ng \u201cl\u01b0\u1ee1ng t\u00ednh v\u00e9c t\u01a1-v\u00f4 h\u01b0\u1edbng\u201d ki\u1ec3u nh\u01b0 \u201cl\u01b0\u1ee1ng s\u00f3ng-h\u1ea1t? Theo quan \u0111i\u1ec3m c\u1ee7a C\u0110M, n\u0103ng l\u01b0\u1ee3ng c\u0169ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 tuy nhi\u00ean, c\u00f2n ph\u00e2n bi\u1ec7t n\u0103ng l\u01b0\u1ee3ng c\u01a1 v\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u1ed5ng (xem l\u1ea1i m\u1ee5c 1.2.3) v\u00e0 v\u00ec v\u1eady, s\u1ef1 b\u0103n kho\u0103n v\u1ec1 \u0111\u1ed9ng n\u0103ng v\u00e0 th\u1ebf n\u0103ng \u1edf tr\u00ean ho\u00e0n to\u00e0n \u0111\u01b0\u1ee3c gi\u1ea3i t\u1ecfa. Ri\u00eang \u0111\u1ed1i v\u1edbi n\u1ed9i n\u0103ng t\u1ed5ng, theo \u0111\u1ecbnh ngh\u0129a, ch\u1ec9 l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng th\u1ed1ng k\u00ea gi\u1ed1ng nh\u01b0 n\u1ed9i l\u1ef1c t\u1ed5ng, th\u00e0nh ra kh\u00f4ng n\u00ean coi n\u00f3 l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 \u2013 \u0111i\u1ec1u n\u00e0y ho\u00e0n to\u00e0n kh\u00f4ng m\u00e2u thu\u1eabn v\u1edbi b\u1ea3n ch\u1ea5t v\u00e9c t\u01a1 c\u1ee7a n\u0103ng l\u01b0\u1ee3ng. Vi\u1ec7c cho r\u1eb1ng \u0111\u1ed9ng n\u0103ng t\u00ednh theo (P8.1) c\u00f3 nguy\u00ean nh\u00e2n s\u00e2u xa t\u1eeb kh\u00e1i ni\u1ec7m qu\u00e3ng \u0111\u01b0\u1eddng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 v\u1eeba n\u00f3i t\u1edbi \u1edf tr\u00ean \u0111\u00e3 d\u1eabn \u0111\u1ebfn c\u00f4ng th\u1ee9c \u0111\u1ed9ng n\u0103ng v\u00f4 h\u01b0\u1edbng n\u00e0y; m\u00e0 kh\u00f4ng ch\u1ec9 c\u00f3 th\u1ebf, n\u00f3 c\u00f2n l\u00e0 nguy\u00ean nh\u00e2n tr\u1ef1c ti\u1ebfp d\u1eabn \u0111\u1ebfn quan ni\u1ec7m \u201cc\u00f4ng c\u1ee7a l\u1ef1c d\u1ecbch chuy\u1ec3n v\u1eadt th\u1ec3 tr\u00ean m\u1ed9t qu\u00e3ng \u0111\u01b0\u1eddng\u201d c\u0169ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng n\u1ed1t: A = F.S. Tuy nhi\u00ean, khi thay qu\u00e3ng \u0111\u01b0\u1eddng trong c\u00f4ng th\u1ee9c n\u00e0y l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng th\u00ec c\u00f4ng c\u0169ng s\u1ebd tr\u1edf th\u00e0nh v\u00e9c t\u01a1 gi\u1ed1ng nh\u01b0 n\u0103ng l\u01b0\u1ee3ng v\u1eady, v\u00e0 \u0111i\u1ec1u n\u00e0y m\u1edbi l\u00e0 h\u1ee3p l\u1ebd. 10. Ngh\u1ecbch l\u00fd \u0111\u1ed9ng n\u0103ng* C\u00f3 m\u1ed9t con t\u1ea7u chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng \u0111\u1ec1u v\u1edbi v\u1eadn t\u1ed1c V1 so v\u1edbi m\u1ed9t HQC qu\u00e1n t\u00ednh H n\u00e0o \u0111\u00f3 (m\u1eb7t \u0111\u1ea5t ch\u1eb3ng h\u1ea1n) v\u00e0 tr\u00ean con t\u1ea7u \u0111\u00f3, c\u00f3 m\u1ed9t v\u1eadt c\u00f3 kh\u1ed1i","PH\u1ee4 L\u1ee4C 280 l\u01b0\u1ee3ng m chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c V2 so v\u1edbi con t\u1ea7u; g\u00f3c gi\u1eefa 2 v\u00e9c t\u01a1 v\u1eadn t\u1ed1c n\u00e0y cho b\u1eb1ng \u03b1 T\u1eeb \u0111\u00e2y suy ra, v\u00e9c t\u01a1 v\u1eadn t\u1ed1c chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a v\u1eadt \u0111\u00f3 so v\u1edbi HQC qu\u00e1n t\u00ednh H b\u1eb1ng: V = V1 + V2 (P10.1) c\u00f3 ngh\u0129a l\u00e0 modul c\u1ee7a n\u00f3 b\u1eb1ng: V 2 = V12 + 2V1V2Cos\u03b1 + V22 (P10.2) T\u1eeb \u0111\u00e2y c\u00f3 th\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c \u0111\u1ed9ng n\u0103ng c\u1ee7a v\u1eadt so v\u1edbi HQC H: K = mV 2 . (P10.3) 2 Tuy nhi\u00ean, v\u00ec n\u0103ng l\u01b0\u1ee3ng, v\u00e0 do v\u1eady, c\u1ea3 \u0111\u1ed9ng n\u0103ng v\u1ed1n \u0111\u01b0\u1ee3c coi l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng n\u00ean c\u00f3 th\u1ec3 vi\u1ebft bi\u1ec3u th\u1ee9c \u0111\u1ed9ng n\u0103ng chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a v\u1eadt trong HQC H n\u00e0y nh\u01b0 m\u1ed9t t\u1ed5ng v\u00f4 h\u01b0\u1edbng: K '= K1 + K2 (P10.4) (P10.5) trong \u0111\u00f3: K1 = mV12 (P10.6) v\u00e0 2 K2 = mV22 . 2 Thay (P10.5) v\u00e0 (P10.6)v\u00e0o (P10.4), ta \u0111\u01b0\u1ee3c: K'= m (V12 + V22 ) = m V '2 , (P10.7) 2 2 \u1edf \u0111\u00e2y k\u00fd hi\u1ec7u V12 + V22 = V '2 (P10.8) So s\u00e1nh (P10.7) v\u1edbi (P10.2) ta th\u1ea5y c\u00f3 s\u1ef1 sai kh\u00e1c gi\u1eefa 2 v\u1eadn t\u1ed1c t\u01b0\u01a1ng \u0111\u1ed1i: \u2206V 2 = V 2 \u2212 V '2 = 2V1V2Cos\u03b1 , (P10.9)","PH\u1ee4 L\u1ee4C 281 v\u00e0 ch\u00eanh l\u1ec7ch gi\u1eefa 2 gi\u00e1 tr\u1ecb \u0111\u1ed9ng n\u0103ng t\u00ednh theo 2 c\u00e1ch l\u00e0: \u2206K 2 = K2 \u2212 K '2 = m (V 2 \u2212 V '2 ) = m \u2206V 2 . (P10.10) 2 2 Thay (P10.9) v\u00e0o (P10.10), ta \u0111\u01b0\u1ee3c: \u2206K = mV1V2Cos\u03b1 . (P10.11) Gi\u1ea3 s\u1eed cho V1 = V2 = V0 v\u00e0 \u03b1 = \u03c0, t\u1eeb (P10.2) ta c\u00f3 V = 0, do \u0111\u00f3 K = 0; trong khi \u0111\u00f3, theo (P10.7) ta l\u1ea1i \u0111\u01b0\u1ee3c K\u2019 = mV\u20192\/2 = mV02. V\u1eady th\u1eadt ra \u0111\u1ed9ng n\u0103ng c\u1ee7a v\u1eadt th\u1ec3 so v\u1edbi HQC H c\u1ea7n ph\u1ea3i x\u00e1c \u0111\u1ecbnh theo c\u00e1ch n\u00e0o m\u1edbi l\u00e0 \u0111\u00fang? Theo C\u0110M, v\u1ea5n \u0111\u1ec1 s\u1ebd kh\u00e1c \u0111i n\u1ebfu ph\u1ea3i x\u00e9t t\u1edbi ngu\u1ed3n g\u1ed1c c\u1ee7a \u0111\u1ed9ng n\u0103ng ch\u1ee9 kh\u00f4ng th\u1ec3 c\u1ed9ng m\u1ed9t c\u00e1ch t\u00f9y ti\u1ec7n \u2013 \u201cc\u1ea3nh r\u00e2u \u00f4ng n\u1ecd c\u1eafm c\u1eb1m b\u00e0 kia\u201d \u0111\u01b0\u1ee3c. \u0110\u1ed9ng n\u0103ng c\u1ee7a v\u1eadt th\u1ec3 trong HQC c\u1ee7a con t\u1ea7u x\u00e1c \u0111\u1ecbnh theo (P10.6) l\u00e0 \u0111\u00fang, nh\u01b0ng \u0111\u1ed9ng n\u0103ng x\u00e1c \u0111\u1ecbnh theo bi\u1ec3u th\u1ee9c (P10.5) ch\u1eb3ng c\u00f3 ngh\u0129a g\u00ec c\u1ea3 v\u00ec v\u1eadn t\u1ed1c V1 \u1edf \u0111\u00e2y l\u00e0 v\u1eadn t\u1ed1c c\u1ee7a con t\u1ea7u so v\u1edbi HQC H ch\u1ee9 kh\u00f4ng ph\u1ea3i v\u1eadn t\u1ed1c c\u1ee7a v\u1eadt th\u1ec3 \u0111\u00f3 so v\u1edbi HQC H; trong HQC H n\u00e0y, v\u1eadn t\u1ed1c c\u1ee7a n\u00f3 l\u00e0 V ph\u1ea3i \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh theo (P10.1), n\u00ean ch\u1ec9 c\u00f3 m\u1ed9t c\u00e1ch duy nh\u1ea5t \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9ng n\u0103ng c\u1ee7a n\u00f3 trong HQC H l\u00e0 theo bi\u1ec3u th\u1ee9c (P10.3) m\u00e0 th\u00f4i. 11. \u0110\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n v\u00e0 chuy\u1ec3n h\u00f3a n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 l\u00e0 \u201c\u1ea3o gi\u00e1c\u201d* C\u00f3 m\u1ed9t v\u1ea5n \u0111\u1ec1 kh\u00f4ng th\u1ec3 kh\u00f4ng \u0111\u1ec1 c\u1eadp \u0111\u1ebfn, \u0111\u00f3 l\u00e0 \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n v\u00e0 chuy\u1ec3n h\u00f3a n\u0103ng l\u01b0\u1ee3ng \u2013 v\u1ed1n \u0111\u01b0\u1ee3c coi nh\u01b0 m\u1ed9t trong nh\u1eefng quy lu\u1eadt n\u1ec1n t\u1ea3ng c\u1ee7a v\u1eadt l\u00fd h\u1ecdc. Tuy nhi\u00ean, \u0111\u1ed1i v\u1edbi c\u01a1 h\u1ecdc Newton, n\u0103ng l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c coi l\u00e0 b\u1ea3o to\u00e0n ch\u1ec9 bao g\u1ed3m \u0111\u1ed9ng n\u0103ng v\u00e0 th\u1ebf n\u0103ng; c\u00f2n \u0111\u1ed1i v\u1edbi c\u01a1 h\u1ecdc Einstein, c\u00f3 th\u00eam th\u00e0nh ph\u1ea7n n\u1ed9i n\u0103ng nh\u01b0ng l\u1ea1i bi\u1ebfn m\u1ea5t th\u00e0nh ph\u1ea7n th\u1ebf n\u0103ng. K\u1ebft qu\u1ea3 l\u00e0 c\u00e1i \u0111\u01b0\u1ee3c b\u1ea3o to\u00e0n ch\u01b0a h\u1ec1 l\u00e0 n\u0103ng l\u01b0\u1ee3ng to\u00e0n ph\u1ea7n c\u1ee7a th\u1ef1c th\u1ec3 v\u1eadt l\u00fd \u2013 \u0111i\u1ec1u n\u00e0y c\u00f3 kh\u00e1c g\u00ec \u201c\u1ea3o gi\u00e1c\u201d?","PH\u1ee4 L\u1ee4C 282 H\u00e3y b\u1eaft \u0111\u1ea7u t\u1eeb c\u01a1 n\u0103ng c\u1ee7a m\u1ed9t v\u1eadt th\u1ec3 trong tr\u01b0\u1eddng l\u1ef1c th\u1ebf, theo ng\u00f4n ng\u1eef c\u1ee7a c\u01a1 h\u1ecdc Newton, l\u00e0 t\u1ed5ng c\u1ee7a \u0111\u1ed9ng n\u0103ng v\u00e0 th\u1ebf n\u0103ng: Wc = K + U . (P11.1) Nh\u01b0ng th\u1ebf n\u0103ng h\u1ea5p d\u1eabn l\u1ea1i quy \u01b0\u1edbc lu\u00f4n mang d\u1ea5u (\u2013) v\u00ec c\u00e1c v\u1eadt th\u1ec3 h\u00fat nhau, m\u00e0 \u0111\u1ed9ng n\u0103ng l\u1ea1i lu\u00f4n (+) n\u00ean: mV 2 \u2212 \u03b1h 2 R Wc = . (P11.2) C\u00e1c bi\u1ec3u th\u1ee9c n\u00e0y \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho m\u1ecdi tr\u01b0\u1eddng h\u1ee3p c\u1ee7a c\u01a1 h\u1ecdc Newton. V\u00e0 h\u01a1n th\u1ebf n\u1eefa, n\u1ebfu 2 v\u1eadt th\u1ec3 l\u00e0 m\u1ed9t h\u1ec7 k\u00edn th\u00ec c\u00e1i g\u1ecdi l\u00e0 \u201cc\u01a1 n\u0103ng\u201d x\u00e1c \u0111\u1ecbnh theo (P11.1) \u0111\u01b0\u1ee3c xem nh\u01b0 l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng ph\u1ea3i \u0111\u01b0\u1ee3c b\u1ea3o to\u00e0n (theo \u201c\u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n v\u00e0 chuy\u1ec3n h\u00f3a n\u0103ng l\u01b0\u1ee3ng\u201d). Ta th\u1eed xem x\u00e9t k\u1ef9 l\u1ea1i tr\u01b0\u1edbc h\u1ebft l\u00e0 \u0111\u1ed1i v\u1edbi chuy\u1ec3n \u0111\u1ed9ng r\u01a1i t\u1ef1 do. C\u00e1i \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cc\u01a1 n\u0103ng\u201d theo bi\u1ec3u th\u1ee9c (P11.2) v\u1ec1 th\u1ef1c ch\u1ea5t ch\u1ec9 l\u00e0 s\u1ef1 ch\u00eanh l\u1ec7ch c\u1ee7a th\u1ebf n\u0103ng (c\u1ee7a tr\u01b0\u1eddng l\u1ef1c th\u1ebf) v\u00e0 \u0111\u1ed9ng n\u0103ng do n\u00f3 sinh ra v\u00e0 v\u00ec v\u1eady, n\u1ebfu cho r\u1eb1ng n\u0103ng l\u01b0\u1ee3ng kh\u00f4ng b\u1ecb th\u1ea5t tho\u00e1t trong qu\u00e1 tr\u00ecnh chuy\u1ec3n h\u00f3a t\u1eeb th\u1ebf n\u0103ng th\u00e0nh \u0111\u1ed9ng n\u0103ng th\u00ec \u0111\u01b0\u01a1ng nhi\u00ean hi\u1ec7u s\u1ed1 n\u00e0y ph\u1ea3i l\u00e0 h\u1eb1ng s\u1ed1. Nh\u01b0ng vi\u1ec7c n\u00f3 l\u00e0 h\u1eb1ng s\u1ed1 l\u00e0 m\u1ed9t chuy\u1ec7n, c\u00f2n n\u00f3 c\u00f3 \u0111\u00fang l\u00e0 c\u01a1 n\u0103ng hay kh\u00f4ng l\u1ea1i l\u00e0 chuy\u1ec7n kh\u00e1c. Gi\u00e1 nh\u01b0 kh\u00f4ng \u00e1p \u0111\u1eb7t d\u1ea5u cho th\u1ebf n\u0103ng (<0) m\u00e0 ch\u1ec9 d\u1eebng l\u1ea1i \u1edf bi\u1ec3u th\u1ee9c (P11.1) th\u00ec kh\u00e1i ni\u1ec7m \u201cc\u01a1 n\u0103ng\u201d c\u00f2n c\u00f3 th\u1ec3 ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c v\u1edbi ngh\u0129a l\u00e0 n\u0103ng l\u01b0\u1ee3ng \u0111\u1eb7c tr\u01b0ng cho tr\u1ea1ng th\u00e1i c\u01a1 h\u1ecdc c\u1ee7a v\u1eadt th\u1ec3. Tuy nhi\u00ean, khi quy \u0111\u1ecbnh d\u1ea5u cho m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng, v\u1ec1 th\u1ef1c ch\u1ea5t, \u0111\u00e3 quy \u0111\u1ecbnh chi\u1ec1u cho \u0111\u1ea1i l\u01b0\u1ee3ng \u0111\u00f3: \u0111\u1ed9ng n\u0103ng v\u00e0 th\u1ebf n\u0103ng c\u00f3 chi\u1ec1u ng\u01b0\u1ee3c nhau. Nh\u01b0ng nh\u01b0 th\u1ebf c\u00f3 kh\u00e1c g\u00ec th\u1eeba nh\u1eadn c\u01a1 n\u0103ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 m\u00e0 kh\u00f4ng ph\u1ea3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng cho d\u00f9 l\u00e0 ch\u1ec9 c\u00f3 2 h\u01b0\u1edbng c\u1ef1c \u0111oan: >0 hay <0? \u2013 M\u1ed9t s\u1ef1 thi\u1ebfu nh\u1ea5t qu\u00e1n! Song, m\u1ed9t khi \u0111\u00e3 n\u00f3i \u0111\u1ebfn h\u01b0\u1edbng th\u00ec \u0111\u1ed9ng n\u0103ng trong c\u00f4ng th\u1ee9c (P11.1) l\u1ea1i ph\u1ea3i c\u00f3 h\u01b0\u1edbng tr\u00f9ng v\u1edbi h\u01b0\u1edbng c\u1ee7a th\u1ebf n\u0103ng m\u1edbi ph\u1ea3i l\u1ebd, v\u00ec v\u1eadn t\u1ed1c chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a c\u00e1c v\u1eadt th\u1ec3 lu\u00f4n h\u01b0\u1edbng v\u1ec1 ph\u00eda nhau, c\u00f9ng v\u1edbi h\u01b0\u1edbng c\u1ee7a l\u1ef1c","PH\u1ee4 L\u1ee4C 283 tr\u01b0\u1eddng th\u1ebf - k\u1ebft qu\u1ea3 c\u1ee7a th\u1ebf n\u0103ng n\u00e0y? V\u00ec v\u1eady, bi\u1ec3u th\u1ee9c (P11.2) kh\u00f4ng h\u1ec1 l\u00e0 c\u01a1 n\u0103ng c\u1ee7a v\u1eadt th\u1ec3. C\u00f3 th\u1ec3 l\u1ea5y v\u00ed d\u1ee5 v\u1ec1 tr\u01b0\u1eddng h\u1ee3p khi 2 v\u1eadt th\u1ec3 \u1edf xa nhau v\u00f4 h\u1ea1n, th\u1ebf n\u0103ng ~0 v\u00e0 \u0111\u1ed9ng n\u0103ng ban \u0111\u1ea7u =0, t\u1ee9c l\u00e0 hi\u1ec7u (P11.2) ~0, th\u00ec trong su\u1ed1t qu\u00e1 tr\u00ecnh r\u01a1i t\u1ef1 do v\u1ec1 ph\u00eda nhau, hi\u1ec7u n\u00e0y lu\u00f4n lu\u00f4n =0 ch\u1eb3ng ph\u1ea3i l\u00e0 \u0111i\u1ec1u g\u00ec l\u1ea1 \u2013 to\u00e0n b\u1ed9 th\u1ebf n\u0103ng chuy\u1ec3n h\u00f3a th\u00e0nh \u0111\u1ed9ng n\u0103ng \u2013 v\u00e0 ch\u1ec9 c\u00f3 v\u1eady th\u00f4i. Nh\u01b0ng ch\u1eb3ng l\u1ebd v\u00ec c\u01a1 n\u0103ng c\u1ee7a v\u1eadt th\u1ec3 ph\u1ea3i b\u1ea3o to\u00e0n th\u00ec l\u1ea1i cho r\u1eb1ng n\u00f3 ph\u1ea3i =0 hay sao? M\u00e0 m\u1ed9t khi c\u01a1 n\u0103ng =0 th\u00ec v\u1eadt th\u1ec3 ph\u1ea3i kh\u00f4ng chuy\u1ec3n \u0111\u1ed9ng m\u1edbi \u0111\u00fang ch\u1ee9? V\u00ec kh\u00f4ng th\u1ec3 n\u00e0o l\u1ea1i c\u00f3 th\u1ec3 chuy\u1ec3n \u0111\u1ed9ng m\u00e0 v\u1edbi n\u0103ng l\u01b0\u1ee3ng =0 \u0111\u01b0\u1ee3c! Nh\u01b0ng v\u1eadt l\u1ea1i v\u1eabn chuy\u1ec3n \u0111\u1ed9ng, kh\u00f4ng nh\u1eefng th\u1ebf c\u00f2n chuy\u1ec3n \u0111\u1ed9ng m\u1ed7i l\u00fac m\u1ed9t nhanh h\u01a1n, v\u00e0 \u0111i\u1ec1u t\u1ec7 h\u1ea1i h\u01a1n n\u1eefa l\u00e0 l\u1ef1c tr\u01b0\u1eddng th\u1ebf ng\u00e0y m\u1ed9t m\u1ea1nh h\u01a1n \u2013 ch\u1eb3ng l\u1ebd kh\u00f4ng ph\u1ea3i v\u00ec th\u1ebf n\u0103ng ng\u00e0y m\u1ed9t l\u1edbn h\u01a1n sao? K\u1ebft c\u1ee5c l\u00e0 c\u1ea3 \u0111\u1ed9ng n\u0103ng, c\u1ea3 th\u1ebf n\u0103ng \u0111\u1ec1u t\u0103ng m\u00e0 l\u1ea1i cho r\u1eb1ng c\u01a1 n\u0103ng =0 th\u00ec h\u1ee3p l\u00fd l\u00e0m sao \u0111\u01b0\u1ee3c? S\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng r\u1ea5t r\u00f5 r\u1ec7t: tho\u1ea1t \u0111\u1ea7u ~0 \u2013 l\u00e0 \u0111i\u1ec1u \u0111\u00e3 qu\u00e1 r\u00f5, nh\u01b0ng v\u1ec1 sau l\u1ea1i \u0111\u1ea1t nh\u1eefng gi\u00e1 tr\u1ecb kh\u1ed5ng l\u1ed3, th\u1ec3 hi\u1ec7n ra khi 2 v\u1eadt va ch\u1ea1m nhau \u2013 \u0111i\u1ec1u n\u00e0y l\u1ea1i kh\u00f4ng th\u1ec3 ch\u1ed1i c\u00e3i, (kh\u1ee7ng long \u0111\u00e3 ch\u1eb3ng tuy\u1ec7t di\u1ec7t v\u00ec n\u0103ng l\u01b0\u1ee3ng n\u00e0y \u0111\u00f3 sao?). Tr\u01b0\u1eddng h\u1ee3p chuy\u1ec3n \u0111\u1ed9ng theo qu\u1ef9 \u0111\u1ea1o tr\u00f2n. Bi\u1ec3u th\u1ee9c (P11.1) qu\u1ea3 th\u1eadt c\u0169ng l\u00e0 m\u1ed9t h\u1eb1ng s\u1ed1 trong su\u1ed1t qu\u00e1 tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng, h\u01a1n th\u1ebf n\u1eefa, c\u00e0ng \u1edf qu\u1ef9 \u0111\u1ea1o b\u00ean trong, \u201cc\u01a1 n\u0103ng\u201d c\u00e0ng l\u1edbn \u2013 \u0111i\u1ec1u n\u00e0y v\u1ec1 \u0111\u1ecbnh t\u00ednh l\u00e0 h\u1ee3p l\u00fd, cho d\u00f9 v\u1eabn b\u1ecb l\u00fang t\u00fang b\u1edfi d\u1ea5u (\u2013) c\u1ee7a n\u00f3: Wc = \u2212 \u03b1h (P11.3) 2R V\u1ec1 th\u1ef1c ch\u1ea5t, n\u1ebfu n\u0103ng l\u01b0\u1ee3ng <0, c\u00e1c v\u1eadt t\u1ea5t ph\u1ea3i h\u00fat nhau d\u1eabn \u0111\u1ebfn chuy\u1ec3n \u0111\u1ed9ng v\u1ec1 ph\u00eda nhau th\u00ec m\u1edbi ph\u1ea3i, nh\u01b0ng \u1edf \u0111\u00e2y, kho\u1ea3ng c\u00e1ch gi\u1eefa 2 v\u1eadt lu\u00f4n lu\u00f4n kh\u00f4ng \u0111\u1ed5i \u2013 \u0111i\u1ec1u n\u00e0y ph\u1ea3i ch\u1ee9ng t\u1ecf r\u1eb1ng theo ph\u01b0\u01a1ng n\u1ed1i t\u00e2m 2 v\u1eadt th\u1ec3, l\u1ef1c t\u00e1c \u0111\u1ed9ng t\u1ed5ng h\u1ee3p l\u00ean n\u00f3 ph\u1ea3i =0 \u2013 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi c\u01a1 n\u0103ng theo ph\u01b0\u01a1ng \u0111\u00f3 =0. \u1ede \u0111\u00e2y, ch\u1ec9 t\u1ed3n t\u1ea1i chuy\u1ec3n \u0111\u1ed9ng theo qu\u1ef9 \u0111\u1ea1o tr\u00f2n v\u1edbi \u0111\u1ed9ng n\u0103ng qu\u1ef9 \u0111\u1ea1o b\u1eb1ng:","PH\u1ee4 L\u1ee4C 284 K = mV 2 (P11.4) 2 T\u1ee9c l\u00e0 c\u00f3 chuy\u1ec3n \u0111\u1ed9ng th\u00ec c\u00f3 c\u01a1 n\u0103ng t\u01b0\u01a1ng \u1ee9ng v\u1edbi n\u00f3 \u2013 \u0111\u00f3 m\u1edbi ch\u00ednh l\u00e0 \u0111i\u1ec1u h\u1ee3p l\u00f4g\u00edc. T\u00f3m l\u1ea1i, trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, bi\u1ec3u th\u1ee9c (P11.1) ho\u00e0n to\u00e0n ch\u1eb3ng \u0103n nh\u1eadp g\u00ec v\u1edbi c\u00e1i g\u1ecdi l\u00e0 \u201cc\u01a1 n\u0103ng\u201d c\u1ee7a v\u1eadt th\u1ec3 c\u1ea3, tr\u00e1i l\u1ea1i, c\u01a1 n\u0103ng c\u1ee7a chuy\u1ec3n \u0111\u1ed9ng tr\u00f2n \u0111\u1ec1u tr\u00ean qu\u1ef9 \u0111\u1ea1o ph\u1ea3i l\u00e0 bi\u1ec3u th\u1ee9c (P11.4) v\u00e0 ch\u1ec9 c\u00f3 th\u1ebf m\u00e0 th\u00f4i. Trong c\u1ea3 2 tr\u01b0\u1eddng h\u1ee3p, \u0111\u1ec1u kh\u00f4ng \u0111\u1ec1 c\u1eadp \u0111\u1ebfn n\u0103ng l\u01b0\u1ee3ng t\u1ed5ng hay n\u0103ng l\u01b0\u1ee3ng to\u00e0n ph\u1ea7n c\u1ee7a th\u1ef1c th\u1ec3 v\u1eadt l\u00fd, v\u00ec v\u1eady, \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n v\u00e0 chuy\u1ec3n h\u00f3a n\u0103ng l\u01b0\u1ee3ng, x\u00e9t cho c\u00f9ng, c\u0169ng m\u1edbi ch\u1ec9 l\u00e0 \u201c\u1ea3o gi\u00e1c\u201d m\u00e0 th\u00f4i. T\u1eeb quan \u0111i\u1ec3m c\u1ee7a C\u0110M, n\u0103ng l\u01b0\u1ee3ng l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e9c t\u01a1 ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng v\u00f4 h\u01b0\u1edbng v\u00e0 h\u01a1n th\u1ebf n\u1eefa l\u1ea1i ph\u00e2n bi\u1ec7t r\u1ea5t r\u00f5 n\u0103ng l\u01b0\u1ee3ng t\u1ed5ng, n\u0103ng l\u01b0\u1ee3ng to\u00e0n ph\u1ea7n, n\u0103ng l\u01b0\u1ee3ng c\u01a1 (\u201cc\u01a1 n\u0103ng\u201d trong c\u01a1 h\u1ecdc Newton), n\u0103ng l\u01b0\u1ee3ng li\u00ean k\u1ebft v.v.. trong \u0111\u00f3 \u0111\u1ecbnh lu\u1eadt b\u1ea3o to\u00e0n n\u0103ng l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c ph\u00e1t bi\u1ec3u cho n\u0103ng l\u01b0\u1ee3ng to\u00e0n ph\u1ea7n ch\u1ee9 kh\u00f4ng ph\u1ea3i cho c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a n\u00f3. N\u1ebfu x\u00e9t theo quan \u0111i\u1ec3m c\u1ee7a C\u0110M, bi\u1ec3u th\u1ee9c (P11.1) ch\u1ec9 \u0111\u01b0\u1ee3c xem nh\u01b0 m\u1ed9t t\u00ednh ch\u1ea5t c\u1ee7a chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng bao g\u1ed3m r\u01a1i t\u1ef1 do v\u00e0 chuy\u1ec3n \u0111\u1ed9ng tr\u00ean qu\u1ef9 \u0111\u1ea1o (theo qu\u00e1n t\u00ednh) ch\u1ee9 ho\u00e0n to\u00e0n kh\u00f4ng li\u00ean quan g\u00ec t\u1edbi t\u1ed5ng n\u0103ng l\u01b0\u1ee3ng c\u1ee7a th\u1ef1c th\u1ec3 v\u1eadt l\u00fd c\u1ea3. C\u0169ng v\u1eabn bi\u1ec3u th\u1ee9c \u0111\u00f3, trong chuy\u1ec3n \u0111\u1ed9ng cong (qu\u1ef9 \u0111\u1ea1o el\u00edp), n\u00f3 kh\u00f4ng c\u00f2n l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng b\u1ea3o to\u00e0n n\u1eefa trong khi \u0111\u1ea1i l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c b\u1ea3o to\u00e0n ch\u1eafc ch\u1eafn v\u1eabn l\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u1ed5ng. 12. C\u1ea5u tr\u00fac c\u1ee7a electron Electron trong l\u00fd thuy\u1ebft tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb \u0111\u01b0\u1ee3c coi l\u00e0 \u0111i\u1ec7n t\u00edch \u0111i\u1ec3m, t\u1ee9c l\u00e0 kh\u00f4ng c\u00f3 k\u00edch th\u01b0\u1edbc v\u1edbi l\u00fd do l\u00e0 m\u1ecdi k\u00edch th\u01b0\u1edbc g\u00e1n cho n\u00f3 \u0111\u1ec1u d\u1eabn \u0111\u1ebfn ngh\u1ecbch l\u00fd: l\u1ef1c n\u00e0o \u0111\u00e3 gi\u1eef l\u1ea1i \u0111i\u1ec7n t\u00edch tr\u00ean b\u1ec1 m\u1eb7t c\u1ee7a n\u00f3? V\u00e0 h\u01a1n th\u1ebf n\u1eefa, \u201c\u0111i\u1ec7n t\u00edch nguy\u00ean t\u1ed1\u201d kh\u00f4ng c\u00f2n b\u1eb1ng 1 n\u1eefa m\u00e0 ph\u1ea3i nh\u1ecf h\u01a1n nhi\u1ec1u \u0111\u1ec3 \u201cph\u1ee7\u201d \u0111\u1ea7y b\u1ec1 m\u1eb7t! T\u1eeb \u0111\u00e2y, ng\u01b0\u1eddi ta \u0111\u00e0nh ch\u1ea5p nh\u1eadn kh\u00e1i ni\u1ec7m \u0111i\u1ec7n t\u00edch \u0111i\u1ec3m \u0111\u1ec3 n\u00e9 tr\u00e1nh ngh\u1ecbch l\u00fd","PH\u1ee4 L\u1ee4C 285 khi coi \u0111i\u1ec7n t\u1eed c\u00f3 c\u1ea5u tr\u00fac. Nh\u01b0ng \u201ctr\u00e1nh v\u1ecf d\u01b0a l\u1ea1i g\u1eb7p v\u1ecf d\u1eeba\u201d, \u0111i\u1ec7n t\u00edch \u0111i\u1ec3m l\u1ea1i c\u00f3 n\u0103ng l\u01b0\u1ee3ng b\u1eb1ng v\u00f4 c\u00f9ng \u2013 hi\u1ec7n t\u01b0\u1ee3ng ph\u00e2n k\u1ef3 kh\u00f4ng h\u1ec1 th\u00fa v\u1ecb h\u01a1n. Th\u00f4i th\u00ec \u0111\u00e0nh \u201ct\u00e1i chu\u1ea9n h\u00f3a\u201d v\u1eady \u2013 c\u00e1c nh\u00e0 v\u1eadt l\u00fd \u0111\u00e0nh \u0111\u1ec3 cho \u201cn\u1eef ho\u00e0ng\u201d to\u00e1n h\u1ecdc \u201cchi\u1ebfm \u0111o\u1ea1t l\u00fd tr\u00ed\u201d c\u1ee7a m\u00ecnh. Theo C\u0110M (xem m\u1ee5c 1.3.3), electron kh\u00f4ng c\u00f3 c\u1ea5u tr\u00fac nh\u01b0ng kh\u00f4ng ph\u1ea3i kh\u00f4ng c\u00f3 k\u00edch th\u01b0\u1edbc; c\u00f3 k\u00edch th\u01b0\u1edbc nh\u01b0ng kh\u00f4ng ph\u1ea3i l\u00e0 \u0111i\u1ec7n t\u00edch b\u1ecb \u201cr\u1ea3i\u201d \u0111\u1ec1u theo k\u00edch th\u01b0\u1edbc \u0111\u00f3 v\u00e0 do \u0111\u00f3 c\u00f3 th\u1ec3 b\u1ecb chia th\u00e0nh c\u00e1c ph\u1ea7n nh\u1ecf. Ta c\u00f3 th\u1ec3 h\u00ecnh dung 2 n\u1eeda tr\u00e1i b\u00f3ng cao su \u2013 b\u00ean trong m\u1ea7u \u0111en c\u00f2n b\u00ean ngo\u00e0i m\u1ea7u tr\u1eafng, m\u1ed9t trong hai n\u1eeda \u0111\u00f3 b\u1ecb l\u1ed9n theo chi\u1ec1u ng\u01b0\u1ee3c l\u1ea1i (\u0111en ra ngo\u00e0i, c\u00f2n tr\u1eafng v\u00e0o trong) t\u01b0\u01a1ng \u1ee9ng v\u1edbi positron, c\u00f2n n\u1eeda kia (tr\u1eafng \u1edf ngo\u00e0i, \u0111en \u1edf trong) \u2013 electron. Khi b\u1ecb t\u00e1c \u0111\u1ed9ng m\u1ea1nh t\u1edbi m\u1ee9c \u0111\u1ed9 n\u00e0o \u0111\u00f3, c\u00e1c n\u1eeda tr\u00e1i b\u00f3ng n\u00e0y s\u1ebd b\u1ecb l\u1ed9n ng\u01b0\u1ee3c l\u1ea1i t\u01b0\u01a1ng \u1ee9ng v\u1edbi s\u1ef1 bi\u1ebfn h\u00f3a t\u1eeb electron th\u00e0nh positron ho\u1eb7c ng\u01b0\u1ee3c l\u1ea1i, t\u1eeb positron th\u00e0nh electron ch\u1ee9 kh\u00f4ng b\u1ecb x\u00e9 nh\u1ecf ra th\u00e0nh t\u1eebng m\u1ea3nh nh\u1ecf. Hay c\u00f3 th\u1ec3 d\u00f9ng m\u1ed9t h\u00ecnh \u1ea3nh kh\u00e1c \u0111\u1ec3 so s\u00e1nh \u0111\u00f3 l\u00e0 \u201cm\u1eaft b\u00e3o\u201d \u2013 m\u1ed9t v\u0169ng t\u0129nh l\u1eb7ng kh\u00f4ng c\u00f3 gi\u00f3 \u0111\u01b0\u1ee3c nh\u00ecn th\u1ea5y kh\u00e1 r\u00f5 r\u00e0ng trong c\u00e1c b\u1ee9c \u1ea3nh c\u01a1n b\u00e3o ch\u1ee5p t\u1eeb v\u1ec7 tinh \u2013 \u201cm\u1eaft b\u00e3o\u201d kh\u00f4ng h\u1ec1 \u0111\u01b0\u1ee3c c\u1ea5u t\u1ea1o t\u1eeb c\u00e1c c\u00e1i g\u1ecdi l\u00e0 \u201cm\u1eaft b\u00e3o nh\u1ecf h\u01a1n\u201d n\u00e0o h\u1ebft \u2013 \u0111\u00f3 ch\u1ec9 \u0111\u01a1n thu\u1ea7n l\u00e0 gi\u1edbi h\u1ea1n c\u1ee7a m\u1ed9t tr\u1ea1ng th\u00e1i v\u1eadt l\u00fd tu\u00e2n theo quy lu\u1eadt l\u01b0\u1ee3ng \u0111\u1ed5i-ch\u1ea5t \u0111\u1ed5i. \u201cM\u1eaft b\u00e3o\u201d l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m cho m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng to\u00e0n v\u1eb9n kh\u00f4ng th\u1ec3 b\u1ecb ph\u00e2n chia nh\u1ecf h\u01a1n n\u1eefa m\u00e0 th\u00f4i! 13. \u0110i\u1ec7n t\u00edch ph\u00e2n s\u1ed1 c\u1ee7a quark M\u1eb7c d\u00f9 \u0111i\u1ec7n t\u00edch c\u1ee7a electron \u0111\u00e3 \u0111\u01b0\u1ee3c coi l\u00e0 \u201cc\u01a1 b\u1ea3n\u201d nh\u01b0ng \u0111i\u1ec7n t\u00edch c\u1ee7a quark l\u1ea1i c\u00f2n \u201cc\u01a1 b\u1ea3n\u201d h\u01a1n: b\u1eb1ng 1\/3! T\u1ea1i sao l\u1ea1i b\u1eb1ng 1\/3 \u2013 ch\u1ee9 kh\u00f4ng ph\u1ea3i 1? Trong c\u00e1c va ch\u1ea1m n\u0103ng l\u01b0\u1ee3ng cao, ng\u01b0\u1eddi ta v\u1eabn kh\u00f4ng thu \u0111\u01b0\u1ee3c c\u00e1c h\u1ea1t quark t\u1ef1 do \u0111\u1ec3 xem \u0111i\u1ec7n t\u00edch c\u1ee7a ch\u00fang c\u00f3 \u0111\u00fang l\u00e0 ph\u00e2n s\u1ed1 1\/3 hay kh\u00f4ng. M\u1ed9t s\u1ed1 c\u00e1c th\u00ed nghi\u1ec7m g\u1ea7n \u0111\u00e2y tr\u00ean c\u00e1c m\u00e1y gia t\u1ed1c l\u1edbn cho l\u00e0 \u201c\u0111\u00e3 ghi nh\u1eadn \u0111\u01b0\u1ee3c quark t\u1ef1 do\u201d,","PH\u1ee4 L\u1ee4C 286 v\u1ec1 th\u1ef1c ch\u1ea5t, ch\u1ec9 c\u00f3 t\u00ednh \u201cnh\u00e2n t\u1ea1o\u201d \u2013 d\u01b0\u1eddng nh\u01b0 xu\u1ea5t ph\u00e1t t\u1eeb mong mu\u1ed1n c\u1ee7a ng\u01b0\u1eddi l\u00e0m th\u00ed nghi\u1ec7m h\u01a1n l\u00e0 m\u1ed9t t\u1ed3n t\u1ea1i kh\u00e1ch quan. \u201cS\u1ef1 ph\u00e1t hi\u1ec7n ra pentaquark\u201d v\u00e0o nh\u1eefng n\u0103m 2003 \u2013 2005 m\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t v\u00ed d\u1ee5. Theo C\u0110M, c\u00e1c h\u1ea1t quark n\u00e0y kh\u00f4ng t\u1ed3n t\u1ea1i, ch\u1ec9 t\u1ed3n t\u1ea1i c\u00e1c dipol v\u00e0 c\u00e1c k\u1ebft c\u1ea5u \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh t\u1eeb c\u00e1c dipol n\u00e0y m\u00e0 th\u00f4i. 14. M\u1ee9c n\u0103ng l\u01b0\u1ee3ng c\u1ee7a nguy\u00ean t\u1eed* \u0110\u1ec3 \u0111\u01a1n gi\u1ea3n, ta ch\u1ec9 l\u1ea5y nguy\u00ean t\u1eed Hy\u0111r\u00f4 l\u00e0m v\u00ed d\u1ee5, c\u00f2n \u0111\u1ed1i v\u1edbi c\u00e1c nguy\u00ean t\u1eed kh\u00e1c, b\u1ee9c tranh c\u0169ng ho\u00e0n to\u00e0n t\u01b0\u01a1ng t\u1ef1 ch\u1ec9 kh\u00e1c v\u1ec1 l\u01b0\u1ee3ng. Gi\u1ea3 s\u1eed c\u00f3 m\u1ed9t kh\u1ed1i kh\u00ed Hy\u0111r\u00f4 \u1edf t\u1ea1i nhi\u1ec7t \u0111\u1ed9 m\u00e0 c\u00e1c li\u00ean k\u1ebft nguy\u00ean t\u1eed tr\u1edf n\u00ean qu\u00e1 y\u1ebfu \u0111\u1ec3 h\u00ecnh th\u00e0nh ph\u00e2n t\u1eed H2 \u2013 ta c\u00f3 kh\u1ed1i kh\u00ed c\u1ea5u th\u00e0nh thu\u1ea7n tu\u00fd t\u1eeb c\u00e1c nguy\u00ean t\u1eed Hy\u0111r\u00f4. C\u00e1c qu\u00e1 tr\u00ecnh b\u1ee9c x\u1ea1 v\u00e0 h\u1ea5p thu n\u0103ng l\u01b0\u1ee3ng do v\u1eady ch\u1ec9 l\u00e0 do c\u00e1c nguy\u00ean t\u1eed n\u00e0y. Theo c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed, m\u1ee9c n\u0103ng l\u01b0\u1ee3ng c\u1ee7a \u0111i\u1ec7n t\u1eed trong nguy\u00ean t\u1eed H \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 tr\u00ean H\u00ecnh P2. N\u0103ng l\u01b0\u1ee3ng k\u00edch th\u00edch c\u00e1c \u0111i\u1ec7n t\u1eed \u1edf \u0111\u00e2y ch\u1ec9 do va ch\u1ea1m gi\u1eefa c\u00e1c nguy\u00ean t\u1eed H trong qu\u00e1 tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng nhi\u1ec7t. Khi nhi\u1ec7t \u0111\u1ed9 c\u00f2n th\u1ea5p, c\u00e1c \u0111i\u1ec7n t\u1eed ch\u1ee7 y\u1ebfu chi\u1ebfm gi\u1eef c\u00e1c v\u1ecb tr\u00ed \u1ee9ng v\u1edbi n\u0103ng l\u01b0\u1ee3ng th\u1ea5p (n=1;2). Khi nhi\u1ec7t \u0111\u1ed9 l\u00ean cao, c\u00e1c \u0111i\u1ec7n t\u1eed b\u1ecb k\u00edch th\u00edch, chi\u1ebfm gi\u1eef c\u00e1c v\u1ecb tr\u00ed \u1ee9ng v\u1edbi n\u0103ng l\u01b0\u1ee3ng cao h\u01a1n (n!5), th\u1eadm ch\u00ed \u0111\u1ebfn m\u1ee9c \u0111\u01b0\u1ee3c gi\u1ea3i ph\u00f3ng ho\u00e0n to\u00e0n kh\u1ecfi nguy\u00ean t\u1eed - tr\u1ea1ng th\u00e1i kh\u00ed chuy\u1ec3n th\u00e0nh tr\u1ea1ng th\u00e1i plazma. V\u1ea5n \u0111\u1ec1 l\u00e0 \u1edf ch\u1ed7 \u0111i\u1ec7n t\u1eed ch\u1ec9 b\u1ee9c x\u1ea1 n\u0103ng l\u01b0\u1ee3ng khi quay v\u1ec1 tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng th\u1ea5p h\u01a1n tr\u1ea1ng th\u00e1i b\u1ecb k\u00edch th\u00edch: \u2206W = Wm \u2013 Wk = hf; \u1edf \u0111\u00e2y m>k; f - t\u1ea7n s\u1ed1 b\u1ee9c x\u1ea1; h - h\u1eb1ng s\u1ed1 Planck. Nh\u01b0ng tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng th\u1ea5p h\u01a1n \u0111\u1ebfn m\u1ee9c n\u00e0o c\u00f2n ph\u1ee5 thu\u1ed9c v\u00e0o c\u01b0\u1eddng \u0111\u1ed9 v\u00e0 t\u1ea7n su\u1ea5t c\u1ee7a k\u00edch th\u00edch t\u1ee9c l\u00e0 v\u00e0o nhi\u1ec7t \u0111\u1ed9. Nhi\u1ec7t \u0111\u1ed9 c\u00e0ng cao, \u0111\u1ed9ng n\u0103ng c\u1ee7a c\u00e1c nguy\u00ean t\u1eed c\u00e0ng l\u1edbn (t\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 k\u00edch th\u00edch c\u00e0ng l\u1edbn) v\u00e0 t\u1ea7n su\u1ea5t va ch\u1ea1m gi\u1eefa c\u00e1c nguy\u00ean t\u1eed c\u00e0ng l\u1edbn (t\u1ee9c t\u1ea7n su\u1ea5t k\u00edch th\u00edch c\u00e0ng","PH\u1ee4 L\u1ee4C 287 l\u1edbn). \u1edf nhi\u1ec7t \u0111\u1ed9 qu\u00e1 cao, x\u00e1c su\u1ea5t c\u00e1c \u0111i\u1ec7n t\u1eed quay tr\u1edf v\u1ec1 tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng th\u1ea5p l\u00e0 r\u1ea5t nh\u1ecf.N\u0103ng l\u01b0\u1ee3ng (eV) D\u00e3y brakett \u221e D\u00e3y Pasen -0,38 6 -0,54 5 4 -0,85 -1,51 3 -3,40 2 D\u00e3y Balmer -13,58 1 D\u00e3y Lyman H\u00ecnh P2. S\u01a1 \u0111\u1ed3 ph\u1ed5 n\u0103ng l\u01b0\u1ee3ng c\u1ee7a Hydrozen. Do \u0111\u00f3 n\u1ea9y sinh m\u1ed9t ngh\u1ecbch l\u00fd l\u00e0 \u1edf nhi\u1ec7t \u0111\u1ed9 c\u00e0ng cao th\u00ec n\u0103ng l\u01b0\u1ee3ng b\u1ee9c x\u1ea1 nh\u1ecf \u1ee9ng v\u1edbi t\u1ea7n s\u1ed1 b\u1ee9c x\u1ea1 th\u1ea5p l\u1ea1i t\u0103ng l\u00ean (\u1ee9ng v\u1edbi d\u00e3y Pashen v\u00e0 d\u00e3y Brakett). Trong khi \u0111\u00f3, \u1edf nhi\u1ec7t \u0111\u1ed9 c\u00e0ng th\u1ea5p th\u00ec n\u0103ng l\u01b0\u1ee3ng b\u1ee9c x\u1ea1 l\u1edbn \u1ee9ng v\u1edbi t\u1ea7n s\u1ed1 b\u1ee9c x\u1ea1 cao l\u1ea1i c\u00e0ng l\u1edbn (\u1ee9ng v\u1edbi d\u00e3y Lyman) v\u00ec ch\u1ec9 \u1edf nhi\u1ec7t \u0111\u1ed9 th\u1ea5p c\u00e1c \u0111i\u1ec7n t\u1eed m\u1edbi c\u00f3 nhi\u1ec1u c\u01a1 may quay tr\u1edf v\u1ec1 tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng th\u1ea5p. Ph\u1ed5 b\u1ee9c x\u1ea1 do \u0111\u00f3 d\u1ecbch chuy\u1ec3n v\u1ec1 ph\u00eda \u201c\u0111\u1ecf\u201d khi nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean v\u00e0 d\u1ecbch chuy\u1ec3n v\u1ec1 ph\u00eda \u201ct\u00edm\u201d khi nhi\u1ec7t \u0111\u1ed9 gi\u1ea3m xu\u1ed1ng. T\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady ta c\u0169ng nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ed5 h\u1ea5p th\u1ee5 tr\u00f9ng v\u1edbi ph\u1ed5 b\u1ee9c x\u1ea1.","PH\u1ee4 L\u1ee4C 288 M\u00f4 h\u00ecnh \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng\u201d n\u00e0y ch\u1ec9 gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c hi\u1ec7n t\u01b0\u1ee3ng gi\u00e1n \u0111o\u1ea1n t\u1ea7n s\u1ed1 v\u00e0 gi\u00e1n \u0111o\u1ea1n n\u0103ng l\u01b0\u1ee3ng b\u1ee9c x\u1ea1 (hay h\u1ea5p th\u1ee5) c\u1ee7a c\u00e1c ch\u1ea5t nh\u01b0ng v\u1edbi hi\u1ec7n t\u01b0\u1ee3ng d\u1ecbch chuy\u1ec3n ph\u1ed5 th\u00ec l\u1ea1i \u0111\u01b0a ra k\u1ebft lu\u1eadn ho\u00e0n to\u00e0n tr\u00e1i ng\u01b0\u1ee3c v\u1edbi th\u1ef1c t\u1ebf. B\u00ean c\u1ea1nh \u0111\u00f3, vi\u1ec7c cho r\u1eb1ng m\u1ee9c n\u0103ng l\u01b0\u1ee3ng th\u1ea5p c\u1ee7a \u0111i\u1ec7n t\u1eed t\u01b0\u01a1ng \u1ee9ng v\u1edbi qu\u1ef9 \u0111\u1ea1o g\u1ea7n h\u1ea1t nh\u00e2n nh\u1ea5t c\u00f2n m\u1ee9c n\u0103ng l\u01b0\u1ee3ng cao l\u1ea1i \u1ee9ng v\u1edbi qu\u1ef9 \u0111\u1ea1o xa h\u1ea1t nh\u00e2n l\u00e0 ho\u00e0n to\u00e0n tr\u00e1i ng\u01b0\u1ee3c v\u1edbi th\u1ef1c t\u1ebf. Theo C\u0110M, \u0111\u1ec3 \u0111i\u1ec7n t\u1eed c\u00f3 th\u1ec3 chuy\u1ec3n \u0111\u1ed9ng \u1edf qu\u1ef9 \u0111\u1ea1o g\u1ea7n h\u1ea1t nh\u00e2n h\u01a1n, n\u00f3 ph\u1ea3i c\u00f3 n\u0103ng l\u01b0\u1ee3ng to\u00e0n ph\u1ea7n l\u1edbn h\u01a1n, c\u00e0ng \u1edf qu\u1ef9 \u0111\u1ea1o c\u00e1ch xa h\u1ea1t nh\u00e2n, n\u0103ng l\u01b0\u1ee3ng n\u00e0y c\u00e0ng gi\u1ea3m v\u00e0 gi\u1ea3m d\u1ea7n cho t\u1edbi c\u1ef1c ti\u1ec3u, t\u01b0\u01a1ng \u1ee9ng v\u1edbi \u0111i\u1ec7n t\u1eed t\u1ef1 do. Khi nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean, t\u1ee9c l\u00e0 \u0111\u1ed9ng n\u0103ng c\u1ee7a c\u00e1c nguy\u00ean t\u1eed H t\u0103ng l\u00ean khi\u1ebfn kh\u1ea3 n\u0103ng va ch\u1ea1m gi\u1eefa ch\u00fang t\u0103ng l\u00ean, k\u1ebft qu\u1ea3 l\u00e0 c\u00e1c \u0111i\u1ec7n t\u1eed b\u1ecb \u0111\u1ea9y v\u00e0o nh\u1eefng qu\u1ef9 \u0111\u1ea1o b\u00ean trong t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi s\u1ef1 gi\u1ea3m k\u00edch th\u01b0\u1edbc nguy\u00ean t\u1eed. N\u1ebfu l\u00fac n\u00e0y c\u00f3 c\u00e1c photon chi\u1ebfu v\u00e0o th\u00ec t\u00f9y thu\u1ed9c v\u00e0o tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng c\u1ee7a photon c\u0169ng nh\u01b0 c\u00e1ch th\u1ee9c va ch\u1ea1m, m\u00e0 n\u00f3 c\u00f3 th\u1ec3 cho hay nh\u1eadn th\u00eam n\u0103ng l\u01b0\u1ee3ng t\u1eeb c\u00e1c \u0111i\u1ec7n t\u1eed \u0111\u00f3. Nh\u1eefng \u0111i\u1ec7n t\u1eed n\u00e0o b\u1edbt \u0111i n\u0103ng l\u01b0\u1ee3ng cho photon th\u00ec s\u1ebd nh\u1ea9y tr\u1edf l\u1ea1i c\u00e1c qu\u1ef9 \u0111\u1ea1o b\u00ean ngo\u00e0i, c\u00f2n nh\u1eefng \u0111i\u1ec7n t\u1eed nh\u1eadn th\u00eam n\u0103ng l\u01b0\u1ee3ng t\u1eeb photon th\u00ec ch\u00fang ho\u1eb7c s\u1ebd nh\u1ea9y v\u00e0o qu\u1ef9 \u0111\u1ea1o b\u00ean trong ho\u1eb7c s\u1ebd tho\u00e1t ra kh\u1ecfi nguy\u00ean t\u1eed. M\u1eb7t kh\u00e1c, c\u00e1c photon sau khi ph\u1ea3n x\u1ea1 tr\u1edf l\u1ea1i s\u1ebd c\u00f3 c\u00e1c m\u1ee9c n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng \u1ee9ng v\u1edbi tr\u1ea1ng th\u00e1i n\u0103ng l\u01b0\u1ee3ng c\u1ee7a kh\u1ed1i kh\u00ed Hydrozen. Nhi\u1ec7t \u0111\u1ed9 c\u00e0ng cao, m\u1ee9c n\u0103ng l\u01b0\u01a1ng c\u00e0ng l\u1edbn, ph\u1ed5 n\u0103ng l\u01b0\u1ee3ng c\u00e0ng b\u1ecb d\u1ecbch chuy\u1ec3n v\u1ec1 ph\u00eda t\u00edm, \u0111\u00fang nh\u01b0 th\u1ef1c t\u1ebf quan s\u00e1t \u0111\u01b0\u1ee3c (xem m\u1ee5c ... ). 15. H\u1ea1t mang t\u01b0\u01a1ng t\u00e1c v\u1eeba h\u00fat v\u1eeba \u0111\u1ea9y* Trong \u0111i\u1ec7n \u0111\u1ed9ng l\u1ef1c h\u1ecdc l\u01b0\u1ee3ng t\u1eed, ng\u01b0\u1eddi ta cho r\u1eb1ng l\u1ef1c \u0111i\u1ec7n t\u1eeb l\u00e0 do c\u00e1c \u0111i\u1ec7n t\u00edch trao \u0111\u1ed5i v\u1edbi nhau c\u00e1c ph\u00f4t\u00f4n nh\u01b0ng l\u00e0 ph\u00f4t\u00f4n \u201c\u1ea3o\u201d v\u00ec ch\u00fang qu\u1ea3 th\u1eadt kh\u00f4ng h\u1ec1 t\u1ed3n t\u1ea1i \u0111\u1ed1i v\u1edbi ng\u01b0\u1eddi quan s\u00e1t. Ch\u00fang sinh ra v\u00e0 bi\u1ebfn m\u1ea5t h\u1ec7t nh\u01b0 nh\u1eefng","PH\u1ee4 L\u1ee4C 289 \u201cb\u00f3ng ma\u201d v\u1eady. Nh\u01b0ng \u0111\u00e3 l\u00e0 \u201c\u1ea3o\u201d th\u00ec ch\u1ec9 l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m trong to\u00e1n h\u1ecdc v\u00e0 \u0111\u00e3 l\u00e0 \u201cma\u201d th\u00ec ch\u1ec9 l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a tr\u00ed t\u01b0\u1edfng t\u01b0\u1ee3ng ch\u1ee9 kh\u00f4ng th\u1ec3 l\u00e0 c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd. V\u00e0 ngh\u1ecbch l\u00fd l\u00e0 \u1edf ch\u1ed7 c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng \u201cth\u1eadt\u201d l\u1ea1i ch\u1ec9 c\u00f3 th\u1ec3 t\u01b0\u01a1ng t\u00e1c v\u1edbi nhau th\u00f4ng qua nh\u1eefng \u0111\u1ed1i t\u01b0\u1ee3ng \u201c\u1ea3o\u201d- m\u1ed9t kh\u00e1i ni\u1ec7m si\u00eau h\u00ecnh nh\u01b0ng l\u1ea1i c\u00f3 \u201cn\u0103ng l\u01b0\u1ee3ng\u201d th\u1ef1c! Trong khi \u0111\u00f3 \u0111\u1ed1i v\u1edbi c\u00e1c t\u01b0\u01a1ng t\u00e1c m\u1ea1nh (nh\u1edd trao \u0111\u1ed5i c\u00e1c h\u1ea1t gluon) v\u00e0 c\u00e1c t\u01b0\u01a1ng t\u00e1c y\u1ebfu (nh\u1edd trao \u0111\u1ed5i c\u00e1c h\u1ea1t bozon W v\u00e0 Z) th\u00ec \u0111i\u1ec1u kh\u00e1c bi\u1ec7t \u1edf \u0111\u00e2y l\u00e0 c\u00e1c h\u1ea1t n\u00e0y c\u00f3 v\u1ebb l\u00e0 c\u00e1c h\u1ea1t \u201cth\u1eadt\u201d \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y trong m\u00e1y gia t\u1ed1c. Nh\u01b0 v\u1eady, c\u0169ng v\u1edbi c\u00f9ng m\u1ed9t m\u1ee5c \u0111\u00edch l\u00e0 truy\u1ec1n t\u1ea3i l\u1ef1c t\u01b0\u01a1ng t\u00e1c nh\u01b0ng m\u1ed9t lo\u1ea1i h\u1ea1t th\u00ec \u201c\u1ea3o\u201d c\u00f2n lo\u1ea1i h\u1ea1t kh\u00e1c th\u00ec l\u1ea1i \u201cth\u1eadt\u201d- kh\u00f4ng nh\u1ea5t qu\u00e1n (!) - kh\u00f4ng ph\u00f9 h\u1ee3p v\u1edbi l\u00f4g\u00edc h\u00ecnh th\u1ee9c. M\u1eb7t kh\u00e1c, vi\u1ec7c trao \u0111\u1ed5i c\u00e1c h\u1ea1t \u201c\u1ea3o\u201d d\u1eabn \u0111\u1ebfn vi\u1ec7c h\u00fat nhau hay \u0111\u1ea9y nhau c\u1ee7a c\u00e1c \u0111i\u1ec7n t\u00edch \u0111\u1ec1u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c v\u00ec m\u1ed9t khi \u0111\u00e3 l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a tr\u00ed t\u01b0\u1edfng t\u01b0\u1ee3ng th\u00ec mu\u1ed1n sao m\u00e0 ch\u1eb3ng \u0111\u01b0\u1ee3c? V\u1ea5n \u0111\u1ec1 s\u1ebd kh\u00e1c \u0111i v\u1edbi c\u00e1c h\u1ea1t \u201cth\u1eadt\u201d. B\u1eb1ng c\u00e1ch n\u00e0o m\u00e0 khi trao \u0111\u1ed5i c\u00e1c h\u1ea1t \u201cth\u1eadt\u201d (c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng v\u00e0 c\u0169ng t\u1ee9c l\u00e0 c\u00f3 xung l\u01b0\u1ee3ng), c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng \u201cth\u1eadt\u201d l\u1ea1i c\u00f3 th\u1ec3 h\u00fat nhau thay v\u00ec l\u1ebd ra ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u1ea9y nhau? Hai h\u1ea1t c\u00f3 xung l\u01b0\u1ee3ng khi va ch\u1ea1m nhau ch\u00fang s\u1ebd ph\u1ea3i \u0111\u1ea9y nhau! H\u01a1n th\u1ebf n\u1eefa, c\u0169ng v\u1eabn nh\u1eefng h\u1ea1t \u0111\u00f3 nh\u01b0ng khi \u0111\u01b0\u1ee3c trao \u0111\u1ed5i \u1edf nh\u1eefng c\u1ef1 ly ng\u1eafn (<<10-15) th\u00ec d\u1eabn \u0111\u1ebfn l\u1ef1c \u0111\u1ea9y nhau c\u00f2n \u1edf nh\u1eefng c\u1ef1 ly v\u1eeba (c\u1ee1 10-15m) th\u00ec l\u1ea1i \u0111\u1ed5i th\u00e0nh h\u00fat nhau??? \u0110\u1ea5y l\u00e0 ch\u01b0a k\u1ec3 t\u1edbi vi\u1ec7c b\u1eb1ng c\u00e1ch n\u00e0o m\u00e0 c\u00e1c h\u1ea1t c\u01a1 b\u1ea3n v\u1ed1n \u0111\u01b0\u1ee3c coi l\u00e0 \u201ch\u1ea1t \u0111i\u1ec3m\u201d l\u1ea1i c\u00f3 th\u1ec3 h\u01b0\u1edbng v\u1ec1 ph\u00eda nhau \u0111\u1ec3 \u201cb\u1eafn ra\u201d c\u00e1c \u201ch\u1ea1t mang t\u01b0\u01a1ng t\u00e1c\u201d n\u00e0y cho nhau \u201cb\u00e1ch ph\u00e1t, b\u00e1ch tr\u00fang\u201d v\u1edbi m\u1ed9t sai s\u1ed1 \u201cn\u1eb1m m\u01a1\u201d c\u0169ng kh\u00f4ng bao gi\u1edd c\u00f3? V\u00ed d\u1ee5 nh\u01b0 v\u1edbi proton v\u00e0 electron c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ee1 10-15m, \u1edf c\u00e1ch nhau m\u1ed9t kho\u1ea3ng b\u1eb1ng 10-9m (k\u00edch th\u01b0\u1edbc ph\u00e2n t\u1eed) s\u1ebd gi\u1ed1ng nh\u01b0 ch\u00fang ta \u1edf c\u00e1ch nhau 1000km m\u00e0 v\u1eabn \u201cb\u1eafn tr\u00fang\u201d \u0111\u01b0\u1ee3c nhau, kh\u00f4ng nh\u1edd v\u00e0o h\u1ec7 th\u1ed1ng ra \u0111a d\u1eabn h\u01b0\u1edbng! 16. Con m\u00e8o Schrodinger","PH\u1ee4 L\u1ee4C 290 Trong th\u00ed nghi\u1ec7m t\u01b0\u1edfng t\u01b0\u1ee3ng c\u1ee7a Schrodinger v\u1ec1 m\u1ed9t con m\u00e8o trong m\u1ed9t c\u00e1i h\u1ed9p k\u00edn v\u1edbi m\u1ed9t lo\u1ea1t c\u00e1c c\u01a1 c\u1ea5u n\u00e0o \u0111\u00f3 d\u1eabn \u0111\u1ebfn kh\u1ea3 n\u0103ng gi\u1ebft ch\u1ebft con m\u00e8o. Tuy nhi\u00ean, kh\u1ea3 n\u0103ng con m\u00e8o v\u1eeba s\u1ed1ng l\u1ea1i v\u1eeba ch\u1ebft l\u1ea1i l\u00e0 k\u1ebft lu\u1eadn m\u00e0 c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn. \u0110\u00f3 ch\u00ednh l\u00e0 h\u1ec7 qu\u1ea3 c\u1ee7a quan \u0111i\u1ec3m cho r\u1eb1ng trong th\u1ebf gi\u1edbi vi m\u00f4, kh\u00f4ng c\u00f3 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng hay s\u1ef1 v\u1eadt n\u00e0o c\u00f3 th\u1ec3 t\u1ed3n t\u1ea1i kh\u00e1ch quan c\u1ea3, tr\u00e1i l\u1ea1i, s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a ch\u00fang ch\u1ec9 c\u00f3 th\u1ec3 n\u00f3i \u0111\u1ebfn khi quan s\u00e1t \u0111\u00e3 \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n, v\u00e0 c\u0169ng ch\u1ec9 khi \u0111\u00f3 ta m\u1edbi c\u00f3 th\u1ec3 n\u00f3i t\u1edbi s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a ch\u00fang. N\u00f3i c\u00e1ch kh\u00e1c, t\u00ednh t\u1ea5t \u0111\u1ecbnh \u0111\u1ed1i v\u1edbi th\u1ebf gi\u1edbi vi m\u00f4 ch\u1ec9 l\u00e0 \u1ea3o t\u01b0\u1edfng. Theo C\u0110M, \u0111i\u1ec1u n\u00e0y c\u00f3 ngu\u1ed3n g\u1ed1c s\u00e2u xa ngay t\u1eeb th\u1ebf gi\u1edbi v\u0129 m\u00f4, khi quan ni\u1ec7m \u201cc\u01b0\u1eddng \u0111\u1ed9 \u0111i\u1ec7n tr\u01b0\u1eddng\u201d (v\u00e9c t\u01a1 E x\u00e1c \u0111\u1ecbnh theo c\u00f4ng th\u1ee9c (3.7)) v\u00e0 \u201ct\u1eeb c\u1ea3m\u201d (v\u00e9c t\u01a1 B x\u00e1c \u0111\u1ecbnh theo c\u00f4ng th\u1ee9c (3.17)) l\u00e0 nh\u1eefng \u0111\u1ea1i l\u01b0\u1ee3ng v\u1ed1n t\u1ed3n t\u1ea1i s\u1eb5n \u0111\u1ed1i v\u1edbi m\u1ed9t \u0111i\u1ec3m nh\u1ea5t \u0111\u1ecbnh n\u00e0o \u0111\u00f3 c\u1ee7a c\u00e1i g\u1ecdi l\u00e0 tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb b\u1ea5t lu\u1eadn \u1edf t\u1ea1i \u201c\u0111i\u1ec3m\u201d \u0111\u00f3 c\u00f3 t\u1ed3n t\u1ea1i \u0111i\u1ec7n t\u00edch hay kh\u00f4ng. Vi\u1ec7c chia l\u1ef1c t\u00e1c \u0111\u1ed9ng cho \u0111i\u1ec7n t\u00edch \u0111\u1ec3 nh\u1eadn \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ee9c (3.7) kh\u00f4ng c\u00f2n ph\u1ee5 thu\u1ed9c v\u00e0o \u0111i\u1ec7n t\u00edch \u0111\u00f3 l\u00e0 m\u1ed9t chuy\u1ec7n \u2013 m\u1ed9t thao t\u00e1c thu\u1ea7n t\u00fay to\u00e1n h\u1ecdc, c\u00f2n \u0111\u1eb7c tr\u01b0ng c\u1ee7a tr\u01b0\u1eddng t\u1ea1i m\u1ed7i \u0111i\u1ec3m c\u1ee7a n\u00f3 l\u1ea1i l\u00e0 chuy\u1ec7n kh\u00e1c h\u1eb3n, kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o vi\u1ec7c ta chia c\u00e1i g\u00ec cho c\u00e1i g\u00ec!!! \u1ede \u0111\u00e2y mu\u1ed1n n\u00f3i \u0111\u1ebfn t\u01b0\u01a1ng t\u00e1c gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd, n\u00f3 l\u00e0 nguy\u00ean nh\u00e2n c\u1ee7a s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a th\u1ef1c th\u1ec3 v\u1eadt l\u00fd \u0111\u00f3, m\u00e0 m\u1ed9t khi \u0111\u00e3 n\u00f3i \u0111\u1ebfn t\u01b0\u01a1ng t\u00e1c c\u00f3 ngh\u0129a l\u00e0 ph\u1ea3i c\u00f3 \u00edt nh\u1ea5t t\u1eeb 2 v\u1eadt th\u1ec3 tr\u1edf l\u00ean, v\u00e0 v\u00ec v\u1eady, c\u00e1c kh\u00e1i ni\u1ec7m c\u01b0\u1eddng \u0111\u1ed9 tr\u01b0\u1eddng hay t\u1eeb c\u1ea3m v\u1eeba \u0111\u1ec1 c\u1eadp t\u1edbi ch\u1ec9 l\u00e0 \u201cc\u00e1ch th\u1ee9c\u201d \u0111\u1ec3 ta nh\u1eadn th\u1ee9c hi\u1ec7n t\u01b0\u1ee3ng v\u00e0 s\u1ef1 v\u1eadt ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u00e0 ch\u00ednh b\u1ea3n th\u00e2n s\u1ef1 v\u1eadt hay hi\u1ec7n t\u01b0\u1ee3ng v\u00e0 v\u00ec v\u1eady n\u00f3 ho\u00e0n to\u00e0n mang t\u00ednh ch\u1ee7 quan. Vi\u1ec7c s\u1eed d\u1ee5ng nh\u1eefng \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0y \u0111\u00fang l\u00e0 r\u1ea5t thu\u1eadn ti\u1ec7n cho \u0111o \u0111\u1ea1c (\u1edf t\u1ea7m v\u0129 m\u00f4) v\u00e0 t\u00ednh to\u00e1n \u0111\u1ec3 nh\u1eadn th\u1ee9c hi\u1ec7n t\u01b0\u1ee3ng v\u00e0 s\u1ef1 v\u1eadt nh\u01b0ng l\u1ea1i l\u00e0m cho ta d\u1ec5 b\u1ecb l\u1ea7m l\u1eabn gi\u1eefa kh\u00e1ch quan v\u00e0 ch\u1ee7 quan, gi\u1eefa kh\u00e1ch th\u1ec3 v\u00e0 ch\u1ee7 th\u1ec3. Khi \u00e1p d\u1ee5ng v\u00e0o th\u1ebf gi\u1edbi vi m\u00f4, khi thao t\u00e1c \u0111o \u0111\u1ea1c c\u1ee7a ch\u00fang ta \u0111\u00e3 tr\u1edf n\u00ean so s\u00e1nh \u0111\u01b0\u1ee3c v\u1edbi b\u1ea3n th\u1ec3 c\u00e1c qu\u00e1 tr\u00ecnh c\u1ee7a c\u00e1c h\u1ea1t s\u01a1 c\u1ea5p th\u00ec s\u1ef1 c\u00f3 m\u1eb7t c\u1ee7a thi\u1ebft b\u1ecb \u0111o \u0111\u00e3 l\u00e0m m\u00e9o m\u00f3, th\u1eadm ch\u00ed l\u00e0m bi\u1ebfn m\u1ea5t hi\u1ec7n t\u01b0\u1ee3ng hay ph\u00e1 h\u1ee7y s\u1ef1 v\u1eadt, k\u1ebft qu\u1ea3 l\u00e0 c\u00e1i m\u00e0 ta nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c","PH\u1ee4 L\u1ee4C 291 ho\u00e0n to\u00e0n kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1i \u0111\u00e3 t\u1eebng t\u1ed3n t\u1ea1i tr\u01b0\u1edbc \u0111\u00f3. Ngh\u1ecbch l\u00fd \u201ccon m\u00e8o n\u1eeda s\u1ed1ng, n\u1eeda ch\u1ebft\u201d n\u00e0y l\u00e0 \u0111i\u1ec1u c\u00f3 th\u1ec3 hi\u1ec3u \u0111\u01b0\u1ee3c \u2013 m\u1ed9t d\u1ea1ng c\u1ee7a ngh\u1ecbch l\u00fd to\u00e1n h\u1ecdc ch\u1ee9 kh\u00f4ng ph\u1ea3i c\u1ee7a th\u1ebf gi\u1edbi v\u1eadt ch\u1ea5t b\u1edfi c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed ch\u1ec9 l\u00e0 m\u1ed9t c\u00f4ng c\u1ee5 to\u00e1n h\u1ecdc \u0111\u1ec3 t\u00ednh to\u00e1n m\u1ed9t s\u1ed1 c\u00e1c th\u00f4ng s\u1ed1 n\u00e0o \u0111\u00f3 kh\u00f4ng \u0111\u1ea7y \u0111\u1ee7, v\u00e0 th\u1eadm ch\u00ed sai l\u1ec7ch v\u1ec1 t\u1ed3n t\u1ea1i kh\u00e1ch quan (l\u01b0\u1ee1ng t\u00ednh s\u00f3ng-h\u1ea1t ch\u1eb3ng h\u1ea1n... ), n\u00ean c\u00f3 ngh\u1ecbch l\u00fd c\u0169ng l\u00e0 l\u1ebd th\u01b0\u1eddng th\u00f4i; c\u00f3 th\u1ec3 xem th\u00eam \u201cGi\u1edbi h\u1ea1n c\u1ee7a to\u00e1n h\u1ecdc\u201d \u1edf Ph\u1ee5 l\u1ee5c 23. 17. H\u1ea1t \u201cbi\u1ebft\u201d tr\u01b0\u1edbc m\u1ecdi kh\u1ea3 n\u0103ng d\u1ecbch chuy\u1ec3n kh\u1ea3 d\u0129 Theo \u0111i\u1ec7n \u0111\u1ed9ng l\u1ef1c h\u1ecdc l\u01b0\u1ee3ng t\u1eed, x\u00e1c su\u1ea5t \u0111\u1ec3 photon \u0111i t\u1eeb m\u1ed9t \u0111i\u1ec3m A \u0111\u1ebfn m\u1ed9t \u0111i\u1ec3m kh\u00e1c B b\u1eb1ng t\u1ed5ng x\u00e1c su\u1ea5t theo m\u1ecdi qu\u00e3ng \u0111\u01b0\u1eddng kh\u1ea3 d\u0129 c\u00f3 th\u1ec3 c\u00f3 n\u1ed1i t\u1eeb A \u0111\u1ebfn B. V\u1ea5n \u0111\u1ec1 l\u00e0 l\u00e0m sao m\u00e0 photon l\u1ea1i c\u00f3 th\u1ec3 \u201cbi\u1ebft\u201d tr\u01b0\u1edbc m\u1ecdi kh\u1ea3 n\u0103ng d\u1ecbch chuy\u1ec3n kh\u1ea3 d\u0129 tr\u01b0\u1edbc khi quy\u1ebft \u0111\u1ecbnh s\u1ebd \u0111i con \u0111\u01b0\u1eddng n\u00e0o? \u0110i\u1ec1u n\u00e0y c\u0169ng gi\u1ed1ng h\u1ec7t nh\u01b0 trong th\u00ed nghi\u1ec7m 2 khe Young, h\u1ea1t t\u1ef1 bi\u1ebft khi n\u00e0o c\u00f3 1 khe v\u00e0 khi n\u00e0o c\u00f3 2 khe v\u00e0 k\u1ec3 c\u1ea3 khi n\u00e0o c\u00f3 \u201cng\u01b0\u1eddi quan s\u00e1t\u201d ch\u00fang \u0111\u1ec3 thay \u0111\u1ed5i h\u00e0nh vi \u2013 l\u00e0 s\u00f3ng hay l\u00e0 h\u1ea1t cho th\u00edch h\u1ee3p! (?) Theo TV\u0110, ch\u1eb3ng c\u00f3 s\u1ef1 \u201cbi\u1ebft\u201d tr\u01b0\u1edbc n\u00e0o c\u1ea3 v\u00ec \u0111\u01a1n gi\u1ea3n l\u00e0 photon \u0111\u01b0\u1ee3c ph\u00e1t ra theo m\u1ecdi h\u01b0\u1edbng m\u00e0 c\u1ea5u tr\u00fac c\u1ee7a n\u00f3 l\u00e0 c\u1eb7p e-- e+ quay v\u1edbi t\u1ea7n s\u1ed1 f \u0111\u00e3 t\u1ef1 \u0111\u1ed9ng h\u00ecnh th\u00e0nh n\u00ean c\u00e1i g\u1ecdi l\u00e0 \u201cv\u00e9c t\u01a1 bi\u00ean \u0111\u1ed9 x\u00e1c su\u1ea5t\u201d c\u1ee7a Pheynman (xem m\u1ee5c 3.3.3) \u2013 m\u1ed9t s\u1ef1 tr\u00f9ng h\u1ee3p kh\u00e1 l\u00fd th\u00fa. 18. V\u1eadn t\u1ed1c \u00e1nh s\u00e1ng l\u00e0 h\u1eb1ng s\u1ed1 Thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng d\u1ef1a tr\u00ean gi\u1ea3 thi\u1ebft v\u1ec1 s\u1ef1 kh\u00f4ng ph\u1ee5 thu\u1ed9c c\u1ee7a v\u1eadn t\u1ed1c c\u1ee7a \u00e1nh s\u00e1ng trong ch\u00e2n kh\u00f4ng v\u00e0o chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a ngu\u1ed3n s\u00e1ng \u0111\u1ed1i v\u1edbi m\u1ecdi HQC qu\u00e1n t\u00ednh (ti\u00ean \u0111\u1ec1 2). Tuy nhi\u00ean, t\u1eeb t\u00ednh to\u00e1n l\u1ea1i r\u00fat ra \u0111\u01b0\u1ee3c c\u1ed9ng th\u1ee9c c\u1ed9ng v\u1eadn t\u1ed1c:","PH\u1ee4 L\u1ee4C 292 V = V1 \u00b1 V2 = V1 \u00b1 V2 V1V2 1\u00b1 \u03b21\u03b2 2 1 \u00b1 c2 C\u00f4ng th\u1ee9c n\u00e0y cho th\u1ea5y khi m\u1ed9t trong hai \u0111\u1ed1i t\u01b0\u1ee3ng, ho\u1eb7c ngu\u1ed3n s\u00e1ng ho\u1eb7c ng\u01b0\u1eddi quan s\u00e1t, \u0111\u1ea1t v\u1eadn t\u1ed1c b\u1eb1ng c th\u00ec v\u1eadn t\u1ed1c t\u01b0\u01a1ng \u0111\u1ed1i gi\u1eefa ch\u00fang c\u0169ng lu\u00f4n \u0111\u1ea1t b\u1eb1ng c! T\u1eeb \u0111\u00e2y m\u1edbi c\u00f3 kh\u00e1i ni\u1ec7m l\u00e0 v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u1ea3 ngu\u1ed3n s\u00e1ng l\u1eabn ng\u01b0\u1eddi quan s\u00e1t hay v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng l\u00e0 h\u1eb1ng s\u1ed1 trong m\u1ecdi HQC qu\u00e1n t\u00ednh. Tuy nhi\u00ean, kh\u00f4ng th\u1ec3 n\u00e0o c\u00f3 th\u1ec3 t\u01b0\u1edfng t\u01b0\u1ee3ng \u0111\u01b0\u1ee3c khi 2 photon chuy\u1ec3n \u0111\u1ed9ng theo c\u00f9ng m\u1ed9t h\u01b0\u1edbng v\u1edbi c\u00f9ng m\u1ed9t v\u1eadn t\u1ed1c b\u1eb1ng v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng trong m\u1ed9t HQC qu\u00e1n t\u00ednh n\u00e0o \u0111\u00f3 th\u00ec trong HQC \u0111\u00f3, 2 photon t\u1ea1i b\u1ea5t k\u1ec3 th\u1eddi \u0111i\u1ec3m n\u00e0o c\u0169ng \u0111\u1ec1u \u201ck\u00e8 k\u00e8\u201d b\u00ean nhau \u201cnh\u01b0 h\u00ecnh v\u1edbi b\u00f3ng\u201d, trong khi \u0111\u00f3, b\u1ea5t k\u1ec3 photon n\u00e0o trong ch\u00fang c\u0169ng th\u1ea5y \u201cb\u1ea1n \u0111\u1ed3ng h\u00e0nh\u201d c\u1ee7a m\u00ecnh r\u1eddi xa m\u00ecnh v\u1edbi v\u1eadn t\u1ed1c ... b\u1eb1ng v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng! (?) C\u1ea7n ph\u1ea3i l\u01b0u \u00fd r\u1eb1ng v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng ch\u1ec9 b\u1eb1ng h\u1eb1ng s\u1ed1 trong ch\u00e2n kh\u00f4ng, t\u1ee9c l\u00e0 b\u1ecf qua m\u1ecdi t\u00e1c \u0111\u1ed9ng c\u1ee7a tr\u01b0\u1eddng l\u1ef1c th\u1ebf. Khi \u00e1nh s\u00e1ng chuy\u1ec3n \u0111\u1ed9ng trong tr\u01b0\u1eddng l\u1ef1c th\u1ebf m\u1ea1nh th\u00ec v\u1eadn t\u1ed1c c\u1ee7a n\u00f3 s\u1ebd nh\u1ecf h\u01a1n 300.000km\/s, th\u1eadm ch\u00ed c\u00f3 th\u1ec3 \u21920. Nh\u01b0ng khi \u0111\u00f3, HQC s\u1ebd kh\u00f4ng c\u00f2n l\u00e0 HQC qu\u00e1n t\u00ednh \u0111\u01b0\u1ee3c n\u1eefa v\u00e0 do \u0111\u00f3 TTH c\u0169ng kh\u00f4ng c\u00f2n hi\u1ec7u l\u1ef1c. 19. Ngh\u1ecbch l\u00fd anh em sinh \u0111\u00f4i Theo TTH, c\u00f3 2 anh em sinh \u0111\u00f4i, ng\u01b0\u1eddi em \u1edf l\u1ea1i HQC \u0111\u1ee9ng y\u00ean c\u00f2n ng\u01b0\u1eddi anh l\u00ean t\u1ea7u v\u0169 tr\u1ee5 bay theo m\u1ed9t \u0111\u01b0\u1eddng g\u1ea5p kh\u00fac kh\u00e9p k\u00edn. Sau m\u1ed9t kho\u1ea3ng th\u1eddi gian, ng\u01b0\u1eddi anh tr\u1edf v\u1ec1 v\u00e0 2 anh em g\u1eb7p l\u1ea1i nhau trong t\u00ecnh c\u1ea3nh: anh v\u1eabn c\u00f2n r\u1ea5t tr\u1ebb m\u00e0 ng\u01b0\u1eddi em th\u00ec \u0111\u00e3 \u201cr\u00e2u d\u00e0i \u0111\u1ebfn r\u1ed1n\u201d? Ngh\u1ecbch l\u00fd l\u00e0 \u1edf ch\u1ed7, l\u1ebd ra tr\u00ean HQC c\u1ee7a ng\u01b0\u1eddi anh, m\u1ecdi vi\u1ec7c c\u0169ng ph\u1ea3i di\u1ec5n ra gi\u1ed1ng h\u1ec7t nh\u01b0 trong HQC c\u1ee7a ng\u01b0\u1eddi em m\u1edbi \u0111\u00fang v\u00ec theo \u0111\u1ecbnh \u0111\u1ec1 1 c\u1ee7a TTH, m\u1ecdi HQC qu\u00e1n t\u00ednh \u0111\u1ec1u t\u01b0\u01a1ng \u0111\u01b0\u01a1ng nhau. N\u1ebfu HQC c\u1ee7a ng\u01b0\u1eddi anh c\u00f3 th\u1ec3 coi l\u00e0 HQC qu\u00e1n t\u00ednh th\u00ec HQC c\u1ee7a ng\u01b0\u1eddi em c\u0169ng","PH\u1ee4 L\u1ee4C 293 nh\u01b0 v\u1eady, v\u00e0 v\u00ec t\u00ednh t\u01b0\u01a1ng \u0111\u1ed1i, ng\u01b0\u1eddi anh th\u1ea5y m\u00ecnh \u0111\u1ee9ng y\u00ean c\u00f2n ng\u01b0\u1eddi em \u201cbay\u201d v\u00e0o V\u0169 tr\u1ee5 c\u0169ng theo \u0111\u01b0\u1eddng g\u1ea5p kh\u00fac kh\u00e9p k\u00edn v\u00e0 \u0111\u01b0\u01a1ng nhi\u00ean sau c\u0169ng b\u1eb1ng \u1ea5y th\u1eddi gian, h\u1ecd c\u0169ng l\u1ea1i g\u1eb7p nhau nh\u01b0ng hi\u1ec7u \u1ee9ng b\u00e2y gi\u1edd l\u1ea1i ng\u01b0\u1ee3c l\u1ea1i: ng\u01b0\u1eddi anh l\u1ea1i th\u1ea5y ng\u01b0\u1eddi em c\u00f2n tr\u1ebb c\u00f2n m\u00ecnh th\u00ec \u201cr\u00e2u d\u00e0i \u0111\u1ebfn r\u1ed1n\u201d? V\u1eady r\u00fat c\u1ee5c ai gi\u00e0 h\u01a1n ai? \u2013 kh\u00f4ng h\u1ec1 c\u00f3 c\u00e2u tr\u1ea3 l\u1eddi x\u00e1c \u0111\u00e1ng!!! V\u00e0 h\u01a1n th\u1ebf n\u1eefa, v\u00ec sao v\u1eadn t\u1ed1c truy\u1ec1n \u00e1nh s\u00e1ng l\u00e0 h\u1eb1ng s\u1ed1 l\u1ea1i c\u00f3 th\u1ec3 \u1ea3nh h\u01b0\u1edfng t\u1edbi nh\u1ecbp sinh h\u1ecdc c\u1ee7a con ng\u01b0\u1eddi? V\u00e0 k\u1ebft c\u1ee5c, th\u1eddi gian l\u00e0 c\u00e1i g\u00ec v\u1eady? Theo C\u0110M, n\u1ed9i n\u0103ng c\u1ee7a m\u1ecdi th\u1ef1c th\u1ec3 v\u1eadt l\u00fd \u0111\u1ec1u gi\u1ea3m \u0111i khi chuy\u1ec3n \u0111\u1ed9ng r\u01a1i t\u1ef1 do trong tr\u01b0\u1eddng l\u1ef1c th\u1ebf; t\u1ed1c \u0111\u1ed9 chuy\u1ec3n \u0111\u1ed9ng c\u00e0ng l\u1edbn ho\u1eb7c tr\u01b0\u1eddng l\u1ef1c th\u1ebf c\u00e0ng l\u1edbn, n\u1ed9i n\u0103ng c\u00e0ng gi\u1ea3m m\u1ea1nh. Trong khi \u0111\u00f3, nh\u1ecbp \u0111\u1ed9 v\u1eadn \u0111\u1ed9ng t\u1ef7 l\u1ec7 v\u1edbi n\u1ed9i n\u0103ng. N\u1ed9i n\u0103ng gi\u1ea3m d\u1eabn \u0111\u1ebfn t\u01b0\u01a1ng t\u00e1c gi\u1eefa c\u00e1c ph\u1ea7n t\u1eed c\u1ea5u th\u00e0nh n\u00ean th\u1ef1c th\u1ec3 v\u1eadt l\u00fd \u0111\u00f3 gi\u1ea3m; m\u00e0 t\u01b0\u01a1ng t\u00e1c gi\u1ea3m \u0111i s\u1ebd khi\u1ebfn nh\u1ecbp \u0111\u1ed9 v\u1eadn \u0111\u1ed9ng gi\u1ea3m v\u00e0 do \u0111\u00f3 \u201cth\u1eddi gian\u201d s\u1ebd ch\u1eadm l\u1ea1i (xem m\u1ee5c 2.5). N\u1ebfu l\u00e0 chuy\u1ec3n \u0111\u1ed9ng trong kh\u00f4ng gian t\u1ef1 do kh\u00f4ng c\u00f3 b\u1ea5t c\u1ee9 m\u1ed9t tr\u01b0\u1eddng l\u1ef1c th\u1ebf n\u00e0o th\u00ec d\u00f9 l\u00e0 chuy\u1ec3n \u0111\u1ed9ng c\u00f3 gia t\u1ed1c hay th\u1eb3ng \u0111\u1ec1u c\u0169ng nh\u01b0 nhau c\u1ea3 th\u00f4i. \u1ea2nh h\u01b0\u1edfng c\u1ee7a chuy\u1ec3n \u0111\u1ed9ng t\u1edbi n\u0103ng l\u01b0\u1ee3ng c\u1ee7a b\u1ea5t k\u1ef3 m\u1ed9t th\u1ef1c th\u1ec3 v\u1eadt l\u00fd n\u00e0o lu\u00f4n lu\u00f4n \u0111\u01b0\u1ee3c g\u1eafn v\u1edbi c\u00e1c v\u1eadt th\u1ec3 kh\u00e1c th\u00f4ng qua tr\u01b0\u1eddng l\u1ef1c th\u1ebf c\u1ee7a ch\u00fang, th\u00f4ng qua ngo\u1ea1i n\u0103ng = \u0111\u1ed9ng n\u0103ng + th\u1ebf n\u0103ng. T\u1eeb \u0111\u00e2y cho th\u1ea5y n\u1ebfu tr\u01b0\u1eddng l\u1ef1c th\u1ebf kh\u00f4ng c\u00f3 th\u00ec ngo\u1ea1i n\u0103ng \u0111\u01b0\u01a1ng nhi\u00ean =0. C\u00f3 ngh\u0129a l\u00e0 chuy\u1ec3n \u0111\u1ed9ng hay kh\u00f4ng chuy\u1ec3n \u0111\u1ed9ng ho\u00e0n to\u00e0n kh\u00f4ng c\u00f3 \u00fd ngh\u0129a g\u00ec \u0111\u1ed1i v\u1edbi v\u1eadt th\u1ec3 c\u1ea3. V\u1ea5n \u0111\u1ec1 l\u00e0 ch\u1ec9 d\u1ef1a v\u00e0o c\u00e1c th\u00f4ng s\u1ed1 \u0111\u1ed9ng h\u1ecdc nh\u01b0 v\u1eadn t\u1ed1c, th\u1eddi gian, qu\u00e3ng \u0111\u01b0\u1eddng... r\u1ed3i \u201cph\u00e1n\u201d ra c\u00e1c th\u00f4ng s\u1ed1 \u0111\u1ed9ng l\u1ef1c h\u1ecdc nh\u01b0 kh\u1ed1i l\u01b0\u1ee3ng, n\u0103ng l\u01b0\u1ee3ng ... l\u00e0 m\u1ed9t vi\u1ec7c l\u00e0m phi l\u00f4g\u00edc n\u00ean vi\u1ec7c n\u1ea9y sinh ngh\u1ecbch l\u00fd l\u00e0 kh\u00f4ng th\u1ec3 tr\u00e1nh kh\u1ecfi. 20. C\u00f4ng th\u1ee9c E = mc2 ch\u01b0a h\u1ec1 \u0111\u01b0\u1ee3c ch\u1ee9ng minh* C\u00f4ng th\u1ee9c E=mc2 \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 l\u00e0 m\u1ed9t trong \u201c10 c\u00f4ng th\u1ee9c \u0111\u1eb9p nh\u1ea5t c\u1ee7a c\u1ee7a m\u1ecdi th\u1eddi \u0111\u1ea1i\u201d nh\u01b0ng vi\u1ec7c ch\u1ee9ng minh n\u00f3 \u0111\u00e3 ch\u1ee9a \u0111\u1ef1ng b\u1ea5t c\u1eadp ngay t\u1eeb \u0111\u1ea7u","PH\u1ee4 L\u1ee4C 294 b\u1edfi ch\u00ednh t\u00e1c gi\u1ea3 - Einstein v\u0129 \u0111\u1ea1i! S\u1ef1 thi\u1ebfu c\u01a1 s\u1edf l\u00f4g\u00edc c\u1ee7a Einstein \u0111\u00e3 \u0111\u01b0\u1ee3c Aivs ch\u1ec9 ra trong \u201cJournal of the Optical Society Of America\u201d, 42, 540 \u2013 543. 1952. T\u1eeb \u0111\u00f3, ng\u01b0\u1eddi ta th\u00f4i kh\u00f4ng d\u00f9ng c\u00e1ch ch\u1ee9ng minh c\u1ee7a t\u00e1c gi\u1ea3 n\u1eefa m\u00e0 s\u1eed d\u1ee5ng s\u1ef1 ph\u1ee5 thu\u1ed9c c\u1ee7a kh\u1ed1i l\u01b0\u1ee3ng qu\u00e1n t\u00ednh v\u00e0o v\u1eadn t\u1ed1c: m= m0 = m0\u03b3 (P20.1) 1\u2212 \u03b22 c\u00f9ng v\u1edbi \u0111\u1ecbnh lu\u1eadt 2 Newton: F = d (mV ) (P20.2) dt \u0111\u1ec3 t\u00ednh ra c\u00f4ng th\u1ee9c \u0111\u00f3. Nh\u01b0ng \u201ctr\u00e1nh v\u1ecf d\u01b0a l\u1ea1i g\u1eb7p v\u1ecf d\u1eeba\u201d, l\u1ea1i xu\u1ea5t hi\u1ec7n b\u1ea5t c\u1eadp m\u1edbi, m\u00e0 l\u1ea7n n\u00e0y th\u00ec ... ch\u1eafc l\u00e0 \u201cv\u00f4 ph\u01b0\u01a1ng c\u1ee9u ch\u1eefa\u201d! Th\u1ee9 nh\u1ea5t, b\u1ea3n th\u00e2n c\u00f4ng th\u1ee9c (P20.1) \u0111\u01b0\u1ee3c ch\u1ee9ng minh ch\u1ec9 cho v\u1eadt th\u1ec3 \u0111ang chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng \u0111\u1ec1u v\u1edbi v\u1eadn t\u1ed1c V trong m\u1ed9t HQC qu\u00e1n t\u00ednh v\u00e0 c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng m0 trong HQC m\u00e0 n\u00f3 \u0111\u1ee9ng y\u00ean trong \u0111\u00f3. C\u00f3 ngh\u0129a l\u00e0 c\u1ea7n ph\u1ea3i \u0111\u01b0\u1ee3c hi\u1ec3u l\u00e0: + N\u1ebfu v\u1eadt th\u1ec3 \u0111ang chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c V1 th\u00ec ta c\u00f3 m1 = m0\u03b31; + N\u1ebfu v\u1eadt th\u1ec3 \u0111ang chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c V2 th\u00ec ta c\u00f3 m2 = m0\u03b32; .... + N\u1ebfu v\u1eadt th\u1ec3 \u0111ang chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c Vn th\u00ec ta c\u00f3 mn = m0\u03b3n v.v.. v\u1edbi V1, V2, ... Vn l\u00e0 c\u00e1c gi\u00e1 tr\u1ecb v\u1eadn t\u1ed1c kh\u00f4ng thay \u0111\u1ed5i theo th\u1eddi gian, th\u1ecfa m\u00e3n y\u00eau c\u1ea7u c\u1ee7a chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng \u0111\u1ec1u, ch\u1ee9 ho\u00e0n to\u00e0n kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1c gi\u00e1 tr\u1ecb v\u1eadn t\u1ed1c t\u1ee9c th\u1eddi; t\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady, kh\u1ed1i l\u01b0\u1ee3ng qu\u00e1n t\u00ednh m1, m2...mn l\u00e0 c\u00e1c gi\u00e1 tr\u1ecb kh\u1ed1i l\u01b0\u1ee3ng t\u01b0\u01a1ng \u1ee9ng t\u00ednh \u0111\u01b0\u1ee3c trong HQC1, HQC2...HQCn t\u01b0\u01a1ng \u1ee9ng ch\u1ee9 ho\u00e0n to\u00e0n kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1c gi\u00e1 tr\u1ecb c\u1ee7a m l\u00e0 m\u1ed9t \u201ch\u00e0m\u201d c\u1ee7a v\u1eadn t\u1ed1c theo c\u00e1ch hi\u1ec3u th\u00f4ng th\u01b0\u1eddng v\u1ec1 m\u1ed9t h\u00e0m s\u1ed1: m = m(V) trong \u0111\u00f3 V l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng bi\u1ebfn thi\u00ean li\u00ean t\u1ee5c, v\u00ec b\u1ea5t k\u1ef3 m\u1ed9t s\u1ef1 bi\u1ebfn thi\u00ean n\u00e0o c\u1ee7a v\u1eadn t\u1ed1c V c\u0169ng \u0111\u1ec1u khi\u1ebfn cho \u0111i\u1ec1u ki\u1ec7n v\u1ec1 HQC qu\u00e1n t\u00ednh c\u1ee7a v\u1eadt th\u1ec3 chuy\u1ec3n \u0111\u1ed9ng b\u1ecb ph\u00e1 v\u1ee1 - c\u00e1c bi\u1ebfn \u0111\u1ed5i Lorenz kh\u00f4ng th\u1ec3 \u00e1p","PH\u1ee4 L\u1ee4C 295 d\u1ee5ng \u0111\u01b0\u1ee3c \u2013 khi \u0111\u00f3, l\u00e0m sao c\u00f3 th\u1ec3 c\u00f3 \u0111\u01b0\u1ee3c c\u00f4ng th\u1ee9c (P20.1) \u0111\u01b0\u1ee3c n\u1eefa? Ch\u00ednh v\u00ec v\u1eady, kh\u00f4ng th\u1ec3 thay (P20.1) v\u00e0o (P20.2) \u0111\u1ec3 t\u00ednh \u0111\u1ea1o h\u00e0m \u0111\u01b0\u1ee3c v\u00ec V \u0111\u00e3 kh\u00f4ng th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e9p bi\u1ebfn thi\u00ean th\u00ec c\u1ea3 m c\u0169ng ch\u1eb3ng c\u00f3 l\u00fd do g\u00ec \u0111\u1ec3 \u201cbi\u1ebfn thi\u00ean\u201d c\u1ea3 n\u00ean \u0111\u1ea1o h\u00e0m \u0111\u00f3 ph\u1ea3i \u22610! C\u00f2n n\u1ebfu c\u1ee9 c\u1ed1 ki\u1ebft cho r\u1eb1ng V l\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng kh\u00f4ng bi\u1ebfn thi\u00ean li\u00ean t\u1ee5c m\u00e0 c\u00f3 d\u1ea1ng \u201cb\u1eadc thang\u201d thay \u0111\u1ed5i t\u1eeb V1 t\u1edbi Vn th\u00ec \u0111\u1ea1o h\u00e0m c\u1ee7a n\u00f3 l\u1ea1i c\u00f3 d\u1ea1ng l\u00e0 h\u00e0m Dirac \u03b4(t)! K\u1ebft qu\u1ea3 l\u00e0 c\u0169ng kh\u00f4ng th\u1ec3 cho ra \u0111\u01b0\u1ee3c c\u00f4ng th\u1ee9c c\u1ea7n ch\u1ee9ng minh. Th\u1ee9 hai, b\u1ea3n th\u00e2n vi\u1ec7c \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c (P20.2) v\u1edbi F \u2260 0 c\u0169ng khi\u1ebfn cho HQC c\u1ee7a v\u1eadt th\u1ec3 s\u1ebd tr\u1edf n\u00ean phi qu\u00e1n t\u00ednh v\u00e0 TTH kh\u00f4ng \u00e1p d\u1ee5ng cho n\u00f3 \u0111\u01b0\u1ee3c n\u1eefa th\u00ec l\u00e0m sao c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u1ec3 ch\u1ee9ng minh c\u00e1i g\u00ec? \u0110\u1ea5y l\u00e0 ch\u01b0a k\u1ec3 \u0111\u1ebfn t\u00ednh phi l\u00f4g\u00edc c\u1ee7a \u0111\u1ecbnh lu\u1eadt 2 c\u1ee7a \u0111\u1ed9ng l\u1ef1c h\u1ecdc nh\u01b0 \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp \u0111\u1ebfn \u1edf ngh\u1ecbch l\u00fd 9 \u201c\u0110\u1ed9ng l\u1ef1c h\u1ecdc ch\u1ec9 l\u00e0 \u1ea3o gi\u00e1c\u201d. T\u00f3m l\u1ea1i, c\u00f4ng th\u1ee9c E = mc2, v\u1ec1 th\u1ef1c ch\u1ea5t cho \u0111\u1ebfn nay v\u1eabn ch\u01b0a h\u1ec1 \u0111\u01b0\u1ee3c ch\u1ee9ng minh!!! 21. Hi\u1ec7u \u1ee9ng Dopler d\u1ecdc** Theo thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i h\u1eb9p, khi \u00e1nh s\u00e1ng ph\u1ea3n x\u1ea1 l\u1ea1i t\u1eeb m\u1ed9t g\u01b0\u01a1ng chuy\u1ec3n \u0111\u1ed9ng v\u1edbi v\u1eadn t\u1ed1c V h\u1ee3p v\u1edbi ph\u01b0\u01a1ng truy\u1ec1n m\u1ed9t g\u00f3c \u03b1 nh\u01b0 tr\u00ean H\u00ecnh P3, t\u1ea7n s\u1ed1 c\u1ee7a n\u00f3 f li\u00ean h\u1ec7 v\u1edbi t\u1ea7n s\u1ed1 c\u1ee7a \u00e1nh s\u00e1ng t\u1edbi f0 theo c\u00f4ng th\u1ee9c: Yf V\u03b1 Yf -V V \u03b1 \u03b1 V\u03b1 f0 X 0 f0 X 0 a) Chuy\u1ec3n \u0111\u1ed9ng ra xa b) Chuy\u1ec3n \u0111\u1ed9ng l\u1ea1i g\u1ea7n H\u00ecnh P3. Hi\u1ec7u \u1ee9ng Dopler d\u1ecdc.","PH\u1ee4 L\u1ee4C 296 f = f0 (1 + \u03b2 2 ) m 2\u03b2 .Cos\u03b1 , (P21.1) 1\u2212 \u03b2 2 \u1edf \u0111\u00e2y d\u1ea5u (\u2013) \u1ee9ng v\u1edbi chuy\u1ec3n \u0111\u1ed9ng ra xa, c\u00f2n d\u1ea5u (+) \u1ee9ng v\u1edbi chuy\u1ec3n \u0111\u1ed9ng l\u1ea1i g\u1ea7n. Bi\u1ec3u th\u1ee9c (P21.1) ch\u00ednh l\u00e0 hi\u1ec7u \u1ee9ng Dopler d\u1ecdc. N\u1ebfu \u03b1 = \u03c0\/2, ta nh\u1eadn \u0111\u01b0\u1ee3c: f = 1+ \u03b2 2 . (P21.2) f0 1\u2212 \u03b2 2 T\u1ee9c l\u00e0 f>f0! Nh\u01b0ng \u0111i\u1ec1u n\u00e0y l\u00e0 kh\u00f4ng th\u1ec3 v\u00ec khi \u0111\u00f3, h\u01b0\u1edbng tia s\u00e1ng t\u1edbi song song v\u1edbi m\u1eb7t g\u01b0\u01a1ng, do \u0111\u00f3 c\u00e1i g\u1ecdi l\u00e0 \u201ctia s\u00e1ng ph\u1ea3n x\u1ea1\u201d th\u1eadt ra c\u0169ng v\u1eabn ch\u00ednh l\u00e0 tia s\u00e1ng t\u1edbi n\u00ean t\u1ea7n s\u1ed1 f v\u1ec1 nguy\u00ean t\u1eafc ph\u1ea3i b\u1eb1ng f0 m\u1edbi \u0111\u00fang ch\u1ee9? Ch\u01b0a h\u1ebft, trong tr\u01b0\u1eddng h\u1ee3p g\u01b0\u01a1ng chuy\u1ec3n \u0111\u1ed9ng l\u1ea1i g\u1ea7n, ho\u00e0n to\u00e0n c\u00f3 kh\u1ea3 n\u0103ng x\u1ea9y ra t\u00ecnh hu\u1ed1ng khi \u00e1nh s\u00e1ng ph\u1ea3n x\u1ea1 t\u1eeb g\u01b0\u01a1ng kh\u00f4ng th\u1ec3 tho\u00e1t ra kh\u1ecfi b\u1ec1 m\u1eb7t g\u01b0\u01a1ng, do th\u00e0nh ph\u1ea7n v\u1eadn t\u1ed1c c\u00f9ng chi\u1ec1u chuy\u1ec3n \u0111\u1ed9ng v\u1edbi g\u01b0\u01a1ng l\u1ea1i nh\u1ecf h\u01a1n ch\u00ednh v\u1eadn t\u1ed1c c\u1ee7a g\u01b0\u01a1ng! C\u00f4ng th\u1ee9c (P21.1) \u0111\u00e3 kh\u00f4ng l\u00e0m s\u00e1ng t\u1ecf \u0111\u01b0\u1ee3c t\u00ecnh hu\u1ed1ng n\u00e0y. Theo C\u0110M, quan h\u1ec7 gi\u1eefa t\u1ea7n s\u1ed1 c\u1ee7a \u00e1nh s\u00e1ng t\u1edbi v\u00e0 \u00e1nh s\u00e1ng ph\u1ea3n x\u1ea1 tu\u00e2n theo c\u00f4ng th\u1ee9c: f '= cos\u03b1 + \u03b2 f (P21.3) cos\u03b1 \u2212 \u03b2 v\u1edbi \u0111i\u1ec1u ki\u1ec7n: \u03b1 > arccos \u03b2 . (P21.4) C\u00f3 th\u1ec3 th\u1ea5y ngay r\u1eb1ng n\u1ebfu \u00e1nh s\u00e1ng chi\u1ebfu vu\u00f4ng g\u00f3c v\u1edbi b\u1ec1 m\u1eb7t g\u01b0\u01a1ng, t\u1ee9c l\u00e0 \u03b1=0, hay cos\u03b1 =1, th\u00ec 2 bi\u1ec3u th\u1ee9c (P21.1) v\u00e0 (P21.3) cho ra c\u00f9ng m\u1ed9t k\u1ebft qu\u1ea3: f '= f \\\" = 1 + \u03b2 f (P21.5) 1 \u2212 \u03b2","PH\u1ee4 L\u1ee4C 297 Nh\u01b0ng v\u1ea5n \u0111\u1ec1 s\u1ebd kh\u00e1c nhi\u1ec1u, n\u1ebfu \u03b1=\u03c0\/2, hay cos\u03b1 =0, t\u1ee9c l\u00e0 \u00e1nh s\u00e1ng \u0111i \u201cs\u01b0\u1ee3t\u201d qua g\u01b0\u01a1ng, bi\u1ec3u th\u1ee9c (P21.3) cho ta k\u1ebft qu\u1ea3 \u0111\u00fang: f\u2019=f (c\u00f3 d\u1ea5u \u201c\u2013\u201d l\u00e0 do \u0111i\u1ec1u ki\u1ec7n (P21.4) \u0111\u00e3 kh\u00f4ng \u0111\u01b0\u1ee3c th\u1ecfa m\u00e3n). 22. V\u1eadt ch\u1ea5t, kh\u00f4ng gian v\u00e0 th\u1eddi gian c\u00f3 \u0111i\u1ec3m b\u1eaft \u0111\u1ea7u V\u1eadt ch\u1ea5t, kh\u00f4ng gian v\u00e0 th\u1eddi gian \u0111\u01b0\u1ee3c sinh ra t\u1eeb \u201ckh\u00f4ng c\u00f3 g\u00ec\u201d! \u2013 \u0111\u00f3 ch\u00ednh l\u00e0 \u0111i\u1ec3m b\u1eaft \u0111\u1ea7u c\u1ee7a V\u0169 tr\u1ee5 theo l\u00fd thuy\u1ebft Big Bang hi\u1ec7n h\u00e0nh. Ng\u01b0\u1eddi ta c\u1ed1 bi\u1ec7n lu\u1eadn c\u00e1i \u201ckh\u00f4ng c\u00f3 g\u00ec\u201d \u1ea5y l\u00e0 n\u0103ng l\u01b0\u1ee3ng, nh\u01b0ng n\u0103ng l\u01b0\u1ee3ng l\u00e0 c\u00e1i g\u00ec m\u00e0 l\u1ea1i t\u1ed3n t\u1ea1i kh\u00f4ng c\u1ea7n t\u1edbi v\u1eadt ch\u1ea5t v\u1eady? V\u00e0 th\u1ebf n\u00e0o ngh\u0129a l\u00e0 \u0111\u01b0\u1ee3c sinh ra? R\u1ed3i sau \u0111\u00f3 kh\u00f4ng gian l\u1ea1i c\u00f2n gi\u00e3n n\u1edf? C\u00f2n l\u1ea1m ph\u00e1t? V\u1eady b\u1ea3n th\u00e2n c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd nh\u01b0 electron, proton ... \u0111\u1ebfn Tr\u00e1i \u0111\u1ea5t, M\u1eb7t tr\u0103ng, M\u1eb7t tr\u1eddi v\u00e0 c\u00e1c v\u00ec sao hi\u1ec7n c\u00f3 d\u00e3n n\u1edf kh\u00f4ng? V\u00ec b\u1ea3n th\u00e2n ch\u00fang c\u0169ng c\u00f3 kh\u00f4ng gian ri\u00eang c\u1ee7a m\u00ecnh nh\u01b0 l\u00e0 m\u1ed9t ph\u1ea7n kh\u00f4ng t\u00e1ch r\u1eddi c\u1ee7a kh\u00f4ng gian V\u0169 tr\u1ee5 kia m\u00e0? R\u1ed3i c\u00f2n th\u1eddi gian, v\u00ec l\u00fd do g\u00ec m\u00e0 n\u00f3 l\u1ea1i kh\u00f4ng \u201cgi\u00e3n n\u1edf\u201d, kh\u00f4ng \u201cl\u1ea1m ph\u00e1t\u201d khi c\u1ea3 kh\u00f4ng gian l\u1eabn v\u1eadt ch\u1ea5t \u0111\u1ec1u \u0111\u00e3 gi\u00e3n n\u1edf? D\u00f9 mu\u1ed1n hay kh\u00f4ng, v\u1eabn ph\u1ea3i th\u1eeba nh\u1eadn: Big Bang = S\u1ef1 s\u00e1ng th\u1ebf c\u1ee7a Ch\u00faa tr\u1eddi!!! C\u00f2n n\u00f3i nh\u01b0 truy\u1ec7n ng\u1ee5 ng\u00f4n c\u1ee7a ng\u01b0\u1eddi Vi\u1ec7t nam th\u00ec l\u00e0 \u201cTr\u1eddi sinh ra th\u1ebf\u201d!!! M\u1ecdi c\u1ed1 g\u1eafng c\u1ee7a Hawking t\u1ea1o ra m\u1ed9t V\u0169 tr\u1ee5 kh\u00f4ng c\u00f3 bi\u00ean nh\u1edd v\u00e0o c\u00e1i g\u1ecdi l\u00e0 \u201cth\u1eddi gian \u1ea3o\u201d kh\u00f4ng \u0111em l\u1ea1i m\u1ed9t \u00fd ngh\u0129a th\u1ef1c ti\u1ec5n v\u1eadt l\u00fd n\u00e0o cho d\u00f9 \u00f4ng c\u1ed1 g\u1eafng thuy\u1ebft ph\u1ee5c m\u1ecdi ng\u01b0\u1eddi r\u1eb1ng: \u201ct\u1edbi m\u1ed9t l\u00fac n\u00e0o \u0111\u00f3, ng\u01b0\u1eddi ta c\u0169ng s\u1ebd ch\u1ea5p nh\u1eadn th\u1eddi gian \u1ea3o gi\u1ed1ng nh\u01b0 ch\u1ea5p nh\u1eadn Tr\u00e1i \u0111\u1ea5t quay xung quanh M\u1eb7t tr\u1eddi v\u1eady\u201d. Theo C\u0110M, v\u1eadt ch\u1ea5t kh\u00f4ng sinh ra, c\u0169ng kh\u00f4ng m\u1ea5t \u0111i n\u00ean kh\u00f4ng gian nh\u01b0 l\u00e0 m\u1ed9t thu\u1ed9c t\u00ednh c\u1ee7a n\u00f3 c\u0169ng v\u1eady; c\u00f2n th\u1eddi gian ch\u1ec9 l\u00e0 \u0111\u1ed9 \u0111o s\u1ef1 v\u1eadn \u0111\u1ed9ng c\u1ee7a v\u1eadt ch\u1ea5t m\u00e0 kh\u00f4ng t\u1ed3n t\u1ea1i kh\u00e1ch quan (xem m\u1ee5c 1.1). H\u01a1n n\u1eefa \u0111\u1eb7c t\u00ednh v\u00f4 c\u00f9ng, v\u00f4 t\u1eadn c\u1ee7a v\u1eadt ch\u1ea5t v\u00e0 s\u1ef1 v\u1eadn \u0111\u1ed9ng kh\u00f4ng ng\u1eebng ngh\u1ec9 c\u1ee7a n\u00f3 kh\u00f4ng cho ph\u00e9p b\u1ea5t c\u1ee9 m\u1ed9t gi\u1ea3 thuy\u1ebft n\u00e0o ki\u1ec3u Big Bang \u0111\u01b0\u1ee3c ph\u00e9p t\u1ed3n t\u1ea1i. 23. Quay m\u00e0 l\u1ea1i kh\u00f4ng \u0111\u01b0\u1ee3c hi\u1ec3u l\u00e0 ... quay!","PH\u1ee4 L\u1ee4C 298 Trong c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed, ng\u01b0\u1eddi ta \u0111\u01b0a ra kh\u00e1i ni\u1ec7m spin \u2013 t\u1ee9c l\u00e0 m\u00f4men quay c\u1ee7a c\u00e1c h\u1ea1t c\u01a1 b\u1ea3n. Tuy nhi\u00ean, c\u00e1c h\u1ea1t c\u01a1 b\u1ea3n \u0111\u1ec1u \u0111\u01b0\u1ee3c xem nh\u01b0 nh\u1eefng h\u1ea1t \u0111i\u1ec3m, kh\u00f4ng c\u00f3 k\u00edch th\u01b0\u1edbc n\u00ean d\u0129 nhi\u00ean kh\u00e1i ni\u1ec7m \u201ct\u1ef1 quay\u201d \u0111\u1ed1i v\u1edbi ch\u00fang l\u00e0 v\u00f4 ngh\u0129a; c\u00f2n n\u1ebfu g\u00e1n cho c\u00e1c h\u1ea1t m\u1ed9t k\u00edch th\u01b0\u1edbc n\u00e0o \u0111\u00f3, th\u00ec c\u00e1c t\u00ednh to\u00e1n m\u00f4 men quay d\u1ef1a tr\u00ean c\u00e1c s\u1ed1 li\u1ec7u c\u00f3 th\u1ec3 \u0111o \u0111\u1ea1c \u0111\u01b0\u1ee3c cho th\u1ea5y v\u1eadn t\u1ed1c quay c\u1ee7a c\u00e1c h\u1ea1t n\u00e0y \u0111\u1ec1u vi ph\u1ea1m nghi\u00eam tr\u1ecdng TTH - ngh\u0129a l\u00e0 ch\u00fang kh\u00f4ng th\u1ec3 n\u00e0o c\u00f3 th\u1ec3 quay \u0111\u01b0\u1ee3c. \u1ea4y v\u1eady m\u00e0 n\u1ebfu \u201cnh\u1eafm m\u1eaft l\u00e0m ng\u01a1\u201d \u0111\u1ec3 c\u1ee9 g\u00e1n cho ch\u00fang spin v\u1edbi ngh\u0129a l\u00e0 m\u1ed9t \u201cthu\u1ed9c t\u00ednh\u201d c\u1ee7a ch\u00fang th\u00ec l\u1ea1i c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c nhi\u1ec1u hi\u1ec7n t\u01b0\u1ee3ng. V\u1eady t\u00f3m l\u1ea1i, c\u1ee9 cho l\u00e0 ch\u00fang c\u00f3 m\u00f4 men quay \u2013 spin nh\u01b0ng \u0111\u1eebng c\u00f3 hi\u1ec3u l\u00e0 ch\u00fang ... quay!(?) X\u00e9t t\u1eeb g\u00f3c \u0111\u1ed9 v\u1eadt l\u00fd hi\u1ec7n \u0111\u1ea1i, nh\u1eefng kh\u00e1i ni\u1ec7m nh\u01b0 v\u1eady tr\u00e0n lan kh\u1eafp n\u01a1i, ch\u1eb3ng h\u1ea1n nh\u01b0 kh\u00f4ng \u2013 th\u1eddi gian 4 chi\u1ec1u, 11 chi\u1ec1u, 23 chi\u1ec1u... r\u1ed3i th\u1eddi gian \u1ea3o, photon \u1ea3o, s\u1ef1 \u201cnh\u00f2e l\u01b0\u1ee3ng t\u1eed\u201d v.v.. kh\u00f4ng th\u1ec3 c\u00f2n h\u00ecnh dung \u0111\u01b0\u1ee3c n\u1eefa. Nh\u1eefng kh\u00e1i ni\u1ec7m si\u00eau h\u00ecnh n\u00e0y d\u1ea7n \u0111\u00e3 tr\u1edf th\u00e0nh \u201cb\u1eaft bu\u1ed9c\u201d \u0111\u1ed1i v\u1edbi v\u1eadt l\u00fd v\u00e0 \u201cbu\u1ed9c t\u1ed9i\u201d \u00fd th\u1ee9c c\u1ee7a con ng\u01b0\u1eddi l\u00e0 qu\u00e1 \u201cth\u00f4 thi\u1ec3n\u201d v\u00e0 \u201c\u1ea5u tr\u0129\u201d \u0111\u1ec3 c\u00f3 th\u1ec3 nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c nh\u1eefng c\u00e1i m\u00e0 \u201cT\u1ef1 nhi\u00ean v\u1ed1n d\u0129 nh\u01b0 th\u1ebf\u201d m\u00e0 kh\u00f4ng th\u1ec3 l\u00e0 th\u1ebf kh\u00e1c! 24. Gi\u1edbi h\u1ea1n c\u1ee7a to\u00e1n h\u1ecdc* \u0110\u1ec3 nghi\u00ean c\u1ee9u c\u00e1c qu\u00e1 tr\u00ecnh v\u1eadt l\u00fd, ng\u01b0\u1eddi ta th\u01b0\u1eddng ph\u1ea3i s\u1eed d\u1ee5ng to\u00e1n h\u1ecdc nh\u01b0 m\u1ed9t c\u00f4ng c\u1ee5 h\u1eefu hi\u1ec7u, m\u1ed9t lo\u1ea1i m\u00f4 h\u00ecnh \u0111\u00f4i khi kh\u00f4ng th\u1ec3 thay th\u1ebf \u0111\u01b0\u1ee3c c\u00f3 t\u00ednh v\u1ea1n n\u0103ng. Tuy nhi\u00ean, to\u00e1n h\u1ecdc ch\u1ec9 l\u00e0 m\u1ed9t s\u1ea3n ph\u1ea9m c\u1ee7a t\u01b0 duy tr\u1eebu t\u01b0\u1ee3ng \u2013 n\u00f3 kh\u00f4ng th\u1ec3 thay th\u1ebf \u0111\u01b0\u1ee3c th\u1ef1c t\u1ea1i kh\u00e1ch quan. V\u00ed d\u1ee5 1. V\u1eadn t\u1ed1c t\u1ee9c th\u1eddi v\u00e0 gia t\u1ed1c t\u1ee9c th\u1eddi. \u0110\u1ec3 m\u00f4 t\u1ea3 chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a m\u1ed9t v\u1eadt th\u1ec3, ta c\u00f3 th\u1ec3 vi\u1ebft ph\u01b0\u01a1ng tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a n\u00f3: ma(t) = m dV (t) = m d 2 x(t) = F (P24.1) dt dt 2 \u1edf \u0111\u00e2y x(t) \u2013 l\u00e0 m\u1ed9t h\u00e0m trong HT\u0110 x0t bi\u1ec3u di\u1ec5n qu\u00e3ng \u0111\u01b0\u1eddng m\u00e0 v\u1eadt \u0111i \u0111\u01b0\u1ee3c;","PH\u1ee4 L\u1ee4C 299 V (t) = dx(t) v\u00e0 a(t) = dV (t) (P24.2) dt dt l\u00e0 v\u1eadn t\u1ed1c t\u1ee9c th\u1eddi v\u00e0 gia t\u1ed1c t\u1ee9c th\u1eddi t\u01b0\u01a1ng \u1ee9ng c\u0169ng trong HT\u0110 \u0111\u00f3. Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh (P24.1) ra ta \u0111\u01b0\u1ee3c h\u00e0m x(t). N\u1ebfu x\u00e9t t\u1eeb ph\u01b0\u01a1ng di\u1ec7n to\u00e1n h\u1ecdc thu\u1ea7n tu\u00fd th\u00ec V(t) l\u00e0 \u0111\u1ed9 d\u1ed1c c\u1ee7a \u0111\u01b0\u1eddng x(t) t\u1ea1i \u0111i\u1ec3m \u1ee9ng v\u1edbi ho\u00e0nh \u0111\u1ed9 l\u00e0 t trong m\u1eb7t ph\u1eb3ng to\u1ea1 \u0111\u1ed9 x0t so v\u1edbi tr\u1ee5c ho\u00e0nh 0t, c\u00f2n a(t) l\u00e0 \u0111\u1ed9 d\u1ed1c c\u1ee7a \u0111\u01b0\u1eddng V(t) c\u0169ng t\u1ea1i \u0111i\u1ec3m \u0111\u00f3. Nh\u01b0ng t\u1eeb ph\u01b0\u01a1ng di\u1ec7n v\u1eadt l\u00fd, kh\u00e1i ni\u1ec7m \u201cv\u1eadn t\u1ed1c t\u1ee9c th\u1eddi\u201d \u0111\u01b0\u1ee3c m\u00f4 ph\u1ecfng b\u1edfi h\u00e0m V(t) l\u1ea1i kh\u00f4ng c\u00f3 ngh\u0129a b\u1edfi v\u00ec \u0111\u01a1n gi\u1ea3n l\u00e0 n\u1ebfu ch\u1ec9 m\u1edbi n\u00f3i t\u1edbi m\u1ed9t \u201cth\u1eddi \u0111i\u1ec3m\u201d t n\u00e0o \u0111\u00f3 th\u00f4i th\u00ec v\u1eadt ch\u01b0a \u201cd\u1ecbch chuy\u1ec3n\u201d \u0111i \u0111\u00e2u c\u1ea3 th\u00ec l\u00e0m g\u00ec c\u00f3 kh\u00e1i ni\u1ec7m \u201cv\u1eadn t\u1ed1c\u201d? \u1ede \u0111\u00e2y ch\u1ec9 c\u00f3 kh\u00e1i ni\u1ec7m \u201cv\u1eadn t\u1ed1c trung b\u00ecnh\u201d \u0111\u01b0\u1ee3c hi\u1ec3u nh\u01b0 l\u00e0 \u201cqu\u00e3ng \u0111\u01b0\u1eddng\u201d m\u00e0 v\u1eadt \u0111i \u0111\u01b0\u1ee3c sau m\u1ed9t \u201ckho\u1ea3ng th\u1eddi gian\u201d m\u1edbi c\u00f3 \u00fd ngh\u0129a v\u1eadt l\u00fd. T\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady \u0111\u1ed1i v\u1edbi \u201cgia t\u1ed1c t\u1ee9c th\u1eddi\u201d. V\u00ed d\u1ee5 2. T\u1ea7n s\u1ed1 t\u1ee9c th\u1eddi. \u0110\u1ed1i v\u1edbi c\u00e1c qu\u00e1 tr\u00ecnh dao \u0111\u1ed9ng, c\u00f3 s\u1ef1 l\u1eb7p \u0111i, l\u1eb7p l\u1ea1i m\u1ed9t tr\u1ea1ng th\u00e1i nh\u1ea5t \u0111\u1ecbnh g\u1ecdi l\u00e0 chu k\u1ef3 T, ng\u01b0\u1eddi ta s\u1eed d\u1ee5ng kh\u00e1i ni\u1ec7m t\u1ea7n s\u1ed1 dao \u0111\u1ed9ng f \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 \u201cs\u1ed1 chu k\u1ef3 dao \u0111\u1ed9ng trong m\u1ed9t \u0111\u01a1n v\u1ecb th\u1eddi gian\u201d: f = 1. (P24.3) T \u1ede \u0111\u00e2y c\u1ea3 chu k\u1ef3 l\u1eabn t\u1ea7n s\u1ed1 \u0111\u1ec1u l\u00e0 c\u00e1c kh\u00e1i ni\u1ec7m ch\u1ec9 thu\u1ed9c v\u1ec1 m\u1ed9t qu\u00e1 tr\u00ecnh di\u1ec5n bi\u1ebfn theo th\u1eddi gian \u1edf d\u1ea1ng hi\u1ec3n ch\u1ee9 kh\u00f4ng th\u1ec3 c\u00f3 kh\u00e1i ni\u1ec7m \u1edf t\u1ea1i m\u1ed9t th\u1eddi \u0111i\u1ec3m v\u00e0, h\u01a1n th\u1ebf n\u1eefa, l\u1ea1i kh\u00f4ng th\u1ec3 li\u00ean t\u1ee5c theo th\u1eddi gian. Th\u00ed d\u1ee5 nh\u01b0 Tr\u00e1i \u0111\u1ea5t quay xung quanh M\u1eb7t tr\u1eddi v\u1edbi chu k\u1ef3 b\u1eb1ng 365 ng\u00e0y, \u0111\u1ed1i v\u1edbi n\u00f3, kh\u00f4ng th\u1ec3 n\u00f3i l\u00e0 t\u1ea1i \u201cth\u1eddi \u0111i\u1ec3m\u201d 0h00\u2019ng\u00e0y 1\/1\/2007 chu k\u1ef3 c\u1ee7a n\u00f3 l\u00e0 365 ng\u00e0y b\u1edfi v\u00ec ch\u1ec9 khi \u0111\u00e3 tr\u1ea3i qua 365 ng\u00e0y, Tr\u00e1i \u0111\u1ea5t m\u1edbi c\u00f3 th\u1ec3 ho\u00e0n th\u00e0nh xong 1 chu k\u1ef3 v\u00e0 r\u1ed3i nh\u1edd v\u00e0o c\u00f4ng th\u1ee9c (P24.3) \u0111\u1ec3 t\u00ednh ra t\u1ea7n s\u1ed1 quay c\u1ee7a n\u00f3. V\u1eady th\u00ec l\u00e0m sao c\u00f3 th\u1ec3 bi\u1ec3u di\u1ec5n T hay f nh\u01b0 m\u1ed9t h\u00e0m c\u1ee7a th\u1eddi gian t\u1ea1i c\u00e1c th\u1eddi \u0111i\u1ec3m 1h00\u2019, 2h00\u2019 v.v.. c\u00f9ng ng\u00e0y 1\/1\/2007 \u0111\u01b0\u1ee3c \u0111\u00e2y? N\u00f3i c\u00e1ch kh\u00e1c, nh\u1eefng \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0y ch\u1ec9 c\u00f3 ngh\u0129a trong m\u1ed9t kho\u1ea3ng th\u1eddi gian ch\u1ee9 kh\u00f4ng c\u00f3 ngh\u0129a t\u1ea1i m\u1ed9t th\u1eddi \u0111i\u1ec3m, k\u1ec3 c\u1ea3 l\u00e0 \u201cth\u1eddi \u0111i\u1ec3m\u201d \u0111\u00e3","PH\u1ee4 L\u1ee4C 300 \u0111\u01b0\u1ee3c hi\u1ec3u v\u1edbi ngh\u0129a \u1edf m\u1ee5c 1.1.3. Ch\u00ednh v\u00ec v\u1eady, kh\u00f4ng th\u1ec3 c\u00f3 kh\u00e1i ni\u1ec7m \u201cchu k\u1ef3 t\u1ee9c th\u1eddi\u201d hay \u201ct\u1ea7n s\u1ed1 t\u1ee9c th\u1eddi\u201d, c\u0169ng nh\u01b0 coi ch\u00fang l\u00e0 m\u1ed9t \u201ch\u00e0m li\u00ean t\u1ee5c c\u1ee7a th\u1eddi gian\u201d \u0111\u1ec3 r\u1ed3i \u00e1p d\u1ee5ng c\u00e1c ph\u00e9p t\u00ednh vi ph\u00e2n hay t\u00edch ph\u00e2n m\u1ed9t c\u00e1ch t\u00f9y ti\u1ec7n. V\u00ed d\u1ee5 3. C\u01b0\u1eddng \u0111\u1ed9 \u0111i\u1ec7n tr\u01b0\u1eddng. Trong l\u00fd thuy\u1ebft tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb, ng\u01b0\u1eddi ta g\u00e1n cho m\u1ed7i \u0111i\u1ec3m c\u1ee7a tr\u01b0\u1eddng m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng \u0111\u1eb7c tr\u01b0ng \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cv\u00e9c t\u01a1 c\u01b0\u1eddng \u0111\u1ed9 \u0111i\u1ec7n tr\u01b0\u1eddng\u201d x\u00e1c \u0111\u1ecbnh theo bi\u1ec3u th\u1ee9c (3.7), v\u1ec1 th\u1ef1c ch\u1ea5t l\u00e0 \u0111em chia l\u1ef1c t\u01b0\u01a1ng t\u00e1c cho gi\u00e1 tr\u1ecb \u0111i\u1ec7n t\u00edch c\u1ee7a v\u1eadt th\u1ec3 \u0111ang t\u1ed3n t\u1ea1i \u1edf \u0111i\u1ec3m \u0111\u00f3, k\u1ebft qu\u1ea3 l\u00e0 bi\u1ec3u th\u1ee9c (3.7) kh\u00f4ng c\u00f2n ph\u1ee5 thu\u1ed9c v\u00e0o \u0111i\u1ec7n t\u00edch c\u1ee7a v\u1eadt th\u1ec3 \u0111\u00f3 n\u1eefa. Tr\u00ean c\u01a1 s\u1edf \u0111\u00f3, ng\u01b0\u1eddi ta ti\u1ebfn h\u00e0nh kh\u1ea3o s\u00e1t c\u00e1i g\u1ecdi l\u00e0 \u0111i\u1ec7n tr\u01b0\u1eddng ho\u00e0n to\u00e0n \u0111\u1ed9c l\u1eadp v\u1edbi c\u00e1c \u0111i\u1ec7n t\u00edch t\u1ed3n t\u1ea1i trong \u0111\u00f3 \u2013 l\u00fd thuy\u1ebft tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb ra \u0111\u1eddi. Tuy nhi\u00ean, ng\u01b0\u1eddi ta l\u1ea1i qu\u00ean \u0111i m\u1ea5t m\u1ed9t chi ti\u1ebft l\u00e0 ph\u00e9p chia \u0111\u00f3, v\u1ec1 th\u1ef1c ch\u1ea5t ch\u1ec9 l\u00e0 m\u1ed9t thao t\u00e1c to\u00e1n h\u1ecdc thu\u1ea7n t\u00fay, kh\u00f4ng v\u00ec th\u1ebf m\u00e0 v\u1eadt th\u1ec3 c\u00f9ng v\u1edbi \u0111i\u1ec7n t\u00edch c\u1ee7a n\u00f3 bi\u1ebfn m\u1ea5t kh\u1ecfi \u0111i\u1ec3m \u0111\u00f3 \u2013 n\u00f3 v\u1eabn t\u1ed3n t\u1ea1i \u1edf \u0111\u00f3 b\u1ea5t lu\u1eadn anh \u201cchia ch\u00e1c\u201d th\u1ebf n\u00e0o! V\u1eady m\u1ed9t c\u00e2u h\u1ecfi \u0111\u1eb7t ra l\u00e0 \u0111i\u1ec1u g\u00ec s\u1ebd x\u1ea9y ra khi c\u00f9ng v\u1edbi thao t\u00e1c chia \u0111\u00f3, ta v\u1ee9t b\u1ecf lu\u00f4n v\u1eadt th\u1ec3 t\u00edch \u0111i\u1ec7n \u0111\u00f3 ra kh\u1ecfi \u0111i\u1ec7n tr\u01b0\u1eddng? T\u1ea1i \u0111i\u1ec3m \u0111\u00f3 s\u1ebd ch\u1ec9 c\u00f2n ch\u01a1 v\u01a1 l\u1ea1i c\u00e1i g\u1ecdi l\u00e0 \u201cv\u00e9c t\u01a1 c\u01b0\u1eddng \u0111\u1ed9 \u0111i\u1ec7n tr\u01b0\u1eddng E\u201d? Th\u1eadt \u0111\u00e1ng ti\u1ebfc l\u00e0 kh\u00f4ng ph\u1ea3i nh\u01b0 v\u1eady. T\u1eeb quan \u0111i\u1ec3m duy v\u1eadt bi\u1ec7n ch\u1ee9ng \u0111\u00e3 n\u00f3i t\u1edbi \u1edf Ch\u01b0\u01a1ng I, m\u1ed7i th\u1ef1c th\u1ec3 v\u1eadt l\u00fd ph\u1ea3i bao g\u1ed3m 2 th\u00e0nh ph\u1ea7n: v\u1eadt th\u1ec3 v\u00e0 tr\u01b0\u1eddng, v\u00e0 h\u01a1n th\u1ebf n\u1eefa, n\u00f3 ch\u1ec9 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c coi l\u00e0 t\u1ed3n t\u1ea1i khi n\u00f3 t\u01b0\u01a1ng t\u00e1c v\u1edbi m\u1ed9t th\u1ef1c th\u1ec3 v\u1eadt l\u00fd kh\u00e1c; khi ch\u1ec9 c\u00f2n l\u1ea1i m\u1ed9t m\u00ecnh \u2013 kh\u00e1i ni\u1ec7m kh\u00f4ng gian \u201cngo\u1ea1i vi\u201d l\u00e0 v\u00f4 ngh\u0129a, t\u1ee9c l\u00e0 kh\u00e1i ni\u1ec7m tr\u01b0\u1eddng c\u0169ng v\u00f4 ngh\u0129a theo, v\u00e0 k\u1ebft qu\u1ea3 c\u00e1i g\u1ecdi l\u00e0 \u201cch\u1ec9 c\u00f2n l\u1ea1i m\u1ed9t m\u00ecnh\u201d c\u0169ng v\u00f4 ngh\u0129a n\u1ed1t! N\u00f3 c\u00e1ch kh\u00e1c, n\u1ebfu v\u1ee9t b\u1ecf v\u1eadt th\u1ec3 t\u00edch \u0111i\u1ec7n ra kh\u1ecfi \u0111i\u1ec3m \u0111ang x\u00e9t \u0111\u1ed3ng ngh\u0129a v\u1edbi \u201ckh\u00f4ng c\u00f2n g\u00ec \u0111\u1ec3 n\u00f3i\u201d. C\u00f3 th\u1ec3 l\u00e0m m\u1ed9t \u0111\u1ed9ng t\u00e1c ng\u01b0\u1ee3c l\u1ea1i, ta s\u1ebd th\u1ea5y r\u00f5 h\u01a1n \u0111i\u1ec1u \u0111\u00f3. C\u1ee5 th\u1ec3 l\u00e0 t\u1ea1i \u0111i\u1ec3m \u0111ang x\u00e9t \u0111\u00f3, ta \u0111\u1eb7t m\u1ed9t v\u1eadt th\u1ec3 c\u00f3 \u0111i\u1ec7n t\u00edch l\u1edbn h\u01a1n r\u1ea5t nhi\u1ec1u \u0111i\u1ec7n t\u00edch c\u1ee7a v\u1eadt th\u1ec3 c\u00f3 \u0111i\u1ec7n tr\u01b0\u1eddng \u0111ang c\u1ea7n kh\u1ea3o s\u00e1t, khi \u0111\u00f3, b\u1ea5t lu\u1eadn anh c\u00f3 th\u1ef1c hi\u1ec7n ph\u00e9p chia \u0111i\u1ec7n t\u00edch hay kh\u00f4ng chia \u0111i\u1ec7n t\u00edch, c\u00e1i \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u0111i\u1ec7n tr\u01b0\u1eddng ban \u0111\u1ea7u \u0111\u00e3 kh\u00f4ng c\u00f2n n\u1eefa \u2013 n\u00f3 \u0111\u00e3 b\u1ecb bi\u1ebfn d\u1ea1ng, v\u00e0 kh\u00f4ng ch\u1ec9 \u1edf ri\u00eang t\u1ea1i \u0111i\u1ec3m \u0111\u00f3 m\u00e0 l\u00e0 to\u00e0n b\u1ed9 c\u00e1c \u0111i\u1ec3m kh\u00e1c n\u1eefa. Ph\u00e9p chia \u0111\u00f3","PH\u1ee4 L\u1ee4C 301 v\u1ec1 m\u1eb7t to\u00e1n h\u1ecdc r\u00f5 r\u00e0ng kh\u00f4ng h\u1ec1 sai nh\u01b0ng n\u00f3 c\u00f3 gi\u1edbi h\u1ea1n c\u1ee7a n\u00f3. Gi\u1edbi h\u1ea1n \u0111\u00f3 c\u1ea7n ph\u1ea3i \u0111\u01b0\u1ee3c t\u00ednh \u0111\u1ebfn. Ngo\u00e0i ra, c\u00f2n ph\u1ea3i k\u1ec3 \u0111\u1ebfn kh\u00f4ng-th\u1eddi gian 4 chi\u1ec1u Mincopsky, Riemann... trong thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i \u2013 \u0111\u1ec1u ch\u1ec9 l\u00e0 nh\u1eefng kh\u00f4ng gian thu\u1ea7n t\u00fay to\u00e1n h\u1ecdc ch\u1ee9 kh\u00f4ng kh\u00f4ng li\u00ean quan g\u00ec t\u1edbi kh\u00f4ng gian v\u1eadt ch\u1ea5t nh\u01b0 \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp t\u1edbi \u1edf m\u1ee5c 1.1.2, hay nh\u01b0 vi\u1ec7c \u00e1p d\u1ee5ng gi\u1ea3i t\u00edch v\u00e9c t\u01a1 \u1edf m\u1ee5c 1.3.3. Nh\u01b0 v\u1eady, cho d\u00f9 l\u00e0 thu\u1eadn ti\u1ec7n \u0111\u1ebfn \u0111\u00e2u \u0111i ch\u0103ng n\u1eefa, v\u1eabn c\u1ea7n ph\u1ea3i bi\u1ebft \u201c\u0111i\u1ec3m d\u1eebng\u201d khi chuy\u1ec3n t\u1ea3i nh\u1eefng kh\u00e1i ni\u1ec7m tr\u1eebu t\u01b0\u1ee3ng c\u1ee7a t\u01b0 duy sang nh\u1eefng kh\u00e1i ni\u1ec7m v\u1eadt l\u00fd, n\u1ebfu kh\u00f4ng, s\u1ebd v\u00f4 t\u00ecnh t\u1ea1o \u0111i\u1ec1u ki\u1ec7n \u0111\u1ec3 \u201csi\u00eau h\u00ecnh\u201d len l\u1ecfi v\u00e0o v\u1eadt l\u00fd l\u00fac n\u00e0o kh\u00f4ng bi\u1ebft. Tr\u01b0\u1eddng h\u1ee3p t\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady \u0111\u00e3 x\u1ea9y ra \u0111\u1ed1i v\u1edbi \u201cs\u00f3ng \u0111i\u1ec7n t\u1eeb\u201d - m\u1ed9t nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh Maxwell nh\u01b0 \u1edf Ph\u1ee5 l\u1ee5c 4. 25. Gi\u1edbi h\u1ea1n c\u1ee7a th\u1ef1c nghi\u1ec7m* C\u00e1c tri\u1ebft gia duy v\u1eadt th\u01b0\u1eddng n\u00f3i: \u201cth\u1ef1c ti\u1ec5n l\u00e0 ti\u00eau chu\u1ea9n c\u1ee7a ch\u00e2n l\u00fd\u201d, c\u00f2n nh\u1eefng nh\u00e0 v\u1eadt l\u00fd th\u00ec n\u00f3i: \u201cl\u00fd thuy\u1ebft c\u1ea7n ph\u1ea3i \u0111\u01b0\u1ee3c ki\u1ec3m ch\u1ee9ng b\u1eb1ng th\u1ef1c nghi\u1ec7m\u201d. Nh\u1eefng \u0111i\u1ec1u \u0111\u00f3 \u0111\u1ec1u \u0111\u00fang c\u1ea3. Tuy nhi\u00ean, v\u1ea5n \u0111\u1ec1 tr\u01b0\u1edbc h\u1ebft l\u1ea1i kh\u00f4ng ph\u1ea3i l\u00e0 \u1edf ch\u1ed7 c\u00f3 \u201c\u0111\u01b0\u1ee3c ki\u1ec3m ch\u1ee9ng\u201d ho\u1eb7c \u201cti\u00eau chu\u1ea9n\u201d h\u00f3a hay kh\u00f4ng, m\u00e0 l\u1ea1i \u1edf ch\u00ednh c\u00e1i \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cth\u1ef1c ti\u1ec5n\u201d hay \u201cth\u1ef1c nghi\u1ec7m\u201d n\u00e0y! H\u1ecdc thuy\u1ebft \u0111\u1ecba t\u00e2m c\u1ee7a Ptoleme ch\u1eb3ng ph\u1ea3i c\u0169ng \u0111\u00e3 t\u1eebng d\u1ef1a v\u00e0o \u201cth\u1ef1c nghi\u1ec7m\u201d \u0111\u00f3 sao? Ai m\u00e0 ch\u1eb3ng \u201ct\u1eadn m\u1eaft\u201d nh\u00ecn th\u1ea5y M\u1eb7t tr\u1eddi m\u1ecdc \u1edf \u0111\u1eb1ng \u0110\u00f4ng r\u1ed3i l\u1eb7n \u1edf \u0111\u1eb1ng T\u00e2y, M\u1eb7t tr\u0103ng v\u00e0 b\u1ea7u tr\u1eddi \u0111\u1ea7y sao c\u0169ng v\u1ea7n xoay quanh ta l\u00e0 c\u00e1i g\u00ec v\u1eady? \u0110\u00f3 ch\u00ednh l\u00e0 gi\u1edbi h\u1ea1n c\u1ee7a th\u1ef1c nghi\u1ec7m! Th\u1ef1c nghi\u1ec7m l\u00e0 qu\u00e1 tr\u00ecnh s\u1eed d\u1ee5ng c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt ch\u1ea5t theo c\u00e1c quy tr\u00ecnh nh\u1ea5t \u0111\u1ecbnh nh\u1eb1m m\u1ee5c \u0111\u00edch ki\u1ec3m tra m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng hay s\u1ef1 v\u1eadt n\u00e0o \u0111\u00f3. Nh\u01b0 v\u1eady \u1edf \u0111\u00e2y c\u00f3 3 y\u1ebfu t\u1ed1 h\u00ecnh th\u00e0nh n\u00ean c\u00e1i g\u1ecdi l\u00e0 \u201cth\u1ef1c nghi\u1ec7m\u201d \u0111\u00f3: + ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt ch\u1ea5t bao g\u1ed3m c\u00e1c thi\u1ebft b\u1ecb \u0111o \u0111\u1ea1c, c\u00e1c thi\u1ebft b\u1ecb h\u1ed7 tr\u1ee3, t\u1ea1o m\u1eabu, t\u00ednh to\u00e1n, m\u00f4 ph\u1ecfng v.v..","PH\u1ee4 L\u1ee4C 302 + c\u01a1 s\u1edf l\u00fd thuy\u1ebft nh\u1edd \u0111\u00f3 x\u00e2y d\u1ef1ng n\u00ean c\u00e1c quy tr\u00ecnh th\u00ed nghi\u1ec7m, ch\u01b0\u01a1ng tr\u00ecnh t\u00ednh to\u00e1n, x\u1eed l\u00ed s\u1ed1 li\u1ec7u ... + ng\u01b0\u1eddi th\u00ed nghi\u1ec7m ti\u1ebfp nh\u1eadn th\u00f4ng tin v\u00e0 \u0111i\u1ec1u khi\u1ec3n to\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh. Nh\u01b0 th\u1ebf c\u00f3 th\u1ec3 th\u1ea5y do c\u1ea3 3 y\u1ebfu t\u1ed1 n\u00e0y kh\u00f4ng bao gi\u1edd c\u00f3 th\u1ec3 ho\u00e0n thi\u1ec7n m\u00e0 lu\u00f4n c\u00f3 nh\u1eefng gi\u1edbi h\u1ea1n kh\u00f4ng th\u1ec3 v\u01b0\u1ee3t qua \u0111\u01b0\u1ee3c n\u00ean c\u00e1i g\u1ecdi l\u00e0 \u201cth\u1ef1c nghi\u1ec7m\u201d, v\u1ec1 nguy\u00ean t\u1eafc, c\u0169ng s\u1ebd c\u00f3 gi\u1edbi h\u1ea1n, v\u00ec v\u1eady, vi\u1ec7c h\u00e0i l\u00f2ng v\u1edbi c\u00e1i g\u1ecdi l\u00e0 \u201ck\u1ebft qu\u1ea3 th\u1ef1c nghi\u1ec7m \u0111\u00e3 ch\u1ec9 ra nh\u01b0 v\u1eady\u201d s\u1ebd d\u1eabn d\u1eaft ch\u00fang ta t\u1edbi nh\u1eefng sai l\u1ea7m m\u00e0 c\u00e1i gi\u00e1 ph\u1ea3i tr\u1ea3 s\u1ebd l\u00e0 r\u1ea5t l\u1edbn. C\u00f3 th\u1ec3 l\u1ea5y th\u00ed nghi\u1ec7m r\u01a1i t\u1ef1 do ki\u1ec3u Galileo l\u00e0m v\u00ed d\u1ee5 minh h\u1ecda. Th\u1ea3 m\u1ed9t c\u00e1i l\u00f4ng ng\u1ed7ng, m\u1ed9t h\u00f2n bi s\u1eaft v\u00e0 m\u1ed9t m\u1ea9u g\u1ed7 v\u00e0o m\u1ed9t \u1ed1ng th\u1ee7y tinh \u0111\u00e3 \u0111\u01b0\u1ee3c h\u00fat ch\u00e2n kh\u00f4ng, \u0111\u1eb7t n\u00f3 d\u1ef1ng \u0111\u1ee9ng l\u00ean r\u1ed3i b\u1ea5t ng\u1edd l\u1eadt ng\u01b0\u1ee3c n\u00f3 xu\u1ed1ng \u2013 c\u1ea3 3 v\u1eadt \u0111\u1ec1u r\u01a1i xu\u1ed1ng \u0111\u00e1y c\u00f9ng m\u1ed9t l\u00fac, v\u1edbi c\u00f9ng m\u1ed9t gia t\u1ed1c r\u01a1i t\u1ef1 do g = 9,8m\/s2, b\u1ea5t ch\u1ea5p kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a ch\u00fang ch\u00eanh l\u1ec7ch nhau c\u1ea3 tr\u0103m l\u1ea7n. T\u1eeb \u0111\u00e2y c\u00f3 th\u1ec3 tuy\u00ean b\u1ed1 r\u1eb1ng \u201cgia t\u1ed1c r\u01a1i t\u1ef1 do c\u1ee7a m\u1ecdi v\u1eadt \u0111\u1ec1u nh\u01b0 nhau, kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a ch\u00fang\u201d. V\u00e0 m\u1ed9t khi gia t\u1ed1c r\u01a1i t\u1ef1 do \u0111\u00e3 nh\u01b0 nhau th\u00ec c\u00f3 th\u1ec3 r\u00fat ra \u0111\u01b0\u1ee3c s\u1ef1 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng gi\u1eefa kh\u1ed1i l\u01b0\u1ee3ng h\u1ea5p d\u1eabn v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng qu\u00e1n t\u00ednh. K\u1ebft qu\u1ea3 l\u00e0 c\u00f3 th\u1ec3 n\u00e2ng l\u00ean th\u00e0nh nguy\u00ean l\u00fd cho t\u1ea5t c\u1ea3 m\u1ecdi v\u1eadt th\u1ec3 trong V\u0169 tr\u1ee5 - nguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. Song, r\u1ea5t ti\u1ebfc \u0111i\u1ec1u \u0111\u00f3 l\u1ea1i l\u00e0 m\u1ed9t sai l\u1ea7m. Ch\u1ec9 c\u1ea7n thay th\u00ed nghi\u1ec7m n\u00e0y b\u1eb1ng m\u1ed9t th\u00ed nghi\u1ec7m t\u01b0\u1edfng t\u01b0\u1ee3ng kh\u00e1c l\u00e0 ch\u1ecdn v\u1eadt r\u01a1i c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng t\u01b0\u01a1ng \u0111\u01b0\u01a1ng kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a Tr\u00e1i \u0111\u1ea5t s\u1ebd th\u1ea5y ngay gia t\u1ed1c r\u01a1i t\u1ef1 do c\u1ee7a n\u00f3 kh\u00f4ng c\u00f2n b\u1eb1ng g n\u1eefa m\u00e0 ph\u1ea3i l\u00e0 ~2g \u2013 nguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng kh\u00f4ng c\u00f2n \u0111\u00fang n\u1eefa! N\u00f3i c\u00e1ch kh\u00e1c, gia t\u1ed1c r\u01a1i t\u1ef1 do ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a c\u1ea3 hai v\u1eadt ch\u1ee9 kh\u00f4ng ch\u1ec9 c\u1ee7a m\u1ed9t v\u1eadt. Sai s\u1ed1 th\u1ef1c nghi\u1ec7m c\u00f3 th\u1ec3 \u0111\u00e1nh gi\u00e1 b\u1edfi t\u1ef7 s\u1ed1 (xem bi\u1ec3u th\u1ee9c (2.29)): \u03b4 \u2248 Mx M T\u0110 V\u1edbi Mx v\u00e0 MT\u0110 l\u00e0 kh\u1ed1i l\u01b0\u1ee3ng h\u1ea5p d\u1eabn c\u1ee7a v\u1eadt th\u1eed v\u00e0 c\u1ee7a Tr\u00e1i \u0111\u1ea5t t\u01b0\u01a1ng \u1ee9ng. Trong th\u00ed nghi\u1ec7m c\u1ee7a Galileo, sai s\u1ed1 n\u00e0y ch\u1ec9 l\u00e0 10-24 \u2013 m\u1ed9t \u0111\u1ed9 ch\u00ednh x\u00e1c \u201cn\u1eb1m m\u01a1 c\u0169ng kh\u00f4ng th\u1ec3 c\u00f3 \u0111\u01b0\u1ee3c\u201d, \u1ea5y v\u1eady m\u00e0 s\u1ebd sai t\u1edbi 100% khi 2 kh\u1ed1i l\u01b0\u1ee3ng \u1ea5y b\u1eb1ng","PH\u1ee4 L\u1ee4C 303 nhau! Nghe n\u00f3i s\u1eafp t\u1edbi, NASA s\u1ebd cho chi 500 tr. USD v\u00e0o v\u0169 tr\u1ee5 \u0111\u1ec3 ki\u1ec3m tra s\u1ef1 sai kh\u00e1c gi\u1eefa 2 kh\u1ed1i l\u01b0\u1ee3ng \u0111\u00f3 v\u1edbi sai s\u1ed1 d\u1ef1 ki\u1ebfn gi\u1ea3m xu\u1ed1ng ch\u1ec9 c\u00f2n 10-16 thay v\u00ec 10-12 nh\u01b0 hi\u1ec7n nay, nh\u01b0ng c\u00f3 th\u1ec3 ti\u00ean \u0111o\u00e1n \u0111\u01b0\u1ee3c tr\u01b0\u1edbc r\u1eb1ng k\u1ebft qu\u1ea3 s\u1ebd v\u1eabn ch\u1eb3ng nh\u1eadn \u0111\u01b0\u1ee3c g\u00ec kh\u00e1c h\u01a1n! 26. S\u1ef1 t\u1ed3n t\u1ea1i t\u1ef1 th\u00e2n c\u1ee7a c\u00e1c t\u00ednh ch\u1ea5t* \u201cCh\u00e2n kh\u00f4ng l\u01b0\u1ee3ng t\u1eed\u201d l\u00e0 n\u01a1i kh\u00f4ng c\u00f3 b\u1ea5t c\u1ee9 d\u1ea1ng t\u1ed3n t\u1ea1i n\u00e0o c\u1ee7a v\u1eadt ch\u1ea5t nh\u01b0ng \u201cn\u0103ng l\u01b0\u1ee3ng\u201d th\u00ec kh\u00f4ng bao gi\u1edd b\u1eb1ng kh\u00f4ng! Theo l\u00fd thuy\u1ebft \u201cBig Bang\u201d th\u00ec v\u1eadt ch\u1ea5t, kh\u00f4ng gian v\u00e0 th\u1eddi gian \u0111\u01b0\u1ee3c sinh ra t\u1eeb m\u1ed9t v\u1ee5 n\u1ed5 - t\u1ee9c l\u00e0 tr\u01b0\u1edbc khi c\u00f3 v\u1eadt ch\u1ea5t \u0111\u00e3 t\u1ed3n t\u1ea1i \u201cn\u0103ng l\u01b0\u1ee3ng t\u1ef1 th\u00e2n\u201d! D\u01b0\u1eddng nh\u01b0 \u1edf \u0111\u00e2y ch\u00fang ta \u0111\u00e3 qu\u00ean m\u1ea5t r\u1eb1ng qu\u00e1 tr\u00ecnh nh\u1eadn th\u1ee9c c\u1ee7a con ng\u01b0\u1eddi tu\u00e2n theo quy lu\u1eadt \u201ct\u1eeb tr\u1ef1c quan sinh \u0111\u1ed9ng \u0111\u1ebfn t\u01b0 duy tr\u1eebu t\u01b0\u1ee3ng\u201d. C\u00e1c kh\u00e1i ni\u1ec7m \u0111\u01b0\u1ee3c sinh ra t\u1eeb qu\u00e1 tr\u00ecnh \u0111\u00f3. Nh\u1eadn th\u1ea5y c\u00e1c v\u1eadt th\u1ec3 khi va ch\u1ea1m nhau t\u1ea1o n\u00ean chuy\u1ec3n d\u1ecbch (m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng tr\u1ef1c quan), ng\u01b0\u1eddi ta \u0111\u01b0a ra kh\u00e1i ni\u1ec7m v\u1ec1 l\u1ef1c, c\u00f4ng (l\u1ef1c nh\u00e2n v\u1edbi chuy\u1ec3n d\u1ecbch) v\u00e0 n\u0103ng l\u01b0\u1ee3ng (kh\u1ea3 n\u0103ng sinh c\u00f4ng). Nh\u01b0 v\u1eady, c\u00e1c kh\u00e1i ni\u1ec7m \u201cl\u1ef1c\u201d, \u201cc\u00f4ng\u201d v\u00e0 \u201cn\u0103ng l\u01b0\u1ee3ng\u201d lu\u00f4n g\u1eafn v\u1edbi m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng c\u1ee5 th\u1ec3, m\u1ed9t qu\u00e1 tr\u00ecnh c\u1ee5 th\u1ec3 n\u00e0o \u0111\u00f3 v\u1edbi t\u01b0 c\u00e1ch l\u00e0 c\u00e1c t\u00ednh ch\u1ea5t c\u1ee7a ch\u00fang. N\u1ebfu ch\u00fang kh\u00f4ng t\u1ed3n t\u1ea1i th\u00ec l\u00e0m g\u00ec c\u00f2n t\u1ed3n t\u1ea1i c\u00e1i g\u1ecdi l\u00e0 \u201ct\u00ednh ch\u1ea5t c\u1ee7a ch\u00fang\\\"? N\u00f3i c\u00e1ch kh\u00e1c, kh\u00f4ng t\u1ed3n t\u1ea1i c\u00e1c \u201ct\u00ednh ch\u1ea5t t\u1ef1 th\u00e2n\u201d m\u00e0 ch\u1ec9 t\u1ed3n t\u1ea1i c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng v\u1eadt l\u00fd c\u00f3 c\u00e1c t\u00ednh ch\u1ea5t \u0111\u00f3 m\u00e0 th\u00f4i. T\u1eeb \u0111\u00e2y x\u00e9t r\u1ed9ng ra - ch\u1ec9 t\u1ed3n t\u1ea1i v\u1eadt ch\u1ea5t d\u01b0\u1edbi c\u00e1c d\u1ea1ng kh\u00e1c nhau v\u00e0 v\u1edbi c\u00e1c t\u00ednh ch\u1ea5t kh\u00e1c nhau c\u1ee7a ch\u00fang ch\u1ee9 kh\u00f4ng t\u1ed3n t\u1ea1i c\u00e1c \u201ct\u00ednh ch\u1ea5t t\u1ef1 th\u00e2n\u201d (\u201cn\u0103ng l\u01b0\u1ee3ng\u201d \u1edf \u0111\u00e2y c\u0169ng kh\u00f4ng ph\u1ea3i l\u00e0 m\u1ed9t ngo\u1ea1i l\u1ec7). Nh\u01b0 v\u1eady, vi\u1ec7c xem v\u1eadt ch\u1ea5t \u0111\u01b0\u1ee3c sinh ra t\u1eeb \u201cn\u0103ng l\u01b0\u1ee3ng\u201d - m\u1ed9t t\u00ednh ch\u1ea5t c\u1ee7a n\u00f3 \u2013 l\u00e0 ho\u00e0n to\u00e0n tr\u00e1i v\u1edbi c\u00e1c \u201cb\u1eb1ng ch\u1ee9ng th\u1ef1c nghi\u1ec7m\u201d. C\u00e1i g\u1ecdi l\u00e0 \u201cth\u0103ng gi\u00e1ng\u201d c\u1ee7a \u201cch\u00e2n kh\u00f4ng l\u01b0\u1ee3ng t\u1eed\u201d, v\u1ec1 th\u1ef1c ch\u1ea5t, ch\u1ec9 l\u00e0 m\u1ed9t c\u00e1ch m\u00f4 t\u1ea3 \u201ctu\u1ef3 h\u1ee9ng\u201d th\u1ef1c t\u1ea1i kh\u00e1ch quan. Kh\u00f4ng \u1edf \u0111\u00e2u v\u00e0 ch\u1eb3ng bao gi\u1edd t\u1ea1o \u0111\u01b0\u1ee3c m\u1ed9t c\u00e1i g\u1ecdi l\u00e0 \u201cch\u00e2n kh\u00f4ng l\u01b0\u1ee3ng t\u1eed\u201d v\u1edbi ngh\u0129a l\u00e0","PH\u1ee4 L\u1ee4C 304 kh\u00f4ng t\u1ed3n t\u1ea1i b\u1ea5t c\u1ee9 h\u00ecnh th\u1ee9c n\u00e0o c\u1ee7a v\u1eadt ch\u1ea5t m\u00e0 l\u1ea1i v\u1eabn t\u1ed3n t\u1ea1i \u201cn\u0103ng l\u01b0\u1ee3ng\u201d c\u1ea3, b\u1edfi \u00edt nh\u1ea5t c\u0169ng kh\u00f4ng th\u1ec3 n\u00e0o lo\u1ea1i b\u1ecf \u0111\u01b0\u1ee3c photon v\u1ed1n t\u1ed3n t\u1ea1i kh\u1eafp m\u1ecdi n\u01a1i. N\u00f3i t\u00f3m l\u1ea1i, \u0111\u00e2y l\u00e0 m\u1ed9t ngh\u1ecbch l\u00fd trong nh\u1eadn th\u1ee9c. Ngh\u1ecbch l\u00fd n\u00e0y c\u00f3 l\u1ebd \u0111\u01b0\u1ee3c c\u1ed5 v\u0169 b\u1edfi c\u00f4ng th\u1ee9c n\u1ed5i ti\u1ebfng c\u1ee7a Einstein: E=mc2. Ng\u01b0\u1eddi ta cho r\u1eb1ng c\u00f4ng th\u1ee9c n\u00e0y n\u00f3i l\u00ean s\u1ef1 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng gi\u1eefa n\u0103ng l\u01b0\u1ee3ng v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng, m\u00e0 kh\u1ed1i l\u01b0\u1ee3ng l\u1ea1i l\u00e0 \u201cth\u01b0\u1edbc \u0111o\u201d l\u01b0\u1ee3ng v\u1eadt ch\u1ea5t n\u00ean c\u0169ng c\u00f3 ngh\u0129a l\u00e0 s\u1ef1 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng gi\u1eefa n\u0103ng l\u01b0\u1ee3ng v\u00e0 v\u1eadt ch\u1ea5t. N\u00f3i nh\u01b0 Einstein, \u0111\u00f3 l\u00e0 s\u1ef1 chuy\u1ec3n ho\u00e1 qua l\u1ea1i gi\u1eefa \u201cn\u0103ng l\u01b0\u1ee3ng\u201d v\u00e0 v\u1eadt ch\u1ea5t \u2013 \u0111i\u1ec1u n\u00e0y l\u00e0 kh\u00f4ng \u0111\u00fang. Kh\u00f4ng n\u00ean qu\u00ean r\u1eb1ng \u0111\u1ec3 d\u1eabn ra c\u00f4ng th\u1ee9c n\u00e0y, ng\u01b0\u1eddi ta ph\u1ea3i d\u1ef1a v\u00e0o ph\u01b0\u01a1ng tr\u00ecnh chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a m\u1ed9t v\u1eadt c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng b\u1eb1ng m trong m\u1ed9t h\u1ec7 quy chi\u1ebfu n\u00e0o \u0111\u00f3. K\u1ebft qu\u1ea3 nh\u1eadn \u0111\u01b0\u1ee3c ch\u1ec9 \u0111\u01a1n thu\u1ea7n l\u00e0 n\u1ebfu m\u1ed9t v\u1eadt c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng l\u00e0 m th\u00ec c\u00f3 th\u1ec3 h\u00e0m ch\u1ee9a m\u1ed9t n\u0103ng l\u01b0\u1ee3ng t\u1ed1i \u0111a b\u1eb1ng mc2 ch\u1ee9 ch\u1eb3ng c\u00f3 m\u1ed9t s\u1ef1 \u201cchuy\u1ec3n ho\u00e1\u201d n\u00e0o c\u1ea3. H\u01a1n n\u1eefa, kh\u1ed1i l\u01b0\u1ee3ng c\u0169ng kh\u00f4ng \u0111\u1ed3ng ngh\u0129a v\u1edbi v\u1eadt ch\u1ea5t m\u00e0 ch\u1ec9 l\u00e0 m\u1ed9t trong v\u00f4 v\u00e0n c\u00e1c t\u00ednh ch\u1ea5t kh\u00e1c nhau c\u1ee7a v\u1eadt ch\u1ea5t m\u00e0 th\u00f4i. \u0110\u1ea5y l\u00e0 ch\u01b0a n\u00f3i \u0111\u1ebfn ngh\u1ecbch l\u00fd \u201cc\u01b0\u1eddi ra n\u01b0\u1edbc m\u1eaft\u201d \u1edf Ph\u1ee5 l\u1ee5c 19 \u2013 c\u00f4ng th\u1ee9c E=mc2 ch\u01b0a h\u1ec1 \u0111\u01b0\u1ee3c ch\u1ee9ng minh. 27. B\u1eb1ng ch\u1ee9ng v\u1ec1 v\u1eadt ch\u1ea5t t\u1ed1i v\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u1ed1i* C\u00e1c s\u1ed1 li\u1ec7u \u0111o \u0111\u1ea1c thi\u00ean v\u0103n cho th\u1ea5y t\u1ed1c \u0111\u1ed9 quay c\u1ee7a c\u00e1c thi\u00ean h\u00e0 qu\u00e1 nhanh so v\u1edbi k\u1ebft qu\u1ea3 t\u00ednh to\u00e1n, \u0111\u1eb7c bi\u1ec7t l\u00e0 c\u00e0ng \u1edf xa t\u00e2m thi\u00ean h\u00e0 ch\u00eanh l\u1ec7ch t\u1ed1c \u0111\u1ed9 quay c\u00e0ng l\u1edbn. L\u00fd thuy\u1ebft hi\u1ec7n h\u00e0nh cho r\u1eb1ng \u0111\u00f3 ch\u00ednh l\u00e0 b\u1eb1ng ch\u1ee9ng thuy\u1ebft ph\u1ee5c v\u1ec1 c\u00e1i g\u1ecdi l\u00e0 \u201cv\u1eadt ch\u1ea5t t\u1ed1i\u201d v\u00e0 \u201cn\u0103ng l\u01b0\u1ee3ng t\u1ed1i\u201d tr\u00e0n ng\u1eadp kh\u1eafp V\u0169 tr\u1ee5, n\u00f3 ph\u1ea3i chi\u1ebfm t\u1edbi 95% t\u1ed5ng s\u1ed1 v\u1eadt ch\u1ea5t trong V\u0169 tr\u1ee5. Nh\u01b0ng v\u1eadt ch\u1ea5t t\u1ed1i v\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u1ed1i l\u00e0 c\u00e1i g\u00ec th\u1ebf m\u00e0 g\u00e2y n\u00ean hi\u1ec7u \u1ee9ng h\u1ea5p d\u1eabn l\u1edbn \u0111\u1ebfn v\u1eady trong khi b\u1ecf qua m\u1ecdi t\u01b0\u01a1ng t\u00e1c \u0111i\u1ec7n t\u1eeb bao g\u1ed3m c\u1ea3 quang h\u1ecdc? H\u01a1n th\u1ebf n\u1eefa, v\u00ec l\u00fd do g\u00ec m\u00e0 n\u00f3 l\u1ea1i ch\u1ec9 t\u1ed3n t\u1ea1i \u1edf kho\u1ea3ng c\u00e1ch r\u1ea5t xa ch\u00fang ta m\u00e0 ngay b\u00ean c\u1ea1nh, ta l\u1ea1i kh\u00f4ng h\u1ec1 th\u1ea5y b\u00f3ng d\u00e1ng khi m\u00e0 \u201cv\u1eadt ch\u1ea5t th\u1ea5y \u0111\u01b0\u1ee3c\u201d ch\u1ec9 l\u00e0 m\u1ed9t ph\u1ea7n r\u1ea5t nh\u1ecf b\u00e9 so v\u1edbi ch\u00fang?","PH\u1ee4 L\u1ee4C 305 Theo C\u0110M, \u0111\u00e2y ch\u1ec9 thu\u1ea7n t\u00fay l\u00e0 hi\u1ec7u \u1ee9ng quang h\u1ecdc. Nh\u1eefng g\u00ec k\u00ednh thi\u00ean v\u0103n ghi nh\u1eadn \u0111\u01b0\u1ee3c \u0111\u01a1n gi\u1ea3n ch\u1ec9 l\u00e0 kh\u00f4ng gian v\u1eadt l\u00fd trong khi kh\u00f4ng gian v\u1eadt ch\u1ea5t do t\u01b0\u01a1ng t\u00e1c h\u1ea5p d\u1eabn v\u1edbi v\u1eadn t\u1ed1c lan truy\u1ec1n h\u1eefu h\u1ea1n \u0111\u00e3 t\u1ea1o n\u00ean \u201c\u1ea3o \u1ea3nh\u201d v\u1ec1 hi\u1ec7n t\u01b0\u1ee3ng quay n\u00f3i tr\u00ean m\u00e0 kh\u00f4ng \u0111i k\u00e8m v\u1edbi b\u1ea5t c\u1ee9 l\u1ef1c t\u01b0\u01a1ng t\u00e1c ph\u1ee5 th\u00eam n\u00e0o \u1ee9ng v\u1edbi c\u00e1i g\u1ecdi l\u00e0 \u201cv\u1eadt ch\u1ea5t t\u1ed1i\u201d (xem m\u1ee5c 1.3.7). Hi\u1ec7u \u1ee9ng n\u00e0y c\u00e0ng l\u1edbn n\u1ebfu kho\u1ea3ng c\u00e1ch t\u1edbi c\u00e1c thi\u00ean h\u00e0 c\u0169ng nh\u01b0 k\u00edch th\u01b0\u1edbc c\u1ee7a ch\u00fang c\u00e0ng l\u1edbn, m\u00e0 \u0111i\u1ec1u n\u00e0y th\u00ec ho\u00e0n to\u00e0n ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c k\u1ebft qu\u1ea3 quan s\u00e1t. B\u00ean c\u1ea1nh \u0111\u00f3, n\u0103ng l\u01b0\u1ee3ng c\u1ee7a c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 l\u1ea1i c\u00f3 t\u00ednh \u0111\u1ebfn tr\u01b0\u1eddng l\u1ef1c th\u1ebf m\u00e0 ch\u00fang t\u1ed3n t\u1ea1i trong \u0111\u00f3 theo m\u1ee5c 2.2, v\u1ec1 th\u1ef1c ch\u1ea5t l\u1edbn g\u1ea5p 2 l\u1ea7n so v\u1edbi c\u00f4ng th\u1ee9c c\u1ee7a Einstein \u0111\u00e3 b\u00f9 \u0111\u1eafp th\u00eam t\u1edbi 100% n\u0103ng l\u01b0\u1ee3ng th\u1ea5y \u0111\u01b0\u1ee3c xung quanh ta r\u1ed3i. 28. M\u1ed9t l\u00fd thuy\u1ebft t\u1ed5ng qu\u00e1t nh\u01b0ng l\u1ea1i d\u1ef1a tr\u00ean ti\u00ean \u0111\u1ec1 mang t\u00ednh c\u1ee5c b\u1ed9. Thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i t\u1ed5ng qu\u00e1t c\u1ee7a Einstein \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng d\u1ef1a tr\u00ean 2 ti\u00ean \u0111\u1ec1 trong \u0111\u00f3 ti\u00ean \u0111\u1ec1 th\u1ee9 2 l\u00e0 nguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng m\u1ea1nh: \u201chi\u1ec7n t\u01b0\u1ee3ng qu\u00e1n t\u00ednh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi hi\u1ec7n t\u01b0\u1ee3ng h\u1ea5p d\u1eabn\\\". Nguy\u00ean l\u00fd n\u00e0y \u0111\u01b0\u1ee3c Einstein ph\u00e1t bi\u1ec3u d\u1ef1a v\u00e0o th\u00ed nghi\u1ec7m t\u01b0\u1edfng t\u01b0\u1ee3ng v\u1ec1 m\u1ed9t phi thuy\u1ec1n c\u00f4 l\u1eadp trong kh\u00f4ng gian, kh\u00f4ng c\u00f3 b\u1ea5t c\u1ee9 m\u1ed9t tr\u01b0\u1eddng h\u1ea5p d\u1eabn n\u00e0o (t\u1ea5t nhi\u00ean c\u0169ng kh\u00f4ng c\u00f3 b\u1ea5t c\u1ee9 m\u1ed9t ngo\u1ea1i l\u1ef1c n\u00e0o t\u00e1c \u0111\u1ed9ng l\u00ean n\u00f3); b\u00e2y gi\u1edd, b\u1eb1ng c\u00e1ch n\u00e0o \u0111\u00f3, cho phi thuy\u1ec1n chuy\u1ec3n \u0111\u1ed9ng v\u1edbi gia t\u1ed1c b\u1eb1ng g, phi h\u00e0nh gia, thay v\u00ec tr\u1ea1ng th\u00e1i kh\u00f4ng tr\u1ecdng l\u01b0\u1ee3ng, gi\u1edd \u0111\u00e2y c\u1ea3m nh\u1eadn th\u1ea5y nh\u01b0 \u0111ang \u0111\u1ee9ng \u1edf tr\u00ean Tr\u00e1i \u0111\u1ea5t v\u1eady. N\u00f3i c\u00e1ch kh\u00e1c, \u201cl\u1ef1c qu\u00e1n t\u00ednh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi l\u1ef1c h\u1ea5p d\u1eabn\u201d t\u00e1c \u0111\u1ed9ng l\u00ean phi h\u00e0nh gia. Nh\u01b0ng, nh\u01b0 ch\u00ednh Einstein c\u0169ng \u0111\u00e3 th\u1eeba nh\u1eadn, s\u1ef1 \u201ct\u01b0\u01a1ng \u0111\u01b0\u01a1ng\u201d n\u00e0y ch\u1ec9 mang t\u00ednh c\u1ee5c b\u1ed9. M\u00e0 kh\u00f4ng ph\u1ea3i ch\u1ec9 c\u00f3 th\u1ebf, th\u1eddi gian \u0111\u1ec3 duy tr\u00ec tr\u1ea1ng th\u00e1i \u201ct\u01b0\u01a1ng \u0111\u01b0\u01a1ng\u201d n\u00e0y l\u1ea1i c\u0169ng ch\u1ec9 c\u00f3 th\u1ec3 h\u1eefu h\u1ea1n, v\u00ec n\u0103ng l\u01b0\u1ee3ng cung c\u1ea5p cho phi thuy\u1ec1n \u0111\u1ec3 duy tr\u00ec gia t\u1ed1c c\u0169ng h\u1eefu h\u1ea1n. Tuy nhi\u00ean, t\u1eeb m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng (n\u1ebfu c\u00f3) c\u0169ng ch\u1ec9 mang t\u00ednh c\u1ee5c b\u1ed9 v\u1ec1 kh\u00f4ng gian, h\u1eefu h\u1ea1n v\u1ec1 th\u1eddi gian l\u1ea1i t\u1ed5ng qu\u00e1t h\u00f3a l\u00ean th\u00e0nh m\u1ed9t nguy\u00ean l\u00fd cho to\u00e0n v\u0169 tr\u1ee5 e","PH\u1ee4 L\u1ee4C 306 r\u1eb1ng kh\u00f4ng h\u1ee3p l\u00f4g\u00edc, v\u00ec th\u1ebf, vi\u1ec7c d\u1eabn \u0111\u1ebfn k\u1ebft lu\u1eadn \u201cV\u0169 tr\u1ee5 trong m\u1ed9t h\u1ea1t d\u1ebb\u201d thay v\u00ec v\u00f4 c\u00f9ng, v\u00f4 t\u1eadn kh\u00f4ng c\u00f3 g\u00ec l\u00e0 l\u1ea1. B\u00ean c\u1ea1nh \u0111\u00f3, ngay c\u1ea3 \u201cnguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng y\u1ebfu\u201d: \u201ckh\u1ed1i l\u01b0\u1ee3ng qu\u00e1n t\u00ednh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng h\u1ea5p d\u1eabn\u201d (mx = Mx ) c\u0169ng c\u00f3 nguy\u00ean nh\u00e2n tr\u1ef1c ti\u1ebfp t\u1eeb quan ni\u1ec7m v\u1ec1 HQC qu\u00e1n t\u00ednh \u2013 h\u1ec7 qu\u1ea3 c\u1ee7a s\u1ef1 t\u1ed3n t\u1ea1i t\u1ef1 th\u00e2n n\u00e0y. R\u00f5 r\u00e0ng theo \u0111\u1ecbnh lu\u1eadt r\u01a1i t\u1ef1 do c\u1ee7a Galileo, th\u00ec ax = g\u0111 v\u1edbi: g\u0111 =\u03b3 M\u0110 R2 l\u00e0 c\u01b0\u1eddng \u0111\u1ed9 tr\u01b0\u1eddng h\u1ea5p d\u1eabn theo \u0111\u1ecbnh lu\u1eadt v\u1ea1n v\u1eadt h\u1ea5p d\u1eabn c\u1ee7a Newton: P = Mxg\u0111; trong khi \u0111\u00f3 theo \u0111\u1ecbnh lu\u1eadt 2 Newton, ta l\u1ea1i c\u00f3: F = mxax; nh\u01b0ng v\u00ec P = F, n\u00ean c\u00f3 th\u1ec3 suy ra mx = Mx! Tuy nhi\u00ean, do \u0111\u1ecbnh lu\u1eadt 2 Newton ch\u1ec9 \u0111\u00fang trong HQC qu\u00e1n t\u00ednh n\u00ean \u0111\u01b0\u01a1ng nhi\u00ean nguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng y\u1ebfu n\u00e0y c\u0169ng kh\u00f4ng th\u1ec3 v\u01b0\u1ee3t ra \u0111\u01b0\u1ee3c ngo\u00e0i ph\u1ea1m vi \u0111\u00f3. Theo quan \u0111i\u1ec3m c\u1ee7a C\u0110M v\u1ec1 s\u1ef1 t\u1ed3n t\u1ea1i ph\u1ee5 thu\u1ed9c c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd th\u00ec th\u00ed nghi\u1ec7m t\u01b0\u1edfng t\u01b0\u1ee3ng c\u1ee7a Einstein tr\u00ean \u0111\u00e2y l\u1ea1i d\u1eabn \u0111\u1ebfn m\u1ed9t k\u1ebft lu\u1eadn ho\u00e0n to\u00e0n kh\u00e1c. Th\u1ee9 nh\u1ea5t, n\u1ebfu ch\u1ec9 c\u00f3 m\u1ed9t phi thuy\u1ec1n \u0111\u01a1n \u0111\u1ed9c trong c\u00e1i g\u1ecdi l\u00e0 \u201ckh\u00f4ng gian\u201d th\u00ec gia t\u1ed1c c\u1ee7a n\u00f3 l\u00e0 so v\u1edbi HQC n\u00e0o? Th\u1ee9 hai, v\u00ec qu\u00e1n t\u00ednh ch\u1ec9 l\u00e0 do t\u01b0\u01a1ng t\u00e1c c\u1ee7a th\u1ef1c th\u1ec3 v\u1eadt l\u00fd n\u00e0y trong tr\u01b0\u1eddng l\u1ef1c th\u1ebf v\u1edbi c\u00e1c th\u1ef1c th\u1ec3 v\u1eadt l\u00fd kh\u00e1c, n\u00ean khi ch\u1ec9 c\u00f2n l\u1ea1i m\u1ed9t m\u00ecnh n\u00f3, hi\u1ec7n t\u01b0\u1ee3ng qu\u00e1n t\u00ednh s\u1ebd bi\u1ebfn m\u1ea5t, v\u00e0 h\u01a1n th\u1ebf n\u1eefa, ch\u00ednh c\u00e1i g\u1ecdi l\u00e0 s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a n\u00f3 c\u0169ng \u0111\u00e3 l\u00e0 v\u00f4 ngh\u0129a r\u1ed3i. R\u00f5 r\u00e0ng trong th\u00ed nghi\u1ec7m t\u01b0\u1edfng t\u01b0\u1ee3ng n\u00e0y, Einstein v\u1eabn t\u01b0 duy theo quan ni\u1ec7m sai l\u1ea7m v\u1ec1 s\u1ef1 t\u1ed3n t\u1ea1i t\u1ef1 th\u00e2n v\u00e0 h\u1ec7 qu\u1ea3 c\u1ee7a n\u00f3 l\u00e0 qu\u00e1n t\u00ednh t\u1ef1 th\u00e2n. C\u00f2n \u201cnguy\u00ean l\u00fd t\u01b0\u01a1ng \u0111\u01b0\u01a1ng y\u1ebfu\u201d v\u1ec1 th\u1ef1c ch\u1ea5t ch\u1ec9 l\u00e0 \u201c\u1ea3o t\u01b0\u1edfng\u201d v\u00ec \u201c\u0111\u1ecbnh lu\u1eadt r\u01a1i t\u1ef1 do\u201d c\u1ee7a Galileo kh\u00f4ng \u0111\u00fang, cho d\u00f9 \u0111\u1ec3 ph\u1ea3n b\u00e1c th\u00ed nghi\u1ec7m tr\u00ean th\u00e1p Pisa ph\u1ea3i c\u1ea7n t\u1edbi thi\u1ebft b\u1ecb \u0111o c\u00f3 sai s\u1ed1 kh\u00f4ng l\u1edbn h\u01a1n 10-24 \u2013 m\u1ed9t \u0111i\u1ec1u kh\u00f4ng t\u01b0\u1edfng! M\u1eb7c d\u00f9 v\u1eady, s\u1ef1 r\u01a1i c\u1ee7a m\u1ecdi v\u1eadt l\u1ea1i v\u1eabn ho\u00e0n to\u00e0n","PH\u1ee4 L\u1ee4C 307 ph\u00f9 h\u1ee3p v\u1edbi quan ni\u1ec7m c\u1ee7a Aristotle: \u201cc\u00e1c v\u1eadt th\u1ec3 kh\u00e1c nhau s\u1ebd r\u01a1i kh\u00e1c nhau\u201d, c\u1ee5 th\u1ec3 \u0111\u1ecbnh l\u01b0\u1ee3ng theo C\u0110M l\u00e0: ax =\u03b3 Mx +M\u0110 = gx + g\u0111 . R2 Hay n\u00f3i c\u00e1ch kh\u00e1c, quan ni\u1ec7m c\u1ee7a Aristotle l\u00e0 \u0111\u00fang, c\u00f2n quan ni\u1ec7m c\u1ee7a Galileo ch\u1ec9 l\u00e0 g\u1ea7n \u0111\u00fang trong ph\u1ea1m vi sai s\u1ed1 cho ph\u00e9p \u03b4cp: Mx \u2264 \u03b4 cp M\u0110. 1 \u2212 \u03b4 cp 29. Ngh\u1ecbch l\u00fd h\u1ea5p d\u1eabn theo l\u00fd thuy\u1ebft h\u1ea5p d\u1eabn Newton** Theo \u0111\u1ecbnh lu\u1eadt v\u1ea1n v\u1eadt h\u1ea5p d\u1eabn c\u1ee7a Newton, c\u00f3 th\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c gi\u00e1 tr\u1ecb l\u1ef1c h\u1ea5p d\u1eabn t\u1ea1i m\u1ed9t \u0111i\u1ec3m n\u00e0o \u0111\u00f3 trong V\u0169 tr\u1ee5 v\u00f4 c\u00f9ng, v\u00f4 t\u1eadn kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o ph\u1ea7n v\u1eadt ch\u1ea5t b\u00ean ngo\u00e0i m\u1eb7t c\u1ea7u b\u00e1n k\u00ednh R ti\u1ebfp x\u00fac v\u1edbi \u0111i\u1ec3m \u0111\u00f3, v\u00e0 v\u00ec v\u1eady, l\u1ef1c h\u1ea5p d\u1eabn t\u1ea1i \u0111i\u1ec3m \u0111\u00f3 kh\u00f4ng \u0111\u01a1n tr\u1ecb m\u00e0 c\u00f3 th\u1ec3 nh\u1eadn b\u1ea5t c\u1ee9 m\u1ed9t gi\u00e1 tr\u1ecb n\u00e0o ph\u1ee5 thu\u1ed9c v\u00e0o \u201cgi\u1ea3 thi\u1ebft ban \u0111\u1ea7u\u201d v\u1ec1 vi\u1ec7c cho tr\u01b0\u1edbc b\u00e1n k\u00ednh R c\u1ee7a ph\u1ea7n kh\u00f4ng gian c\u00f3 ch\u1ee9a v\u1eadt ch\u1ea5t h\u00ecnh c\u1ea7u \u0111\u00f3 trong kh\u00f4ng gian c\u00f2n l\u1ea1i tr\u1ed1ng r\u1ed7ng c\u1ee7a V\u0169 tr\u1ee5 r\u1ed3i sau \u0111\u00f3 m\u1edbi l\u1ea5p \u0111\u1ea7y v\u1eadt ch\u1ea5t. Theo C\u0110M, \u1edf \u0111\u00e2y c\u00f3 hai \u0111i\u1ec1u ph\u1ee7 nh\u1eadn t\u00ednh \u201cngh\u1ecbch l\u00fd\u201d: th\u1ee9 nh\u1ea5t, V\u0169 tr\u1ee5 v\u1ed1n d\u0129 kh\u00f4ng bao gi\u1edd tr\u1ed1ng r\u1ed7ng \u0111\u1ec3 r\u1ed3i ph\u1ee5 thu\u1ed9c v\u00e0o vi\u1ec7c \u201cai \u0111\u00f3\u201d l\u1ef1a ch\u1ecdn kh\u1ed1i v\u1eadt ch\u1ea5t h\u00ecnh c\u1ea7u ban \u0111\u1ea7u c\u00f3 b\u00e1n k\u00ednh R \u0111\u1ec3 \u201ct\u00ednh to\u00e1n\u201d l\u1ef1c h\u1ea5p d\u1eabn, m\u00e0 tr\u00e1i l\u1ea1i, V\u0169 tr\u1ee5 \u201ckh\u00f4ng sinh ra, c\u0169ng kh\u00f4ng m\u1ea5t \u0111i\u201d \u2013 m\u1ed9t \u201cgi\u1ea3 thi\u1ebft ban \u0111\u1ea7u\u201d nh\u01b0 v\u1eady kh\u00f4ng kh\u1ea3 thi; th\u1ee9 hai l\u00e0 n\u1ebfu qu\u1ea3 th\u1eadt c\u00f3 \u0111i\u1ec1u \u0111\u00f3 x\u1ea9y ra th\u00ec c\u00f3 g\u00ec l\u00e0 l\u1ea1 \u0111\u00e2u? Trong th\u1ef1c t\u1ebf, thi\u1ebfu g\u00ec nh\u1eefng hi\u1ec7n t\u01b0\u1ee3ng x\u1ea9y ra b\u1ecb ph\u1ee5 thu\u1ed9c v\u00e0o \u0111i\u1ec1u ki\u1ec7n ban \u0111\u1ea7u khi m\u00e0 qu\u1ea3 th\u1eadt c\u00f3 nh\u1eefng \u0111i\u1ec1u ki\u1ec7n ban \u0111\u1ea7u \u1ea3nh h\u01b0\u1edfng t\u1edbi qu\u00e1 tr\u00ecnh \u0111\u00f3, v\u00ed d\u1ee5 m\u1ed9t vi\u00ean \u0111\u1ea1n b\u1ecb b\u1eafn \u0111i v\u1edbi v\u1eadn t\u1ed1c ban \u0111\u1ea7u kh\u00e1c nhau s\u1ebd r\u01a1i kh\u00e1c nhau cho d\u00f9 c\u00f9ng m\u1ed9t g\u00f3c b\u1eafn. Gi\u00e1 nh\u01b0 V\u0169 tr\u1ee5 c\u0169ng c\u00f3 \u0111i\u1ec3m ban \u0111\u1ea7u \u0111\u00f3, v\u00e0 gi\u00e1 nh\u01b0 c\u0169ng c\u00f3 th\u1ec3 l\u1eb7p l\u1ea1i th\u1eddi \u0111i\u1ec3m","PH\u1ee4 L\u1ee4C 308 ban \u0111\u1ea7u \u0111\u00f3 v\u1edbi b\u00e1n k\u00ednh R ban \u0111\u1ea7u n\u00e0o \u0111\u00f3 kh\u00e1c \u0111i th\u00ec vi\u1ec7c l\u1ef1c h\u1ea5p d\u1eabn c\u00f3 g\u00eda tr\u1ecb kh\u00e1c v\u1edbi hi\u1ec7n nay, kh\u00e1c v\u1edbi k\u1ebft qu\u1ea3 \u201cquan s\u00e1t\u201d hi\u1ec7n nay th\u00ec c\u00f3 g\u00ec l\u00e0 ngh\u1ecbch l\u00fd \u0111\u00e2u? \u0110\u01a1n gi\u1ea3n l\u00e0 ch\u00fang ta s\u1ebd s\u1ed1ng trong m\u1ed9t V\u0169 tr\u1ee5 kh\u00e1c v\u1edbi hi\u1ec7n nay \u2013 th\u1ebf th\u00f4i! \u2013 Big Bang l\u00e0 m\u1ed9t v\u00ed d\u1ee5: ch\u1ec9 c\u1ea7n thay \u0111\u1ed5i m\u1ed9t \u201cch\u00fat x\u00edu\u201d l\u1ef1c t\u01b0\u01a1ng t\u00e1c ban \u0111\u1ea7u th\u00ec c\u00e1c ng\u00f4i sao \u0111\u00e3 kh\u00f4ng th\u1ec3 \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh v\u00e0 k\u1ec3 c\u1ea3 con ng\u01b0\u1eddi c\u0169ng v\u1eady! 30. Ngh\u1ecbch l\u00fd Olbers (1823) \u2013 b\u1ea7u tr\u1eddi s\u00e1ng v\u1ec1 \u0111\u00eam** Olbers cho r\u1eb1ng n\u1ebfu kh\u00f4ng gian v\u0169 tr\u1ee5 l\u00e0 v\u00f4 t\u1eadn th\u00ec n\u00f3 ph\u1ea3i c\u00f3 nhi\u1ec1u sao \u0111\u1ebfn m\u1ee9c khi nh\u00ecn l\u00ean b\u1ea7u tr\u1eddi, \u00e1nh m\u1eaft ta bao gi\u1edd c\u0169ng g\u1eb7p m\u1ed9t ng\u00f4i sao. V\u00e0 ta s\u1ebd th\u1ea5y b\u1ea7u tr\u1eddi lu\u00f4n s\u00e1ng r\u1ef1c nh\u01b0 ban ng\u00e0y ngay c\u1ea3 v\u00e0o ... ban \u0111\u00eam. Nh\u01b0ng th\u1ef1c t\u1ebf, b\u1ea7u tr\u1eddi ban \u0111\u00eam l\u1ea1i t\u1ed1i \u0111en, v\u00e0 b\u1ea7u tr\u1eddi \u0111\u00eam t\u1ed1i \u0111en ch\u1ee9ng t\u1ecf v\u0169 tr\u1ee5 kh\u00f4ng th\u1ec3 l\u00e0 v\u00f4 c\u00f9ng, v\u00f4 t\u1eadn. Gi\u1ea3 thuy\u1ebft n\u00e0y \u0111\u00f3ng vai tr\u00f2 quy\u1ebft \u0111\u1ecbnh trong vi\u1ec7c h\u00ecnh th\u00e0nh l\u00fd thuy\u1ebft Big Bang. Tuy nhi\u00ean, v\u1ea5n \u0111\u1ec1 kh\u00f4ng ph\u1ea3i ch\u1ec9 l\u00e0 s\u1ef1 c\u00f3 m\u1eb7t c\u1ee7a m\u1ed9t ng\u00f4i sao n\u00e0o \u0111\u00f3 theo h\u01b0\u1edbng nh\u00ecn c\u1ee7a ta m\u00e0 \u0111i\u1ec1u c\u01a1 b\u1ea3n c\u00f2n ph\u1ea3i l\u00e0 \u0111\u1ed9 s\u00e1ng c\u1ee7a ng\u00f4i sao \u0111\u00f3 n\u1eefa ch\u1ee9? Ng\u00f4i sao c\u00e0ng \u1edf xa, \u0111\u1ed9 s\u00e1ng c\u1ee7a n\u00f3 c\u00e0ng nh\u1ecf theo t\u1ef7 l\u1ec7 ngh\u1ecbch v\u1edbi b\u00ecnh ph\u01b0\u01a1ng kho\u1ea3ng c\u00e1ch, do \u0111\u00f3, nh\u1eefng ng\u00f4i sao \u1edf qu\u00e1 xa Tr\u00e1i \u0111\u1ea5t s\u1ebd c\u00f3 \u0111\u1ed9 s\u00e1ng nh\u1ecf d\u01b0\u1edbi ng\u01b0\u1ee1ng \u0111\u1ed9 nh\u1eady c\u1ee7a m\u1eaft ng\u01b0\u1eddi th\u00ec l\u00e0m sao c\u00f3 th\u1ec3 n\u00f3i t\u1edbi s\u1ef1 chi\u1ebfu s\u00e1ng nh\u01b0 ban ng\u00e0y \u0111\u01b0\u1ee3c? Ngo\u00e0i ra, ngh\u1ecbch l\u00fd n\u00e0y c\u00f2n \u0111\u01b0\u1ee3c g\u1ee1 b\u1ecf do t\u00ednh ch\u1ea5t gi\u00e0 h\u00f3a c\u1ee7a photon theo kho\u1ea3ng c\u00e1ch nh\u01b0 \u0111\u01b0\u1ee3c x\u00e9t \u0111\u1ebfn \u1edf m\u1ee5c 1.3.3 n\u1eefa, cho d\u00f9 V\u0169 tr\u1ee5 v\u1eabn v\u00f4 c\u00f9ng, v\u00f4 t\u1eadn. 31. Con l\u1eafc Foucault ** Ng\u01b0\u1eddi ta cho r\u1eb1ng m\u1eb7t ph\u1eb3ng dao \u0111\u1ed9ng c\u1ee7a con l\u1eafc Foucault l\u00e0 do nh\u1eefng thi\u00ean th\u1ec3 \u1edf xa x\u0103m trong V\u0169 tr\u1ee5 kh\u1ed1ng ch\u1ebf (nguy\u00ean l\u00fd Mach). B\u1eb1ng ch\u1ee9ng l\u00e0 khi h\u01b0\u1edbng m\u1eb7t ph\u1eb3ng \u0111\u00f3 t\u1edbi c\u00e1c ng\u00f4i sao c\u00e0ng xa th\u00ec s\u1ef1 sai l\u1ec7ch theo th\u1eddi gian gi\u1eefa","PH\u1ee4 L\u1ee4C 309 ch\u00fang ng\u00e0y c\u00e0ng nh\u1ecf. V\u00e0 h\u01a1n th\u1ebf n\u1eefa, s\u1ef1 kh\u1ed1ng ch\u1ebf \u0111\u00f3 x\u1ea9y ra g\u1ea7n nh\u01b0 t\u1ee9c th\u1eddi, b\u1ea5t ch\u1ea5p thuy\u1ebft t\u01b0\u01a1ng \u0111\u1ed1i! Theo C\u0110M, m\u1eb7t ph\u1eb3ng dao \u0111\u1ed9ng c\u1ee7a con l\u1eafc Foucault th\u1eadt ra do tr\u01b0\u1eddng h\u1ea5p d\u1eabn c\u1ee7a Tr\u00e1i \u0111\u1ea5t l\u00e0 ch\u1ee7 y\u1ebfu, c\u00f3 s\u1ef1 nhi\u1ec5u lo\u1ea1n kh\u00f4ng \u0111\u00e1ng k\u1ec3 c\u1ee7a M\u1eb7t tr\u0103ng v\u00e0 M\u1eb7t tr\u1eddi. Tr\u00e1i \u0111\u1ea5t tuy t\u1ef1 quay quanh m\u00ecnh n\u00f3 nh\u01b0ng tr\u01b0\u1eddng l\u1ef1c th\u1ebf - kh\u00f4ng gian v\u1eadt ch\u1ea5t d\u1ea1ng c\u1ea7u c\u1ee7a n\u00f3 l\u1ea1i g\u1ea7n nh\u01b0 kh\u00f4ng quay, m\u00e0 m\u1eb7t ph\u1eb3ng dao \u0111\u1ed9ng c\u1ee7a con l\u1eafc l\u1ea1i lu\u00f4n \u0111\u1ecbnh h\u01b0\u1edbng theo tr\u01b0\u1eddng l\u1ef1c th\u1ebf n\u00e0y, chia tr\u01b0\u1eddng l\u1ef1c th\u1ebf l\u00e0m 2 ph\u1ea7n \u0111\u1ed1i x\u1ee9ng nhau. Khi \u0111\u00f3, kh\u00f4ng kh\u00f3 kh\u0103n g\u00ec \u0111\u1ec3 c\u00f3 th\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c ngay r\u1eb1ng n\u1ebfu m\u1eb7t ph\u1eb3ng con l\u1eafc h\u01b0\u1edbng v\u1ec1 ph\u00eda M\u1eb7t tr\u1eddi th\u00ec sau 1 th\u00e1ng, M\u1eb7t tr\u1eddi s\u1ebd di chuy\u1ec3n l\u1ec7ch so v\u1edbi m\u1eb7t ph\u1eb3ng \u0111\u00f3 m\u1ed9t g\u00f3c 30\u00b0 \u0111\u00fang nh\u01b0 k\u1ebft qu\u1ea3 quan s\u00e1t thi\u00ean v\u0103n. Tr\u00ean th\u1ef1c t\u1ebf, do c\u1ea5u t\u1ea1o c\u1ee7a Tr\u00e1i kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t, th\u1eadm ch\u00ed c\u0169ng kh\u00f4ng ho\u00e0n to\u00e0n h\u00ecnh c\u1ea7u, n\u00ean s\u1ebd ph\u00e1t sinh chuy\u1ec3n \u0111\u1ed9ng quay c\u1ee7a tr\u01b0\u1eddng h\u1ea5p d\u1eabn c\u1ee7a n\u00f3, khi\u1ebfn m\u1eb7t ph\u1eb3ng dao \u0111\u1ed9ng c\u1ee7a con l\u1eafc c\u0169ng quay theo nh\u01b0 nh\u1eefng th\u00ed nghi\u1ec7m ch\u00ednh x\u00e1c nh\u1ea5t, m\u1edbi \u0111\u00e2y, \u0111\u01b0\u1ee3c NASA th\u1ef1c hi\u1ec7n."]
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