{"id":17024,"date":"2021-12-07T16:02:38","date_gmt":"2021-12-07T09:02:38","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=17024"},"modified":"2021-12-07T16:02:39","modified_gmt":"2021-12-07T09:02:39","slug":"bi-an-cua-set-hon","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/bi-an-cua-set-hon\/","title":{"rendered":"B\u00cd \u1ea8N C\u1ee6A S\u00c9T H\u00d2N"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">T\u1eeb kh\u00f3a t\u00ecm ki\u1ebfm: Nh\u1eefng b\u00ed \u1ea9n c\u1ee7a nh\u00e2n lo\u1ea1i &#8211; Minh Anh<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong \u0111\u00eam m\u01b0a s\u1ea5m s\u00e9t, m\u1ed9t v\u1eadt s\u00e1ng l\u00f3a h\u00ecnh c\u1ea7u k\u00edch th\u01b0\u1edbc b\u1eb1ng qu\u1ea3 cam hay qu\u1ea3 nho bay v\u1ee5t qua c\u1eeda s\u1ed5 v\u00e0o nh\u00e0 v\u00e0 l\u01b0\u1edbt qua s\u00e2n, ch\u1edbp nho\u00e1ng trong v\u00e0i gi\u00e2y, ph\u00e1 h\u1ee7y \u0111\u1ed3 \u0111\u1ea1c r\u1ed3i bi\u1ebfn m\u1ea5t, \u0111\u1ec3 l\u1ea1i \u0111\u1eb1ng sau \u00e2m thanh v\u00e0 m\u1ed9t th\u1ee9 m\u00f9i k\u1ef3 l\u1ea1. \u0110\u00f3 l\u00e0 \u201cnh\u1eadn d\u1ea1ng\u201d s\u01a1 b\u1ed9 c\u1ee7a s\u00e9t h\u00f2n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n l\u00e0 m\u1ed9t trong nh\u1eefng hi\u1ec7n t\u01b0\u1ee3ng v\u1eadt l\u00fd ch\u01b0a c\u00f3 l\u1eddi gi\u1ea3i th\u00edch th\u1ecfa \u0111\u00e1ng. Nhi\u1ec1u ng\u01b0\u1eddi g\u1eafn ch\u00fang v\u1edbi ma qu\u1ef7 hay v\u1eadt th\u1ec3 bay kh\u00f4ng x\u00e1c \u0111\u1ecbnh (UFO). M\u1ed9t s\u1ed1 nh\u00e0 khoa h\u1ecdc kh\u00f3 t\u00ednh xem ch\u00fang l\u00e0 k\u1ebft qu\u1ea3 c\u1ee7a \u1ea3o gi\u00e1c hay nh\u1eefng sai l\u1ec7ch trong ho\u1ea1t \u0111\u1ed9ng c\u1ee7a c\u00e1c gi\u00e1c quan trong c\u01a1 th\u1ec3 con ng\u01b0\u1eddi. Tr\u00ean th\u1ef1c t\u1ebf, s\u00e9t h\u00f2n l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng t\u1ef1 nhi\u00ean \u0111\u00e3 \u0111\u01b0\u1ee3c quan s\u00e1t v\u00e0 mi\u00eau t\u1ea3 t\u1ec9 m\u1ec9 t\u1eeb th\u1eddi Hy L\u1ea1p c\u1ed5.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Theo \u00fd ki\u1ebfn c\u1ee7a McNally (\u0111\u01b0a ra v\u00e0o th\u1eadp ni\u00ean 1960) kho\u1ea3ng 5% d\u00e2n s\u1ed1 tr\u00ean tr\u00e1i \u0111\u1ea5t \u0111\u00e3 t\u1eadn nh\u00ecn th\u1ea5y s\u00e9t h\u00f2n. Trong m\u1ed9t l\u00e1 th\u01b0 g\u1eedi Nh\u1eadt b\u00e1o B\u01b0u \u0111i\u1ec7n London, Moris (1936) \u0111\u00e3 m\u00f4 t\u1ea3 tr\u01b0\u1eddng h\u1ee3p s\u00e9t h\u00f2n l\u00e0m s\u00f4i c\u1ea3 m\u1ed9t k\u00e9t n\u01b0\u1edbc.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u201cB\u1ea1n \u0111\u1ed3ng h\u00e0nh\u201d c\u1ee7a s\u00e9t<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Ph\u1ea7n l\u1edbn c\u00e1c quan s\u00e1t \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n khi c\u00f3 s\u1ea5m s\u00e9t. \u0110a ph\u1ea7n nh\u1eefng s\u00e9t h\u00f2n \u0111\u00f3 xu\u1ea5t hi\u1ec7n h\u1ea7u nh\u01b0 \u0111\u1ed3ng th\u1eddi v\u1edbi m\u1ed9t tia s\u00e9t \u0111\u00e1nh t\u1eeb m\u00e2y xu\u1ed1ng \u0111\u1ea5t. Ch\u00fang xu\u1ea5t hi\u1ec7n c\u00e1ch m\u1eb7t \u0111\u1ea5t v\u00e0i m\u00e9t. C\u00f2n khi xu\u1ea5t hi\u1ec7n l\u00fac kh\u00f4ng c\u00f3 s\u00e9t \u0111\u00e1nh, ch\u00fang bay th\u1ea5p h\u01a1n n\u1eefa. Ng\u01b0\u1eddi ta c\u0169ng quan s\u00e1t \u0111\u01b0\u1ee3c nh\u1eefng s\u00e9t h\u00f2n bay cao tr\u00ean kh\u00f4ng v\u00e0 nh\u1eefng s\u00e9t h\u00f2n t\u1eeb m\u1ed9t \u0111\u00e1m m\u00e2y \u0111\u00e1nh nhanh xu\u1ed1ng m\u1eb7t \u0111\u1ea5t.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Kh\u00f4ng c\u1ee9 ph\u1ea3i tr\u00f2n<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Ch\u00fang th\u01b0\u1eddng c\u00f3 d\u1ea1ng h\u00ecnh c\u1ea7u nh\u01b0ng c\u0169ng c\u00f3 h\u00ecnh d\u1ea1ng kh\u00e1c. \u0110\u01b0\u1eddng k\u00ednh qu\u1ea3 c\u1ea7u thay \u0111\u1ed5i t\u1eeb 0,01-1 m, trong \u0111\u00f3 th\u01b0\u1eddng g\u1eb7p l\u00e0 \u0111\u01b0\u1eddng k\u00ednh 0,1 \u2013 0,2 m. S\u00e9t h\u00f2n c\u00f3 nhi\u1ec1u m\u00e0u kh\u00e1c nhau, th\u00f4ng th\u01b0\u1eddng l\u00e0 m\u00e0u \u0111\u1ecf, da cam v\u00e0 m\u00e0u v\u00e0ng. Ch\u00fang kh\u00f4ng nh\u1ea5t thi\u1ebft ph\u1ea3i t\u1ecfa s\u00e1ng r\u1ef1c r\u1ee1 nh\u01b0ng c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y r\u1ea5t r\u00f5 d\u01b0\u1edbi \u00e1nh s\u00e1ng ban ng\u00e0y. Ch\u00fang th\u01b0\u1eddng gi\u1eef nguy\u00ean \u0111\u1ed9 s\u00e1ng v\u00e0 k\u00edch th\u01b0\u1edbc trong su\u1ed1t th\u1eddi gian xu\u1ea5t hi\u1ec7n, tuy kh\u00f4ng hi\u1ebfm tr\u01b0\u1eddng h\u1ee3p c\u00f3 s\u1ef1 thay \u0111\u1ed5i.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u201cH\u00e0nh vi\u201d k\u1ef3 qu\u1eb7c<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n th\u01b0\u1eddng chuy\u1ec3n \u0111\u1ed9ng theo ph\u01b0\u01a1ng n\u1eb1m ngang v\u1edbi v\u1eadn t\u1ed1c v\u00e0i m\u00e9t m\u1ed9t gi\u00e2y. Ch\u00fang c\u00f3 th\u1ec3 \u0111\u1ee9ng y\u00ean tr\u00ean kh\u00f4ng trung ho\u1eb7c t\u1eeb tr\u00ean m\u00e2y bay xu\u1ed1ng m\u1eb7t \u0111\u1ea5t. Ch\u00fang \u00edt khi bay l\u00ean nh\u01b0 tr\u01b0\u1eddng h\u1ee3p c\u00e1c qu\u1ea3 kh\u00ed c\u1ea7u n\u00f3ng chuy\u1ec3n \u0111\u1ed9ng trong kh\u00f4ng kh\u00ed. Nhi\u1ec1u b\u00e1o c\u00e1o m\u00f4 t\u1ea3 ch\u00fang t\u1ef1 xoay khi \u0111ang chuy\u1ec3n \u0111\u1ed9ng. Th\u1ec9nh tho\u1ea3ng ch\u00fang bay l\u00ean tr\u00ean c\u00e1c \u0111\u1ed3 v\u1eadt c\u1ee9ng hay tr\u00ean m\u1eb7t \u0111\u1ea5t. \u201cH\u00e0nh vi\u201d c\u1ee7a s\u00e9t h\u00f2n l\u00e0 \u0111i\u1ec1u g\u00e2y ch\u00fa \u00fd nh\u1ea5t \u0111\u1ed1i v\u1edbi c\u00e1c nh\u00e0 khoa h\u1ecdc. Kh\u00f4ng gi\u1ed1ng c\u00e1c lo\u1ea1i s\u00e9t th\u00f4ng th\u01b0\u1eddng v\u00e0 hi\u1ec7n t\u01b0\u1ee3ng \u0111i\u1ec7n kh\u00e1c, n\u00f3 kh\u00f4ng \u201cch\u00fa \u00fd\u201d t\u1edbi d\u00e2y d\u1eabn, v\u1eadt kim lo\u1ea1i v\u00e0 n\u01b0\u1edbc h\u01a1n c\u00e1c v\u1eadt d\u1ee5ng k\u00e9m hay kh\u00f4ng d\u1eabn \u0111i\u1ec7n. Thay v\u00e0o \u0111\u00f3 l\u00e0 m\u1ed9t h\u00e0nh vi gi\u1ed1ng nh\u01b0 \u0111\u01b0\u1ee3c \u0111i\u1ec1u khi\u1ec3n b\u1edfi s\u1ef1 t\u00f2 m\u00f2 v\u00e0 tr\u00ed th\u00f4ng minh c\u1ee1 lo\u00e0i v\u1eadt: Bay v\u00f2ng quanh v\u00e0 bay theo ng\u01b0\u1eddi, \u201ckh\u00e1m ph\u00e1\u201d c\u00e1c c\u0103n ph\u00f2ng v\u00e0 treo gi\u1eefa kho\u1ea3ng kh\u00f4ng g\u1ea7n c\u00e1c \u0111\u1ed3 v\u1eadt nh\u01b0 \u0111\u1ec3 \u201cnh\u00ecn\u201d cho r\u00f5 h\u01a1n. S\u00e9t h\u00f2n th\u01b0\u1eddng b\u00e1m v\u00e0o c\u00e1c \u0111\u1ed3 v\u1eadt kim lo\u1ea1i nh\u01b0 h\u00e0ng r\u00e0o d\u00e2y th\u00e9p gai hay \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i. Sau khi b\u00e1m, ch\u00fang th\u01b0\u1eddng chuy\u1ec3n \u0111\u1ed9ng d\u1ecdc theo nh\u1eefng \u0111\u1ed3 v\u1eadt n\u00e0y.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>T\u1ed3n t\u1ea1i ng\u1eafn ng\u1ee7i<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n th\u01b0\u1eddng c\u00f3 th\u1eddi gian t\u1ed3n t\u1ea1i kh\u00f4ng qu\u00e1 5 gi\u00e2y. M\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p t\u1ed3n t\u1ea1i h\u01a1n m\u1ed9t ph\u00fat.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u00cdt ng\u01b0\u1eddi khi quan s\u00e1t c\u1ea3m th\u1ea5y s\u1ee9c n\u00f3ng c\u1ee7a nhi\u1ec7t. Tuy nhi\u00ean, nhi\u1ec1u s\u00e9t h\u00f2n l\u00e0m ch\u00e1y \u0111\u1ed3 v\u1eadt hay l\u00e0m n\u00f3ng ch\u1ea3y kim lo\u1ea1i. B\u00e1o c\u00e1o c\u1ee7a McNally n\u0103m 1996 m\u00f4 t\u1ea3 m\u1ed9t s\u00e9t h\u00f2n ch\u1ea1m v\u00e0o b\u00ecnh n\u01b0\u1edbc c\u00f9ng v\u1edbi \u0111\u00f3 l\u00e0 ti\u1ebfng x\u00e8o x\u00e8o ph\u00e1t ra nh\u01b0 khi nh\u00fang m\u1ed9t mi\u1ebfng kim lo\u1ea1i nung \u0111\u1ecf v\u00e0o n\u01b0\u1edbc. \u0110\u00f4i khi, ch\u00fang ph\u00e1t ra \u00e2m thanh nh\u01b0 ti\u1ebfng hu\u00fdt c\u00f2i. Nhi\u1ec1u ng\u01b0\u1eddi ng\u1eedi th\u1ea5y m\u00f9i kh\u00e1c l\u1ea1, r\u1ea5t kh\u00f3 ch\u1ecbu, gi\u1ed1ng nh\u01b0 m\u00f9i ozone, sulphur ch\u00e1y hay oxit nitric.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u0110\u1ed9t nh\u1eadp nh\u01b0 \u201cth\u1ea7n\u201d<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n th\u01b0\u1eddng v\u00e0o nh\u00e0 qua m\u00e0n che hay \u1ed1ng kh\u00f3i. \u0110\u00f4i khi, ch\u00fang \u0111\u1ed9t nh\u1eadp qua c\u1eeda k\u00ednh m\u00e0 kh\u00f4ng l\u00e0m v\u1ee1 k\u00ednh. C\u0169ng \u0111\u00e3 th\u1ea5y tr\u01b0\u1eddng h\u1ee3p s\u00e9t h\u00f2n xu\u1ea5t hi\u1ec7n ch\u00ednh trong c\u00e1c t\u00f2a nh\u00e0, c\u00f3 tr\u01b0\u1eddng h\u1ee3p t\u1eeb m\u00e1y \u0111i\u1ec7n tho\u1ea1i. S\u00e9t h\u00f2n c\u0169ng c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n v\u00e0 t\u1ed3n t\u1ea1i trong m\u1ed9t c\u1ea5u tr\u00fac to\u00e0n kim lo\u1ea1i, v\u00ed d\u1ee5 trong khoang m\u00e1y bay, nh\u01b0 m\u1ed9t b\u00e1o c\u00e1o c\u1ee7a Uman n\u0103m 1968.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Ho\u00e0n t\u1ea5t \u201cchuy\u1ebfn du ngo\u1ea1n\u201d<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n ph\u00e2n r\u00e3 theo m\u1ed9t hai c\u00e1ch: Im l\u1eb7ng hay k\u00e8m theo m\u1ed9t ti\u1ebfng n\u1ed5. Ph\u00e2n r\u00e3 im l\u1eb7ng c\u00f3 th\u1ec3 x\u1ea3y ra nhanh hay ch\u1eadm. Sau khi ph\u00e2n r\u00e3, th\u1ec9nh tho\u1ea3ng s\u00e9t h\u00f2n \u0111\u1ec3 l\u1ea1i m\u1ed9t ch\u00fat s\u01b0\u01a1ng m\u00f9 hay ch\u1ea5t b\u00e3. Hi\u1ebfm khi quan s\u00e1t th\u1ea5y m\u1ed9t s\u00e9t h\u00f2n ph\u00e2n r\u00e3 th\u00e0nh hai hay nhi\u1ec1u s\u00e9t h\u00f2n nh\u1ecf h\u01a1n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L\u1eeda St. Elmo tr\u00ean c\u1ed9t bu\u1ed3m, th\u01b0\u1eddng b\u1ecb \u0111\u00e1nh \u0111\u1ed3ng l\u00e0 s\u00e9t h\u00f2n<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">N\u0103m 1928, Reverend John Henry Lehn \u0111ang \u1edf ph\u00f2ng t\u1eafm t\u1ea1i c\u0103n nh\u00e0 \u1edf Jim Thorpe, Pennsylvania (M\u1ef9) th\u00ec nh\u00ecn th\u1ea5y gi\u1eefa m\u1ed9t c\u01a1n gi\u00f4ng c\u00f3 s\u00e9t th\u00ec xu\u1ea5t hi\u1ec7n m\u1ed9t qu\u1ea3 c\u1ea7u l\u1eeda m\u00e0u v\u00e0ng c\u1ee1 b\u1eb1ng qu\u1ea3 nho ngay b\u00ean ngo\u00e0i r\u00e8m c\u1eeda s\u1ed5. N\u00f3 t\u1eeb t\u1eeb xuy\u00ean qua t\u1ea5m r\u00e8m m\u00e0 kh\u00f4ng l\u00e0m r\u00e1ch hay h\u1ecfng r\u00e8m r\u1ed3i l\u01b0\u1ee3n tr\u00f2n quanh b\u00e0n ch\u00e2n Reverend. Sau \u0111\u00f3 n\u00f3 bay v\u00e0o m\u1ed9t ch\u1eadu d\u00f9ng \u0111\u1ef1ng n\u01b0\u1edbc v\u00e0 l\u00e0m n\u00f3ng ch\u1ea3y s\u1ee3i d\u00e2y th\u00e9p tr\u00ean c\u00e1i n\u00fat ng\u1eaft n\u01b0\u1edbc. R\u1ea5t k\u1ef3 l\u1ea1 l\u00e0 v\u00e0i tu\u1ea7n sau, Reverend g\u1eb7p tr\u01b0\u1eddng h\u1ee3p t\u01b0\u01a1ng t\u1ef1, nh\u01b0ng l\u1ea7n n\u00e0y h\u00e0nh tr\u00ecnh c\u1ee7a s\u00e9t k\u1ebft th\u00fac \u1edf b\u1ed3n t\u1eafm, c\u0169ng v\u1edbi vi\u1ec7c l\u00e0m n\u00f3ng ch\u1ea3y c\u00e1i n\u00fat ng\u1eaft! \u0110i\u1ec1u th\u00fa v\u1ecb l\u00e0 d\u00f9 c\u00f3 kh\u1ea3 n\u0103ng g\u00e2y ra ch\u1ea5n th\u01b0\u01a1ng v\u00e0 c\u00e1i ch\u1ebft, d\u01b0\u1eddng nh\u01b0 s\u00e9t h\u00f2n r\u1ea5t nh\u1eb9 nh\u00e0ng trong c\u00e1ch \u0111\u1ed1i x\u1eed v\u1edbi con ng\u01b0\u1eddi. C\u00f3 m\u1ed9t tr\u01b0\u1eddng h\u1ee3p, s\u00e9t h\u00f2n bay ch\u1ea7m ch\u1eadm qua s\u00e2n h\u01b0\u1edbng t\u1edbi m\u1ed9t c\u00e1i b\u00e0n, n\u01a1i hai \u0111\u1ee9a tr\u1ebb \u0111ang ch\u01a1i \u0111\u00f9a. M\u1ed9t ch\u00fa b\u00e9 \u0111\u00e1 v\u00e0o qu\u1ea3 c\u1ea7u v\u00e0 n\u00f3 ph\u00e1t n\u1ed5. K\u1ebft qu\u1ea3 l\u00e0 11 con b\u00f2 trong chu\u1ed3ng b\u1ecb ch\u1ebft, c\u00f2n hai c\u1eadu b\u00e9 v\u1eabn v\u00f4 s\u1ef1. \u1ede tr\u01b0\u1eddng h\u1ee3p kh\u00e1c, s\u00e9t h\u00f2n bay quanh m\u1ed9t b\u00e9 g\u00e1i r\u1ed3i ch\u1ea1m v\u00e0o ch\u00fa m\u00e8o con \u0111ang ng\u1ed3i trong l\u00f2ng b\u00e9. Ch\u00fa m\u00e8o ch\u1ebft t\u1ee9c th\u00ec trong khi em b\u00e9 kh\u00f4ng sao c\u1ea3. R\u1ea5t nhi\u1ec1u s\u00fac v\u1eadt b\u1ecb s\u00e9t h\u00f2n l\u00e0m ch\u1ebft, c\u00f2n con ng\u01b0\u1eddi \u00edt khi ph\u1ea3i ch\u1ecbu th\u1ea3m c\u1ea3nh \u0111\u00f3.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>C\u00e1c l\u00fd thuy\u1ebft v\u1ec1 s\u00e9t h\u00f2n<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c m\u00f4 h\u00ecnh n\u1ea1p n\u0103ng l\u01b0\u1ee3ng b\u00ean trong:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>S\u00e9t h\u00f2n l\u00e0 m\u1ed9t lo\u1ea1i kh\u00ed hay kh\u00f4ng kh\u00ed \u201ch\u00e0nh x\u1eed\u201d m\u1ed9t c\u00e1ch b\u1ea5t th\u01b0\u1eddng. Trong m\u00f4 h\u00ecnh n\u00e0y, s\u00e9t h\u00f2n l\u00e0 lo\u1ea1i kh\u00ed ch\u00e1y ch\u1eadm.<\/li><li>S\u00e9t h\u00f2n l\u00e0 qu\u1ea3 c\u1ea7u kh\u00f4ng kh\u00ed, b\u1ecb nung n\u00f3ng \u1edf \u00e1p su\u1ea5t kh\u00ed quy\u1ec3n.<\/li><li>S\u00e9t h\u00f2n l\u00e0 m\u1ed9t kh\u1ed1i plasma c\u00f3 m\u1eadt \u0111\u1ed9 r\u1ea5t cao, v\u1edbi c\u00e1c t\u00ednh ch\u1ea5t l\u01b0\u1ee3ng t\u1eed \u0111\u1eb7c tr\u01b0ng cho ch\u1ea5t r\u1eafn (Neugebauer, 1937).<\/li><li>S\u00e9t h\u00f2n l\u00e0 m\u1ed9t trong nh\u1eefng c\u1ea5u h\u00ecnh c\u1ee7a m\u1ed9t d\u00f2ng \u0111i\u1ec7n kh\u00e9p k\u00edn \u0111\u01b0\u1ee3c duy tr\u00ec b\u1edfi t\u1eeb tr\u01b0\u1eddng do ch\u00ednh n\u00f3 sinh ra. Finkelstein v\u00e0 Rubinstein (1964) cho r\u1eb1ng plasma lo\u1ea1i n\u00e0y kh\u00f4ng th\u1ec3 xu\u1ea5t hi\u1ec7n trong \u0111i\u1ec1u ki\u1ec7n th\u1eddi ti\u1ebft th\u00f4ng th\u01b0\u1eddng.<\/li><li>S\u00e9t h\u00f2n l\u00e0 m\u1ed9t v\u00f9ng kh\u00f4ng kh\u00ed xo\u00e1y (gi\u1ed1ng nh\u01b0 c\u00e1c v\u00f2ng kh\u00f3i).<\/li><li>S\u00e9t h\u00f2n l\u00e0 tr\u01b0\u1eddng b\u1ee9c x\u1ea1 vi s\u00f3ng trong m\u1ed9t v\u00e0nh \u0111ai plasma h\u00ecnh c\u1ea7u m\u1ecfng (Dawson v\u00e0 Jones, 1968).<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c m\u00f4 h\u00ecnh n\u0103ng l\u01b0\u1ee3ng b\u00ean ngo\u00e0i:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb t\u1ea7n s\u1ed1 cao (h\u01a1n 100 MHz): Cerrillo (1943) v\u00e0 Kapitsa (1955) gi\u1ea3 \u0111\u1ecbnh v\u1ec1 n\u0103ng l\u01b0\u1ee3ng s\u00f3ng v\u00f4 tuy\u1ebfn h\u1ed9i t\u1ee5 t\u1eeb \u0111\u00e1m m\u00e2y t\u00edch \u0111i\u1ec7n c\u00f3 th\u1ec3 h\u00ecnh th\u00e0nh v\u00e0 duy tr\u00ec m\u1ed9t s\u00e9t h\u00f2n. Tuy nhi\u00ean, ch\u01b0a bao gi\u1edd ng\u01b0\u1eddi ta th\u1ea5y m\u1ed9t tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb l\u1edbn, c\u1ea7n thi\u1ebft cho c\u01a1 ch\u1ebf n\u00e0y.<\/li><li>D\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i t\u1eeb \u0111\u00e1m m\u00e2y xu\u1ed1ng \u0111\u1ea5t: Finkelstein v\u00e0 Rubinstein (1964), Uman v\u00e0 Helstrom (1966) gi\u1ea3 \u0111\u1ecbnh m\u1ed9t d\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i ch\u1ea1y t\u1eeb \u0111\u00e1m m\u00e2y xu\u1ed1ng \u0111\u1ea5t s\u1ebd co l\u1ea1i v\u1ec1 ti\u1ebft di\u1ec7n ngang \u1edf v\u00f9ng c\u00f3 \u0111\u1ed9 d\u1eabn cao (qu\u1ea3 c\u1ea7u). L\u00fd thuy\u1ebft n\u00e0y kh\u00f4ng ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c s\u00e9t h\u00f2n h\u00ecnh th\u00e0nh trong c\u00e1c c\u1ea5u tr\u00fac, \u0111\u1eb7c bi\u1ec7t trong c\u00e1c c\u1ea5u tr\u00fac kim lo\u1ea1i nh\u01b0 khoang m\u00e1y bay hay t\u00e0u ng\u1ea7m.<\/li><li>C\u00e1c h\u1ea1t v\u0169 tr\u1ee5 h\u1ed9i t\u1ee5? Arabadzhi (1957) gi\u1ea3 \u0111\u1ecbnh c\u00e1c h\u1ea1t v\u0169 tr\u1ee5 ph\u00f3ng x\u1ea1 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c h\u1ed9i t\u1ee5 b\u1edfi \u0111i\u1ec7n tr\u01b0\u1eddng trong c\u01a1n d\u00f4ng, ch\u00fang t\u1ea1o ra m\u1ed9t s\u1ef1 ph\u00f3ng \u0111i\u1ec7n trong kh\u00f4ng kh\u00ed \u1edf t\u1ea1i \u0111i\u1ec3m sinh ra s\u00e9t h\u00f2n.<\/li><li>B\u00ed \u1ea9n c\u1ee7a s\u00e9t h\u00f2n<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n kh\u00f4ng bao gi\u1edd xu\u1ea5t hi\u1ec7n \u1edf v\u00e1ch n\u00fai cao, c\u00e1c cao \u1ed1c hay c\u00e1c \u0111i\u1ec3m cao th\u01b0\u1eddng thu h\u00fat c\u00e1c lo\u1ea1i s\u00e9t kh\u00e1c. N\u00f3 \u201ct\u1edbi g\u1ea7n\u201d c\u00e1c n\u00f4ng d\u00e2n v\u00e0 l\u1ea3ng tr\u00e1nh c\u00e1c nh\u00e0 khoa h\u1ecdc! Nh\u1eefng \u0111i\u1ec1u n\u00e0y \u0111\u00e3 \u1ee7ng h\u1ed9 cho l\u00fd thuy\u1ebft kh\u1ea3 d\u0129 nh\u1ea5t v\u1ec1 s\u00e9t h\u00f2n: Soliton-Maser.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ee9c \u1ea3nh n\u00e0y do m\u1ed9t ng\u01b0\u1eddi ch\u1ee5p t\u1ea1i Queensland, Australia n\u0103m 1987. M\u1edbi \u0111\u00e2y, khi \u0111\u1ecdc v\u1ec1 nghi\u00ean c\u1ee9u s\u00e9t h\u00f2n, \u00f4ng \u0111\u00e3 g\u1eedi cho c\u00e1c nh\u00e0 khoa h\u1ecdc.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong s\u1ed1 c\u00e1c m\u00f4 h\u00ecnh v\u1ec1 s\u00e9t h\u00f2n, ch\u1ec9 c\u00f3 l\u00fd thuy\u1ebft c\u1ee7a nh\u00e0 v\u1eadt l\u00fd Nga Nobel Pyotr Kapista (m\u00f4 h\u00ecnh Tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb t\u1ea7n s\u1ed1 cao) l\u00e0 \u0111\u01b0\u1ee3c nhi\u1ec1u ng\u01b0\u1eddi quan t\u00e2m ch\u1ec9nh l\u00fd, b\u1ed5 sung. Ban \u0111\u1ea7u, Kapista coi s\u00e9t h\u00f2n l\u00e0 s\u1ef1 ph\u00f3ng \u0111i\u1ec7n phi \u0111i\u1ec7n c\u1ef1c, t\u1ea1o ra b\u1edfi c\u00e1c s\u00f3ng \u0111\u1ee9ng si\u00eau cao t\u1ea7n UHF, ngu\u1ed3n g\u1ed1c ch\u01b0a r\u00f5, t\u1ed3n t\u1ea1i gi\u1eefa m\u1eb7t \u0111\u1ea5t v\u00e0 \u0111\u00e1m m\u00e2y.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u00ean c\u01a1 s\u1edf l\u00fd thuy\u1ebft n\u00e0y, Gi\u00e1o s\u01b0 Peter H. Handel, \u0110\u1ea1i h\u1ecdc Misourri (M\u1ef9) \u0111\u00e3 \u0111\u01b0a ra l\u00fd thuy\u1ebft Soliton-Maser n\u0103m 1975. Theo \u0111\u00f3, s\u00e9t h\u00f2n ngo\u00e0i tr\u1eddi \u0111\u01b0\u1ee3c t\u1ea1o ra b\u1edfi m\u1ed9t maser kh\u00ed quy\u1ec3n c\u00f3 th\u1ec3 t\u00edch nhi\u1ec1u km3. Maser l\u00e0 thi\u1ebft b\u1ecb t\u1ea1o ra s\u1ef1 khu\u1ebfch \u0111\u1ea1i \u00e1nh s\u00e1ng. Trong m\u1ed9t s\u1ed1 \u0111i\u1ec1u ki\u1ec7n nh\u1ea5t \u0111\u1ecbnh, maser t\u1ea1o ra m\u1ed9t \u0111i\u1ec7n tr\u01b0\u1eddng \u0111\u1ecbnh x\u1ee9 (hay soliton), xu\u1ea5t hi\u1ec7n nh\u01b0 m\u1ed9t s\u00e9t h\u00f2n quan s\u00e1t \u0111\u01b0\u1ee3c. N\u00f3i c\u00e1ch kh\u00e1c, s\u00e9t h\u00f2n l\u00e0 c\u00e1c soliton (c\u00e1c h\u1ea1t gi\u1ea3) do maser t\u1ea1o ra trong kh\u00f4ng kh\u00ed. Tuy nhi\u00ean, m\u1ed9t s\u1ef1 xu\u1ea5t hi\u1ec7n nh\u01b0 v\u1eady ch\u01b0a \u0111\u01b0\u1ee3c t\u1ea1o ra trong ph\u00f2ng th\u00ed nghi\u1ec7m.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f3 ba l\u00fd gi\u1ea3i \u1ee7ng h\u1ed9 cho l\u00fd thuy\u1ebft Soliton-Maser:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ea7u ti\u00ean, s\u00e9t h\u00f2n kh\u00f4ng h\u1ec1 c\u00f3 m\u1eb7t t\u1ea1i c\u00e1c v\u00e1ch n\u00fai cao, nh\u00e0 cao t\u1ea7ng hay c\u00e1c \u0111i\u1ec3m cao th\u01b0\u1eddng thu h\u00fat c\u00e1c lo\u1ea1i s\u00e9t kh\u00e1c. Ch\u00ednh \u0111i\u1ec1u \u0111\u00f3 khi\u1ebfn nhi\u1ec1u ng\u01b0\u1eddi nghi ng\u1edd s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a ch\u00fang. Tuy nhi\u00ean, theo l\u00fd thuy\u1ebft Soliton-Maser, c\u00e1c v\u00f9ng kh\u00f4ng gian ch\u1eadt h\u1eb9p b\u00ean c\u1ea1nh c\u00e1c c\u1ea5u tr\u00fac \u0111\u1ed9 cao l\u1edbn nh\u01b0 th\u1ebf l\u00e0 kh\u00f4ng th\u00edch h\u1ee3p cho s\u1ef1 xu\u1ea5t hi\u1ec7n s\u00e9t h\u00f2n. Ng\u01b0\u1ee3c l\u1ea1i, khi s\u00e9t \u0111\u00e1nh xu\u1ed1ng c\u00e1nh \u0111\u1ed3ng v\u1eafng, tr\u01b0\u1eddng t\u00e1c \u0111\u1ed9ng cao 3 km v\u00e0 r\u1ed9ng t\u1edbi 10 km. \u0110\u00f3 l\u00e0 l\u00fd do s\u00e9t h\u00f2n gi\u1eef \u0111\u01b0\u1ee3c b\u00ed m\u1eadt c\u1ee7a m\u00ecnh: N\u00f3 \u201ct\u00ecm g\u1eb7p\u201d nh\u1eefng n\u00f4ng d\u00e2n v\u00e0 \u201ctr\u00e1nh xa\u201d nh\u1eefng nh\u00e0 khoa h\u1ecdc!<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Th\u1ee9 hai, s\u00e9t h\u00f2n v\u00f4 h\u1ea1i trong khoang m\u00e1y bay, t\u00e0u ng\u1ea7m hay nh\u1eefng ng\u00f4i nh\u00e0 c\u00f3 c\u1ea5u tr\u00fac d\u1eabn \u0111i\u1ec7n. Theo l\u00fd thuy\u1ebft Soliton-Maser, n\u0103ng l\u01b0\u1ee3ng c\u1ee7a maser trong c\u00e1c c\u1ea5u tr\u00fac \u0111\u00f3 ch\u1ec9 kho\u1ea3ng 10 jun, so v\u1edbi m\u1ee9c h\u00e0ng t\u1ef7 jun ngo\u00e0i tr\u1eddi, n\u00ean kh\u00f4ng nguy hi\u1ec3m \u0111\u1ed1i v\u1edbi con ng\u01b0\u1eddi.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Th\u1ee9 ba, s\u00e9t h\u00f2n ngo\u00e0i tr\u1eddi th\u01b0\u1eddng k\u1ebft th\u00fac b\u1eb1ng m\u1ed9t v\u1ee5 n\u1ed5 m\u1ea1nh, \u0111\u00f4i khi c\u00f3 s\u1ee9c ph\u00e1 ho\u1ea1i gh\u00ea g\u1edbm. \u0110\u1eb7c bi\u1ec7t l\u00e0 c\u00e1c \u0111\u1ed3 v\u1eadt c\u00f3 t\u00ednh d\u1eabn \u0111i\u1ec7n ch\u1ecbu t\u00e1c \u0111\u1ed9ng m\u1ea1nh h\u01a1n r\u1ea5t nhi\u1ec1u so v\u1edbi v\u1eadt kh\u00f4ng d\u1eabn \u0111i\u1ec7n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ngo\u00e0i ra, l\u00fd thuy\u1ebft tr\u00ean c\u00f2n \u0111\u01b0\u1ee3c \u1ee7ng h\u1ed9 b\u1edfi nh\u1eefng th\u00ed nghi\u1ec7m v\u1ec1 ph\u00f3ng \u0111i\u1ec7n UHF c\u1ee7a hai nh\u00e0 nghi\u00ean c\u1ee9u s\u00e9t h\u00f2n Ohtsuki v\u00e0 Ofuruton t\u1ea1i \u0110\u1ea1i h\u1ecdc K\u1ef9 thu\u1eadt h\u00e0ng kh\u00f4ng, Nh\u1eadt B\u1ea3n v\u00e0 c\u1ee7a c\u00e1c nh\u00e0 khoa h\u1ecdc t\u1ea1i Trung t\u00e2m khoa h\u1ecdc Kurchatov, n\u01b0\u1edbc Nga, b\u1eaft \u0111\u1ea7u t\u1eeb nh\u1eefng n\u0103m \u0111\u1ea7u c\u1ee7a th\u1eadp ni\u00ean 90.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Nh\u1ea7m l\u1eabn v\u00f4 h\u1ea1i<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">S\u00e9t h\u00f2n v\u00e0 ng\u1ecdn l\u1eeda St. Elmo (ng\u1ecdn l\u1eeda c\u1ee7a Th\u00e1nh Elmo) th\u01b0\u1eddng b\u1ecb \u0111\u00e1nh \u0111\u1ed3ng v\u1edbi nhau m\u1ed9t c\u00e1ch sai l\u1ea7m. L\u1eeda St.Elmo l\u00e0 s\u1ef1 ph\u00f3ng \u0111i\u1ec7n t\u1eeb m\u1ed9t v\u1eadt d\u1eabn nh\u1ecdn khi\u1ebfn cho m\u1eadt \u0111\u1ed9 \u0111i\u1ec7n t\u00edch t\u0103ng cao, d\u1eabn t\u1edbi s\u1ef1 ph\u00f3ng \u0111i\u1ec7n do c\u00f3 \u0111i\u1ec7n tr\u01b0\u1eddng m\u1ea1nh. Gi\u1ed1ng s\u00e9t h\u00f2n, l\u1eeda St.Elmo c\u00f3 d\u1ea1ng h\u00ecnh c\u1ea7u. Nh\u01b0ng c\u00f3 \u0111i\u1ec3m kh\u00f4ng gi\u1ed1ng v\u1edbi s\u00e9t h\u00f2n, \u0111\u00f3 l\u00e0 ng\u1ecdn l\u1eeda n\u00e0y v\u1eabn ti\u1ebfp x\u00fac v\u1edbi v\u1eadt d\u1eabn, m\u1eb7c d\u00f9 c\u00f3 l\u00fac n\u00f3 di chuy\u1ec3n d\u1ecdc theo v\u1eadt d\u1eabn. H\u01a1n n\u1eefa, l\u1eeda St. Elmo c\u00f3 l\u00fac th\u1eddi gian t\u1ed3n t\u1ea1i l\u00e2u h\u01a1n s\u00e9t h\u00f2n r\u1ea5t nhi\u1ec1u. c\u00e1c v\u00f2ng tr\u00f2n \u0111\u00e1,b\u00ean trong l\u00e0 \u0111\u1ea5t<\/p>\n","protected":false},"excerpt":{"rendered":"<p>T\u1eeb kh\u00f3a t\u00ecm ki\u1ebfm: Nh\u1eefng b\u00ed \u1ea9n c\u1ee7a nh\u00e2n lo\u1ea1i &#8211; Minh Anh Trong \u0111\u00eam m\u01b0a s\u1ea5m s\u00e9t, m\u1ed9t v\u1eadt s\u00e1ng l\u00f3a h\u00ecnh c\u1ea7u k\u00edch th\u01b0\u1edbc b\u1eb1ng qu\u1ea3 cam hay qu\u1ea3 nho bay v\u1ee5t qua c\u1eeda s\u1ed5 v\u00e0o nh\u00e0 v\u00e0 l\u01b0\u1edbt qua s\u00e2n, ch\u1edbp nho\u00e1ng trong v\u00e0i gi\u00e2y, ph\u00e1 h\u1ee7y \u0111\u1ed3 \u0111\u1ea1c r\u1ed3i bi\u1ebfn m\u1ea5t, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[24],"tags":[],"class_list":["post-17024","post","type-post","status-publish","format-standard","hentry","category-kham-pha"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/17024","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=17024"}],"version-history":[{"count":1,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/17024\/revisions"}],"predecessor-version":[{"id":17025,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/17024\/revisions\/17025"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=17024"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=17024"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=17024"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}