{"id":10354,"date":"2021-11-21T19:53:09","date_gmt":"2021-11-21T12:53:09","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=10354"},"modified":"2021-11-21T20:11:20","modified_gmt":"2021-11-21T13:11:20","slug":"goi-dien-thoai-ma-co-hien-tuong-hoi-am-la-sao-vay","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/goi-dien-thoai-ma-co-hien-tuong-hoi-am-la-sao-vay\/","title":{"rendered":"G\u1ecdi \u0111i\u1ec7n tho\u1ea1i m\u00e0 c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m l\u00e0 sao v\u1eady?"},"content":{"rendered":"\n

Hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m th\u00ec \u1edf \u0111\u00e2u c\u0169ng c\u00f3, khi ta n\u00f3i to trong hang n\u00fai th\u00ec ch\u1ec9 l\u00e1t sau s\u1ebd nghe v\u1ecdng t\u1edbi m\u1ed9t lo\u1ea1t h\u1ed3i \u00e2m. Nguy\u00ean do l\u00e0 ti\u1ebfng n\u00f3i truy\u1ec1n v\u00e0o hang v\u00e0 l\u00e1t sau ph\u1ea3n x\u1ea1 tr\u1edf l\u1ea1i. \u0110i\u1ec1u n\u00e0y thuy\u1ebft minh r\u1eb1ng s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh c\u1ea7n ph\u1ea3i c\u00f3 m\u1ed9t qu\u00e3ng th\u1eddi gian nh\u1ea5t \u0111\u1ecbnh.<\/p>\n\n\n\n

Khi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i c\u0169ng c\u00f3 h\u1ed3i \u00e2m nh\u01b0 v\u1eady. Ch\u1ec9 c\u00f3 \u0111i\u1ec1u l\u00e0 s\u00f3ng \u0111i\u1ec7n truy\u1ec1n t\u1ea3i \u00e2m thanh c\u00f3 v\u1eadn t\u1ed1c \u00e1nh s\u00e1ng, m\u1ed9t gi\u00e2y c\u00f3 th\u1ec3 v\u00f2ng quanh Tr\u00e1i \u0110\u1ea5t b\u1ea3y v\u00f2ng. Th\u01b0\u1eddng l\u00e0 kho\u1ea3ng c\u00e1ch \u0111i\u1ec7n tho\u1ea1i trong th\u00e0nh ph\u1ed1 r\u1ea5t g\u1ea7n, hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m x\u1ea3y ra r\u1ea5t nhanh khi\u1ebfn ta kh\u00f4ng c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c. Th\u1ebf nh\u01b0ng, n\u1ebfu ta g\u1ecdi \u0111i\u1ec7n tho\u1ea1i \u0111\u01b0\u1eddng d\u00e0i qu\u1ed1c t\u1ebf th\u00ec l\u1ea1i kh\u00e1c. B\u1edfi v\u00ec \u0111i\u1ec7n tho\u1ea1i qu\u1ed1c t\u1ebf c\u00f3 kho\u1ea3ng c\u00e1ch xa \u0111\u01b0\u1ee3c truy\u1ec1n t\u1ea3i b\u1eb1ng v\u1ec7 tinh th\u00f4ng tin qua b\u1ea7u tr\u1eddi.<\/p>\n\n\n\n

Ch\u00fang ta bi\u1ebft v\u1ec7 tinh vi\u1ec5n th\u00f4ng \u0111\u1ed3ng b\u1ed9 \u1edf \u0111\u1ed9 cao c\u00e1ch m\u1eb7t \u0111\u1ea5t ch\u1eebng 36 tri\u1ec7u m\u00e9t (36 ngh\u00ecn km). V\u1edbi c\u00f9ng m\u1ed9t v\u1ec7 tinh vi\u1ec5n th\u00f4ng \u0111\u1ed3ng b\u1ed9, t\u00edn hi\u1ec7u \u0111i\u1ec7n tho\u1ea1i t\u1eeb tr\u1ea1m m\u1eb7t \u0111\u1ea5t c\u1ee7a v\u1ec7 tinh \u1edf \u0111i\u1ec3m A qua v\u1ec7 tinh chuy\u1ec3n ph\u00e1t \u0111\u1ebfn tr\u1ea1m m\u1eb7t \u0111\u1ea5t c\u1ee7a v\u1ec7 tinh \u1edf \u0111i\u1ec3m B, r\u1ed3i ph\u1ea3n h\u1ed3i t\u1edbi tr\u1ea1m m\u1eb7t \u0111\u1ea5t v\u1ec7 tinh \u1edf \u0111i\u1ec3m A. H\u00e0nh tr\u00ecnh 2 l\u00ean 2 xu\u1ed1ng n\u00e0y d\u00e0i kho\u1ea3ng 144 tri\u1ec7u m\u00e9t. N\u1ebfu t\u00ednh theo v\u1eadn t\u1ed1c lan truy\u1ec1n c\u1ee7a s\u00f3ng \u0111i\u1ec7n m\u1ed7i gi\u00e2y l\u00e0 300 tri\u1ec7u m\u00e9t (30 v\u1ea1n km) th\u00ec th\u1eddi gian l\u00ean tr\u1eddi xu\u1ed1ng \u0111\u1ea5t n\u00e0y \u01b0\u1edbc kho\u1ea3ng 0,54 gi\u00e2y. Ta kh\u00f4ng n\u00ean coi th\u01b0\u1eddng kho\u1ea3ng th\u1eddi gian ch\u1eadm tr\u1ec5 ng\u1eafn ng\u1ee7i n\u00e0y. Khi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i, c\u1ee9 c\u00e1ch 0,54 gi\u00e2y l\u1ea1i ph\u1ea3n h\u1ed3i m\u1ed9t ti\u1ebfng n\u00f3i c\u1ee7a m\u00ecnh. Nh\u01b0 v\u1eady s\u1ebd g\u00e2y ra nhi\u1ec5u h\u1ed3i \u00e2m kh\u00f3 ch\u1ecbu cho c\u1ea3 hai b\u00ean, khi\u1ebfn ng\u01b0\u1eddi nghe ph\u1ea3i ph\u00e2n v\u00e2n. \u0110\u00f3 ch\u00ednh l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m trong \u0111i\u1ec7n tho\u1ea1i.<\/p>\n\n\n\n

\u0110\u1ec3 x\u00f3a b\u1ecf hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y, c\u00e1c chuy\u00ean gia<\/a> \u0111\u00e3 nghi\u00ean c\u1ee9u ch\u1ebf t\u1ea1o ra thi\u1ebft b\u1ecb tri\u1ec7t h\u1ed3i \u00e2m. N\u00f3 \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf<\/a> d\u1ef1a v\u00e0o \u0111\u1eb7c \u0111i\u1ec3m l\u00e0 ng\u01b0\u1eddi s\u1eed d\u1ee5ng \u0111i\u1ec7n tho\u1ea1i khi n\u00f3i th\u00ec kh\u00f4ng nghe v\u00e0 khi nghe th\u00ec kh\u00f4ng n\u00f3i. Thi\u1ebft b\u1ecb n\u00e0y \u0111\u01b0\u1ee3c chia ra l\u1eafp \u0111\u1eb7t t\u1ea1i tuy\u1ebfn \u0111\u01b0\u1eddng d\u00e2y th\u00f4ng tin c\u1ee7a tr\u1ea1m m\u1eb7t \u0111\u1ea5t v\u1ec7 tinh \u1edf hai \u0111\u1ea7u. Khi thu\u00ea bao b\u00ean A n\u00f3i, t\u00edn hi\u1ec7u \u0111i\u1ec7n tho\u1ea1i truy\u1ec1n sang b\u00ean B, \u0111\u01b0\u1eddng \u0111i\u1ec7n tri\u1ec7t h\u1ed3i \u00e2m s\u1ebd ch\u1ea1y v\u00e0o thi\u1ebft b\u1ecb l\u00e0m suy gi\u1ea3m khi n\u1ed1i th\u00f4ng \u0111\u01b0\u1eddng truy\u1ec1n, v\u00e0 s\u1ebd gi\u1ea3m nh\u1eb9 h\u1ed3i \u00e2m n\u00e0y. Khi b\u00ean A nghe b\u00ean B n\u00f3i, thi\u1ebft b\u1ecb tri\u1ec7t h\u1ed3i \u00e2m s\u1ebd ng\u1eaft \u0111\u01b0\u1eddng truy\u1ec1n ph\u00e1t t\u1eeb b\u00ean A \u0111\u1ec3 ph\u00f2ng ch\u1ed1ng vi\u1ec7c t\u00edn hi\u1ec7u ti\u1ebfp nh\u1eadn quay tr\u1edf v\u1ec1 \u0111\u1ed1i ph\u01b0\u01a1ng qua \u0111\u01b0\u1eddng truy\u1ec1n l\u1eddi ph\u00e1t \u0111i, t\u1ea1o n\u00ean \u0111\u01b0\u1eddng truy\u1ec1n nhi\u1ec5u.<\/p>\n\n\n\n

Th\u1ebf nh\u01b0ng, trong \u0111\u01b0\u1eddng \u0111i\u1ec7n h\u1ed3i \u00e2m \u1ee9c ch\u1ebf, vi\u1ec7c \u0111\u00f3ng ng\u1eaft \u0111i\u1ec3m ti\u1ebfp x\u00fac theo c\u00e1ch m\u00e1y m\u00f3c \u0111i\u1ec1u khi\u1ec3n vi\u1ec7c \u0111\u00f3ng v\u00e0 m\u1edf \u0111\u01b0\u1eddng d\u00e2y truy\u1ec1n th\u00f4ng l\u1ea1i ch\u1ecbu s\u1ef1 kh\u1ed1ng ch\u1ebf b\u1edfi hai b\u00ean cu\u1ed9c g\u1ecdi c\u00f3 n\u00f3i chuy\u1ec7n kh\u00f4ng. Khi \u0111\u1ed9ng t\u00e1c t\u1eaft b\u1eadt kh\u00f4ng theo k\u1ecbp nh\u1ecbp \u0111\u1ed9 n\u00f3i chuy\u1ec7n c\u1ee7a hai b\u00ean A v\u00e0 B th\u00ec nhi\u1ec5u h\u1ed3i \u00e2m s\u1ebd “th\u1eeba c\u01a1 l\u1ebbn v\u00e0o”, khi\u1ebfn cho ng\u01b0\u1eddi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i c\u1ea3m th\u1ea5y c\u00f3 h\u1ed3i \u00e2m. C\u00f3 khi \u0111i\u1ec3m ti\u1ebfp x\u00fac t\u1eaft b\u1eadt m\u00e1y m\u00f3c trong \u0111\u01b0\u1eddng \u0111i\u1ec7n kh\u1ed1ng ch\u1ebf x\u1ea3y ra s\u1ef1 c\u1ed1 th\u00ec c\u0169ng m\u1ea5t \u0111i t\u00e1c d\u1ee5ng tri\u1ec7t h\u1ed3i \u00e2m. V\u00e0 trong m\u00e1y \u0111i\u1ec7n tho\u1ea1i s\u1ebd l\u1ea1i c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m.<\/p>\n\n\n\n

\u0110\u1ec3 kh\u1eafc ph\u1ee5c khuy\u1ebft \u0111i\u1ec3m c\u1ee7a thi\u1ebft b\u1ecb tri\u1ec7t h\u1ed3i \u00e2m, ng\u01b0\u1eddi ta l\u1ea1i ph\u00e1t minh ra m\u1ed9t thi\u1ebft b\u1ecb tri\u1ec7t ti\u00eau h\u1ed3i \u00e2m. N\u00f3 \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf<\/a> d\u1ef1a tr\u00ean nguy\u00ean l\u00ed t\u00edn hi\u1ec7u \u00e2m d\u01b0\u01a1ng tri\u1ec7t ti\u00eau l\u1eabn nhau. L\u1eafp \u0111\u1eb7t thi\u1ebft b\u1ecb tri\u1ec7t ti\u00eau h\u1ed3i \u00e2m \u1edf ngay hai \u0111\u1ea7u \u0111\u01b0\u1eddng d\u00e2y th\u00f4ng tin v\u1ec7 tinh. Khi A n\u00f3i chuy\u1ec7n, \u0111\u01b0\u1eddng \u0111i\u1ec7n tri\u1ec7t ti\u00eau h\u1ed3i \u00e2m s\u1ebd h\u00e0nh \u0111\u1ed9ng, n\u00f3 l\u1ea5y m\u1eabu t\u00edn hi\u1ec7u l\u1eddi n\u00f3i b\u00ean A ph\u00e1t ra, \u0111\u1ea3o \u1ea3nh qua \u0111\u01b0\u1eddng \u0111i\u1ec7n s\u1ed1 v\u00e0 bi\u1ebfn th\u00e0nh t\u00edn hi\u1ec7u tri\u1ec7t ti\u00eau h\u1ed3i \u00e2m ng\u01b0\u1ee3c l\u1ea1i. N\u00f3 \u0111\u01b0\u1ee3c t\u1ea1m th\u1eddi l\u01b0u tr\u1eef. Khi t\u00edn hi\u1ec7u l\u1eddi n\u00f3i t\u1eeb A \u0111\u00e3 \u0111\u1ebfn B, t\u00edn hi\u1ec7u h\u1ed3i \u00e2m l\u1ea1i \u0111\u01b0\u1ee3c \u0111\u01b0a v\u1ec1 b\u00ean A. L\u00fac n\u00e0y t\u00edn hi\u1ec7u tri\u1ec7t ti\u00eau c\u00f3 t\u00edch c\u1ef1c ng\u01b0\u1ee3c l\u1ea1i \u0111\u00e3 \u0111\u01b0\u1ee3c chu\u1ea9n b\u1ecb s\u1eb5n l\u1eadp t\u1ee9c ra \u0111\u00f3n, khi\u1ebfn cho t\u00edn hi\u1ec7u h\u1ed3i \u00e2m bi\u1ebfn m\u1ea5t. Th\u1ebf nh\u01b0ng, c\u00f3 l\u00fac t\u00edn hi\u1ec7u tri\u1ec7t ti\u00eau ch\u1ea1y ra ch\u1eadm m\u1ed9t ch\u00fat, c\u00e1i nhi\u1ec5u h\u1ed3i \u00e2m s\u1ebd tri\u1ec7t ti\u00eau kh\u00f4ng h\u1ebft v\u00e0 \u0111\u01b0\u1eddng d\u00e2y s\u1ebd v\u1eabn c\u00f2n hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m nh\u1eb9.<\/p>\n\n\n\n

T\u1eeb kh\u00f3a: Hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m; Th\u00f4ng tin v\u1ec7 tinh; Thi\u1ebft b\u1ecb tri\u1ec7t h\u1ed3i \u00e2m.<\/p>\n","protected":false},"excerpt":{"rendered":"

Hi\u1ec7n t\u01b0\u1ee3ng h\u1ed3i \u00e2m th\u00ec \u1edf \u0111\u00e2u c\u0169ng c\u00f3, khi ta n\u00f3i to trong hang n\u00fai th\u00ec ch\u1ec9 l\u00e1t sau s\u1ebd nghe v\u1ecdng t\u1edbi m\u1ed9t lo\u1ea1t h\u1ed3i \u00e2m. Nguy\u00ean do l\u00e0 ti\u1ebfng n\u00f3i truy\u1ec1n v\u00e0o hang v\u00e0 l\u00e1t sau ph\u1ea3n x\u1ea1 tr\u1edf l\u1ea1i. \u0110i\u1ec1u n\u00e0y thuy\u1ebft minh r\u1eb1ng s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh c\u1ea7n […]<\/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":[15,13],"tags":[],"class_list":["post-10354","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-tin-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/10354","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=10354"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/10354\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=10354"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=10354"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=10354"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}