{"id":6837,"date":"2021-11-20T12:27:37","date_gmt":"2021-11-20T05:27:37","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=6837"},"modified":"2021-11-20T13:24:48","modified_gmt":"2021-11-20T06:24:48","slug":"vi-sao-thien-van-phai-dung-nam-anh-sang-de-tinh-khoang-cach","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/vi-sao-thien-van-phai-dung-nam-anh-sang-de-tinh-khoang-cach\/","title":{"rendered":"V\u00ec sao thi\u00ean v\u0103n ph\u1ea3i d\u00f9ng n\u0103m \u00e1nh s\u00e1ng \u0111\u1ec3 t\u00ednh kho\u1ea3ng c\u00e1ch?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Trong cu\u1ed9c s\u1ed1ng ta th\u01b0\u1eddng l\u1ea5y: cm, m, km l\u00e0 \u0111\u01a1n v\u1ecb t\u00ednh \u0111\u1ed9 d\u00e0i. V\u00ed d\u1ee5 m\u1ed9t t\u1ea5m k\u00ednh c\u00f3 \u0111\u1ed9 d\u00e0y 1 cm, 1 ng\u01b0\u1eddi cao 1,8 m, kho\u1ea3ng c\u00e1ch gi\u1eefa hai th\u00e0nh ph\u1ed1 l\u00e0 1000 km v.v. Ta c\u00f3 th\u1ec3 th\u1ea5y: khi bi\u1ec3u th\u1ecb \u0111\u1ed9 d\u00e0i ng\u1eafn d\u00f9ng \u0111\u01a1n v\u1ecb nh\u1ecf, bi\u1ec3u th\u1ecb \u0111\u1ed9 d\u00e0i l\u1edbn d\u00f9ng \u0111\u01a1n v\u1ecb l\u1edbn h\u01a1n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong thi\u00ean v\u0103n h\u1ecdc c\u0169ng c\u00f3 l\u00fac d\u00f9ng \u0111\u01a1n v\u1ecb km. V\u00ed d\u1ee5 ta th\u01b0\u1eddng n\u00f3i b\u00e1n k\u00ednh x\u00edch \u0111\u1ea1o c\u1ee7a Tr\u00e1i \u0110\u1ea5t l\u00e0 6.378 km, b\u00e1n k\u00ednh M\u1eb7t Tr\u0103ng l\u00e0 3.476 km, M\u1eb7t Tr\u0103ng c\u00e1ch Tr\u00e1i \u0110\u1ea5t 38 v\u1ea1n km v.v. Nh\u01b0ng n\u1ebfu d\u00f9ng km \u0111\u1ec3 bi\u1ec3u th\u1ecb kho\u1ea3ng c\u00e1ch gi\u1eefa c\u00e1c h\u1eb1ng tinh th\u00ec \u0111\u01a1n v\u1ecb n\u00e0y qu\u00e1 nh\u1ecf, s\u1eed d\u1ee5ng kh\u00f4ng ti\u1ec7n l\u1ee3i. V\u00ed d\u1ee5: h\u1eb1ng tinh g\u1ea7n ta nh\u1ea5t c\u00f3 kho\u1ea3ng c\u00e1ch \u0111\u1ed1i v\u1edbi ch\u00fang ta l\u00e0 40.000.000.000.000 km. B\u1ea1n xem vi\u1ebft v\u00e0 \u0111\u1ecdc r\u1ea5t kh\u00f3 kh\u0103n, hu\u1ed1ng h\u1ed3 \u0111\u00f3 ch\u1ec9 m\u1edbi l\u00e0 c\u1ef1 ly c\u1ee7a h\u1eb1ng tinh g\u1ea7n ta nh\u1ea5t. C\u1ef1 ly c\u1ee7a nh\u1eefng h\u1eb1ng tinh kh\u00e1c \u0111\u1ed1i v\u1edbi ch\u00fang ta c\u00f2n xa h\u01a1n r\u1ea5t nhi\u1ec1u.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ng\u01b0\u1eddi ta ph\u00e1t hi\u1ec7n t\u1ed1c \u0111\u1ed9 \u00e1nh s\u00e1ng r\u1ea5t l\u1edbn, m\u1ed7i gi\u00e2y \u00e1nh s\u00e1ng c\u00f3 th\u1ec3 \u0111i \u0111\u01b0\u1ee3c 30 v\u1ea1n km (con s\u1ed1 ch\u00ednh x\u00e1c l\u00e0 299.792.458 km) qu\u00e3ng \u0111\u01b0\u1eddng c\u1ee7a 1 n\u0103m \u00e1nh s\u00e1ng kho\u1ea3ng 1 v\u1ea1n t\u1ec9 km, ch\u00ednh x\u00e1c l\u00e0 9.460,5 t\u1ec9 km. V\u1eady c\u00f3 th\u1ec3 d\u00f9ng qu\u00e3ng \u0111\u01b0\u1eddng \u0111i c\u1ee7a n\u0103m \u00e1nh s\u00e1ng g\u1ecdi l\u00e0 &#8220;n\u0103m \u00e1nh s\u00e1ng&#8221; \u0111\u1ec3 l\u00e0m \u0111\u01a1n v\u1ecb t\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa c\u00e1c thi\u00ean th\u1ec3 \u0111\u01b0\u1ee3c kh\u00f4ng? \u0110\u00f3 l\u00e0 m\u1ed9t g\u1ee3i \u00fd r\u1ea5t quan tr\u1ecdng. Ng\u00e0y nay c\u00e1c nh\u00e0 thi\u00ean v\u0103n h\u1ecdc \u0111\u00e3 d\u00f9ng n\u0103m \u00e1nh s\u00e1ng \u0111\u1ec3 t\u00ednh c\u1ef1 ly gi\u1eefa c\u00e1c thi\u00ean th\u1ec3, n\u0103m s\u00e1ng \u0111\u00e3 tr\u1edf th\u00e0nh m\u1ed9t \u0111\u01a1n v\u1ecb c\u01a1 b\u1ea3n trong thi\u00ean v\u0103n h\u1ecdc.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">N\u1ebfu d\u00f9ng n\u0103m \u00e1nh s\u00e1ng \u0111\u1ec3 bi\u1ec3u th\u1ecb kho\u1ea3ng c\u00e1ch c\u1ee7a ng\u00f4i sao l\u00e2n c\u1eadn \u0111\u1ed1i v\u1edbi ch\u00fang ta th\u00ec \u0111\u00f3 l\u00e0 4,22 n\u0103m \u00e1nh s\u00e1ng. Sao Ng\u01b0u Lang c\u00e1ch ta 16 n\u0103m \u00e1nh s\u00e1ng, sao Ch\u1ee9c N\u1eef l\u00e0 26,3 n\u0103m \u00e1nh s\u00e1ng. Ch\u00f2m sao Ti\u00ean N\u1eef n\u1eb1m ngo\u00e0i h\u1ec7 Ng\u00e2n h\u00e0 c\u00e1ch ta kho\u1ea3ng 220 v\u1ea1n n\u0103m \u00e1nh s\u00e1ng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ng\u00e0y nay ng\u01b0\u1eddi ta quan tr\u1eafc \u0111\u01b0\u1ee3c thi\u00ean th\u1ec3 c\u00f3 c\u1ef1 ly xa nh\u1ea5t \u0111\u1ed1i v\u1edbi ch\u00fang ta tr\u00ean 10 t\u1ec9 n\u0103m \u00e1nh s\u00e1ng. \u0110\u01b0\u1eddng k\u00ednh c\u1ee7a h\u1ec7 Ng\u00e2n h\u00e0 l\u00e0 10 v\u1ea1n n\u0103m \u00e1nh s\u00e1ng. Nh\u1eefng kho\u1ea3ng c\u00e1ch n\u00e0y \u0111\u1ec1u r\u1ea5t kh\u00f3 d\u00f9ng km \u0111\u1ec3 bi\u1ec3u th\u1ecb.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong thi\u00ean v\u0103n h\u1ecdc c\u00f2n c\u00f3 m\u1ed9t \u0111\u01a1n v\u1ecb kh\u00e1c \u0111\u1ec3 t\u00ednh kho\u1ea3ng c\u00e1ch. C\u00f3 lo\u1ea1i \u0111\u01a1n v\u1ecb nh\u1ecf h\u01a1n n\u0103m \u00e1nh s\u00e1ng, v\u00ed d\u1ee5 \u0111\u01a1n v\u1ecb thi\u00ean v\u0103n. M\u1ed9t \u0111\u01a1n v\u1ecb thi\u00ean v\u0103n b\u1eb1ng kho\u1ea3ng c\u00e1ch b\u00ecnh qu\u00e2n t\u1eeb Tr\u00e1i \u0110\u1ea5t \u0111\u1ebfn M\u1eb7t Tr\u1eddi (149,6 tri\u1ec7u km) lo\u1ea1i \u0111\u01a1n v\u1ecb n\u00e0y ch\u1ee7 y\u1ebfu \u0111\u1ec3 t\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa c\u00e1c thi\u00ean th\u1ec3 trong ph\u1ea1m vi h\u1ec7 M\u1eb7t Tr\u1eddi. C\u00f2n c\u00f3 lo\u1ea1i \u0111\u01a1n v\u1ecb l\u1edbn h\u01a1n n\u0103m \u00e1nh s\u00e1ng, nh\u01b0 pacsec (m\u1ed9t pacsec b\u1eb1ng 3,26 n\u0103m \u00e1nh s\u00e1ng, m\u1ed9t megapacec b\u1eb1ng 106 pacsec).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1eeb kho\u00e1: N\u0103m \u00e1nh s\u00e1ng; \u0110\u01a1n v\u1ecb thi\u00ean v\u0103n;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"<p>Trong cu\u1ed9c s\u1ed1ng ta th\u01b0\u1eddng l\u1ea5y: cm, m, km l\u00e0 \u0111\u01a1n v\u1ecb t\u00ednh \u0111\u1ed9 d\u00e0i. V\u00ed d\u1ee5 m\u1ed9t t\u1ea5m k\u00ednh c\u00f3 \u0111\u1ed9 d\u00e0y 1 cm, 1 ng\u01b0\u1eddi cao 1,8 m, kho\u1ea3ng c\u00e1ch gi\u1eefa hai th\u00e0nh ph\u1ed1 l\u00e0 1000 km v.v. Ta c\u00f3 th\u1ec3 th\u1ea5y: khi bi\u1ec3u th\u1ecb \u0111\u1ed9 d\u00e0i ng\u1eafn d\u00f9ng \u0111\u01a1n v\u1ecb nh\u1ecf, bi\u1ec3u [&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":[15,7],"tags":[],"class_list":["post-6837","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-vat-ly"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/6837","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=6837"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/6837\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=6837"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=6837"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=6837"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}