{"id":1012,"date":"2010-06-28T14:39:00","date_gmt":"2010-06-28T12:39:00","guid":{"rendered":"https:\/\/kids.esa.int\/the_asteroid_and_the_disappearing_star\/"},"modified":"2026-10-08T00:34:51","modified_gmt":"2026-10-07T22:34:51","slug":"the_asteroid_and_the_disappearing_star","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/the_asteroid_and_the_disappearing_star\/","title":{"rendered":"Asteroidi ja katoava t\u00e4hti"},"content":{"rendered":"
\n

8. hein\u00e4kuuta melko kirkas t\u00e4hti, joka tunnetaan nimell\u00e4 Delta Ophiuchi, katoaa y\u00f6taivaalta. Huolestua ei kuitenkaan tarvitse. Paljaalla silm\u00e4ll\u00e4 n\u00e4kyv\u00e4\u00e4 t\u00e4hte\u00e4 ei ole sy\u00f6ty eik\u00e4 se ole kuolemassa \u2013 se vain j\u00e4\u00e4 nopeasti liikkuvan asteroidin varjoon.<\/p>\n<\/div>\n

Muutaman sekunnin ajan t\u00e4m\u00e4 pieni kivenpala, joka tunnetaan nimell\u00e4 (472) Roma, on juuri oikeassa paikassa oikeaan aikaan est\u00e4\u00e4kseen t\u00e4hden valon p\u00e4\u00e4syn Maahan. T\u00e4m\u00e4 on harvinainen tapahtuma \u2013 ainoa kerta t\u00e4ll\u00e4 vuosisadalla, jolloin on mahdollista n\u00e4hd\u00e4 asteroidin peitt\u00e4v\u00e4n t\u00e4hden ilman kiikareita tai kaukoputkea.<\/p>\n

Kaikki tiet\u00e4v\u00e4t, mit\u00e4 auringonpimennys on: kun Kuu kulkee Auringon edest\u00e4, taivas pimenee muutamaksi minuutiksi. Vaikka Kuu on 400 kertaa pienempi kuin Aurinko, se on my\u00f6s 400 kertaa l\u00e4hemp\u00e4n\u00e4, joten se pystyy peitt\u00e4m\u00e4\u00e4n l\u00e4himm\u00e4n t\u00e4htemme koko kiekon.<\/p>\n

\"A
Saturnuksen kuun Rhean peittyminen toisen kuun, Dionen, takana<\/figcaption><\/figure>\n

Sama ilmi\u00f6 voi tapahtua my\u00f6s kaukaisempien t\u00e4htien kohdalla. Roma-asteroidin kaltainen 50 km leve\u00e4 asteroidi voi hetkellisesti peitt\u00e4\u00e4 valtavan t\u00e4hden, kuten Delta Ophiuchin, koska avaruuskivi on paljon l\u00e4hemp\u00e4n\u00e4 meit\u00e4. T\u00e4llaiset tapahtumat ovat t\u00e4rkeit\u00e4, koska niiden avulla t\u00e4htitieteilij\u00e4t voivat selvitt\u00e4\u00e4 asteroidien koon ja muodon \u2013 mukaan lukien sellaisten, jotka saattavat jonain p\u00e4iv\u00e4n\u00e4 t\u00f6rm\u00e4t\u00e4 Maahan.<\/p>\n

T\u00e4hden katoaminen n\u00e4kyy vain noin 50 km leve\u00e4ll\u00e4 vy\u00f6hykkeell\u00e4, joka yhdist\u00e4\u00e4 Tukholman, K\u00f6\u00f6penhaminan, Bremenin, Nantesin, Bilbaon ja Kanariansaaret. Se tapahtuu noin klo 23.57 CEST, vaikka tarkka kellonaika vaihtelee paikkakunnittain.<\/p>\n

\"Star
T\u00e4htikartta, joka esitt\u00e4\u00e4 taivaan Keski-Euroopasta n\u00e4htyn\u00e4<\/figcaption><\/figure>","protected":false},"excerpt":{"rendered":"

On 8 July, a fairly bright star, known as Delta Ophiuchi, will disappear from the night sky. However, there is no need to worry. The naked eye star is not […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2003\/04\/asteroids_come_in_many_shapes_and_sizes2\/17886580-2-eng-GB\/Asteroids_come_in_many_shapes_and_sizes.jpg","esa_banner_description":"Asteroids come in many shapes and sizes","esa_banner_credit":"courtesy Observatoire de Paris","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2003\/04\/Asteroids_come_in_many_shapes_and_sizes2","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[46,10,11],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1012","post","type-post","status-publish","format-standard","hentry","category-comets-and-meteors","category-learn","category-our-universe"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1012","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/comments?post=1012"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1012\/revisions"}],"predecessor-version":[{"id":4795,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1012\/revisions\/4795"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=1012"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=1012"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=1012"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=1012"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=1012"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=1012"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=1012"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=1012"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=1012"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=1012"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}