{"id":297,"date":"2019-04-04T12:15:36","date_gmt":"2019-04-04T10:15:36","guid":{"rendered":"https:\/\/kids.esa.int\/esa_test_a_new_pulsar_clock\/"},"modified":"2026-10-08T00:26:33","modified_gmt":"2026-10-07T22:26:33","slug":"esa_test_a_new_pulsar_clock","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/da\/esa_test_a_new_pulsar_clock\/","title":{"rendered":"ESA tester et nyt pulsarur"},"content":{"rendered":"<div class=\"lede\">\n<p>Hvorn\u00e5r var sidste gang, du tjekkede klokken? M\u00e5ske har du et armb\u00e5ndsur eller et v\u00e6gur. Har du nogensinde t\u00e6nkt over, hvor pr\u00e6cis det er? I vores dagligdag beh\u00f8ver ure egentlig kun at v\u00e6re pr\u00e6cise inden for et par minutter eller sekunder. Men hvad nu, hvis du er videnskabsmand, ingeni\u00f8r eller astronaut? S\u00e5 har du m\u00e5ske brug for at m\u00e5le tiden meget pr\u00e6cist. ESA-forskere er begyndt at teste en ny type yderst pr\u00e6cist ur, der bruger pulsarer! Det hedder \u201cPulChron\u201d og m\u00e5ler tidens gang ved hj\u00e6lp af radiopulser med millisekundfrekvens fra flere hurtigt roterende neutronstjerner!<\/p>\n<\/div>\n<p>Neutronstjerner er utroligt t\u00e6tte objekter, der er dannet af de sammenbrudte kerner fra eksploderende stjerner. De er bittesm\u00e5 sammenlignet med almindelige stjerner og planeter \u2013 de har kun en diameter p\u00e5 omkring 10 til 20 km \u2013 men de indeholder mere \u201cstof\u201d, ogs\u00e5 kaldet masse, end Solen! Nogle gange roterer neutronstjerner meget hurtigt. De kaldes da pulsarer, og det er netop disse, som PulChron-forskerne benytter. N\u00e5r pulsarer roterer, udsender de str\u00e5ler af radiob\u00f8lger, der kan opfanges her p\u00e5 Jorden. Effekten minder lidt om, hvordan vi ser de blinkende lys fra et fyrt\u00e5rn. Disse radiob\u00f8lgeudbrud er s\u00e5 regelm\u00e6ssige, at de kunne danne grundlag for et meget pr\u00e6cist ur-system \u2013 pr\u00e6cis det, som PulChron-teamet er i gang med at teste.\u00a0<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"768\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2018\/12\/PulChron_setup\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2018\/12\/pulchron_setup\/19174617-1-eng-GB\/PulChron_setup.jpg\" alt=\"PulChron setup\"><figcaption>Ops\u00e6tning af PulChron<\/figcaption><\/figure>\n<p>Vi har allerede opfundet nogle rigtig gode metoder til at m\u00e5le tiden. Vores bedste metode indtil videre er en anordning, der kaldes et atomur. Elektroner i atomer kan absorbere eller afgive meget pr\u00e6cise m\u00e6ngder energi. Denne energi frigives som en lysb\u00f8lge med en bestemt frekvens \u2013 et bestemt antal fulde b\u00f8lger pr. sekund \u2013 som kan bruges til at m\u00e5le tiden, ligesom antallet af fulde svingninger af et pendul p\u00e5 et minut styrer et standur.<\/p>\n<p>Atomure er m\u00e5ske bedre p\u00e5 korte tidsskalaer, s\u00e5som \u00e5r, men pulsarure som PulChron kunne v\u00e6re bedre over \u00e5rtier, hvor de enkelte atomure risikerer at svigte. Det betyder, at pulsarure kan v\u00e6re meget nyttige for fremtidige satellitnavigationssystemer, s\u00e5som ESA\u2019s Galileo, der kr\u00e6ver utrolig pr\u00e6cis tidsm\u00e5ling over mange \u00e5r.<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"3895\" data-credit=\"Mike Peel; Jodrell Bank Centre for Astrophysics, University of Manchester.\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2018\/12\/Lovell_Telescope_Jodrell_Bank\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2018\/12\/lovell_telescope_jodrell_bank\/19173940-1-eng-GB\/Lovell_Telescope_Jodrell_Bank.jpg\" alt=\"Lovell Telescope, Jodrell Bank\"><figcaption>Lovell-teleskopet, Jodrell Bank<\/figcaption><\/figure>\n<p>Men hvad sker der, hvis data fra en pulsar forvr\u00e6nges \u2013 m\u00e5ske af gravitationsb\u00f8lger, som er ligesom krusninger i rummet for\u00e5rsaget af kraftige kosmiske begivenheder? Det kunne kortvarigt f\u00e5 det til at se ud, som om pulsaren roterer hurtigere eller langsommere. PulChron-teamet har t\u00e6nkt p\u00e5 dette, og derfor bruger de fem store radioteleskoper spredt over hele Europa til at observere ikke blot \u00e9n, men hele 18 pulsarer!\u00a0<\/p>\n<p>M\u00e5ske vil pulsarure i fremtiden blive mere udbredte og sammen med atomure hj\u00e6lpe os med at m\u00e5le tiden bedre end nogensinde f\u00f8r!<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"6500\" data-credit=\"ESA-P. Carril\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2014\/07\/Galileo_satellite_in_orbit\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2014\/07\/galileo_satellite_in_orbit\/14632177-1-eng-GB\/Galileo_satellite_in_orbit.jpg\" alt=\"Galileo satellite in orbit\"><figcaption>Galileo-satellit i kredsl\u00f8b<\/figcaption><\/figure>\n<p><i>Interessant faktum: Pulsarer blev opdaget i 1967 af den britiske astronom Jocelyn Bell Burnell. F\u00f8rst troede hun, at de m\u00e5ske var tegn p\u00e5 intelligent udenjordisk liv, der fors\u00f8gte at kommunikere med os!\u00a0<\/i><\/p>","protected":false},"excerpt":{"rendered":"<p>When was the last time you checked the time? Maybe you have a wristwatch, or a clock on the wall. Did you stop to think about how accurate the time [&hellip;]<\/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\/2017\/05\/crab_on_lcd\/16946171-1-eng-GB\/Crab_on_LCD.jpg","esa_banner_description":"A pulsar is hidden deep within this supernova bubble. Copyright: NASA, ESA, G. Dubner (IAFE, CONICET-University of Buenos Aires) et al.; A. Loll et al.; T. Temim et al.; F. Seward et al.; VLA\/NRAO\/AUI\/NSF; Chandra\/CXC; Spitzer\/JPL-Caltech; XMM-Newton\/ESA; and Hubble\/STScI, CC BY 4.0","esa_banner_credit":"NASA, ESA, G. Dubner (IAFE, CONICET-University of Buenos Aires) et al.; A. Loll et al.; T. Temim et al.; F. Seward et al.; VLA\/NRAO\/AUI\/NSF; Chandra\/CXC; Spitzer\/JPL-Caltech; XMM-Newton\/ESA; and Hubble\/STScI,CC BY 4.0","esa_banner_licence":"CC BY 4.0 INT or ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2017\/05\/Crab_on_LCD","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":[26],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-297","post","type-post","status-publish","format-standard","hentry","category-news"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/297","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/comments?post=297"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/297\/revisions"}],"predecessor-version":[{"id":4394,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/297\/revisions\/4394"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/media?parent=297"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/categories?post=297"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/tags?post=297"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/panel?post=297"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/language?post=297"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/age?post=297"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/duration?post=297"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/resource_type?post=297"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/audience?post=297"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/wf_post_folders?post=297"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}