{"created":"2023-06-20T15:28:22.446940+00:00","id":7412,"links":{},"metadata":{"_buckets":{"deposit":"b552dbe4-2c23-404b-8b2c-a30290a0229e"},"_deposit":{"created_by":3,"id":"7412","owners":[3],"pid":{"revision_id":0,"type":"depid","value":"7412"},"status":"published"},"_oai":{"id":"oai:ouj.repo.nii.ac.jp:00007412","sets":["470:394:445"]},"author_link":["9260","9261"],"item_10002_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2000-03-31","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"120","bibliographicPageStart":"107","bibliographicVolumeNumber":"17","bibliographic_titles":[{"bibliographic_title":"放送大学研究年報"},{"bibliographic_title":"Journal of the University of the Air","bibliographic_titleLang":"en"}]}]},"item_10002_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"　夜空が何故暗いか？　という疑問が17世紀に指摘されて以来，一部の天文学者を悩ましていた．それは，恒星が宇宙空間に無限に広がって輝いているならば夜空が昼間よりもはるかに明るいことになる，という現実とは異なる結論が導かれるからである．これをオルバースのパラドックスという．それを回避するために，宇宙有限説，孤立宇宙説，無限階前説，吸収説など様々な説が唱えられた．しかし，いずれの説も成り立たないことがわかった．\n　現在，ハッブルの法則に従う宇宙の膨張によりこのパラドックスが回避されると考えられている．すなわち，宇宙の膨張から帰結される宇宙年齢の有限性と宇宙の膨張に伴う膨張効果（ドップラー効果と希釈効果）によりパラドックスは回避される．\n　しかし，通俗書に書かれているパラドックスの記述には，歴史の記述が不正確であったり，パラドックスの回避の説の記述が誤解を招いたり誤っている本が見られる．また，宇宙年齢の有限性の効果の方が膨張効果よりも圧倒的に効くのにその記述も見られない．\n　一方，宇宙の膨張を持ち出さなくても恒星の寿命が有限で空間密度が低いことでパラドックスを回避できる，と考えることもできるが，その場合も現在恒星が輝いていることの自然な説明を宇宙の膨張が与えることを指摘した．また，パラドックスが認識されるためには，背景となる理論が確立されている必要のあることも指摘した．","subitem_description_type":"Abstract"}]},"item_10002_source_id_11":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN10019636","subitem_source_identifier_type":"NCID"}]},"item_10002_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0911-4505","subitem_source_identifier_type":"ISSN"}]},"item_10002_textarea_25":{"attribute_name":"抄録（英）","attribute_value_mlt":[{"subitem_textarea_language":"en","subitem_textarea_value":"　Why is it dark at night? This question had worried some astronomers since it was pointed out in the seventeenth century, that a night sky should be far brighter than the present sky in the daytime, if flxed stars continue shining and they are distributed in the universe without end. This is called Olbers' paradox. Astronomers advanced various opinions to resolve the paradox, for example, a finite universe, an island universe, a hierarchical universe, and an absorption in interstellar space.\n　At present, the paradox is considered to be resolved by the expanding universe which obeys Hubble's law. The paradox, i.e., resolved by two effects which follow as a result of the expanding universe: 1) The universe has a finite age; 2) Both the number density of photons and their energy are lowered.\n　The descriptions of Olbers' paradox in popular science books contain many problems. Some historical descriptions are incorrect, and some descriptions concerning the resolution of the paradox are incorrect or cause misunderstanding. Moreover, no book describes the fact that the finit age of the universe is much effective than the other effect in lowering the brightness of night sky.\n　It is pointed out that the paradox can be resolved by the finit age of fixed stars without the expansion of the universe, though the expanding universe gives a persuasive explanation why many fixed stars shine presently. Furthermore, it is pointed out that an establishment of a theory is necessary for a recognition of a paradox."}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"吉岡, 一男"},{"creatorName":"ヨシオカ, カズオ","creatorNameLang":"ja-Kana"}],"nameIdentifiers":[{"nameIdentifier":"9260","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Yoshioka, Kazuo","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"9261","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2013-06-14"}],"displaytype":"detail","filename":"NO_17-107-120.pdf","filesize":[{"value":"1.6 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"NO_17-107-120","url":"https://ouj.repo.nii.ac.jp/record/7412/files/NO_17-107-120.pdf"},"version_id":"b470b06b-64d7-4948-99c3-7a8cc5660c7f"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"オルバースのパラドックスについて","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"オルバースのパラドックスについて"},{"subitem_title":"A Study of Olber's Paradox","subitem_title_language":"en"}]},"item_type_id":"10002","owner":"3","path":["445"],"pubdate":{"attribute_name":"公開日","attribute_value":"2013-06-14"},"publish_date":"2013-06-14","publish_status":"0","recid":"7412","relation_version_is_last":true,"title":["オルバースのパラドックスについて"],"weko_creator_id":"3","weko_shared_id":3},"updated":"2023-06-20T16:16:59.451065+00:00"}