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2021年09月08日:仙女大星系方向的深空影像-(The Deep Sky Toward Andromeda)
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2017年11月29日:M42:猎户座大星云-(M42: The Great Orion Nebula)
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2017年08月06日:银河与炸裂的流星-(Milky Way and Exploding Meteor)
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2024年02月11日:直指月亮的火箭烟尘影子-(Rocket Plume Shadow Points to the Moon)
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2023-07-05
2023年07月05日:可观测宇宙的分布图-(A Map of the Observable Universe)
2023年07月05日:可观测宇宙的分布图-(A Map of the Observable Universe)--原图下载{mtitle title="可观测宇宙的分布图"/}Image Credit & Copyright: B. Ménard & N. Shtarkman;Data: SDSS, Planck, JHU, Sloan, NASA, ESA说明: 假如你能看到可观测宇宙的边缘,会看见什么?你会看到星系、星系、星系,然后…或许加上类星体,因为它们是遥远星系的明亮核心。为了增进人类对可见宇宙最大尺度的了解,史隆数位巡天计划把2000年到2020年之间所发现的、有些甚至位于可观测宇宙边缘的星系和类星体,绘製成分布图。上面这张主题图示呈现了其中的一个区块,大约由分布在回溯时间约120亿年及宇宙红移5之内的20万个星系和类星体所聚成之楔形区。在这个楔形图示的下半部,几乎每个点都代表一个星系,而愈暗的红色代表星系的红移愈大距离愈远。类似的,在楔形图示的上半部,几乎每个点都代表一个类星体,而其中的蓝点比红点近。在所获得的诸多发现之中,包括可清楚看到由于星系间的重力吸引之故,邻近宇宙空间凝聚出的丝状结构比遥远宇宙的要来得明显{lamp/}原文:{mtitle title="A Map of the Observable Universe"/}Image Credit & Copyright: B. Ménard & N. Shtarkman;Data: SDSS, Planck, JHU, Sloan, NASA, ESAExplanation: What if you could see out to the edge of the observable universe?You would see galaxies, galaxies, galaxies, and then, well, quasars, which are the bright centers of distant galaxies. To expand understanding of the very largest scales that humanity can see, a map of the galaxies and quasars found by the Sloan Digital Sky Survey from 2000 to 2020 -- out to near the edge of the observable universe -- has been composed.Featured here, one wedge from this survey encompasses about 200,000 galaxies and quasars out beyond a look-back time of 12 billion years and cosmological redshift 5. Almost every dot in the nearby lower part of the illustration represents a galaxy, with redness indicating increasing redshift and distance.Similarly, almost every dot on the upper part represents a distant quasar, with blue-shaded dots being closer than red.Clearly shown among many discoveries, gravity between galaxies has caused the nearby universe to condense and become increasingly more filamentary than the distant universe.
2023年07月05日
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2022-02-22
2022年02月22日:图示:宇宙早期的类星体-(Illustration: An Early Quasar)
2022年02月22日:图示:宇宙早期的类星体-(Illustration: An Early Quasar)--原图下载{mtitle title="图示:宇宙早期的类星体"/}Illustration Credit & License: ESO, M. Kornmesser说明: 第一批类星体长什么模样呢?我们附近的类星体,目前咸认与活跃星系核心的超大质量黑洞有关。而当气体和尘埃掉入这种类星体时,所发出的辉光有时甚至比它所在的星系还来得亮。不过,出现在宇宙诞生后10亿年之内的类星体,则较神祕难解。这张根据最新资料所建构的画家图示,呈现宇宙早期类星体的可能模样:在其中心的大质量黑洞,周围环拱着片状的气体及吸积盘,并射出很强烈的喷流。类星体除了是人类可见的最遥远天体之一,同时也带着早期及中后期宇宙的独特资讯。目前所知的最古老类星体之红移略小于8,出现的年代相当于在宇宙发生大爆炸后的7亿年,该时宇宙之年龄大约只有目前的百分之五。{lamp/}原文:{mtitle title="Illustration: An Early Quasar"/}Illustration Credit & License: ESO, M. KornmesserExplanation: What did the first quasars look like? The nearest quasars are now known to involve supermassive black holes in the centers of active galaxies. Gas and dust that falls toward a quasar glows brightly, sometimes outglowing the entire home galaxy. The quasars that formed in the first billion years of the universe are more mysterious, though.Featured, recent data has enabled an artist's impression of an early-universe quasar as it might have been: centered on a massive black hole, surrounded by sheets of gas and an accretion disk, and expelling a powerful jet.Quasars are among the most distant objects we see and give humanity unique information about the early and intervening universe.The oldest quasars currently known are seen at just short of redshift 8 -- only 700 million years after the Big Bang -- when the universe was only a few percent of its current age.
2022年02月22日
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2021-10-17
2021年10月17日:爱因斯坦的重力透镜十字架-(The Einstein Cross Gravitational Lens)
2021年10月17日:爱因斯坦的重力透镜十字架-(The Einstein Cross Gravitational Lens)--原图下载{mtitle title="爱因斯坦的重力透镜十字架"/}Image Credit & License: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOIRLab,NSF说明: 大部份的星系只有单一个核心,不过,上面这个星系真的有四个核心吗? 由于这种答案实在太怪异了,让天文学家断言,在这张影像里,根本就看不见这个星系的核心。影像中心的苜蓿叶形天体,其实是来自一个位于背景的类星体,由于前景星系的强大重力场,才把遥远类星体的光,分裂成四个独立的影像。要出现这种类似海市蜃楼的现象,类星体要恰好排列在大质量星系核心的正后方。 这个效应称为重力透镜,而上面这种形态的影像称为爱因斯坦十字架。更有意思的是,这例爱因斯坦十字架的亮度会有变化,会因为前景星系中恒星所造成的重力微透镜效应,亮度偶而会增加。{lamp/}原文:{mtitle title="The Einstein Cross Gravitational Lens"/}Image Credit & License: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOIRLab,NSFExplanation: Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross. Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy.
2021年10月17日
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2017-12-17
2017年12月17日:爱因斯坦的重力透镜十字架 -(The Einstein Cross Gravitational Lens)
2017年12月17日:爱因斯坦的重力透镜十字架 -(The Einstein Cross Gravitational Lens)--原图下载{mtitle title="爱因斯坦的重力透镜十字架 "/}Image Credit & Copyright: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOAO,NSF说明: 大部份的星系只有单一个核心,不过,上面这个星系真的有四个核心吗? 由于这种答案实在太怪异了,让天文学家断言,在这张影像里,根本就看不见这个星系的核心。影像中心的苜蓿叶形天体,实际上是因为前景星系的强大重力场,才把遥远类星体的光,分裂成四个单独的影像。要出现这种类似海市蜃楼的现象,类星体要恰好排列在大质量星系核心的正后方。 这个效应称为重力透镜,而上面这种形态的影像称为爱因斯坦十字架。更有意思的是,这个爱因斯坦十字架的亮度会有变化,会因为前景星系中恒星所造成的重力微透镜效应,亮度偶而会增加。{lamp/}原文:{mtitle title="The Einstein Cross Gravitational Lens"/}Image Credit & Copyright: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOAO,NSFExplanation: Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross. Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy.
2017年12月17日
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2017-02-27
2017年02月27日:星系透镜与周围的4个类星体影像-(Four Quasar Images Surround a Galaxy Lens)
2017年02月27日:星系透镜与周围的4个类星体影像-(Four Quasar Images Surround a Galaxy Lens)--原图下载{mtitle title="星系透镜与周围的4个类星体影像"/}Image Credit: ESA/Hubble, NASA, Sherry Suyu et al.说明: 影像中心附近4个光点的怪异之处是:它们其实是源自同一个遥远的类星体。。这是因为位在这幅影像与及类星体影像中心的前景星系,行为像是一个不均匀的引力透镜。另一个更怪异的事情是:经由观测背景类星体闪烁,我们可以估计宇宙的膨胀速率。这是因为闪烁的时间,会随着膨胀速率的增加而变长。而对某些天文学家而言,最怪异的事是:这个多重影像类星体指出,我们宇宙膨胀的速率,比其他用于估计早期宇宙膨胀速率的方法之结果要高。而这是因为…呃…没人能说得准。可能的原因包括出乎预期的暗物质分布、引力的某些预料之外的效应、或者其他某些完全不同的效应。未来针对这个或其他类似引力透镜影像的观测与分析,或许能解开这些古怪疑点。{lamp/}原文:{mtitle title="Four Quasar Images Surround a Galaxy Lens"/}Image Credit: ESA/Hubble, NASA, Sherry Suyu et al.Explanation: An odd thing about the group of lights near the center is that four of them are the same distant quasar. This is because the foreground galaxy -- in the center of the quasar images and the featured image -- is acting like a choppy gravitational lens.A perhaps even odder thing is that by watching these background quasars flicker, you can estimate the expansion rate of the universe. That is because the flicker timing increases as the expansion rate increases. But to some astronomers, the oddest thing of all is that these multiply imaged quasars indicate a universe that is expanding a bit faster than has been estimated by different methods that apply to the early universe.And that is because ... well, no one is sure why. Reasons might include an unexpected distribution of dark matter, some unexpected effect of gravity, or something completely different. Perhaps future observations and analyses of this and similarly lensed quasar images will remove these oddities.
2017年02月27日
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2013-01-02
2013年01月02日:爱因斯坦重力透镜十字架-(The Einstein Cross Gravitational Lens)
2013年01月02日:爱因斯坦重力透镜十字架-(The Einstein Cross Gravitational Lens)--原图下载{mtitle title="爱因斯坦重力透镜十字架"/}Image Credit & Copyright: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOAO,NSF说明: 绝大部份的星系只有单一个核心,不过,上面这个星系真的有四个核心吗?由于这种答案实在太怪异了,让天文学家断定在这张影像里看不见这个星系的核心。 中央四叶型的天体,实际上是来自背景类星体的光,因为前景星系的强大重力场,才把遥远类星体的光分裂成四个单独的影像。要出现这种类似海市蜃楼的现象,类星体要恰好位在大质量星系核心的正后方。这个效应称为重力透镜,而上面这种形态的影像称为爱因斯坦十字架。更有意思的是,爱因斯坦十字架有亮度的变化,它会因为前景星系中恒星所造成的重力微透镜效应,亮度偶而会有所增加。{lamp/}原文:{mtitle title="The Einstein Cross Gravitational Lens"/}Image Credit & Copyright: J. Rhoads(Arizona State U.) et al.,WIYN,AURA,NOAO,NSFExplanation: Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing, and this specific case is known as the Einstein Cross. Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy.
2013年01月02日
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