标签： 光谱

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天文·每日一图

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太阳消失的色光

2023年6月11日 The Sun and Its Missing Colors Image Credit: Nigel Sharp (NSF), FTS, NSO, KPNO, AURA, NSF Explanation: Here are all the visible colors of the Sun, produced by passing the Sun’s light through a prism-like device. The spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits l...

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天文·每日一图

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辇道增七

2022年2月24日 Beautiful Albireo AB Image Credit & Copyright: Robert Eder Explanation: Beta Cygni is a single bright star to the naked eye. About 420 light-years away it marks the foot of the Northern Cross, famous asterism in the constellation Cygnus. But a view through the eyepiece of a small telescope will transform it into a beautiful double star, a tre...

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天文·每日一图

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CG4：破裂的彗星状云球

2021年7月26日 CG4: A Ruptured Cometary Globule Image Credit & Copyright: Nicolas Rolland & Martin Pugh Explanation: Can a gas cloud grab a galaxy? It’s not even close. The “claw” of this odd looking “creature” in the featured photo is a gas cloud known as a cometary globule. This globule, however, has ruptured. Cometary g...

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天文·每日一图

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环状星云及附近恒星的色彩

2021年7月21日 Colors: Ring Nebula versus Stars Image Credit: Robert Vanderbei (Princeton U.) Explanation: What if you could see, separately, all the colors of the Ring? And of the surrounding stars? There’s technology for that. The featured image shows the Ring Nebula (M57) and nearby stars through such technology: in this case, a prism-like diffraction g...

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天文·每日一图

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解析遥远的星光

2020年9月20日 Breaking Distant Light Image Credit: VIMOS, VLT, ESO Explanation: In the distant universe, time appears to run slowly. Since time-dilated light appears shifted toward the red end of the spectrum (redshifted), astronomers are able to use cosmological time-slowing to help measure vast distances in the universe. Featured, the light from distant galax...

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资讯

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当韦伯望远镜观测地球大气层

韦伯空间望远镜全尺寸模型，2010年5月30日拍摄于纽约炮台公园。 CREDIT: NASA and STScI 如果地球是一颗围绕行遥远恒星的系外行星，那么我们该如何了解其大气成分？ 詹姆斯韦伯空间望远镜拥有测量数千种微弱红光到红外光（0.6到28.3微米；1微米=1m的一百万分之一）的能力，能够检测到水蒸气、二氧化碳、氧气、甲烷、以及地球大气层中其他分子的特征。 免责声明 首先，让我们明确一点：韦伯并不会观测地球。地球非常温暖，因此它会发出大量红外线，正是韦伯探测的波段。从160万公里外观测，地球的红外能量太高，会烧毁韦伯的探测器。更糟糕的是，由于韦伯绕轨道运行的方式，如果它要观测地球，它也必须直视太阳，这也会直接摧毁韦伯。 韦伯将观测到太阳系中更遥远的行星以及系外行星。其中一些系外行星可能与地球非常相似。...