保护地球，探索宇宙，发现文明
The barred spiral galaxy NGC 3887, seen here as viewed by the Wide Field Camera 3 aboard the NASA/ESA Hubble Space Telescope, lies over 60 million light-years away from us in the southern constellation of Crater (the Cup). It was discovered on Dec. 31, 1785, by astronomer William Herschel. Its orientation to us, while not exactly face-on, allows us to see NG...
This bright, somewhat blob-like object — seen in this image taken by the NASA/ESA Hubble Space Telescope — is a galaxy named NGC 1803. It is about 200 million light-years away, in the southern constellation of Pictor (the Painter’s Easel). NGC 1803 was discovered in 1834 by astronomer John Herschel. Herschel is a big name in astronomy; John, his father Willi...
Credit:NASA 天文学家一般在恒星的“宜居带”，也被称为“金凤花区域”（Goldilocks zone）内的行星上寻找地外生命。“宜居带”指一颗恒星周围的一定距离范围，在这一范围内温度适宜使水能够以液态形式存在于行星表面，从而可以孕育生命。 经过三十年的恒星调查，一个新兴的观点认为：存在“金凤花恒星”（Goldilocks stars”），其行星环境既不太热也不太冷，最重要的是，能够支持生命存在。 太阳滋养了地球上的生命已近40亿年，因此传统观点认为，像太行这样的恒星是寻找其他潜在宜居星球的主要候选者。实际上，那些温度和亮度比太阳稍低的K型矮星才是真正的“宜居恒星”。宾夕法尼亚州维拉诺瓦大学的爱德华•吉南（Edward Guinan）表示：“K型矮星处于’最佳位置’，其特性介于更稀有、更明亮、寿命更短的...
天文学家们利用NASA的哈勃太空望远镜和一项新的观测技术，天文学家发现暗物质形成的团块比以前所知的要小得多。这个结果证实了被广泛接受的“冷暗物质”理论的一个基本预测。 根据这个理论，所有的星系都形成并嵌入在暗物质云中。暗物质本身由缓慢移动的或“冷”粒子组成，它们聚集在一起形成的结构，从质量是银河系几十万倍的，到质量不超过商用飞机重量的团块。(在这里，“冷”指的是粒子的速度。) 哈勃的观测使我们对暗物质的性质和它的活动方式有了新的认识。“我们对冷暗物质模型进行了非常有说服力的观测测试，它出色的通过了。”加州大学洛杉矶分校(UCLA)的TommasoTreu说，他是观察小组的成员之一。 暗物质是一种看不见的物质，它构成了宇宙的大部分质量，并为星系的形成提供了基础。尽管天文学家看不到暗物质，但他们可以通过测量其重力如...
This smattering of celestial sequins is a spiral galaxy named NGC 4455, located in the northern constellation of Coma Berenices (Berenice’s Hair). This might sound like an odd name for a constellation — and in fact it is somewhat unusual. It’s the only modern constellation to be named in honor of a real person from history: Queen Berenice II of Egypt. The st...
A galaxy about 23 million light years away is the site of impressive, ongoing fireworks. Rather than paper, powder and fire, this galactic light show involves a giant black hole, shock waves and vast reservoirs of gas. This galactic fireworks display is taking place in NGC 4258, also known as M106, a spiral galaxy like our own Milky Way. This galaxy is famou...
During the 18th century, French astronomer Charles Messier compiled a list of over 100 cosmic objects that might fool fellow comet hunters into thinking they had discovered new comets. In the 1980s, an Englishman named Sir Patrick Moore produced an additional list to highlight more cosmic wonders visible to amateur astronomers. Unlike the Messier catalog, wh...
“超松软”（Super-Puffs）听起来像一种新推出的早餐麦片，但实际上这是一种独特而罕见的年轻系外行星（exoplanets）的绰号。它们的密度跟棉花糖一样，我们的太阳系中并没有这种行星。 这张图描绘了类太阳恒星开普勒51和NASA开普勒太空望远镜在2012至2014年间发现的三颗巨行星。这些行星大约都与木星大小相当，但质量要比木星小的多。根据哈勃太空望远镜的最新观测，它们的密度极低，更像是泡沫聚苯乙烯，而不是岩石或水。这些行星很可能在远离恒星的地方形成，之后再向内迁移到现在的位置。如今它们膨胀的氢/氦大气正慢慢渗入太空，最终可能会留下体积更小的行星。如果我们沿着银河系的猎户座螺旋臂从开普勒51（约2600光年的距离）望向太阳，就会看到这张图所展示的星空。但我们的太阳太微弱，在模拟裸眼视图中无法看到。 Cr...
This image from the NASA/ESA Hubble Space Telescope shows IC 2051, a galaxy in the southern constellation of Mensa (the Table Mountain) lying about 85 million light-years away. It is a spiral galaxy, as evidenced by its characteristic whirling, pinwheeling arms, and it has a bar of stars slicing through its center. This galaxy was observed for a Hubble study...
NGC 3175 is located around 50 million light-years away in the constellation of Antlia (the Air Pump). The galaxy can be seen slicing across the frame in this image from the NASA/ESA Hubble Space Telescope, with its mix of bright patches of glowing gas, dark lanes of dust, bright core, and whirling, pinwheeling arms coming together to paint a beautiful celest...