保护地球，探索宇宙，发现文明
2020 April 27 Fresh Tiger Stripes on Saturn’s Enceladus Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team Explanation: How will humanity first learn of extraterrestrial life? One possibility is to find it under the icy surface of Saturn’s moon Enceladus. A reason to think that life may exist there are long features — dubbed tiger stri...
2019 October 18 Interstellar Interloper 2I/Borisov Image Credit: NASA, ESA, and D. Jewitt (UCLA) et al. Explanation: After the 2017 detecton of 1I/’Oumuamua, comet 2I/Borisov has become the second recognized interstellar interloper. Like ‘Oumuamua, Borisov’s measured hyperbolic trajectory and speed as it falls toward the Sun confirm that it...
2019 October 17 Moons of Saturn Image Credit: Cassini Imaging Team, SSI, JPL, NASA Explanation: On July 29, 2011 the Cassini spacecraft’s narrow-angle camera took this snapshot and captured 5 of Saturn’s moons, from just above the ringplane. Left to right are small moons Janus and Pandora respectively 179 and 81 kilometers across, shiny 504 kilom...
在这张由美国国家航空航天局（NASA）的卡西尼号（Cassini）探测器于2007年拍摄的图片中，土卫二（Enceladus）的羽状物清晰可见。从卡西尼号的角度看去，月球几乎就在太阳前面。 版权：NASA/喷气推进实验室-加州理工学院（JPL-Caltech） 从土卫二（Enceladus）喷发出的羽状物中发现了新的有机化合物，即氨基酸的成分。这些发现是对NASA卡西尼号任务数据继续进行深入挖掘的结果。 强大的热液喷口将来自土卫二核心的物质向外喷发，这些物质与土卫二巨大的地下海洋中的水混合在一起，并以水蒸气和冰粒的形式被喷射到太空中。新发现的分子凝聚在冰粒上，被确定为是含氮和含氧的化合物。 在地球上，类似的化合物是产生氨基酸的化学反应的一部分，氨基酸是生命的基石。海底的热液喷口为这些反应提供了能量。科学家们认为...