保护地球, 探索宇宙, 发现文明
2022年1月3日 Comet Leonard’s Long Tail Image Credit & Copyright: Jan Hattenbach Explanation: You couldn’t see Comet Leonard’s extremely long tail with a telescope — it was just too long. You also couldn’t see it with binoculars — still too long. Or with your eyes — it was too dim. Or from a city — the sky was too bright. But from a ...
2020年7月8日 Mercury’s Sodium Tail Image Credit & Copyright: Andrea Alessandrini Explanation: What is that fuzzy streak extending from Mercury? Long exposures of our Solar System’s innermost planet may reveal something unexpected: a tail. Mercury’s thin atmosphere contains small amounts of sodium that glow when excited by light from the S...