[NASA/APOD/오늘의 천체사진] 화성의 나트륨 꼬리

Mercury's Sodium Tail Image Credit & Copyright: Sebastian Voltmer Explanation: That's no comet. Below the Pleiades star cluster is actually a planet: 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 Sun.

Sunlight also liberates these atoms fro.....