Dense metal planets like Mercury are probably rare in the universe
Thursday, September 6, 2018 - 09:50
in Astronomy & Space
The planet Mercury, the closet planet to our Sun, is something of an exercise in extremes. It's days last longer than it's years and at any given time, it's sun-facing side is scorching hot while its dark side is freezing cold. It is also one of the least understood planets in our solar system. While it is a terrestrial (i.e. rocky) planet like Earth, Venus and Mars, it has a significantly higher iron-to-rock ratio than the others.