“rocky planet”簡單造句，rocky planet造句子

1、If a rocky planet is big enough - say, 10 times the mass of Earth - it can vacuum up so much hydrogen that its atmosphere ends up constituting most of the planet.

3、Mercury is known to have a high density in comparison with other rocky planets.

2、The surface formed mostly in the last billion years, which makes it fresher and more recently active than any rocky planet other than earth.