(The Moon is currently about 384,000 km or 60 Earth radii away from Earth, which is about fifteen times further away than it was when it first formed.) The Moon probably couldn't have formed closer than 3 Earth radii because tidal forces from the Earth would just pull it apart again, and it is unlikely that the impact could have ejected material ...
About 78% of Earthâs atmosphere is made up of nitrogen. Credit: NASA We might commonly think of Earth as having an oxygen-dominated atmosphere, but in reality the molecule makes up only a fifth of our air.
Are there planets that are not composed of rock, like Mercury, Venus, Earth and Mars? Are there planets where there is no land, just all nothingness? Yes, there are, they are known as a Gas Giants, they are large celestial bodies that are instead made up of gases. They may have a solid core, and their storm-laden atmosphere is very thick. They are all so large they could fit ten Earths. Solar Systemâs outer planets Jupiter, Saturn, Uranus and Neptune are all gas giants. Jupiter and Saturn are composed mainly of molecular hydrogen, metallic hydrogen and helium.