The Earth – Moon distance is on a scale. Did you think the Moon was this far from Earth?
The Moon probably originated because a protoplanet collided with the Earth, so part of the Earth’s crust flew away and formed the Moon. Therefore, the composition of the Moon is almost equal to the composition of the Earth’s crust. The Moon is only slightly smaller than the planet Mercury. There is almost talk of a double planet Earth – Moon.
Earth is also a rock planet with a core of Iron and Nickel. Iron and Nickel are heavy and therefore dropped to the center when the earth was completely melted. Most of the rocky material is still melted and our continents float on top of it, and on top of that lies water and air. The core of the Earth is 5000 C hot, as hot as the surface of the sun.
If you put all the water and air together, you get:
Walk a little further and find Mars