The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, colder neighbor.

Making Mars Earthlike is not impossible in principle, but the scale of mass, heat, oxygen, and energy required makes it far beyond current capability.

Like Earth, Mars was formed about 4.5 billion years ago, but its early surface was very different than today's. Mars' surface then had high rates of meteorite and asteroid impacts from the period ...