Earth is percieved as a rocky planet, what are other planets like? Did you know Mars is cold and that outer planets are really gigantic gas envelopes? What about a liquid planet? Could such a planet ...

When the solar system was first organizing itself, a disk of gas and dust took shape around the sun's central mass. It eventually sorted itself into the system of planets we see today. But there are ...

Generations of scientists have tried to explain how the solar system began. None of the explanations is wholly adequate. The trouble is that the solar system is not a haphazard collection of planets ...