Look east around 4 a.m. local time, just before dawn, to see the slender form of the crescent moon climb above the horizon.

The bold question-askers at What If explore whether life could survive on Venus given its gravity is 91% that of Earth's.

Over the course of that violent stretch, which lasted about 500 million years, Mercury, Venus, Earth, Mars, and the moon were regularly pounded by asteroids, meteors, and other cosmic ordnance ...

Mercury, Venus, Earth and Mars are terrestrial planets. They have a solid surface and are mostly made of metals or silicate minerals – where the rocks are composed of silicon, oxygen and other ...