What If You Cut the Moon in Half?

What causes moonquakes? What would happen if half of our Moon drifted away? Has the Moon already split in half? As friendly neighbors in the sky, the Moon and Earth have...

What If Every Planet Had a Twin?

Our Solar System has eight planets, a few dwarf planets and more than 200 moons. But wait. Are you seeing double? Or did every planet suddenly get a twin? Where would...