Little is known about the long-destroyed moon-forming planet, Theia. But it may have been born in the inner solar system—just like Earth—a new study suggests ...

Space has a knack for bending our sense of scale. The Moon feels close enough to touch—after all, we see its craters with ...

To our best of our understanding, the Moon formed from Earth following a colossal impact. A Mars-sized world we nicknamed ...

Discover how scientists have used iron isotopes to determine the likely origin of the Mars-sized planet named Theia.

Scientists traced the Moon's parent planet Theia to the inner Solar System, solving a 4.5-billion-year mystery.

If you know any bit of information about how the moon was created, new research indicates that everyone has believed wrong.

New research suggests Earth's Moon formed from the catastrophic collision of our planet with its "sister" planet, Theia, born nearby. This "sibling" planet theory, supported by iron isotope evidence, ...

Here's everything you need to know about this week's parade of seven planets. Getty Images A seven-luminaries-deep parade of planets will line up and light up the night sky this week, folks. Just ...

The moon's orbit isn't a perfect circle. Instead, it's more stretched out, kind of like an oval, which means its distance from Earth varies by about 30,000 miles (48,000 km). The surface of the moon ...

Is the moon a star or a planet? The correct answer is "neither," but that's not the consensus reached when the argument comes up in this funny TV clip. During a recent show for the QVC shopping ...