Roughly four and a half billion years ago the planet Theia slammed into Earth, destroying Theia, melting large fractions of Earth’s mantle and ejecting a huge debris disk that later formed the moon.

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

Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A cloud of collapsing gas created our Sun, the first thing to form in ...

Theia, the world that helped form the Moon, came from the Solar System. Chemical clues in Earth and Moon rocks reveal this ...

When a meteor streaks across the sky, it's not just beautiful. It's nature's way of delivering a time capsule to Earth.

Moon’s precursor planet, Theia, disappeared billions ago, leaving scientists no direct chemical evidence to support the ...

Astronomers have discovered icy rocks in the outer solar system that seem to defy the laws of physics, suggesting the ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Curious Kids is a series for children of all ages. If you have a question you’d like ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Christopher Palma, Penn State and Lucas Brefka, Penn State (THE CONVERSATION) ...