If Planet Nine Is Out There, It May Not Be Where We Think

Remnants of an ancient planet buried inside the Earth may be the cause of a weak spot in the magnetic field

Nearest Exoplanet to Our Solar System: Jupiter-Mass Planet Orbiting Epsilon Eridani

The remnants of an ancient planet might be buried inside Earth. New research suggests the Moon-forming Theia impactor (a Mars-size body that struck Earth 4.5 billion years ago) might have merged with our planet, forming two dense clumps in Earth's mantel that still exist to this day.