Ever since the cameras of NASA's New Horizons mission discovered a large heart-shaped structure on the surface of the dwarf planet Pluto in 2015, this "heart" has puzzled scientists because of its ...

Object hurtling towards supermassive black hole may be low-mass star and a disc of planet-forming matter Discovery hints planets could form in the heart of galaxy Astronomers say planets could be ...

At the planet's heart lies the inner core ... But unlike its rocky siblings, almost 70 percent of Earth's surface is covered in oceans of liquid water that average 2.5 miles deep.

The first layer is the crust, a thin outer shell that extends about 18 miles (30 km) below the planet's surface. The next layer, the mantle, stretches about 1,800 miles (2,900km) below Earth's ...