Hygeia was first seen in 1849 as a moving spot in a telescope. It’s thought to have formed into its current shape between 2 billion and 3 billion years ago, when it collided with another asteroid.

The observations have shown that Hygeia could be classified as a dwarf planet. The object is said to be the fourth-largest asteroid in the belts behind Ceres, Vesta, and Pallas.

Two billion years ago, one world was destroyed, but a new one was born. Hygiea, the 4th largest asteroid in the main-belt, is the result of this catastrophic disruption of an asteroid. A team of ...

Although it's just 270 miles across — about as big as Alabama — the asteroid Hygeia has surprised astronomers by being round.