Ceres is the largest object in the asteroid belt between Mars and Jupiter. It was once thought to be just the largest of the asteroids there, but now planetary scientists are starting to call it a protoplanet: An object that was well on its way to becoming a true planet in the early days of the solar system before it ran out of “food” (smaller asteroids colliding with it and adding to its size).
By Phil Plait | Bad Astronomy
And while you might be hard pressed to compare it to Earth —it’s far smaller, colder, rockier, airless, and and and— there is one striking similarity it has to our home world: It’s covered in water.
New results from the Dawn spacecraft indicate the presence of water all over Ceres. Now mind you, at an average distance of 400 million kilometers from the Sun, that water is in the form of ice, but still. This is very cool news!