The composition of comet Hartley 2 suggests that comets might have been a bigger source of Earth's water than previously thought. It's also challenging models of solar system formation.
Fried egg nebula: The European Southern Observatory's Very Large Telescope has spotted a massive yellow hypergiant star surrounded by a dusty double shell, prompting astronomers to think of breakfast.
Super-Earth: The newfound haul of alien planets includes 16 super-Earths, which are potentially rocky worlds that are more massive than our planet. One in particular has captured astronomers' attention because it orbits at the edge of its star's habitable zone, suggesting conditions could be ripe to support life.
Trojan asteroid: NASA has discovered that Earth has an asteroid companion traveling just ahead of our planet as it orbits the sun. This so-called Trojan asteroid could serve as a stepping stone to celestial objects farther afield.
Satellite Cassini flew through geyser plumes spouting from Enceladus and gathered ice crystals. These crystals are salt-rich, suggesting that a hidden salty sea lurks beneath Enceladus's icy cap.
NASA's Kepler spacecraft, which is searching for Earth-mass planets orbiting sun-like stars, is finding hundreds of candidate planets, and many more multi-planet systems than expected.
This wider view of Uranus reveals the planet's faint rings and several of its satellites. The area outside Uranus was enhanced in brightness to the faint rings and moons. The outermost ring is brighter on the lower side, where it is wider. It is made of dust and small pebbles, which create a thin, dark, and almost vertical line across the right side of Uranus (especially visible on the natural-color image).
For the first time, scientists have confirmed an exoplanet that is rocky like Earth – not a gas giant. It's also 2,500 degrees F and denser than iron, so it's no candidate for life, say members of the team working with the planet-hunting Kepler spacecraft.
A burping black hole, water in weird places, and whopper-size new planets are some top space stories of 2010. If you have different discoveries on your list, post them in the comments section.