Scientists want to know if habitable planets are common. And if they are, how close are some to us? Learn about Gliese 581, one of the 100 closest stars to us.

The largest spiral galaxy known to astronomers is Malin 1. Its disk of stars measures 650,000 light-years across, several times the diameter of the disk of our Milky Way galaxy. In 2007, a newly found image from the Hubble Space Telescope revealed that the central part of Malin 1 looks like an ordinary barred spiral galaxy, somewhat like our Milky Way.

On Oct. 11, 2006, astronomers witnessed a stellar outburst. It was labeled Supernova (SN) 2006jc. This same star had undergone a mysterious outburst two years earlier.

Early stargazers named Neptune for the god of the sea. Now the possibility exists for Neptune to have an ocean of its own ... someday. Astronomers say our sun will become a faint white dwarf star some 8 billion years from now. Then Neptune will cool, possibly causing rain to fall from Neptune's clouds - which might create a water layer, or ocean, up in Neptune's thick atmosphere.

Here's news about the most famous stellar nursery of all, the Orion Nebula. Previously, the distance to the Orion Nebula was estimated at about 1,500 or 1,600 light-years. But the Orion Nebula is actually closer than that by about 200 light-years, according to Rob Jeffries at Keele University in England.

... but that liquid isn't water. The lakes can't hold water because Titan is so far from the sun that any water on its surface would be solid ice. Instead of having liquid water, Titan's lakes are thought to be filled with methane in a liquid form.

Wolf 359 is one of the closest stars to Earth at only 7.8 light-years away. It is a red dwarf star, known to be a single star. Former studies of bright, easy-to-see stars indicated that most of them lie in multiple systems of two or three stars. But those earlier studies neglected small, faint stars like Wolf 359.

Most stars reside in a galaxy. In 2006, astronomers used the Hubble Space Telescope to study over 5,000 stars found in the space between galaxies in the Virgo cluster. The lack of iron in these stars indicated that they may have come from small galaxies that got ripped apart when they passed too close to larger galaxies.

Older dwarf stars, such as Proxima Centauri, have fewer flares and starspots (the stellar equivalent of sunspots). Read more about older dwarf stars here.

The astronomers who accomplished this research likened the effect to being able to look at the quasars under a microscope.