In 1994, finding planets orbiting other sun-like stars was still something of a dream. Then, just a year later, the first one was found, opening a floodgate of discoveries.

We know of nearly 500 other planets orbiting other stars. However, the methods of finding these exoplanets are indirect. We measure their effect on their parent stars, but we didn't directly see the planets themselves... until 2005, when the first image of an actual world orbiting another star was announced.

As of October 2010, only 7 such planets have been imaged, but we'll soon have more. This gallery shows the best of these images, including the first alien solar system to have its picture taken.

The picture above is an artist's drawing of the planet Gliese 581c. Until recently, the only tool we had to see alien planets was our imagination. But that's changed... it'll be a long time before we get pictures as detailed as this, but in the meantime, we're still getting amazing images and learning a lot about these exotic worlds.

Click the image to go to the next one in the gallery, or use the nifty index slider at the top of the post.

Original Gliese 581 c blog post: Possible earthlike planet found in the Goldilocks zone of a nearby star!

Artwork credit: ESO