Exoplanets - We've found A LOT!

This week, we're looking at humanity's search for planets outside of our solar system, which we call exoplanets. While we can see stars outside of our solar system ("exostars?") easily because they emit light, seeing planets orbiting those stars is rather difficult. The first observation of an exoplanet orbiting a star wasn't made until 1995.

However, since then, we've found over 1700 exoplanets, with even more waiting to be found by NASA's ongoing Kepler mission. The Kepler mission uses the transit method of looking for a dimming of a star's light as a planet passes between the star and Kepler's view.

There are several great visual guides to learn about the exoplanets we've found; here are a few:

Some important planets discovered by Kepler: http://pbs.twimg.com/media/BujAPsrIEAAo2JG.jpg:large

xkcd's 786 planets to scale: http://xkcd.com/1071/ and interactive version: http://visual.ly/exoplanets-interactive-version-xkcd-1071?view=true

xkcd's set of habitable-zone planets within 60 light-years of earth: http://xkcd.com/1298/

Video of Kepler's candidates: http://www.universetoday.com/83200/video-visualization-of-kepler-exoplanet-data/