We are all in the gutter, but some of us are looking at the stars.
Posted 29 May 2007 - 01:06 PM
awesome...i hope they find an actual planet that is a little further away from the sun...and not a gas giant
Most of the exoplanets found so far have been detected by noticing a slight "wobble" in the motion of parent star caused by the planets orbiting them. This method is not yet sensitive enough to detect small, rocky, planets like the earth so it tends to find gas giants or massive rocky planets (which have been nicknamed "super Earths"). In order to know whether the planet is there this wobble must be observed for at least half an orbit of the planet. The so called "hot Jupiters" and "hot Neptunes" can be detected with just a few days of observation. A planet as far out as Earth requires that it's parent star be observed for at least 6 months. To find a planet in an orbit as far out as Jupiter would require an observation period of close to 6 years. This method, therefore, currently favours worlds that orbit close to their star. The longer the search go on the more planets will be discovered that orbit further out. This method will always favour finding massive planets though.
This is all about to change. The French satellite, COROT, launched last year used a totally different technique to search for planets. It looks for transits. This is when the planet appears to move across the face of it's star. As it does so the brightness of the star will dip and then return to normal once the planet has moved on. This technique has been employed with some success using Earth based telescopes but COROT, orbiting above the atmosphere, should have a much higher degree of sensitivity. This technique can spot small, rocky worlds in distant orbits as long the planets orbit is correctly aligned so that it transits the star as seen from Earth. COROT has already detected its first planet.
NASA is also building a planet finding mission, called Kepler. Kepler will be launched in November 2008 and will have a larger and more sensitive telescope than COROT.
"Space is big. Really big. You just won't believe how vastly, hugely, mind-boggingly big it is. I mean, you may think it's a long way down the street to the chemist, but that's just peanuts to space." - The Hitch-Hikers Guide to the Galaxy - Douglas Adams 1952 - 2001