Exoplanets (or extra solar planets) are simply planets that exist outside of our solar system. Most of the time these exoplanets are “giants,” about the size of Jupiter, and occur by themselves or with one other planet. The discovery being considered for publication by the journal Astronomy and Astrophysics, though, shows seven exoplanets orbiting the star HD 10180, one of which is very close in size to Earth.
Hunting exoplanets is not an easy activity, to say the least. Unable to see the planets against the glare of the star they orbit, scientists use telescopes and highly sensitive devices to measure the star’s “wobble.” By observing the movement of a star over time, it is possible to determine the gravitational forces working on it and, as a result, the potential planets orbiting it. (The larger the exoplanet, the more gravitational pull, which explains why most of the systems discovered contain planets much larger than our own.) Other detection techniques are also used in conjunction to further identify size and composition. This is not an easy task when you consider how far away they are! HD 10180 is approximately 100 light years away from Earth.
As more and more exoplanets are discovered, scientists are becoming confident that planets and systems like our own exist. Now, if only someone could figure out a way of getting us there in less than 100 years…