New Planetary Discovery

Scientists have discovered more than 300 planets outside of our solar system and this week, they found one more.    Only about twenty light years away from Earth, it orbits a red dwarf called Gliese 581.  The planet is known as Gliese 581e and there’s building science buzz around this little planet for two reasons. First, it’s the lightest exoplanet ever discovered at only about twice Earth’s mass and, second, its discovery means that its neighboring planet, Gliese 581d may very well be in the habitable zone of its star.

To date 346 plantes have been dicovered around 292 stars. Most exoplanets that have been identified are gas giants like Jupiter and Saturn. They’re just simply easier to detect, since they affect the orbit of the surrounding bodies to a greater degree. It’s only because Gliese 581 is a very small star that the gravitational pull of a small planet can be detected. This discovery speaks volumes for the future of exoplanet exploration.

A more tantilizing debate is around whether or not Gliese 581e is really in its star’s habitable zone.  The habitable zone is a very specific area around a sun in which water can exist in its liquid form. Of course, this would differ from star to star and depend on a variety of factors, like the mass of the planet and the nature of its atmosphere. Some scientists dispute that this new Gliese 581d is anything more than another ball of ice.