Planets are more than a billion times dimmer than the stars they orbit, which is why it's so hard to see them. Even indirect methods are tricky. A transit of another Earth would dim a star such as the sun by less than a hundredth of one percent. This is one reason Guinan is excited about red dwarfs, also called M dwarfs. They hold less than half the sun's mass and give off less than a tenth of its energy. If an Earth-size planet passes in front of a red dwarf, it will cause a relatively big dip in the star's brightness compared with what Kepler would see if the same planet transited a bright star like the sun. Another reason red dwarfs are so interesting is that they make up about 80 percent of the stars in the galaxy. In the last two years, astronomers have begun to find some of the most Earth-like planets yet around red dwarfs - not quite Earths, but a class called "super Earths." Ranging from two to about 20 times the size of our planet, super Earths may be covered in ice, rock, or even oceans. But could planets around such low-wattage stars sustain life? Guinan's calculations show it's possible.
Kepler looking at Red Dwarfs
The whole thread (35 posts)
- Kepler looking at Red Dwarfs
- The supernova hail. an active SETI technique.
- re: Kepler looking at Red Dwarfs URL problem fixed here
- The SETI implications
- What are alien "Keplers" seeing?