In the 2005, scientists found a planet orbiting Gliese 581. The scientists, led by Stephen Vogt, used a method called Doppler spectroscopy to find the planet and some facts about the planet. They said that the planet, named Gliese 581b, has a size close to the size of Neptune (the eighth planet in our solar system). They found that 581b weighs 16.6 times as much as the Earth, and that its orbit around GL 581 lasts for 5.366 days.