The National Aeronautics and Space Administration (NASA) announced today (Feb. 22) it has found seven Earth-sized planets – three of which are firmly within a habitable zone – around a star about 40 light years away from Earth.
The discovery, by NASA’s Spitzer Space Telescope, is historic in several ways. It sets a record for the greatest number of habitable-zone planets found around a single star outside Earth’s solar system, and – although the chances of finding liquid water are highest on the three habitable-zone planets – all seven planets could have liquid water under the correct atmospheric conditions. Liquid water is an important element because it is key to life as understood on Earth.
The planetary system is called TRAPPIST-1, named for the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, which was used to find the first three planets in the system.
Robert Morehead, director of Texas Tech University’s Preston Gott Observatory and an instructor in the Department of Physics & Astronomy, recently completed his dissertation on exoplanets and systems with multiple planets are his particular interest. He can discuss the implications of the discovery for the potential of extraterrestrial life and for scientists’ understanding of the galaxy.
Robert Morehead,Preston Gott Observatory director and instructor, Department of Physics & Astronomy, (806) 834-7940 or [email protected]
- The TRAPPIST-1 star system has seven nearly Earth-sized planets that we see pass in front of the small star they are orbiting. Three of these planets are at the right distance from their star so that water could be liquid on their surface. This is often called the habitable zone or “Goldilocks Zone” – not too hot, not too cold.
- Since the star is so small and dim, the TRAPPIST-1 planets orbit very close to the star and each other. This means scientists can learn a lot about the planets by measuring both their mass and radius, so we know they are very likely to be rocky planets like Earth and the other inner planets in our solar system.
- Three planets with the potential to have similar conditions to Earth make this a very interesting system to look for signs of life with future telescopes. Since most stars in the galaxy are more like TRAPPIST-1 than the Sun, finding a system like this that is so relatively close is more evidence that suggests potentially habitable planets might be very common in our galaxy.