Astronomers Find Three Earth-Sized Planets And Plan To Search Them For Alien Life

Three planets in orbit around an ultracool dwarf star 40 light years from the earth appear to be the same size and temperature as earth and Venus. They also seem to harbour the promise of life outside the solar system.

This is the first time ever that astronomers from MIT, the University of Liège and other areas of the world discover planets in orbit around a distant star.

A 60-centimeter TRAnsiting Planets and PlanetesImals Small Telescope (TRAPPIST), based in Chile, was used in order to focus on 60 nearby dwarf stars. These are not visible to optical telescopes. By analyzing the stars at infrared wavelengths, TRAPPIST can search for planets near their area.

TRAPPIST focused on the ultracool dwarf star 2MASS J23062928-0502285. This has been renamed TRAPPIST-1. It is about Jupiter's size---one-eighth that of our sun, yet much cooler.

Scientists found that the two innermost planets orbit the star in 1.5 and 2.4 days. However, the radiation received is just four and two times the amount received by the earth.

The third planet orbits the star anywhere from four to 73 days, receiving less radiation than the earth.

The three planets seem to have regions with temperatures within a range of below 400 kelvins in order to sustain water and life.

Being just 40 light years away, their atmospheric compositions, habitability, and life conditions can be researched much more by the experts.

"These planets are so close, and their star so small, we can study their atmosphere and composition, and further down the road, which is within our generation, assess if they are actually inhabited," said Julien de Wit of MIT and co-author of the study. "All of these things are achievable, and within reach now. This is a jackpot for the field."

"We will investigate what kind of atmosphere they have, and then will search for biomarkers and signs of life," he added. "We have facilities all over the globe and in space that are helping us, working from UV to radio, in all different wavelengths to tell us everything we want to know about this system. So many people will get to play with this [system]."

The findings were published in the May 2 issue of Nature.