NASA just discovered 7 Earth-sized exoplanets, 3 in the habitable zone of a dwarf star

Seven Earth-sized planets have been discovered around a star that’s roughy 39 light-years from our solar system, by a team behind NASA’s Spitzer Space Telescope. Three of these exoplanets are believed to orbit the star’s “Goldilocks zone,” the single largest haul of potentially habitable planets around a single star. The agency made the announcement today in a news conference and published the findings in the journal Nature.

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate, said in a press release. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

The exoplanets were discovered around TRAPPIST-1, an ultra-cool dwarf star 235 trillion miles from Earth. Compared to our Sun, TRAPPIST-1 is small and cold, making the habitable zone much closer to the star. Thus, the planets orbit very close to the star and close to each other.

By using data collected by Spitzer, the team was able to measure the exact size of the seven exoplanets, while making estimates of the mass and density of six of these. The measurements suggest that all of them are likely rocky.

“The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star,” said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey. “It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds.”

Atmosphere is necessary for life as we know if. As such, the  studying these planets’ atmospheres will be a major focus in the coming years.

“The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets,” said Nikole Lewis, co-leader of the Hubble study.

NASA released a 360º simulation of what it would be like to stand on one of the potentially habitable planets.