Here’s an artist’s depiction of the seven planets:

(NASA / JPL-Caltech)

The astronomers found the four newcomers by again measuring fluctuations in stellar light as the objects transited the parent star, revealing both their existence and information about their mass. (NASA/JPL-Caltech)

Forthy light-years from Earth, scientists have discovered seven "Earth-sized planets" in the largest-ever cache of planets found around a single star outside of our solar system. Three of these planets are located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system.All of the seven planets could have liquid water - key to life as we know it - under right atmospheric conditions, but the chances are highest with the three in the habitable zone. We get to test many theories about these worlds, being tidally-locked and amount of radiation coming from host star.”

Thomas Zurbuchen – the associate administrator of NASA’s Science Mission Directorate – was also on hand at the briefing. “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.”



 Seven Earth-sized planets have been observed by NASA’s Spitzer Space Telescope around a tiny, nearby, ultra-cool dwarf star called TRAPPIST-1. Three planets are in the habitable zone of the star, known as TRAPPIST-1e, f and g, and may even have oceans on the surface. Using the The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) telescope at the European Southern Observatory’s (ESO) La Silla Observatory in Chile, he and his colleagues first noticed the presence of two planets in the TRAPPIST-1 system in May of 2016. The discovery of the planets, which are all about the size of Earth or smaller, was announced at the NASA headquarters in Washington, DC, and published in the journal Nature on Wednesday. Based on preliminary climate modeling, the researchers believe that the three planets closest to the star may be too warm to support liquid water, while the outermost planet, TRAPPIST-1h, is probably too distant and cold to support water on the surface. As Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, said in a NASA press release:

Nikole Lewis, the co-leader of the Hubble study and an astronomer at the Space Telescope Science Institute, was also on hand at the NASA press briefing where the findings were announced. Standing on the surface of one of the planets, you would receive 200 times less light than you get from the sun, but you would still receive just as much energy to keep you warm since the star is so close. Demory said that future telescopes, including the James Webb Space Telescope, which is to succeed the orbiting Hubble Space Telescope, "will have the possibility to detect the signature of ozone if this molecule is present in the atmosphere of one of these planets".
NASA and the European Southern Observatory announce the discovery of four new Earth-like planets in the Goldilocks zone of the star TRAPPIST-1, in addition to the three discovered there last year.