Look up this evening towards the constellation Aquarius and you may be looking at another Earth — seven of them in fact. NASA announced this week that the Spitzer space telescope has found seven earth-sized planets orbiting a small, dim star closely enough to allow for liquid water. Three of the planets are within the so-called “habitable zone,” the area around a star most likely to support life.
The TRAPPIST-1 system, named for the the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) that first identified three of the planets last spring, offers the greatest opportunity yet to determine if life exists beyond Earth.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “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.”
TRAPPIST-1, at 40 light years away, relatively close to us. It’s star is substantially cooler than the earth, allowing planets very close to it to still be cool enough to allow liquid water. The next step will be further analysis of the chemical components of their atmosphere to determine whether the basic building blocks of life, principally water, exist on the planets.
NASA will be following up with further study with the Spitzer, Hubble, and Kepler space telescopes in advance of the upcoming James Webb Space Telescope, launching in 2018, which will be able to observe the TRAPPIST-1 system with far greater sensitivity. Webb, according to NASA, “will be able to detect the chemical fingerprints of water, methane, oxygen, ozone, and other components of a planet’s atmosphere. Webb also will analyze planets’ temperatures and surface pressures–key factors in assessing their habitability.”
The newly discovered planets, known as exoplanets, are closely grouped. Close enough together in fact that standing on the surface of one of the planets, the other nearby planets would be easily visible, appearing larger than the moon in the sky.
“This is the most exciting result I have seen in the 14 years of Spitzer operations,” said Sean Carey, manager of NASA’s Spitzer Science Center at Caltech/IPAC in Pasadena, California. “Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”
The discovery promises the possibility that the question of whether the miracle of life is unique to Earth could be answered within our lifetimes.