NASA discovered a record number of potentially habitable planets orbiting another star.
NASA announced that the agency’s Spitzer Space Telescope has discovered a system of seven Earth-sized planets orbiting another star. Three of the planets fall well within their host star’s habitable zone and may host water at their surface. The findings were published Wednesday in the journal Nature.
The discovery marks the first time a planetary system comprised of seven Earth-sized planets orbiting a single star has been found. The planetary system also set a record for the greatest number of planets found within the habitable zone of a star.
Initial observations indicate that all seven planets are Earth-sized, are likely to be rocky in composition and have the potential to have water. Three of the planets lie in the star’s habitable zone where liquid water can be sustained at the surface. Additional observations will be required to determine if any of the planets have water at their surface.
“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 NASA’s Science Mission Directorate said in a statement. “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 planetary system is known as TRAPPIST-1, named after the The Transiting Planets and Planetesimals Small Telescope in Chile that first discovered three planets transiting the star in 2015. It is the first star observed by the Chilean telescope that has been found to have transiting planets. TRAPPIST-1 is located approximately 40 light-years away from Earth in the constellation Aquarius.
The TRAPPIST-1 star is classified as an ultra-cool dwarf, which means that liquid water can survive on the surface of planets that orbit much closer to it than stars such as the sun. All seven of TRAPPIST-1’s known planets have orbits closer to their host star than Mercury’s orbit is to the sun.
The planets have orbits so close to one another that according to NASA, “If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.”
NASA’s Spitzer Space Telescope assisted by other ground-based telescopes, including European Southern Observatory’s Very Large Telescope, confirmed the existence of two of the three planets originally discovered by the TRAPPIST telescope and uncovered five additional planets transiting the same star, bringing the total to seven.
“The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star,” according to Michael Gillon, lead author of the Nature paper. “It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds.”