Planets Similar To Earth Might Be Right Next Door
The artist's conception shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. Credit:NASA
A planet suitable for life might be a lot closer to Earth than previously thought.
Scientists at the Harvard-Smithsonian Center for Astrophysics have determined that about six percent of the galaxy's red dwarf stars have Earth-sized planets located in the ideal position for the existence of liquid water. Now, they're not sure whether or not these planets are made up of rock or gas, but their research does open up new possibilities in the search for extraterrestrial life.
Out of the 95 planets scientists analyzed that are orbiting red dwarf stars, three of them were discovered to be within the "habitable zone," the range at which a planet's temperature could sustain life. These planets were approximately the size of Earth, and the closest one is only 13 light-years away.
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"We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined," said Natalie Batalha, Kepler mission scientist at NASA's Ames Research Center, according to the agency's Jet Propulsion Laboratory.
Since red dwarfs make up three out of every four stars in our galaxy, they offer astronomers nearby venues to search for life. Red dwarfs are only about 33 percent the size of our own sun, and they don't burn nearly as bright or generate as much heat. Ultimately, that means the habitable zone for Earth-like planets is closer to the heat-generating star than it would normally be, resulting in an environment that could be quite different than what we're used to seeing on Earth. If life were to exist, it may need to be in a radically different form in order to survive in such a unique environment.
"This close-in habitable zone around cooler stars makes planets more vulnerable to the effects of stellar flares and gravitational interactions, complicating our understanding of their likely habitability," said Victoria Meadows, professor at the University of Washington, Seattle, and principal investigator with the NASA Astrobiology Institute. "But, if the planets predicted by this study are indeed found very nearby, then it will make it easier for us to make the challenging observations needed to learn more about them, including whether or not they can or do support life."
It may be a long shot, but by extending the search for life to planets orbiting red dwarf stars, scientists only increase the odds of making a highly anticipated discovery that many think is inevitable.