Life on Earth might not be alone.
Scientists have discovered a rocky, Earth-sized planet that might also be home to water – a critical component for life as we know it.
The planet, Kepler-186f, is the fifth and outermost world orbiting a slow-burning, red-dwarf sun known as Kepler-186. It’s about 500 light years away from Earth, making it invisible to the naked eye.
Scientists discovered Kepler-186f using NASA’s Kepler telescope, which scans the skies for Earthlike worlds. This planet, just one of roughly 1,800 worlds that have been found outside our solar system, stood out for two reasons:
First, it was within its sun’s “habitable zone,” neither too close nor too far from for lakes, rivers and oceans to exist as liquids.
Second, at about 1.1 times the size of Earth, the planet is also the right size. If it were much larger than Earth, it would buildup a thick atmosphere or hydrogen and helium, similar to the atmospheres that the “gas giants” Jupiter and Saturn have in our own solar system.
Planets are more likely to be habitable if they are no more
than 1.5 times the size of Earth.
“One of the most interesting questions in science is whether life can arise on other planets or, alternatively, if life on this planet is unique,” said scientist Fred Adams, who co-authored a paper on the discovery, in a statement sent to reporters. “The discovery of planets with Earthlike properties is one important link in the chain required to answer this question. And the discovery of the planet Kepler-186f is an important step toward finding a planet that is like our Earth.”
Kepler-186f was found by researchers using NASA’s Kepler telescope, which scans the skies for Earthlike planets. Adams, a theoretical astrophysicist and a professor at the University of Michigan, helped researchers analyze the telescope’s findings, which included estimating Kepler-186f’s radius and orbit by observing how its sun dimmed as the planet passed by.
“We found that this solar system does seem to be stable, it can be formed under reasonable conditions, and the planet is likely to be rocky, or Earthlike, and not gaseous,” Adams said.
Further examination, though, may prove a challenge: Kepler-186f’s solar system might be too dim to allow deeper study’s of the planet’s atmosphere. Systems with brighter suns, combined with a new generation of NASA telescopes that are being constructed, likely prove the best candidates for finding habitable planets.
"Our research tells us that we should be able to find planets around bright stars that will be ideal targets to observe with James Webb,” Elisa Quintana, an astronomer at NASA and the SETI Institute, which searches for extraterrestrial intelligence, said in a statement, referring to the James Webb orbiting telescope.