A planet that could potentially host life has been discovered orbiting Proxima Centauri, the star closest to our solar system, according to a report published Wednesday by more than 30 international scientists in the journal Nature.
The planet, dubbed Proxima b, is about the same size as Earth. Scientists say its location within the habitable zone of the red dwarf star it orbits suggets it may support liquid water, which could possibly harbor life forms.
“The host star is about a thousand times fainter than the sun, so in order to warm up the planet similar to Earth, it has to get very close,” said Michael Endl, a research scientist at the University of Texas at Austin and one of the study’s authors. “It’s at the right temperature to have liquid water stable. It’s not too hot to boil off and not too hot to totally freeze.”
In fact, the 4.3 million miles between the newly discovered planet and star it orbits represents roughly 5 percent of the distance between the Earth and sun.
Scientists haven't actually seen Proxima b. Instead, they discovered the planet by observing and measuring how the star it orbits “wobbles” from the gravitational pull of the planet.
“We’re not detecting the planet at all, which is interesting, but from the behavior of the star we can infer it has a planetary companion,” Endl said.
The changing velocity of the star repeated every 11.2 days, which is how the orbit period was determined.
Scientists believe Proxima b doesn’t rotate as it orbits, which indicates that one side of the planet is constantly bathed in light while the other side remains dark. If life were to thrive on Proxima b, it would have to be on the side receiving light.
To determine whether the planet is truly suitable for life, Endl said researchers must find out whether it has an atmosphere or magnetic field, like Earth does.
Proxima b is the closest exoplanet, or planet orbiting a star other than the sun, to Earth. But at a little more than four light-years away, a trip to the planet wouldn’t be short – Endl said it would take about 80,000 years for a contemporary spacecraft to reach it.
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