Astronomers are buzzing about the discovery of a nearby exoplanet that’s about the same size as our home planet and with similar temperatures. Dubbed Ross 128 b, the newfound world is about 11 light-years from our solar system, in the constellation Virgo.
It's the closest temperate planet to be discovered after Proxima b, which is about 4 light-years away. In addition, it's the closest planet to have been observed orbiting an inactive red dwarf star — an arrangement that may raise the likelihood that it could sustain life.
No extraterrestrials have been spotted on Ross 128 b, nor even any alien germs. But the possibility that the exoplanet is habitable has excited some scientists involved in the ongoing search for extraterrestrial life (SETI).
“Twenty years ago, no one would have believed that red dwarf stars — the runts of the cosmos — were good candidates for biology,” Dr. Seth Shostak, senior astronomer at the SETI Institute in Mountain View, California, told NBC News MACH in an email. “But Ross 128 b is at least theoretically habitable — and what’s more, it’s extremely nearby.”
Other astronomers weren't so wowed by the discovery.
"This small advance in finding exoplanets will interest people who are especially interested in the search for life, but too many such moderately interesting announcements may turn off those who really want to hear only of real breakthroughs," Dr. Jay Pasachoff, an astronomy professor at Williams College in Williamstown, Massachusetts, told MACH in an email.
Ross 128 b was discovered by an international team of scientists using the High Accuracy Radial velocity Planet Searcher (HARPS), a light-splitting instrument mounted on a telescope in Chile. The telescope is maintained by the European Southern Observatory, a multinational astronomy organization with its headquarters in Garching, Germany.
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Statistical evidence suggests that Ross 128 b is a rocky planet, like the four innermost planets in our solar system. But whether it has liquid water on its surface — considered a critical ingredient for life — remains unknown. And "we still don’t know if Ross 128 b is Earth-like or Venus-like," Dr. Nicola Astudillo-Defru, an astronomer at the University of Geneva in Switzerland and co-author of a paper about the discovery, said in an email to MACH. "We have to wait for further observations to elucidate this question."
Going forward, ESO will likely use its Extremely Large Telescope to look for so-called "biomarkers" in the planet’s atmosphere, which could indicate the presence of life. But the telescope, now under construction in Chile, isn't expected to see first light until 2024. Astudillo-Defru said we might have to wait until the following year to determine whether biomarkers are present.
Let the countdown begin.