It's Confirmed: An Earth-Like Exoplanet Has Been Found in Our Nearest Star System

Wednesday, 24 August 2016 - 1:46PM
Astronomy
Astrobiology
Wednesday, 24 August 2016 - 1:46PM
It's Confirmed: An Earth-Like Exoplanet Has Been Found in Our Nearest Star System
Earlier this month, rumors started flying that astronomers had found a small, terrestrial planet orbiting in the Goldilocks zone of Proxima Centauri, which lies in the nearest star system to ours. This is the closest Earth-like planet ever discovered, and may well be the most exciting astronomical discovery of the century.

The rocky planet, called Proxima b, orbits small red dwarf Proxima Centauri, which is in the same star system as Alpha Centauri, the closest star to Earth. It is a much smaller and fainter star than our Sun: it's approximately ten times smaller than our Sun and its luminosity is only .15% of our Sun's. But since Proxima b has a much tighter orbit than Earth's (its year lasts for only eleven Earth days), it lies within the temperate range that allows liquid water to exist on the surface.

Scientists from the University of Hertfordshire first observed the planet in 2000, and posited the existence of a planet in 2009, but didn't have enough evidence to reach a conclusion. The latest observation campaign was called Pale Red Dot, and aimed to detect the "wobble" of a star, or the slight back-and-forth movement caused by the gravitational pull of planets as they orbit the star.

Proxima Centauri is a relatively active star, which means that its movements and active features can often mimic the activity caused by nearby planets. But a new study, published today in Nature, confirms that the wobble wasn't caused by any active features on the star, but a terrestrial planet approximately 1.3 times the size of the Earth, with temperatures that comfortably allow for liquid water.

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"Once we had established that the wobble wasn't caused by star spots, we knew that that there must be a planet orbiting within a zone where water could exist, which is really exciting," co-author Dr. John Barnes of Open University said in a statement. "If further research concludes that the conditions of its atmosphere are suitable to support life, this is arguably one of the most important scientific discoveries we will ever make."
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There's still much that we don't know about Proxima b, including whether it has an atmosphere or not. As a result of Proxima Centauri's activity, the planet is exposed to 400 times the number of x-ray fluxes as Earth, which may have wiped out any atmosphere long ago. But still, this is definitely one of the most promising candidates for extraterrestrial life that will be accessible to humans in the foreseeable future.

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"Succeeding in the search for the nearest terrestrial planet beyond our Solar System has been an experience of a lifetime, and has drawn on the dedication and passion of a number of international researchers," said lead author Dr. Guillem Anglada-Escudé from QMUL's School of Physics and Astronomy. "We hope these findings inspire future generations to keep looking beyond the stars. The search for life on Proxima b comes next."
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