London – British astronomers have discovered the nearest Earth-like planet that could be home to alien life.
Named Proxima b, it orbits Proxima Centauri, the closest star to our sun.
At 4.2 light years away, in space terms it is right on the doorstep – and high speed spaceships now being devised could reach it within decades. In time, scientists say, the rocky planet 1.3 times the size of Earth could even be colonised by space travellers.
Proxima b is thought to be only 4.7million miles from its star, one-twentieth of the Earth’s distance from the Sun. Its year lasts just 11.2 of our days.
One side may be perpetually stuck in daytime, while the other experiences perpetual night. But Proxima Centauri, part of the Alpha Centauri star system, is much smaller and cooler than our sun.
This means Proxima b lies within the “habitable zone” where it is not too hot or too cold but just right for liquid water – and thus life – to exist, according to the research team, who published their findings in the journal Nature.
While other planets with the potential to sustain life have been identified, Proxima b is by far the nearest to Earth. An artist’s impression shows a mountainous surface, bathed in an eerie red light. Researcher Professor Richard Nelson of Queen Mary University of London said it may be bathed in vast, deep oceans. “This is the sort of discovery that you dream of as an astronomer,” he added.
The first hints of Proxima b’s existence came from work done at the University of Hertfordshire in 2013. Powerful telescopes in Chile’s Atacama desert detected “wobbles” in the movement of Proxima Centauri which were characteristic of it being tugged by a planet’s gravity.
But it has taken until now for scientists to be confident of their findings. Co-author Dr John Barnes, of the Open University, said: “If further research concludes that the conditions are suitable to support life, this is arguably one of the most important scientific discoveries we will ever make.”
Dr Guillem Anglada-Escude, also of QMUL, who led the international research team, told New Scientist: “I think of [it as] something like Mars, as it is under a red sun. A planet with polar caps, reddish on the surface, maybe with a thin atmosphere. Succeeding in the search for the nearest terrestrial planet beyond the solar system has been an experience of a lifetime.
“We hope these findings inspire future generations to keep looking beyond the stars. The search for life on Proxima b comes next.”
Any life would have to be able to survive powerful UV rays and X-ray flares that bombard the planet.
Conventional spacecraft would take many thousands of years to reach Proxima b. But Professor Stephen Hawking and Facebook chief Mark Zuckerberg have announced Starshot – an ambitious project to build tiny laser-driven spaceships that could accelerate to a quarter of the speed of light.
On Wednesday night, Proxima b become the project’s primary target. The aim is to launch probes within the next two to three decades.
They would take 20 years to reach Proxima b. Photos of the planet would then take another four years to be beamed back to Earth. Professor Abraham Loeb, chairperson of the Starshot advisory board, said: “A spacecraft equipped with a camera and various filters could take colour images of the planet and infer whether it is green (harbouring life as we know it), blue (with water oceans on its surface) or just brown (dry rock). The curiosity to know more about the planet – most importantly whether it hosts life – will give the Starshot initiative a sense of urgency.”