The newfound planet Proxima b is the closest planet outside our solar system and its potential to host life. You probably have questions, and we have answers
Scientists have announced the discovery of an Earth-sized planet orbiting the star (Proxima Centauri) nearest our Sun, opening up the glittering prospect of a habitable world that may one day be explored by robots. Named Proxima b, the planet is in a "temperate" zone compatible with the presence of liquid water — a key ingredient for life. The findings, based on data collected over 16 years, were reported in the peer-reviewed journal Nature. Proxima b would probably be the first exoplanet visited by a probe made by humans. An exoplanet is any planet outside our Solar System.
About Proxima b?
Proxima b is a rocky, terrestrial planet with a surface — unlike a gas giant, such as Jupiter — that is 1.3 times the size of Earth and orbits its star every 11.2 days. It orbits a red-dwarf star at 7.5million kilometres — just 5% of the distance between Earth and the Sun. But because its star is much cooler and fainter than our sun, Proxima b has a temperature that is suitable for liquid water to exist on the surface without evaporating.
How is the atmosphere?
Scientists don’t know whether it has an atmosphere or not. It all depends, they say, on how Proxima b evolved as a planet. "You can come up with formation scenarios that end up with and Earth-like atmosphere, a Venus-like atmosphere" — 96 percent carbon dioxide — "or no atmosphere at all," said co-author Ansgar Reiners, an expert on "cold" stars at the University of Goettingen's Institute of Astrophysics in Germany.
Computer models suggest the planet's temperature, with an atmosphere, could be "in the range of minus 30 degree Celsius (-22 Fahrenheit) on the dark side, and 30 degree Celsius (80F) on the light side," a researcher said. Like the Moon in relation to Earth, Proxima b is "tidally locked," with one face always exposed to its star and the other perpetually in shadow. An atmosphere would help deflect these rays, as would a strong magnetic field.
Is there a life on the planet?
Speculation is rife that as well as being habitable, Proxima b may already be home to life — but unfortunately for film fans, nothing like the spear-wielding blue Na'vi people of Pandora. At the moment, no one can tell. Dr Mikko Tuomi, from the University of Hertfordshire, said: "It is the closest possible exoplanet to us and may be the closest to support life outside the solar system. Proxima b is probably similar to Earth in some ways, in mass and temperature, for example, which ups the chance of finding life there. But it is also very different: unlike Earth, one side of the planet is probably in permanent daylight, the other in perpetual darkness. Life could evolve in these conditions, but it’s hard to say, given that we only know of one other example – our own. In any case, if life does exist on Proxima b, it’s more likely to be microbes than little green men.
Can we go visit it?
The planet is more than 25 trillion miles away, a distance that would take around 30,000 years to reach with current technology. As of now, the question of visiting the planet doesn’t arises.
Can’t we build something faster?
Early efforts are already under way. Recently, astrophysicist Stephen Hawking and Russian billionaire Yuri Milner have announced a new space exploration initiative called “Breakthrough Starshot”. The project aims for sending featherweight robotic spacecrafts to our nearest star system— Alpha Centauri — at one-fifth of the speed of light. These tiny 'nanocraft' will carry cameras and a built in GPS to hunt for alien life in Alpha Centauri star system. Technology for the mission will likely take about two decades to develop. After that, the probes would take roughly 20 years to reach their destination— which is 25 trillion miles (4.37 light years) away.
Are there other planets like Proxima b?
Yes. Some 3,500 exoplanets have been discovered since the first confirmed sighting in 1995. Most of these distant worlds -- like our own Jupiter and Neptune -- are composed of gas, an inhospitable environment for life. Even the 10 percent that do have rocky surfaces are mostly too cold or too hot to host water in liquid form. And — until today — the handful that are in a temperate zone are effectively beyond reach. Last year, for example, NASA unveiled Kepler 452b, a planet about 60 percent larger than Earth that could have active volcanoes, oceans, sunshine like ours, and a year lasting 385 days. But at a distance of 1,400 light-years, humankind would have little hope of reaching this Earth-twin any time soon.
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