Proxima Centauri, our neighbour, could have earth-sized planet

Scientists' investigations of the closest star, Proxima Centauri, has show that there is an Earth-sized planet orbiting about it. What is more, this rocky globe is moving in a zone that would make liquid water on its surface a possibility. 

Proxima is 40 trillion km away but the discovery of a planet potentially favourable to life in our cosmic neighbourhood is likely to fire the imagination.

The distance between the star and its planet is considerably smaller than Earth's separation from the Sun (149 million km). But Proxima Centauri is what is termed a red dwarf star. It is much reduced in size and dimmer compared with our Sun, and so a planet can be nearer and still enjoy conditions that are potentially as benign as those on Earth.

Scientists have found that this planet is at 5% of the Earth's distance from the Sun. However, Proxima is 1,000 times fainter than the Sun. So the flux - the energy - reaching Proxima b is about 70% of what the Earth receives. It's like taking Earth a bit further away, but it's comparable.

Whether the temperatures on Proxima b are favourable for life to exist is going to depend on the presence of an atmosphere. An envelope of greenhouse gases would warm surface conditions and provide sufficient pressure to keep water - essential for biology - in a liquid state.

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