Historic Potentially Earth-Like World Proxima B
The historic discovery of potentially Earth- like world Proxima-b was announced 24 August 2016. Orbiting Proxima Centauri, a Red Dwarf star in the habitable zone and the nearest star to our own Sun Proxima-b marks not only the closest alien planet ever found but also with the potential to be habitable.
This artist’s impression shows what the sky might look like on Proxima Centauri b if the planet has a surface. The exoplanet orbits the red dwarf star Proxima Centauri, currently the closest star to the solar system at 4.2 light-years. The other two members of the Alpha Centauri triple, Alpha Centauri A and B, would appear in the sky, too.
ESO / M. Kornmesser
If this proves to be the case, then there is no shortage of time for some form of life to originate based on the fact that red dwarf stars such as Proxima Centauri burn for trillions of years.
From the point of view of the average Earth-based visitor stopping by for a summer vacation, Proxima-b runs the risk of being a rather boring holiday resort. The sun-tan would be awesome, not so much so the destruction of the biological cells exposed to the intensely dodgy UV radiation that is present. Combined with the prospect of heavy duty sun-screen to protect from the sun’s constant bombardment of energy flares bouncing around the planetary surface probably wouldn’t be classed as entirely awesome either. On top of which the Proxima Centauri flares would also banish any hope of using mobile phones, tablets, X-boxes or any other such devices thanks to its electronics-disabling qualities. so no ET calling home and definitely no Skype!
Although it is a tidally locked planet– roasting hot on its star- facing side, freezing cold on the other, there is also enough wind around in the atmosphere to circulate the heat, balancing out the extreme temperatures that would otherwise exist. None-the-less a visit to the the planetary darkside, where it is bathed in perpetual night could prove to be the safest, and possibly the only option.
Unfortunately astronomers are choosing to be particularly pessimistic about this little world following the initial euphoria and have currently decided it is probably a dead, airless rock that will never harbour life due to it’s close proximity sun (20x nearer than Earth to the Sun) creating a risk of it boiling off the water and thereby stripping away the planet’s atmosphere. Researchers its oxygen will be gone in about 10 million years. Life on Earth took billions of years to develop.
Young M dwarf stars can unleash dangerous flares, (“planet-frying radiation”) that strip off atmosphere-forming oxygen spelling doom for closely orbiting planets. NASA Goddard Space Flight Center / S. Wiessinger
However hope lives eternal. Theoretically it is possible life could advance to endure the high levels of radiation, by altering the worst of Proxima Centauri’s emissions into inoffensive visible light. We know this is plausible, because due to a process known as biofluorescence this —has already happened on many occasions on Earth.
Ultimately It is expected that the 2018 launch of The James Webb Space Telescope, will provide answers to the critical question of whether there is any chance at all that Proxima b is capable of supporting life.
Proxima b – Habitable ‘Ocean Planet’??
Another possibility is the Proxima b could be an ocean world whose entire surface consists of a liquid ocean. This may bear a similarity to the Jupiter and Saturn moons that are icy worlds with subsurface oceans.
On the other hand the more optimistic researchers suggest that Proxima b may in fact be habitable after all. So don’t put the suitcases back in the attic just yet intrepid cosmic holiday makers! If Proxima b had in reality formed further out from it’s sun than its current position this would also offer a high possibility of there being water. This idea is based on the outer realms of planetary systems being more likely to form ice. If it then moved inwards for a up closer and more personal relationship with its sun then this ice could melt and form seas. Maybe 😉
Proxima b – A Desert World??
But it still seems most likely, according to Victoria Meadows (University of Washington), that this exoplanet is a desert world since the radiation bombarding it would almost certainly have evaporated the majority of the water. This process could have collected the oxygen and hydrogen in the water and created an atmosphere rich in oxygen. Then again it could a 2nd Venus with an atmosphere rich in Carbon Dioxide, or even another Uranus or Neptune.
The Other Closest Habitable-Zone Worlds
If all else fails cosmic holiday makers may wish to try some of the nearby, potentially habitable exoplanet worlds, for size….: Kapteyn b (13 light-years away) and Wolf 1061 c (14 light-years). Both planets are just over half again as wide as Earth, with minimum masses of 4 to 5 Earths, and both are in their stars’ habitable zones. Wolf 1061 c does not look at all hopeful in terms of habitability. But Kapteyn b looks good. It’s about 3½ times farther from its sun than Proxima b is from its sun so potentially it could be far enough out of reach of its sun’s rather violent output to provide a half decent holiday resort!