Is ‘Super-Earth’ home to alien life?
The extreme gravity would make walking impossible and the sunlight is so fierce that developing cancer would be inevitable.
Yet planet K2-18b, which lies about 110 light years away in the constellation Leo, is the first world to be found that could realistically support alien life.
In a groundbreaking discovery, scientists at University College London (UCL) have determined that the rocky planet contains liquid water and has an atmosphere, raising hope of finding living extraterrestrial organisms.
Water was detected by measuring light waves filtering through hydrogen molecules in the planet’s atmosphere, using data captured by Nasa’s Hubble Space Telescope in 2016 and 2017.
Although Hubble did not carry any instruments able to spot signs of life, such as methane, telescopes will soon be launched with the capability to look for biosignatures.
‘‘Finding water in a potentially habitable world other than Earth is incredibly exciting,’’ said Dr Angelos Tsiaras, of the UCL Centre for Space Exochemistry Data. ‘‘This is the only planet we know outside of the Solar System that has the correct temperature for liquid water, making it the best candidate for habitability that we know right now.
He added: ‘‘It brings us closer to answering the fundamental question: Is the Earth unique?’’
K2-18b was discovered in 2015 by Nasa’s Kepler mission, which was looking for worlds in the Goldilocks Zone, where the temperature is neither too hot nor cold for liquid water.
Water and an atmosphere are now thought to be crucial for life, so much so that scientists no longer think living organisms will be found on Mars, which was stripped of its atmosphere and water billions of years ago. In contrast, K2-18b is wet and warm enough for life. It is about twice the size of Earth and eight times the mass, orbiting a highly-active red dwarf star every 33 days, meaning one year is roughly the equivalent of a month on Earth.
‘‘We are hoping this is one of many ‘Super-Earths’,’’ said Dr Ingo Waldmann, of UCL. ‘‘We don’t really know what it’s like down there. It could be a water world, or we may have an entirely dry surface.
‘‘But it will certainly have a high surface gravity so it would be hard to walk on, and if you looked up you would see a red star. There is higher UV radiation on the surface and for life on Earth that would be bad, as we would all get cancer.
‘‘Maybe this is not quite your vacation destination just yet, but life may have evolved differently there.’’
Visiting would be impossible – the planet is 1000 trillion kilometres away and it would take 3.7 million years to get there travelling at 32,000kmh. The research was funded by the Government’s Science Technology Funding Council and published in Nature Astronomy.
Dr Colin Vincent, the head of STFC’s astronomy division, said: ‘‘Finding other planets that might have the capability to support life is one of the holy grails of the astronomy community.
‘‘This result gives an exciting taste of what may be possible in the next few years as a number of new telescopes and space missions come online.’’
– Telegraph Group