It’s Earth, but not as we know it!
By Victoria Allen, Frazer Norwell and Tom Leonard.
Scientists have found the first planet other than earth that could support life.
The bad news is that K2-18b is 110 light years away, so far deo moue solar system that with current rocket technology it would take 2 million years to get there.
On the bright side, it does have water, an atmosphere and the right temperature to make it habitable. Astronomers now say it is “the best candidate for habitability that we know right now.”
It is less than 30 years since we first discovered the first ‘exoplanets’ outside our own solar system. Of more than 4,000 discovered since, K2- 18b- found four years ago- is the first to show clear signs it could host life.
It is in the “Goldilocks zone’ of its solar system- the right distance from the sun for the temperature not to be too hot nor too cold for the existence of liquid water, considered crucial for the existence of life as we know it.
Despite having a cooler ‘red dwarf’ sun, it orbits closer to its sun than Earth does to our Sun, so receiving the same amount of heat. Although water vapour has been found on similar exoplanets, K2-18b is the first to lie within a Goldilocks Zone.
Scientists, including a team from University College London, who have been studying K2-18b suspect it may have oceans and an atmosphere that is up to 50 percent water vapour.
At 17,700 miles across it is twice the diameter of Earth and eight times heavier, meaning it is classified as a Super-Earth.
K2-18b is not the first planet thought to have water, signs of which have been found on 40 planets including Mars. But most of those planets are too hot and hostile to support life- and, unlike Mars, K2-18b has an atmosphere that can deflect damaging cosmic radiation that might otherwise kill living creatures.
The planet, in the constellation of Leo, is too far away for astronomers to see it. But, using data from Hubble Space Telescope, the UCL team developed algorithms to analyse the starlight filtered through K2-18b’s atmosphere as it passed around its sun.
This showed the presence of water vapour. They also detected hydrogen and helium. The researchers, whose study is published in the journal Nature Astronomy, stress that they have found no signs of life, and do not have the technology to do so yet.
The next step is using a new generation of telescopes to search for the presence of methane or nitrogen, which would indicate the presence of bacteria or more complex life forms.
Researchers hope the James Webb telescope, which will begin capturing images in early 2021, could detect chemicals.
Dr Angelos Tsiaras, from UCL’s Centre for Space Exochemistry Data, first author of the study said, ‘It’s the only planet outside our solar system that we know has the correct temperature, an atmosphere and water.’ But he cautioned against seeing K2-18b as a planet humans could one day move to from Earth.
‘Finding water in a potentially habitable world other than is incredibly exciting but K2-18b is not “Earth 2.0”as it is significantly heavier and has a different atmospheric composition.’ he said.
‘The search for habitable planets, it’s very exciting, but it’s here to always remind us that this is our only home and it’s probably out of the question that we will be able to travel to other planets.’
K2-18b has also been studied by scientists at the University of Montreal in Canada, who reached the same conclusions. Professor Bjorn Benneke and his team believe the planet is covered in clouds of water droplets.
‘That’s in some ways the “holy grail” of studying extra-solar planets… evidence of liquid water’ he said. But K2-18b’s thick atmosphere probably prevents life as we know it existing on the planet’s surface.
‘There is certainly not some animal crawling around on this planet,’ he told Space.com