Numerous science fiction films have already played it through: If humanity has made the earth uninhabitable, it must move. But how likely is it to find a new home in space?
For the first time, astronomers have now detected water on an exoplanet outside of our solar system that also provides life-friendly temperatures.
The so-called Super Earth K2-18b circles around a dwarf star in the constellation Leo, about 110 light-years away from Earth. It has eight times the mass and more than twice the diameter of the earth, reports the research team led by Angelos Tsiaras and Ingo Waldmann from University College London in the journal Nature Astronomy. Astronomers call super terrestrials planets that are at least as heavy as Earth but lighter than Uranus.
"Is the earth unique?"
There are already numerous exoplanets known, which lie within the so-called habitable zone. That is, they circle around their sun at exactly the right distance, so that temperatures prevail that allow liquid water - the basic requirement for life as we know it.
Exoplanet K2-18b had already been discovered in 2015. But the detection of water in the atmosphere was only possible with the space telescope "Hubble". For this, the astronomers used a shadow play trick: When K2-18b moves from the ground in front of his home star, she shadows him a bit.
Which parts of the light are swallowed exactly reveals the chemical composition of the planet's atmosphere. In addition to water vapor, the researchers showed there hydrogen and helium. Clues to life on the planet they have not found so far.
MORE ON THE SUBJECT
"Finding water on a potentially habitable world beyond Earth is incredibly exciting," said Tsiaras. However, K2-18b is not a second earth because it is much heavier and has a different composition of the atmosphere. "Nevertheless, the discovery of an answer to the fundamental question brings us closer to reality: is the earth unique?" Says Tsiaras.
The properties of his sun speak against possible life on the exoplanet: the red dwarf star is very active and the planet is probably exposed to increased radiation.
Nevertheless, according to the researchers, further research is worthwhile. Probably the planet is only the first of many similar worlds.
