WATER is “common” across alien worlds according to the most extensive study of exoplanet atmospheres yet.
Scientists say it offers hope in the hunt for life on other planets – and could improve how we target our search.
Exoplanets are alien worlds that sit outside our own Solar System, and are key to finding alien life.
A team of researchers at the University of Cambridge studied the atmospheres of 19 exoplanets
Some of these were Neptune-like planets around 10 times heavier than Earth, while others were toasty “super-Jupiters” 600 times bigger still.
They found that water vapour is “common in the atmospheres of many exoplanets”.
However, scientists were also surprised to find that the amounts of water vapour were lower than expected.
“We are seeing the first signs of chemical patterns in extra-terrestrial worlds,” said Dr Nikku Madhusudhan, of the Institute of Astronomy at Cambridge.
“And we’re seeing just how diverse they can be in terms of their chemical compositions.”
The study found that there was an “abundance” of water vapour in 14 or the 19 planets surveyed.
There was also evidence of lots of sodium and potassium in six planets each.
It’s a major scientific coup for those investigating the possibility of life on other planets.
“Measuring the abundances of these chemicals in exoplanetary atmospheres is something extraordinary, considering that we have not been able to do the same for giant planets in our solar system yet – including Jupiter our nearest gas giant neighbour,” said Luis Welbanks, lead author of the study, and PhD student at the Institute of Astronomy.
Measuring water vapour on Jupiter is very difficult, and not for lack of trying.
“Since Jupiter is so cold, any water vapour in its atmosphere would be condensed, making it difficult to measure,” said Welbanks.
“If the water abundance in Jupiter were found to be plentiful as predicted, it would imply that it formed in a different way to the exoplanets we looked at in the current study.”
Alien-hunting scientists will now be able to use the findings of this study to better hone their hunt for life.
“Given that water is a key ingredient to our notion of habitability on Earth, it is important to know how much water can be found in planetary systems beyond our own,” said Madhusudhan.
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