A Cambridge team says in a study that water is "common" on other planets. The research could change our understanding of how planets form and where we can find extraterrestrial life.
The discovery comes from the largest survey of the chemical compositions of planets ever conducted and encourages us to search for extraterrestrial life and water on other planets within the solar system and elsewhere. In the recent past we have had evidence from individual exoplanets (a surprising is from this September).
The research
The researchers used data from 19 exoplanets to obtain detailed measurements of their chemical and thermal properties.
They looked at a wide variety of different worlds. From relatively small “mini-Neptunes” (only 10 times larger than our Earth) to “super-Jupiters” 600 times the size of our planet, and celestial bodies found in a temperature range between 20°C and 2000°C
Extraterrestrial water is common. That's life?
The result of this research was the finding that water was "common" in many of those exoplanets.
“We are seeing the first signs of chemical patterns in extraterrestrial worlds and seeing how different they can be in terms of chemical compositions,” said the head of the project, dr. Nikku Madhusudhan, of the Institute of Astronomy in Cambridge.
Using data from a wide range of different telescopes both in space and on the ground, the researchers they found out water vapor in 14 of the 19 observed planets, and an abundance of sodium and potassium in 6 planets.
Water on other planets, "little" but "almost everywhere"
Common water, therefore. But not abundant. The presence of oxygen in the observed exoplanets, and this is a surprising fact when talking about water, is lower than other elements. The "average" atmosphere of the exoplanets observed so far eliminates a good part of the oxygen as a common stain remover would do.
“It is incredible to see such a low amount of water in the atmospheres of so many planets orbiting a star”, says dr. Madhusudhan.
The new data give us a more detailed understanding of exoplanets than we have of the closest planets, scientists said.
“Measuring the abundance of these chemicals in exoplanetary atmospheres is something extraordinary, considering that we have not yet been able to do the same for planets in our solar system, including Jupiter, the gas giant closest to us”, he claims Luis Welbanks, one of the study's lead authors and a doctoral student at the Institute for Astronomy.
The discovery changes our understanding of extraterrestrial life and the presence of water on other planets.
“Given that water is a key ingredient in our notion of habitability on Earth, it is important to know how much water can be found in planetary systems beyond our own, to measure the presence of life on other planets”, he adds Madhusudhan. And the search for the planets with water (who knows, the next one could be Venus, also because clues to life on Venus there are) will be increasingly massive.
The findings, part of the immense 5-year research into the chemical composition of the atmospheres of planets outside the solar system, are reported in the magazine Astrophysical Journal Letters.
New impulse to search for extraterrestrial life.
