Water found on alien worlds, extraterrestrial life a possibility

Scientists have found in a study that water is common on alien worlds. This discovery comes from an extensive survey of the chemical compositions of 19 exoplanets, conducted by a team of researchers led by the University of Cambridge.

The data for the research were collected using an array of different telescopes - both in space and on the ground.

Researchers have stated that this could change the understanding of how planets form, and where alien life might be found. 

Finding water elsewhere in the universe is likely to be central to discovering whether aliens exist elsewhere in the universe as water is thought to be a key component of extraterrestrial life.

An exoplanet or extrasolar planet is a planet outside the Solar System. Data from the sample exoplanets were used to get detailed measurements of the chemical and thermal properties of exoplanets. 

The sample included a wide variety of different worlds: from relatively small ones, smaller than Neptune, to ones only ten times bigger than Earth to extrasolar planets that are 600 times bigger than our own planet. The temperature in those places range between 20 degrees Celsius to more than 2,000 degrees Celsius. 

Across many of those exoplanets water has been common; albeit, with greater variety in levels. Scientists also discovered that there was less water on those planets than expected.

"We are seeing the first signs of chemical patterns in extra-terrestrial worlds, and we are seeing just how diverse they can be in terms of their chemical compositions," said project leader Dr Nikku Madhusudhan from the Institute of Astronomy at Cambridge.

There is much more carbon relative to hydrogen in the atmospheres of the giant planets than there is in the sun in our solar system. It is thought to have come about at the formation of the planets, when large amounts of ice and other particles were pulled into the planet, scientists say. 

There will be a similar situation on other giant exoplanets. This entails that there should also be large amounts of water on those planets, the research suggested. 

Researchers found presence of water vapour in 14 of the 19 planets, and also an abundance of sodium and potassium in six planets. But they also found that there was less oxygen relative to other elements, and that they might have formed without gathering significant amounts of ice.

"It is incredible to see such low water abundances in the atmospheres of a broad range of planets orbiting a variety of stars," said Dr Madhusudhan.

"The new data gives us a detailed understanding of exoplanets that we don't even have of our nearest neighbours," he added. 

Lead author of the study and a PhD student at the Institute of Astronomy at Cambridge, Luis Welbanks said: "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."

"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," Dr Madhusudhan further commented.