More planets could contain water than previously believed

By Gwyn Wright via SWNS

More planets could contain water than previously believed increasing the likelihood of habitable worlds, according to a new study.

Scientists say many planets are too light to be made up purely of rock and could instead consist of around half rock and half water or another lighter molecule.

Researchers compare this to the difference between picking up a bowling ball and a soccer ball- they are both around the same size but a soccer ball is much lighter.

The study’s authors say the water is likely to be embedded in rock rather than flowing on the surface in oceans and rivers.

Water is probably mixed into the rock or exists in pockets below the surface.

These conditions are similar to those of Jupiter’s moon Europa, which is thought to have liquid water underground.

The findings match a theory of how exoplanets, which are planets outside the solar system, form.

The theory, which had fallen out of favor with academics in the past few years, suggests many planets form from clumps of ice and rock in cold conditions far out in their solar systems before being pulled towards their suns by gravity.

Thanks to better telescopes, scientists are discovering more and more planets in distant solar systems.

By observing more planets, they are able to better understand patterns that are difficult to pick out by just looking at individual planets.

For the study, the team from the US and Spain looked at 43 planets which revolve around a type of star called an M-dwarf.

These are the most common type of star we see around us in the galaxy and dozens of planets around them have been discovered so far.

However, because stars are so much brighter than planets we cannot see the actual planets themselves.

To understand these planets, scientists look for faint signs of their effect on their stars.

Two different ways of looking at planets can give people different information.

By catching the shadow created when a planet crosses in front of its star, scientists can work out the diameter of the planet.

By measuring the tiny gravitational pull that a planet exerts on a star, they can work out its mass.

When these measurements are combined scientists can get a better idea of the makeup of the planet.

For example, it could be a large planet made up mainly of gas like Jupiter or a small, rocky planet like Earth.

This has been done for many individual planets but rarely for as many as the team examined.

“It was a surprise to see evidence for so many water worlds orbiting the most common type of star in the galaxy," said the study’s first author Dr. Rafael Luque from the University of Chicago.

“It has enormous consequences for the search for habitable planets.”

While the evidence from the study is compelling, the team would like to see further proof that one of the planets they studied is a water world.

They are hoping to do that using JWST, NASA’s brand-new telescope that is set to replace the Hubble Telescope.

The findings were published in the journal Science.