Are there planets MORE suitable for life than Earth? ‘Superhabitable' worlds may exist in nearby solar systems



These planets would likely be three times larger than Earth and much older

Study says liquid would be found in shallow reservoirs rather than oceans

The planets would have a magnetic field to shield them from space weather



Scientists also believe tidal heating could create conditions where life would emerge on an icy planet once thought to be uninhabitable



The search for alien life has so far focused on planets that are similar to Earth.

But astronomers may have missed a trick by looking too closely at worlds that are like our own, according to a new report.

The study suggests there may be planets that do not necessarily look like Earth, but that could have environments more favourable to supporting life.



Scroll down for video



Superhabitable worlds would most likely be two to three times bigger than Earth and much older, the researchers say. Given these characteristics, Alpha Centauri B, a member of the closest stellar system to the sun, is an ideal target for searches of a superhabitable world

‘In my point of view, astronomers and biologists are biased,’ Rene Heller, an astrophysicist at Canada's McMaster University who is the study's lead author, told NPR.

POTENTIAL FEATURES OF A 'SUPERHABITABLE' PLANET

Scientists believe 'superhabitable' planets would most likely be two to three times bigger than Earth and much older. They believe any liquid would be found over the surface of the planet in shallow reservoirs rather than in giant, deep oceans.

Like Earth, the planets would have a magnetic field to shield them from space weather. However, scientists predict that the planets would have much thicker atmospheres.

In the study ‘Superhabitable Worlds’, Professor Heller proposes that tidal heating can create conditions where life could emerge on an icy or terrestrial planet once thought to be uninhabitable.

Tidal heating is the frictional heating of a satellite's core caused by the gravitational pull of its parent planet and possibly neighbouring satellites.

These planets would most likely be two to three times bigger than Earth and much older, the researchers say.

They believe any liquid would be found over the surface of the planet in shallow reservoirs rather than in giant, deep oceans.



Given these characteristics, they claim Alpha Centauri B, a member of the closest stellar system to the sun, is an ideal target for searches of a superhabitable world.



'From a potpourri of habitable worlds that may exist, Earth might well turn out as one that is marginally habitable, even bizarre from a biocentric standpoint,' the researchers write.



In the study 'Superhabitable Worlds', Professor Heller proposes that tidal heating can create conditions where life could emerge on an icy or terrestrial planet once thought to be uninhabitable. Pictured is an artist's impression of an exoplanet

WHAT IS THE GOLDILOCKS ZONE?

The Goldilocks zone is the belt around a star where temperatures are ideal for liquid water to pool on a planet's surface. To determine the location of a star's habitable zone, scientists have to first learn how much total radiation it emits.

Knowing precisely how far away a habitable zone needs to be from a star also depends on chemistry.

For example, molecules in a planet's atmosphere will absorb a certain amount of energy from starlight and radiate the rest back out.

How much of this energy is trapped can mean the difference between a turquoise sea and erupting volcanoes.

Like Earth, the planets would have a magnetic field to shield them from space weather. However, scientists predict that the planets would have much thicker atmospheres.

‘A tidally heated planet would be unpleasant though spectacular to visit,’ said Norman Sleep, Senior Editor for Astrobiology and Professor in the School of Earth Sciences at Stanford University.

Current studies suggest that super-Earths are more common than Earth-size planets



So far, scientists have detected about a thousand planets orbiting other stars in something known as the Goldilocks zone.

The Goldilocks zone is the belt around a star where temperatures are ideal for liquid water to pool on a planet's surface.

This has started a race to find the one that most resembles Earth. But in a separate study, UK researchers suggested that Earth-sized planets can support life at least ten times further away from stars than previously thought.

This means that cold rocky planets previously considered uninhabitable may be teeming with life beneath the surface.

Academics at the University of Aberdeen and University of St Andrews believe the definition of the ‘Goldilocks’ zone is flawed.

They argue this definition fails to take into account life that can exist beneath a planet’s surface.