'Eyeball Earth' Planets Could Hold Extraterrestrial Life
According to scientists, planets that resemble giant eyeballs due to the unusual distribution of ice, water and land, may exist around red dwarf stars and may be capable of supporting life.
When a planet is very close to its star, the gravitational pull of the star can force the world to become tidally locked with it. This means that the planet has a permanent day on one side and a permanent night on the other. The result is an unusual world in which the night side would be covered in any icy shell, while the day side would hold a giant ocean of water. "For me, the eyeballs are just one example of the plethora of crazy things we are finding out there in space," study lead author Daniel Angerhausen said.
The idea of an eyeball Earth, as such a world is called, was spurred by the detection of an exoplanet called Gliese 581g about 20 light-years away, which may be the first known potentially habitable alien world.
Given the differences between the day and night sides of eyeball Earths, "they are potentially the easiest habitable terrestrial planets to detect and distinguish," Angerhausen said. However, it is not yet known how easy they are to detect and how habitable they really are.
Angerhausen and his team will be investigating these matters by carrying out a project in Brazil called ‘Exploring Habitability of Eyeball-Exo-Earths’.
The scientists first aim to construct a variety of eyeball Earth models that vary in mass, distance from their stars, how much radiation they receive, magnetic field strength and their ice composition and density. By providing general and extreme cases of stable and transient eyeball Earths, they can help predict how well telescope surveys can detect and characterize them. The researchers then aim to test how well life could survive on an eyeball Earth by using a planetary simulation chamber. The researchers will test the survival and genetic activity of the microbes to see how well they behave.
According to Angeerhausen: "These planets — water, eyeball or snowball — will most probably be the first habitable planets we will find and be able to characterize remotely. That’s why it is so important to study them now."