An exoplanet only becomes habitable when it falls under the category of a rocky planet. More importantly, it should lie within what is considered as habitable zone in space. In the great desire of humans to look for a planet that may be habitable to human life, astronomers explore every possibility there is. In fact, they have long assumed why some planets may be explored for a possible life to flourish and why others are not.
This is the area in space when the planet's distance from a star can exist. It should also mean that the planet has water or any other liquid in its surface. However, a new study suggests that even the icy, frozen planetscan theoretically be capable of supporting life in general.
"You have all these planets that may not traditionally be considered as habitable, but the new report says that it might be habitable after all," said Adiv Paradise, lead author of the study and astronomer and physicist from the University of Toronto.
The new study looked into the potential of "snowball planets," most of them the size of the Earth. They also have oceans that go a long way to their equators. The researchers tested several simulations of different climates in snowball planets. They worked by manipulating variables like the amount of sunlight at which the planet receives as well as the positioning of the continents. One particular factor that came into play was the amount of carbon dioxide in the atmosphere. The presence of the carbon dioxide in the atmosphere keeps the heat trapped within warming up the surface of the planet.
If the levels of carbon dioxide in the atmosphere of the planet is low, it would be impossible for the planet to warm up; thus it would always be the snowball planet that it is. This happens when a heavy rainfall that absorbs the carbon dioxide, turns it into acid which then causes erosion on the surface rock. The acid is then broken down, sinking into the seafloor, gradually removing the presence of carbon dioxide in the atmosphere.
In the simulations they have created, snowball planets come with some land area that was getting warm enough to host possible water on its surface, even if the rest of the planet even up to their equator remains frozen. This only shows that these planets are capable of hosting life even at their cold state.
In support of these theories, the authors have also pointed out 'snowball' episodes of the planet Earth and how despite that, it was able to breathe in life to a lot of the creatures in it. "Back then, all of the lives survived in the oceans, there was nothing about the land in it," Paradise said.
The findings of this new study were published in the Journal of Geophysical Research.
