New research suggests that extraterrestrial life could survive on frozen Earthlike planets. Previously, this was unthinkable!
A team of astronomers at the University of Toronto ran thousands of simulations to explore the temperature fluctuations of planets inside habitable zones.
The research suggests some snowball planets might have areas of land near their equators that reach livable temperatures.
“You have these planets that traditionally you might consider not habitable and this suggests that maybe they can be,” said Adiv Paradise, an astronomer and physicist at the University of Toronto and lead author of the new study.
The habitable zone is the range of distances from a star where liquid water and life could exist.
But the new research says distance is not the only factor.
If a planet in the habitable zone has a very elliptical orbit, it’s too tilted on their axis, or other atmospheric and geological processes intervene, the planet could freeze. In these cases, the oceans would freeze all the way to the equator. Therefore creating a “snowball planet” effect which could be very hostile to life.
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Geologists suggest Earth has probably gone through up to three snowball phases in the past. They believe that marine microorganism likely survived through at least one of those periods.
“We know that Earth was habitable through its own snowball episodes because life emerged before our snowball episodes and life remained long past it,” Paradise said. “But all of our life was in our oceans at that time. There’s nothing about the land.”
So, to know if areas of land on snowball planets could reach life-sustaining temperatures, the team ran computer simulations. They created theoretical snowball planets, adjusting conditions like the amount of sunlight and configuration of the continents.
According to their models, these frozen planets could remain habitable under some conditions. Areas in the middle of continents away from the frozen oceans could reach temperatures above 10 degrees Celsius (50° Fahrenheit). That’s warm enough for life to flourish and to release enough carbon dioxide, further heating the planet and potentially thawing its ice-covered oceans.
So, the findings suggest that scientists need to rethink their ideas on what is a habitable planet and what’s not.