Frozen Earth-Like Planets Could Support Life

Eddie Gonzales Jr. – MessageToEagle.com – Icy planets once thought too cold to support life might have livable land areas above freezing, challenging the typical assumption of what kinds of planets might be habitable.

Scientists have long thought snowball planets – Earthlike planets with oceans frozen to the equator – were hostile to life because of the extreme cold. However, a new study shows that planets, found that some snowball planets might have areas of land near their equators that reach livable temperatures.

An artist’s rendition of what a snowball planet might look like. Ice covers the oceans to the equators. Credit: NASA

“You have these planets that traditionally you might consider not habitable and this suggests that maybe they can be,” Adiv Paradise, an astronomer and physicist at the University of Toronto and lead author of the new study, said  in  a press release.

The habitable zone is a range of distances from a star where a planet could theoretically have liquid water and temperatures warm enough to support life.

Planets in the habitable zone can be warm and temperate like Earth, or entirely frozen, like snowball planets.

“We know that Earth was habitable through its own snowball episodes, because life emerged before our snowball episodes and life remained long past it. But all of our life was in our oceans at that time. There’s nothing about the land,” Paradise said.

Paradise and his team used a computer program to simulate different climate variables on theoretical snowball planets, adjusting conditions like the amount of sunlight and configuration of the continents.

It was previously thought that carbon dioxide removal from a planet’s atmosphere stopped during snowball phases because all of its surface water was frozen.

The new study found some snowball planets continue to lose carbon dioxide even after they’ve frozen. This means the planets would have to have some non-frozen ground and occasional rainfall for water to continue to remove carbon dioxide from the atmosphere.

Some of the warmer snowball planets the study’s authors simulated had land areas warm enough to hold liquid water and life even when their oceans were frozen to their equators. They found land areas in the center of the continents away from the frozen oceans could reach temperatures above 10 degrees Celsius (50 degrees Fahrenheit).

This is much warmer than the lowest temperature at which life can reproduce, which scientists estimate to be minus 20 degrees Celsius (minus 4 degrees Fahrenheit).

The results also suggest Earthlike planets can become stuck in a snowball state under certain conditions.

Paper

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff