[ad_1]
A new study suggests that frozen extraterrestrial worlds could support greater diversity and complexity of life than previously thought.
Researchers already knew that life can persist icy snowballs, what sea ice sports all down to their equators. After all, it happened on Earth, which went through several snowball phases during its long history.
"But all of our life was in our oceans at that time," senior writer of the study, Adiv Paradise, astronomer and physicist at the University of Toronto, said in a statement. "There is nothing about the land."
Related: How do habitable areas around stars work (infographic)
The new study addresses this gap in knowledge. Paradise and his colleagues have made thousands of 3D computer simulations, modeling the atmospheres of theoretical snowball planets with a wide variety of continent configurations, stellar energy inputs, and carbon dioxide levels.
CO2 is a particularly important variable for modelers because the concentration of this heat-trapping gas is one of the most important drivers of climate change on the planet. We see it on Earth today, where temperatures are rising at an alarming rate because we are pumping huge amounts of CO2 into the atmosphere.
On the other hand, when there is not enough CO2 in the air, a planet can snowball. Geologists think that precipitation and erosion can contribute to this: The water reacts with CO2, generating carbonic acid, which then reacts with rocks and binds to minerals. These minerals eventually end up in the ocean, where they are locked at the bottom of the sea.
This graph shows the relationship between carbon dioxide produced by volcanic activity and carbon dioxide extracted from rainfall and erosion for temperate and snowball climates. Planets get stuck in the snowball when volcanic activity and weathering rates counterbalance each other.
(Image credit: AGU)
But this process does not necessarily exclude the possibility of a terrestrial life, discovered the researchers. Some of their modeled snowball worlds included patches of potentially habitable land, particularly inland areas close to the equator, which sometimes had temperatures above 10 ° C (50 ° F).
"You have those planets that you could traditionally consider un-habitable, and that suggests that they can be," said Paradise.
The team's work also offers other perspectives on the worlds of the snowball and the livability of the planet. For example, volcanic eruptions can shake a snowball planet by emitting a lot of CO2 and other greenhouse gases into the atmosphere. But that does not always happen, suggests the new study; Simulations of the researchers showed that erosion could balance the CO2 production of volcanoes.
Thus, the distinction between the worlds that can and can not support life as we know it is probably not as clear as the researchers had thought, said the members of the team d & # 39; study.
"What we find, in fact, is that this line is a little blurry," said Paradise.
the new study was published on July 18 in the Journal of Geophysical Research: Planets.
Mike Wall's book on the search for extraterrestrial life, "Over there"(Grand Central Publishing, 2018, illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on twitter @Spacedotcom or Facebook.
[ad_2]
Source link
