When searching for planets on whichthere is life outside our solar system, scientists tend to pay great attention to the planets like Earth. There is a certain logic in this, because if life could originate on our planet, then there is a probability of its occurrence in similar conditions. But this statement may be wrong. For example, recently a team of astronomers from the University of Toronto has demonstrated that life can exist in very extreme conditions. For example, on completely frozen planets.
Where are scientists looking for extraterrestrial life?
As a rule, potentially habitable are consideredsmall planets located at a certain distance from their star. This is necessary so that the temperature there is not too high so that the star “burns” the planet, and not too low so that the water can be kept in liquid form. However, the elongated shape of the orbit and the composition of the atmosphere can make such planets lifeless.
This is interesting: the rover found something on Mars. Life or not?
It is believed that such heavenly bodies may havepotentially habitable zones, located under a thick layer of ice that lasts thousands of years. However, as it turned out, life can not exist only in this way. A new study by a group of scientists led by Adiv Paradise shows that ice planets may have habitable land areas above freezing.
Our home planet, Earth, is in habitablea zone where the planet could theoretically have liquid water and a temperature sufficient to sustain life. But distance is not the only factor. If the orbits of the planets are too elliptical, the planets are inclined along their axis. In these cases, the oceans would freeze to the very equator, creating a snowball effect.
Similar icy planets are formed due tothe presence of carbon dioxide (CO2) in the atmosphere. As you know, as a result of volcanic activity a lot of carbon dioxide is formed. However, in parallel with this, there are processes of "weathering", that is, the removal of CO2 from the atmosphere. At the same time, at the moment when these processes counterbalance each other, the planets also get stuck in a “snowball” state, freezing “forever”. As shown on the graph below.
How did scientists understand that there could be life on frozen planets?
Experts from the University of Toronto decided to find outwhether there are areas on frozen planets that reach temperatures within which life can potentially exist. Therefore, using a computer program, they conducted several thousand simulations, adjusting conditions such as orbital parameters, the composition of the atmosphere, the amount of energy coming from the nearest star, distance from the star, the presence of land islands and so on.
As a result, scientists have found that these frozenthe planets may remain quite livable. For example, in land areas above freezing or even when there are sufficiently large continents, far from frozen oceans, the temperature may be above 10 degrees Celsius. This is quite enough for the existence of life and the release of a sufficient amount of carbon dioxide, which further heats the planet and potentially has the potential to melt its ice-covered oceans.
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