Other planets may not be “blue dots”

Modeling has shown that the terrestrial balance of water and land may be unique. Most exoplanets of similar mass may turn out to be either practically devoid of water, or water worlds. 

Earth-like exoplanet. Source: Wikipedia

Other planets may be completely different from Earth

Once upon a time, Carl Sagan, looking at a photograph of the Earth taken by the Voyager apparatus, called it a pale blue dot. Our planet is dominated by oceans, but land also accounts for a significant percentage of the surface. However, as Swiss and German scientists have shown in a joint study, things may not be the same for those planets that orbit other stars.

Even if a planet has a mass similar to Earth’s and rotates in the “habitable zone”, this does not mean that it will have a climate similar to Earth’s. The model created by scientists shows that about 80 percent of such worlds will not have oceans. At the same time, almost 20 percent should be completely covered with water.

Worlds with both land and oceans, according to these studies, should make up no more than one percent of the total. But even if you put together planets similar to Earth and oceanids, it still turns out that most of them will not be blue at all.

Geological processes and climate of exoplanets

The reason that most exoplanets are not similar to Earth is the correlation of geological processes. Crust formation forces continents to grow. Erosion erodes them. We have these two processes more or less balanced, but scientists are sure that this is not the case on most worlds.

At the same time, the model shows that both oceanids and worlds without seas will still be useful for life. Average temperatures will not differ by more than 5 degrees, but the heat distribution will differ significantly. On those planets dominated by water expanses, there will be a very humid and warm climate, similar to that on Earth in the Mesozoic era.

Worlds where oceans occupy less than 30 percent of the surface will not only be dry, cold and harsh. Most of their surface will be occupied by deserts, where there will be strong differences between frosty and warm weather. Most of all, their climate will resemble the Earth during the last glaciation.

According to phys.org

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