After 2025, a Russian spacecraft with a descent module will go to Venus. One of the main questions is where to target it. RIA Novosti, together with an expert, tells what the "planet of crimson clouds" is and what places are best for landing.
Where did the oceans go
Venus is similar to Earth in size, density, and possibly chemical composition. Based on this, scientists suggest that both planets formed at the same time in the same part of the protoplanetary disk and from the same material.
But the atmosphere, surface condition, physical conditions differ dramatically. Earth and Venus are like twins, separated immediately after birth and raised in different countries. Over billions of years, the Earth has turned into a blooming warm paradise full of life, and Venus has become a scorched desert without a drop of moisture.
It is possible, however, that there were oceans there once. There is only one argument in favor of this, but it is very convincing.
The main component of the water molecule, hydrogen is a light element that quickly evaporates. First, its main isotope leaves, then heavy ones, that is, deuterium and tritium.
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Russian planet
The first attempts to land spacecraft on Venus, undertaken by Soviet scientists in the 1960s, showed that the conditions there are very difficult. Due to the strong greenhouse effect, the surface temperature reaches almost five hundred degrees, the dense toxic atmosphere creates pressure, like on the ocean floor. The devices worked for only a few minutes, maximum an hour.
The last on Venus were the devices of the Soviet mission "Vega" in 1985. Since then, the planet has only been studied from orbit. But Russia intends to return. Several research teams together with their American colleagues under the leadership of the Space Research Institute of the Russian Academy of Sciences are working on the Venera-D (Long-lived) project.
At the end of March, the working group summed up the results of the second stage of research. It was, among other things, about a possible landing site.
A country chained in basalts
There are continents and oceans on Earth. Continents are ancient sections of the earth's crust towering over the oceans on a granite basement with a thick sediment cover. On the contrary, the ocean floor is composed of relatively young basalts and is strongly bowed.
There is nothing like this on Venus. There, the entire surface, as the gypsum gram shows, is relatively flat, of the same level. And it probably consists of basalts, that is, it was formed during the outpouring of volcanic lava. Scientists distinguish areas only by age, based on their relative position. The most ancient are called tessera.
Judging by the density of meteorite craters, the oldest sites that can be observed were formed at least half a billion years ago. Researchers consider this a conditional beginning of the history of Venus that we see.
Why the bowels of the earth after a couple of hundred million years of stormy life have calmed down is a big question. According to one of the versions, when the internal heat of the planet went to the surface along with magma, the lithosphere - the upper stony shell of the planet - thickened, blocking the path of the melt.
Perhaps there are active volcanoes on Venus somewhere, but they have not yet been observed.
Where to put the device
It is these plains that researchers consider as priority landing sites.
Craters with a smooth bottom look tempting. On Mars, rovers are planted there.
In his opinion, landing on impact plains is not so interesting, since the ejected material can change significantly as it passes through the atmosphere.
The volcanic plains are better preserved, given that there is no weathering on Venus, as on Earth. That is, rocks on the surface are not destroyed by water, wind, temperature drops.
Thus, scientists choose from two types of smooth volcanic plains. The first was probably formed from the material of the upper mantle, the second was melted from the planet's crust.
