The anomalous temperature changes in the lower layers of the atmosphere of Venus, recorded by the Soviet Vega-2 in 1985, were generated by unusual differences in the behavior of carbon dioxide and nitrogen at ultrahigh pressures, according to an article published in the journal Nature Geoscience.
“Over the past 50 years, the United States and Russia have sent dozens of probes and a few descent vehicles to Venus, only one of which – Vega-2 – was able to reach the surface of the planet and measure its air temperature in the lower layers of the atmosphere.” At a distance of 7 kilometers from the surface, Abnormal “jumps” of temperatures that remained unexplained until today, “says Sebastian Lebonnois of the Sorbonne in Paris, France.
Venus, despite the conditions of formation similar to the Earth, differs in its external appearance from our planet. Thus, the atmosphere of the “morning star” is hot at 462 degrees Celsius, there is practically no water, its surface is covered with volcanoes, and the atmosphere consists of carbon dioxide and sulfuric acid. While among scientists there is no common opinion about how Venus could lose its water reserves and turn into a giant greenhouse.
In addition, according to Lebonnoy, the heaviest part of the Venusian atmosphere – a near-surface layer only 7 km thick, containing about a third of its mass – actually remains a white spot for scientists.
The fact is that all attempts to study the properties and chemical composition of Venusian air at this altitude or failed completely, as happened with American probes of the Pioneer-Venus series, or were carried out successfully, as was the case with the Soviet Venus and Vegami, However, the low accuracy of the tools did not allow them to obtain accurate data. In other words, until the planetologists have almost no information about what the Venusian air consists of at the surface of the planet.
For this reason, scientists today can not find an accurate explanation of why the temperature of different layers of air in the lower layers of the Venusian atmosphere changes sharply and differs by tens of degrees with a rise or fall in height by several tens and hundreds of meters. On average, the air temperature does not increase when approaching the surface of the planet, but falls, which has long been a mystery to scientists.
Lebonnoy and his colleague Gerald Schubert of the University of California in Los Angeles (USA) found a possible explanation for this, trying to build a model of the atmosphere of Venus on the basis of data from Vega-2, Venera-10 and a number of other probes and Descent vehicles.
Creating this model, scientists paid special attention to the two distinctive properties of Venus – the super-high density of the atmosphere and the fact that its air shell rotates much faster than the planet itself.
According to Lebonnoy, recent experiments with carbon dioxide and nitrogen, the two main gases in the atmosphere of Venus, have shown that they begin to behave in an unusual way at the pressures that reign over the surface of the morning star.
Calculations by planetologists have shown that differences in the reaction of CO2 and nitrogen to high pressures interfere with their mixing and cause CO2, as a heavier gas, to “sink” to the bottom of the atmosphere and accumulate at the surface, and nitrogen – to “float” into its less dense layers and accumulate there. As a result, there is, as the planetologists say, a kind of cycle of giant “bubbles” of both gases, constantly moving to the surface and from the surface of Venus.
The existence of these bubbles can explain why the Vega-2 recorded such a wide spread of temperature – a Soviet probe, as planetary scientists suppose, could fly through such “bubbles” of nitrogen and carbon dioxide upon landing on Venus, the temperatures inside which will differ significantly due to Different properties of these gases.
Of course, verification of all these theories is not yet possible, since for their confirmation or refutation it is necessary to carry out measurements in the concentration of CO2 and nitrogen at the surface of Venus. As scientists hope, the new descent devices, which are now thought to be created in NASA and Roskosmos, will finally solve the riddle of the last Soviet probe from Venus.