Astrophysicists wonder where the water disappeared from the second planet of the solar system
A spacecraft flying past the Earth's twin discovered a leak of carbon and oxygen atoms from Venus, and this discovery is combined with previous ones data on the loss of hydrogen may provide the key to understanding the amazing transformation of the planet.
Photo : Wikipedia.org.
According to astronomers, planetary atmospheres tend to leak. The Earth loses about 90 tons of atmospheric matter every day. But it is believed that Venus was once a temperate planet like ours, with liquid water on the surface. Now the second planet of the solar system is losing carbon and oxygen.
“Determining the nature of the loss of heavy ions and understanding the mechanisms of their release on Venus is critical to understanding how the planet’s atmosphere evolved and how it lost all its water,” — explains astrophysicist Dominique Delcourt of the National Center for Scientific Research (CNRS) in France.
Despite the fact that Venus is its closest orbital neighbor and the most Earth-like planet in the solar system, there is not much information about Venus . At the moment, there is only one dedicated mission to study Venus close to – the Akatsuki orbiter, which has been studying the planet’s atmosphere since 2010.
BepiColombo — it is a joint mission of the Japan Aerospace Exploration Agency and the European Space Agency to study Mercury. Its mission included two close flybys of Venus, one in 2020 and the other in 2021. It is noted that during the second of them, the probe penetrated into that part of the magnetic field of Venus that had not previously been studied.
Venus does not have a magnetic field that is generated inside the planet, like Earth does. Most likely, its magnetic field is the result of a series of interactions between charged particles in Venus's upper atmosphere, magnetic fields, and moving ions in the solar wind. The result is a weak «sphere» magnetism, which has the shape of a drop, and its tail is carried away by the solar wind.
The magnetosphere is surrounded by a layer located between the outer boundary of the magnetosphere and a compressed substance called a shock wave. This is what BepiColombo flew through, between Venus and the Sun, almost touching the planet. And his instruments detected oxygen and carbon, which had somehow accelerated enough to overcome the planet's gravity.
«This is the first time that positively charged carbon ions have been seen escaping from the atmosphere of Venus, — explains astrophysicist Lina Hadid from CNRS. — These are heavy ions that usually move slowly, so we are still trying to understand the mechanisms at play here. Perhaps the electrostatic "wind" carries them away from the planet, or they can be accelerated by centrifugal processes.
At least three missions to study Venus are planned in the near future, which will shed light on many remaining questions. These include the carbon escape mechanism, volcanic activity on the planet, and the burning question of whether life could be hiding among the clouds.
Astrophysicists say recent results suggest that atmospheric leakage from Venus cannot fully explain loss of its historical water content.
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