Atomic oxygen was first discovered on the “day” side of Venus

The second planet in our solar system in terms of distance from the Sun, Venus is the subject of many studies: despite its notable similarities to Earth, particularly in terms of size and composition, the two planets have had very different histories.

When the Earth evolved towards an environment suitable for the development of life, with moderate temperatures and climateclimate Relatively stable VenusVenusThe planet, sometimes referred to as Earth’s “twin sister,” has turned out to be a very inhospitable planet, with surface temperatures of around 462 degrees Celsius and an atmosphere-dominated planet. Carbon DioxideCarbon Dioxide So dense that the pressure on Earth is 92 times greater than on Earth. Scientists seek to understand betterAtmosphereAtmosphere The Venus complex in order to explain the mechanisms that led to its evolution differently from Earth.

A hellish world that is difficult to understand

Due to its relatively short distance from Earth, Venus was the first planet to be visited by a space probe (NASA’s Mariner 2 probe flew by Venus in 1962), and the first planet to be successfully landed by a lander (the Soviet Union’s Venera). Probe No. 7 landed on Venus in 1970). However, studying its surface and atmosphere is still very difficult.

In its thick atmosphere dominated by carbon dioxide – which gives it Global WarmingGlobal Warming It is so powerful that its surface temperature is on average higher than that of Mercury, the planet closest to the Sun cloudsclouds toSulfuric acidSulfuric acidAt altitudes ranging between 45 and 70 km. These clouds are highly reflective, meaning they reflect most of the light back into space. a lighta light The solar energy they receive. Venus’s atmosphere is thus so opaque that it is impossible to see its surface in visible light (by comparison, Earth’s surface can be easily seen from space in the absence of clouds).

Consequently, very little information was collected about the planet before technologies were invented that would allow it to be observed in other regions of the world. DomainDomain Electromagnetic – usually radar fields, InfraredInfrared And ultravioletultraviolet — allowing you to penetrate its dense clouds. And if these technologies arrive, they mark a veritable bond in advance for the exploration of this sulfurous planet, the scientists that enter the new discoveries, a little bit of new briquettes of information to be sent to our reader. Understand.

The fruit of the development of these new technologies is the Stratospheric Observatory for Infrared Astronomy (Sofia, short for Stratospheric Observatory for Infrared AstronomyStratospheric Observatory for Infrared Astronomy), resulting from cooperation between the American and German space agencies, monitors space in the infrared field from a Boeing aircraft operating in space StratosphereStratosphere terrestrial, at altitudes high enough that our planet’s atmosphere doesn’t obstruct its observations. Thanks to the data collected by SOFIA, a team of scientists announced that they had discovered this for the first timeOxygenOxygen Atomic (O) on the “day” (sunlit) side of Venus. They publish their results in the journal Nature Communications.

Atomic oxygen, a sign of atmospheric dynamics

Although it also exists on Earth, atomic oxygen is different from the oxygen we breathe: we inhale it MoleculesMolecules Of dioxygen (consists of two AtomsAtoms oxygen), while what we call atomic oxygen corresponds to a single oxygen atom. It is very complex detectordetector Which constantly seeks to bind to other molecules. Although its presence in Venus’ atmosphere has long been suggested thanks to various atmospheric models, atomic oxygen has so far only been observed on the “night” side of the planet. The discovery of atomic oxygen on the sunlit side sheds new light on the dynamics of Venus’ atmosphere.

On Earth, atomic oxygen is relatively abundant at high altitudes in the atmosphere, where it is formed by… Solar raysSolar rays On atmospheric molecules: PhotonsPhotons Coming from the Sun can “break” the molecules they encounter, leading to the formation of two new compounds. This phenomenon is called photodissociation. Thus, atomic oxygen is formed on Earth by photodissociation of dioxygen.

According to the researchers, a similar process seems to occur in the atmosphere of Venus: under the influence of solar radiation, carbon dioxide molecules (composed of one carbon atom and two oxygen atoms) in the atmosphere break down to form oxygen atoms and molecules for Carbon MonoxideCarbon Monoxide (It consists of a carbon atom and an oxygen atom). Thus it appears that atomic oxygen is formed in the luminous face of Venus (where it was just first discovered), before recombining with other molecules in the face. LaylaLayla.

But what interests the authors most is the heights at which atomic oxygen has been detected. According to their results, at all points where atomic oxygen was observed (seven on the day side, nine on the night side, and one on the breakbreak (which separates the illuminated and unilluminated sides of the planet), and the maximum concentration was at an altitude of about 100 km. It is located between two main atmospheric currents on Venus: the powerful super-rotating current, at an altitude of less than 70 kilometers, where WindWind Strong blows in the opposite direction of the planet’s rotation, and anti-solar flow under the sun, at an altitude greater than 120 km, where the wind blows from the sunny side towards the night side.

Floral atomic oxygen thus represents an as yet untapped source of information for understanding the transport between these two major atmospheric currents. Researchers hope that future observations will provide more detailed data on Venus’ atmosphere, especially since understanding its dynamics is crucial for the smooth operation of future missions to our neighbor.