Sun’s UV radiations play a vital role in leakage of Mars’ atmosphere, says study

The planets residing in our solar system have different levels of atmosphere inside them. While our Earth has an atmosphere that supports life, Mars lost most of its atmosphere during its initial period. Hence, the red planet got transformed from a warm and watery planet to a dry and cold planet. But Venus, on the other hand, has a very dense atmosphere even if it is completely inhospitable.

The latest study mainly focuses on the atmosphere of Mars and how it behaves against the solar winds and UV radiations of the Sun. Earth has its own magnetic field which helps it to reflect back the solar winds and UV radiations through a layer called magnetosphere. But as Mars has no internal magnetic field it depends on its upper atmosphere called ionosphere to deflect the charged particles of the solar wind. The ionized layer on Mars interacts directly with the solar wind and its magnetic field and hence an induced magnetosphere is created.

The solar ultraviolet radiations lead to the formation of more number of ions and some get escaped from the atmosphere. So, the latest study looked at the data collected by European Space Agency’s Mars Express regarding the charged ions like oxygen and carbon that flow out to space from Martian atmosphere. The scientists found out that the solar UV rays play a more vital role than previously thought regarding the escape of ions.

Robin Ramstad of the Swedish Institute of Space Physics, and lead author of the Mars Express study said they used to think that the ion escape occurs because of an effective transfer of the solar wind energy through the Martian induced magnetic barrier to the ionosphere. But, they actually found out that the increased ion production driven by ultraviolet solar radiation shields the planet’s atmosphere from the energy carried by the solar wind, but very little energy is actually required for the ions to escape by themselves, due to the low gravity binding the atmosphere to Mars. That means although the induced magnetosphere is there to defend the ionosphere of Mars but most of the ions get escaped to the outer space. This occurs because the solar UV radiations produce more ions in ionosphere and these ions require less energy to escape into the outer space. Hence, energy of the solar wind is enough to remove charged ions from Martian atmosphere and the Mars’ weak gravity cannot hold these ions.


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