NASA’s MAVEN mission discovers how solar wind creates auroras on Mars without a global magnetic field

The space mission of NASA, known as MAVEN, has provided new insights into the auroras on Mars, revealing how the solar wind interacts with the atmosphere of the red planet. Through detailed observations, it has been discovered that these luminous phenomena occur without a global magnetic field, unlike what happens on Earth.

MAVEN Discoveries about Auroras on Mars

Unlike Earth, where an iron core generates a magnetic defense, Mars has lacked such a dynamo for millennia. However, MAVEN has detected that remanent magnetic fields in its crust play a vital role in channeling energetic particles.

A significant finding is the identification of three types of auroras: diffuse, proton, and discrete. Each responds to specific atmospheric phenomena caused by the impact of the solar wind or massive solar eruptions.

The diffuse auroras extend over large areas of the nighttime hemisphere, triggered by coronal mass ejections. These extreme solar events allow energetic electrons to penetrate deeply into the atmosphere, generating an ultraviolet glow across almost all of Mars.

On the other hand, the discrete auroras are related to local magnetic anomalies in the rocks of the southern hemisphere. Here, the remanent magnetic fields act as conduits for electrons into the upper atmosphere.

The third type, the proton aurora, was discovered by MAVEN on the daytime side of Mars. It occurs when solar wind protons convert hydrogen atoms in the Martian corona into neutral hydrogen atoms, which cross the magnetic barrier and emit ultraviolet light upon impacting the Martian thermosphere.

The MAVEN team has noted that this phenomenon is more frequent and intense during the summer of the southern hemisphere of Mars. The IUVS (Imaging Ultraviolet Spectrograph) has been crucial in capturing how the Martian atmosphere is progressively lost due to these prolonged energetic interactions.

According to scientists from NASA, understanding the auroras provides a unique window to explore the history of water and the potential habitability of Mars. These observations not only redefine planetary physics but also offer a framework to study the atmospheres of distant exoplanets.

Thanks to MAVEN, aerospace science advances in understanding the evolution of rocky worlds under the constant attack of their host stars.