Pause in solar wind ‘blew up’ Mars atmosphere: Why is this interesting?

The NASA MAVEN probe, located in orbit of Mars, recorded a unique phenomenon on December 26, 2022 - a kind of pause in the solar wind, which led to an explosive expansion of the atmosphere of the Red Planet. This rare phenomenon has opened new horizons for studying space weather and understanding potentially habitable worlds in distant star systems.

The intensity of the solar wind, made up of electrons and hydrogen ions, depends on the activity of the star and the magnetic fields in the surrounding space. At times, the star ejects particles with greater force and speed, and they catch up with the slower particles released earlier. This creates zones of high and low concentrations of solar wind particles that affect planetary atmospheres.

A similar phenomenon was first observed in 1999, when a sudden weakening of the solar wind increased the volume of the Earth's atmosphere and magnetosphere by 100 times. Mars, unlike Earth, does not have a magnetic field that protects the planet from cosmic particles, but there is an induced magnetic field that arises during the interaction of the solar wind with the planet’s ionosphere. The equipment of NASA's MAVEN orbital probe can record this field and solar wind particles.

During a new observation, on December 26, 2022, the probe recorded a 10-fold decrease in solar wind pressure and a 100-fold decrease in the density of its particles. Analysis of the data showed that Mars' ionosphere and induced magnetic field expanded threefold, creating an effect similar to an explosion within the planet's atmosphere.

According to scientists, if Mars had been in a system with a less “windy” star instead of our Sun, its evolution would have taken a different path.

These discoveries highlight the importance of in situ observations: without in situ orbiters, it would be impossible to obtain information about such processes.

According to experts, studying these phenomena in our solar system will provide data for modeling atmospheric phenomena on other planets in various star systems, contributing to a better understandiA pause in the solar wind "blew up" the atmosphere of Mars.