Compile / Di Rui
Scientists know that Earth’s auroras are the result of interactions between the solar wind and the magnetic field, and have seen similar phenomena on other celestial bodies, such as Mercury, some of Jupiter’s moons, comets, and even Mars.
Mars doesn’t have a magnetic field that covers the globe as it does on Earth, so why does aurora occur? Scientists have not known why for years. A new study sheds light on the likely cause of the auroras on Mars.
Scientists believe that when Mars was young, it once had a global magnetic field like Earth, but then this magnetic field gradually weakened and now almost disappears. However, there are some regional, small-scale magnetic fields in the crust of Mars’ southern hemisphere. The new study suggests that these small-scale magnetic fields interact with the solar wind to produce discrete auroras on Mars.
One of the principal investigators is Zachary F., a researcher at the Department of Physics and Astronomy at The University of Iowa. “For the first time, we have studied in detail the effects of the solar wind on the auroras on Mars,” said Zachary Girazian, director of the research team.
“Our main finding is that the frequency of auroras depends on the orientation of the solar wind and the magnetic field in regions with strong crustal magnetic fields; outside the regions with strong magnetic fields, the frequency of auroras depends on the dynamic pressure of the solar wind.”
The researchers analyzed more than 200 discrete auroras collected by the Mars Atmosphere and Volatile Evolution Mission (MAVEN). MAVEN, a space probe launched by NASA in 2013, was also the first spacecraft to provide data on the aurora on Mars.
The researchers found that most of the auroras on Mars occur in the southern hemisphere, and they believe that some interaction between the solar wind and a localized area produces the auroral phenomenon.
“This is a fruitful and exciting time to study the auroras on Mars,” Gilazian said in a press release. “The data from MAVEN is the first of its kind and helps us understand the basics of auroras for the first time. characteristics.”
The research was published March 27 in the journal JGR Space Physics. ◇