Mercury has geomagnetic storms similar to those on Earth
Mercury is the smallest planet in our solar system, but it shares one key similarity with Earth: it boasts geomagnetic storms, according to new research by scientists in the United States, Canada and China revealed on March 29, 2022.
Two studies about an often overlooked planet
The first study indicates that the planet has a ring current consisting of charged particles that flows laterally around the planet and excludes the poles while the second points to the existence of geomagnetic storms triggered by this specific ring current.
“The processes are quite similar to here on Earth," said in the statement Hui Zhang, a space physics professor at the University of Alaska Fairbanks Geophysical Institute. “The main differences are the size of the planet and Mercury has a weak magnetic field and virtually no atmosphere.”
The question now remains: do these storms on Mercury produce aurora displays as they do on Earth? It turns out they don't as solar wind particles on the distant planet don’t encounter an atmosphere, allowing them to reach the surface unimpeded.
The scientists further speculate that Mercury's storms would therefore only be visible through X-ray and gamma-ray examination.
A fortuitous coincidence
If the storms are invisible, how were they found to exist? It required a fortuitous coincidence: a series of coronal mass ejections from the sun on April 8-18, 2015, and the end of NASA’s Messenger space probe which crashed into the planet’s surface on April 30, 2015.
It was a new analysis of data from Messenger, which had begun dropping closer to the planet as a result of its upcoming crash, that showed "the presence of a ring current intensification that is essential for triggering magnetic storms," states the second of the two papers.
It was more specifically the coronal mass ejection of April 14 that proved to be the key for scientists to understand how the planet's storms function as it compressed Mercury’s ring current on the sun-facing side and increased the current’s energy.
In the past, scientists have studied Mercury's inner core through its gravity and spin and have also deduced that its surface is covered in diamonds. What other secrets may our neighboring planet hold?