Hurricanes don’t swirl ferociously just at Earth’s surface. The ionosphere — an upper layer of the atmosphere charged by solar radiation — also contains cyclones. Scientists sometimes refer to these as “space hurricanes.” The first was seen three years ago. It swirled for hours above Earth’s northernmost magnetic site, or pole. Now, research has turned up parallel space hurricanes swirling high above the south magnetic pole.
Scientists spotted the first space hurricane in 2021. It was a cyclone-shaped aurora — a type of northern light show. Unlike sea-level hurricanes, however, this one rained electrons, not water.
Space physicist Sheng Lu at Shandong University in Weihai, China was part of a team that wanted to know if this type of special aurora was just a northern event. To find out, the group pored over satellite data on the southern hemisphere’s ionosphere.
Between 2005 and 2016 they turned up 259 space hurricanes. That’s about 23 per year, on average. It’s also close to the rate that had been estimated to develop in the northern ionosphere.
The team identified other parallels, too. For instance, space hurricanes tend to emerge over the poles in each region’s summer months.
Lu’s team shared its findings June 25 in the Journal of Geophysical Research: Space Physics.
A barrage of charged particles rains down on Earth from the sun. This solar wind can split our planet’s magnetic-field lines. Later, the lines will reconnect. As they do, they churn up ionized gas — or plasma — in the ionosphere. This can drive flows of electric current upward, Lu’s team suggests. Those flows then bend and begin to spin. That creates a cyclonic “eye” at the center.
So those shifts in Earth’s magnetic field are what likely set off a space hurricane, the researchers now argue. This, they propose, would be similar to the rise of warm, humid air at the center of the tropical cyclones that spin across Earth’s oceans.
