When higher atmospheric particles from the magnetosphere contact with energized ones, they generate light that is known as an aurora.
The Starlink destructor incident
n February 2022, SpaceX launched 49 Starlink Internet satellites into low Earth (LEO). This was the 36th Starlink launch that SpaceX had done, and they expected it to go off without a hitch, just like the 35 before it.
On the day of launch, the Earth was hit by a coronal mass ejection – a large burst of plasma ejected from the Sun. This caused a geomagnetic storm in the atmosphere at an altitude of about 100 to 500 kilometers, in the target area of Starlink.
That event injected massive amounts of electromagnetic energy directly into the Earth’s upper atmosphere. This produced beautiful northern lights, but the energy also increased the density of the air. Higher air density is usually not a big deal for LEO satellites, as it is already very low at normal operating altitudes (above 400 kilometers).
However, Starlink was initially launched at an altitude of 210 kilometers. It is much closer to Earth and the air density is exponentially greater. Thirty-eight of the original 49 launch satellites were later lost to atmospheric drag from the dense atmosphere pulling them back to Earth.
Surprise solar cycle
The Sun goes through a cycle – 11 years to be exact – during which its activity periodically waxes and wanes. At the height of the period, we see more sunspots, more radiation and more solar flares on the surface of the sun. Geomagnetic storms like the one that destroyed Starlink are relatively common, especially when the Sun reaches the peak of its 11-year waxing and waning cycle.
In the latest period alone, which ended in 2019 (the 24th monitored period since 1755), there were 927 storms classified as moderate or weak — an average of one every five days.
Solar cycle 25 is now four years old, but it’s already proving surprising. The maximum activity of the 25th cycle was predicted to be in 2025, but solar activity has already exceeded it. This means we’ve seen more geomagnetic storms, more auroras (and at lower latitudes than usual), and potentially more dangerous conditions for LEO satellites.
Space weather – the invisible force of nature
If geomagnetic storms are so common, why don’t they cause more problems? The reality is that they do, but the consequences are far less obvious than satellites burning up in the atmosphere.
When cosmic weather energy enters the Earth’s upper atmosphere, for example, the composition of the ionosphere changes in addition to the air becoming denser. High frequency or “shortwave” radio communication relies on a predictable ionosphere that transmits over long distances.
Geomagnetic storms that affect the composition of the ionosphere can cause radio disruptions, such as the one in North America on August 7. Even small storms can weaken radio signals used in military and naval systems, aviation or radio communications.
Extreme storms can cause hours-long radio outages around the world. Large storms can also cause more notable problems, such as the nine-hour blackout experienced by Hydro-Québec in 1989.
Warning systems in space
But it’s not all destruction and exploding missiles. We can detect when a solar flare leaves the surface of the Sun and roughly predict when it will hit Earth, giving us early warning of certain types of storms and the opportunity to see the aurora borealis.