The most powerful solar storm in nearly six years hit Earth today (March 24), but strangely, space weather experts didn’t expect it. The geomagnetic storm peaked as a severe G4 storm on the 5-point scale used by the US National Oceanic and Atmospheric Administration (NOAA) to rate the severity of space weather. The storm’s unexpected ferocity not only made the auroras visible as far south as New Mexico in the US, but also forced spaceflight company Rocket Lab to delay the launch by 90 minutes. Geomagnetic storms are disturbances in the Earth’s magnetic field caused by coronal mass ejections (CMEs) – large ejections of plasma and magnetic field from the solar atmosphere. It turns out that this particular geomagnetic storm was triggered by a “stealth” CME, which – as the name suggests – is difficult to detect, writes Space.com. NOAA’s National Space Weather Service initially announced a possible G2 storm forecast on March 24. So the forecasters were not completely unprepared; however, they did not expect a G4 storm.
It wasn’t until 4:41 GMT (6:41 a.m. Bulgarian time) on March 24 that NOAA raised the warning to a severe G4 storm. The storm escalated to G4 at 4:04 GMT. American space weather forecaster Tamita Skov explained why the space weather community has gotten it so wrong. “These nearly invisible storms start much more slowly than eruptive CMEs and are very difficult to observe,” she says, adding that “stealth” CMEs can also be masked by other, denser structures emanating from the Sun that host them. makes it hard to observe. “That’s why they’re the cause of ‘problematic geomagnetic storms’ like the G4 storm we’re in now,” Skov continues.
NOAA ranks geomagnetic storms on a scale from G1, which can cause increased auroral activity around the poles and minor power fluctuations, to G5, which includes extreme cases such as the Carrington Event, a colossal solar storm that occurred in September 1859 when it interrupted telegraph services around the world and produced auroras so bright and powerful that they could be seen as far south as the Bahamas. Strong geomagnetic storms can be troublesome for spaceflight because they increase the density of gases in Earth’s upper atmosphere, thereby increasing drag on satellites and other spacecraft. In February 2022, SpaceX lost up to 40 brand new Starlink satellites when they failed to reach orbit after launch in a small geomagnetic storm.
Rocket Lab delayed its launch this morning by approximately 90 minutes while it assessed changing geomagnetic storm conditions, the company said on Twitter. Another side effect of powerful geomagnetic storms is the incredible auroras they cause. As charged solar particles slam into Earth’s atmosphere at speeds of up to 72 million kph, our planet’s magnetic field directs the particles toward the poles. The resulting supercharging of molecules in the Earth’s atmosphere triggers the colorful spectacles, which normally remain confined to high-latitude regions. This time, sky watchers everywhere were treated to a dazzling glow that reached as far south as Colorado and New Mexico. For March 25 and 26, NOAA’s forecast is for a G1 storm. We can expect more extreme space weather events like this powerful geomagnetic storm as the Sun heads toward a peak in its 11-year cycle of solar activity, which is expected to occur in 2025.
