The strongest solar storm in almost 6 years hit the Earth

The most powerful solar storm in almost six years hit Earth today (March 24), but, oddly enough, space weather forecasters did not foresee its approach.

The geomagnetic storm peaked at 4 on the 5-point scale used by the US National Oceanic and Atmospheric Administration (NOAA) to rate the severity of space weather events.

Geomagnetic storms are disturbances in the Earth's magnetic field caused by solar material from coronal mass ejections (CMEs), large ejections of plasma and magnetic field from the Sun's atmosphere. It turns out that this particular geomagnetic storm was caused by a "hidden" CME—which, as the name suggests, is quite difficult to detect.

National Space Weather Service NOAA initially announced a "Geomagnetic Storm Watch" on March 22(opens in a new tab) to go into effect March 23-25, with a moderate G2 storm expected on March 24. Thus, forecasters were not completely taken by surprise, however, they did not expect a G4 storm.

Severe geomagnetic storms can create problems for spaceflight because they increase the density of gases in the Earth's upper atmosphere, thereby increasing the drag of satellites and other spacecraft.

Another side effect of powerful geomagnetic storms is the incredible auroras they cause. When charged particles from the Sun crash into Earth's atmosphere at speeds up to 45 million miles per hour (72 million km/h), our planet's magnetic field sends the particles toward the poles. The subsequent overload of molecules in the Earth's atmosphere causes colorful spectacles that usually remain limited to areas at high latitudes. This time, skywatchers around the world witnessed a dazzling aurora that extended as far south as Colorado and New Mexico.

We can expect more extreme space weather events, such as this powerful geomagnetic storm, as the sun approaches its peak in its 11-year solar activity cycle, which is expected to occur in 2025.