The National Oceanic and Atmospheric Administration of the United States (NOAA) warned this Friday. It is a geomagnetic storm of great intensity. It could have significant consequences on technology and infrastructure until Sunday, May 12. The solar storm that hits the Earth also influences the panorama: it would cause enormous northern lights.
How do solar or geomagnetic storms occur? It begins with a significant emission of energetic particles and electromagnetic radiation from the Sun. This affects the Earth’s atmosphere and its magnetic field.
Classification
Storms are born from activities on the solar surface. For example, coronal mass ejections (CMEs), solar flares, and high-speed solar wind streams. They interact with the Earth’s magnetic field. They cause so-called induced geomagnetic currents, which are capable of affecting the electrical and communications infrastructure of the planet. They also cause spectacular auroras. Many people are posting them on social media in the last few hours.
NOAA classifies solar or geomagnetic storms on a 5-level scale:
- G1 – Minor: with slight effects on electrical networks and possibility of auroras in high latitudes.
- G2 – Moderate: causing broader auroras, effects on power systems and satellites.
- G3 – Strong: with impacts on electrical networks, satellite navigation and auroras in low latitudes.
- G4 – Severe: seriously affecting electrical systems, communications and navigation, with auroras at even lower latitudes.
- G5 – Extreme: causing failures in electrical networks, damage to transformers, interruptions in communications and navigation, and auroras in very low latitudes.
Storm and auroras
The solar storm that hits the Earth these days is level G5. And it is the most severe in the last 20 years. The State Meteorological Agency details why the auroras appear. It is due to the interaction between the solar wind, with electrically charged particles, and the Earth’s magnetic field. This solar wind is strongest at times of maximum solar activity.
“The Earth’s magnetic field channels particles, mainly electrons and protons. And they collide with the atoms and molecules of the gases in the upper layers of the atmosphere,” explains the AEMET.
Thus, electrons in the nitrogen and oxygen atoms are temporarily moved to a higher energy level. Upon returning to their usual energy state, they release the accumulated energy in the form of photons of light. They manifest in different wavelengths and create auroras.
