What is a solar flare? 2022 warning explained, do they cause solar storms - how they are ranked from G1 to G5

NASA has said that an ‘X-class flare’ was captured by its solar dynamics observatory

According to a new statement from NASA, the sun emitted a “strong solar flare on May 3, 2022, peaking at 9:25am EDT”.

Solar flares as described by NASA as “powerful bursts of energy” and says that “flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts”.

NASA’s Solar Dynamics Observatory captured an image of the solar flare (Photo: NASA)

The flare that occured on 3 May has been classifed as an “X-class flare” by NASA, also known as “the most intense flare”.

If the exchange of energy from the sun reaches the space surrounding Earth through solar wind after a solar flare occurs, a geomagnetic storm, also called a solar storm, can happen.

What is a solar storm?

The National Oceanic and Atmospheric Administration (NOAA) defines a solar storm, also known as a geomagnetic storm, as a “major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth”.

Talking to the Conversation, Piyush Mehta, Assistant Professor of Mechanical and Aerospace Engineering at West Virginia University, says that geomagnetic storms occur “when space weather hits and interacts with the Earth”.

Mehta says: “The sun is always releasing a steady amount of charged particles into space. This is called solar wind. Solar wind also carries with it the solar magnetic field.

A major solar eruption shown in progress (Photo: Solar & Heliospheric Observatory/NASA via Getty Images)

“Sometimes, localised fluctuations on the sun will hurl unusually strong bursts of particles in a particular direction. If Earth happens to be in the path of an enhanced solar wind generated by one of these events and gets hit, you get a geomagnetic storm.”

There are two common causes for geomagnetic storms - coronal mass ejections (CME), which refers to explosions of plasma from the surface of the sun, and solar wind that escapes through coronal holes, which are spots of low density in the sun’s outer atmosphere.

Are they dangerous?

These kinds of storms aren’t really that dangerous to us down on Earth’s surface as we’re protected by Earth’s atmosphere - however, geomagnetic storms can be a threat to items orbiting in space, like satellites.

Mehta says that “when the atmosphere absorbs energy from magnetic storms, it heats up and expands upward” which results in the density of the “thermosphere” significantly increasing.

High density means more drag, which poses a problem for satellites. Geomagnetic storms can also disrupt satellites’ ability to communicate with Earth via radio waves.

Many communication technologies around the world depend on radio waves, like GPS for example.

“During geomagnetic storms, changes in the ionosphere – the charged equivalent of the thermosphere that spans roughly the same altitude range – will change how radio waves travel through it,” Mehta says.

“The calibrations in place for a quiet atmosphere become wrong during geomagnetic storms.

A solar spot in the centre of the Sun is captured from which the first X-class flare was emitted in four years on February 14, 2011 (Image: NASA/Solar Dynamics Observatory via Getty Images)

“This, for example, makes it difficult to lock onto GPS signals and can throw off the positioning by a few metres.

“For many industries – aviation, maritime, robotics, transportation, farming, military and others – GPS positioning errors of a few metres are simply not tenable.”

NOAA also says: “While the storms create beautiful aurora, they also can disrupt navigation systems such as the Global Navigation Satellite System (GNSS) and create harmful geomagnetic induced currents (GICs) in the power grid and pipelines.”

The strongest geomagnetic storm on record occurred in September 1859, when a mass of particles hit Earth and caused electrical surges in telegraph lines that shocked operators and, in some cases, set telegraph instruments on fire.

Mehta says: “Research suggests that if a geomagnetic storm of this magnitude hit Earth today, it would cause roughly $2 trillion in damage.”

What do the storm rankings mean?

Geomagnetic storms are ranked by NOAA from G1 to G5 based on how minor or extreme said storm is.

The scale goes:

  • G1, minor
  • G2, moderate
  • G3, strong
  • G4, severe
  • G5, extreme 

G5 storms can cause widespread voltage control problems and result in grid systems experiencing complete collapse or blackouts.

What causes the Northern Lights?

The aurora borealis, also known as the “Northern Lights”, is caused by activity on the surface of the sun.

Solar storms on the sun’s surface give out huge clouds of electrically charged particles, with some of these particles travelling millions of miles and colliding with the Earth.

Royal Observatory astronomer Tom Kerss says “These particles then slam into atoms and molecules in the Earth’s atmosphere and essentially heat them up.

“We call this physical process “excitation”, but it’s very much like heating a gas and making it glow.”

An aurora borealis illuminates the night sky above the Kellostapuli Fell in Kolari, Finnish Lapland (Photo: IRENE STACHON/Lehtikuva/AFP via Getty Images)

So what we’re seeing when we’re looking at the aurora borealis is the atoms and molecules in our atmosphere colliding with the sun - the characteristic “wavy” patterns of the lights are caused by the lines of force found in the Earth’s magnetic field.

The different colours seen in the aurora borealis is caused by the fact that different gases give off different colours when they’re heated.

The aurora borealis can be seen in the northern hemisphere, hence the “Northern Lights”, and the aurora australis can be found in the southern hemisphere.

In the UK, we can, on occasion, see the aurora borealis - the further north you head, the more likely you are to see the display.