What is a solar flare and what happens when it hits earth?

You may not have noticed it, but a massive solar flare has made its presence known on Earth this week, amid warnings it could cause some disruption to satellite systems and power grids.

The US National Oceanic and Atmospheric Administration (NOAA), the resulting geomagnetic storm, which began on Monday and is expected to continue into today, has been rated a G2 – meaning it’s moderately strong, although it’s not expected to cause serious widespread problems.

The Met Office said the flare would produce ‘minor to moderate geomagnetic storms’ resulting in ‘enhanced auroral activity’.

It also means that folks in parts of Scotland, northern England, and northern Ireland have been lucky enough to see a stunning display of the Aurora Borealis – also known as the Northern Lights – with the spectacle also stretching to Canada and the US.

These can heat electromagnetic material to millions of degrees in just minutes, resulting in a burst of radiation across the electromagnetic spectrum, including from radio waves to gamma ways and X-rays.

Solar flares are classified by scientists according to how bright they are in X-ray wavelengths.

They are also used to try and predict solar activity on earth and in space.

What happens if a solar flare hits earth?

That depends largely on what size the solar flare is – nothing may happen at all if they are very small, but larger ones could have catastrophic consequences.

The smallest, C-class, are unlikely to make much impact on Earth, medium-sized ones – known as M-class, could cause some low-level damage, while the largest, known as X-Class, could be seriously disruptive.

Solar flares differ from Coronal Mass Ejections, which are a release of plasma and radiation from the sun – although they can sometimes accompany these flares.

The most famous Coronal Mass Ejection occurred in 1859, causing a geomagnetic storm called the ‘Carrington Event’ as a pulse of charged particles bombarded Earth’s magnetosphere, and caused telegraph systems across the US and Europe to fail

If this happened today, the results would be devastating – potentially wiping out satellite systems and power grids and causing trillions of pounds worth of damage.

In April last year, Nasa wrote: ‘The Carrington Event compressed the Earth’s magnetic field so violently that currents were created in telegraph wires so great that many wires sparked and gave telegraph operators shocks.

‘Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced.’