This blend of two images taken by Nasa's Solar Dynamics Observatory shows a solar eruption. (Solar Dynamics Observatory, AP)
Cape Town - The sun has taken aim at Earth and delivered what could be a knock-out blow to modern technology.
On Wednesday a massive solar flare was detected and blasted radiation toward Earth. However, the resultant Coronal Mass Ejection or CME is expected to hit the home planet on Friday.
"Solar activity is moderate with background X-ray flux at C-class levels. Geomagnetic conditions are at unsettled levels. Local HF working frequencies are highly elevated compared to monthly average predicted values," said the Southern African National Space Agency (Sansa).
The agency operates a space weather observatory at Hermanus in the Western Cape where activity of the sun and the performance of the Earth's magnetic field is observed.
Two X-class and two C-class solar flares were observed, and while not unprecedented, they come against a background of fairly stable and muted solar activity.
Astronomers generally recognise three major categories of solar flares.
X-class flares are big and are major events that can trigger planet-wide radio blackouts. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions. C-class flares are small with few noticeable consequences here on Earth.
These flares can cause significant damage to sensitive electronic equipment such as GPS satellites,lower power electronics and even power lines.
The last major CME affected Earth in 1958, but there were not many high tech devices that could have been affected.
The sun goes through periods of major activity known as a solar maximum where a great number of sun spots are observed. These cycles last around 11 years, but in the current one, solar activity has been muted.
The current CME is scheduled to hit the Earth on Friday and South Africans should avoid being exposed directly to the sun and not panic.
Watch this online video that explains how solar flares work:
- Follow Duncan on Twitter