During the total eclipse viewers will be afforded a rare opportunity to see the corona of the Sun, outlined around the silhouette of the moon, which can usually not be seen from Earth.
This area just above the surface of the Sun – that can be difficult to observe even from space observatories such as the SOHO project – is home to some of the most extraordinary, and potentially dangerous, examples of solar phenomena.
The Sun almost constantly produces a ‘solar wind’, an outpouring of material from the Sun’s atmosphere created by the transition of the solar magnetic fields between its poles.
The more extraordinary explosions from the Sun’s atmosphere are solar flares. Solar flares are visible from Earth and are produced by gases in the atmosphere heating up to between 10 to 30 million degrees centigrade and exploding out from the Sun in great arcs of fire.
Even more extraordinary, and more frightening, are the events that solar flares tend to predict and precede. These are the Coronal Mass Ejections, storms that build up in the solar atmosphere, constrained by the magnetic fields until they are too strong, and then explode out into the solar system at speeds reaching 1250 miles a second.
CMEs, are these are known, can cause large magnetic storms in space and on Earth. In a benign mood they cause the aurora borealis and aurora australis, but they can also cause massive disruption to communication and electrical systems.
Unfortunately it has often been difficult to predict CME’s since those most easily visible are those heading out from the ‘side’ of the Sun, in other words, not in our direction. It is now becoming possible to detect CME’s that will come in our direction, giving us a chance to predict their arrival and prepare for their effects.