It is reportedly the largest solar flare in four fairly quiet years for sun activity, and it erupted on Monday. Radiation from it is expected to reach Earth today and tomorrow and may interfere with communication systems, power distribution, and navigation satellites.
X-rays from the event will have taken no more than 8 minutes to get here, however, it is the charged particles which are much slower, which can cause effects on earth that will now be arriving. 93 million miles separate us from the sun and x-rays are much quicker because they travel at the speed of light.
Sunspot eruptions occur when magnetic field lines on the sun’s surface, in effect get short-circuited, releasing large amounts of energy into space. Three such events occurred Monday, and the largest of them was a so-called “class X event “— the most powerful form of solar flare. Astronomers have been expecting the sun to ramp up its activity after several years of of quiet as part of its normal 11-year cycle of high and low activity. The peak in solar activity for this cycle is expected in 2013.
A solar flare is understood to happen when stored magnetic energy within the corona is released by magnetic reconnection.
A solar flare is a violent explosion in the sun’s atmosphere caused by huge magnetic activity. They happen when energy stored in twisted magnetic fields (usually above sunspots) is suddenly released. Flares produce a burst of radiation right across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays.
Although moderate in size, this flare has released an enormous amount of energy equivalent to tens of millions of hydrogen bombs. Heating the gas to tens of millions of degrees K and accelerating electrons, protons and the higher mass ions to near the speed of light. The sheer size of these tremendous spontaneous releases of energy is so huge thatit most people can hardly comprehend it alin its scale.
The Sun’s surface can be thought of as containing large magnetic loops which can break out from the surface and their presence can be seen at times in the shape of the ejected material.
Coronal mass ejections often accompany solar flares, although scientists are still trying to determine exactly how the two phenomena are related. Coronal holes can take a long time to disappear and may last for months or years.
Corona mass ejections (CMEs) often occur along with solar flares. These ejections of a large amount of plasma can disturb the Earth’s entire magnetic field. When that happens they are known as geomagnetic storms.
Magnetic instabilities in the strong fields found in and near sunspot groups may cause the prominences, although the details are still not completely understood. A typical solar prominence measures some 100,000 km in extent, nearly 10 times the diameter of planet Earth.
During strong solar activity, satellites may be overcome by high-energy particle impacts. Communication satellites suffer drag and gradually tend to begin to drop back to earth. When this occurs they tend drift slightly out of their perfect orbits, affected by solar wind but also in response to from variations in gravitational pull of the Earth and moon. These natural influences most often push a satellite off-station at a rate of about one degree a year.
Heated electrified plasma particles are what is arriving at the earth at the moment from the flares first seen on Monday, having taken around 48 hours to travel to earth.