Many books describe the sun as a ball of very hot gas. However, a ball of hot gas would be a sort of fuzzy blob. Images of the sun show it is nothing like that. I add a word of caution here, don't try to check this out for yourself unless you know the dangers and techniques for observing the sun through a telescope. You could blind yourself.
Images of the sun show a ball with a well-defined edge, a mottled surface with dark spots on, and loop structures sticking upwards into space. The reason for the sun looking like that is the presence of strong magnetic fields. These cling to the hot gas. The result is a rubbery sort of stuff: stretchy, twistable, compressible, and capable of flowing around slowly inside the sun. This very hot gas, threaded with magnetic fields is often referred to as "magnetoplasma." Because solar magnetoplasma is stretchy, twistable and compressible, it can store energy, just as we can store energy by stretching or twisting elastic.
The constant motion of the solar material leads to the eruption of new loops of magnetic field through the surface and rearrangement of the magnetoplasma, causing it to be stressed, storing energy. Eventually a point is reached where the magnetoplasma cannot take it anymore, and it snaps, releasing its stored energy. The result is an explosion equivalent to tens of millions of hydrogen bombs. Bursts of high-energy X-rays are given off, accompanied by beams of high-speed particles moving at almost the speed of light. Quite often a huge chunk of solar material is blasted off into space at speeds of hundreds or even thousands of kilometres a second. These are coronal mass ejections, or CME's. However, they are often referred to as "solar storms."
For much of human history the only consequence of the sun's bad behaviour was displays of the aurora. These are caused by solar-driven particles following the lines of the Earth's magnetic field down into the polar regions, where they hit atoms in our atmosphere, making them emit green or red light. However, in today's high-tech world, the effects solar flares and CME's have on us can be very serious: an issue receiving a lot of attention.
In 1859, a coronal mass ejection triggered a huge magnetic storm. This generated electric currents in the wires making up the telegraph network, giving the operators electric shocks and in some cases causing the equipment to catch fire.
In March 1989, a large solar flare and coronal mass ejection caused massive communication blackouts and power outages.
Today, thanks to a bigger dependence on global communications infrastructure than ever before, we are more sensitive to the sun's bad behaviour than any time in our history. For example, imagine losing the Internet for a few hours, or maybe days, or longer. After all, the Internet is just a massive, integrated communications network, involving wires, fibres and satellite communication links. Then there is "the cloud," which consists of massive "server farms," where we store huge amounts of data. These are buildings loaded with computers and data storage equipment, and depending on the Internet. If anything, our dependence on easy, global communications is going to increase. This means there is a growing international interest in solar activity and what it can do to us. We are monitoring the sun more and more comprehensively, and getting into solar weather forecasting. Probably most importantly, we are looking at how to make our infrastructure more robust and if brought down, how can we minimize the damage and bring it back up as quickly as possible. The Canadian effort is spearheaded by the National Research Council, Natural Resources Canada and the Canadian Space Agency.
• Venus and Mars lie close together very low in the west after sunset.
• In the early hours, Saturn lies in the southwest and Jupiter in the southeast.
• The moon will be full on the 1st.
Ken Tapping is an astronomer with the National Research Council's Dominion Radio Astrophysical Observatory near Penticton.
This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.