The sun has got its hat on; it’s coming out to play

10.06.2010

It seems that the universe has a rare cosmological surprise waiting for many students who heading up north at the end of term. Our sun is approaching a period of heightened activity, rendering the aurora borealis visible from latitudes as far south as 53 degrees north, which is approximately where Manchester and Leeds are located, with locations further north subjected to even more captivating and dazzling shows in the night sky.

Solar activity goes through a series of cycles which heighten and diminish the amount of solar wind and photons emitted by the sun at any particular time. There are three major cycles, lasting approximately 11 years, 70 years and a few hundred years. Scientists are uncertain about the length of the longest cycle as scientific data has only been recorded for a relatively short time, thus many of their calculations are based entirely on solar theory. Every so often, these phases coincide, creating an amplified period of maximal and minimal solar activity, where space weather becomes more dangerous and more ethereal.

The academic year 2011 to 2012 has been predicted to be the timing for one of the most climatic peaks that we have experienced in known history. Scientists have hypothesised that at the height of activity, most of northern Europe and North America will be bathed in sunlight 24 hours a day for a few weeks, very much like the situation in the land of the midnight sun. Those areas on the other side of the world, which would typically experience night at those times, will receive the brightest and most stunning aurora borealis ever recorded.

Typically found between 65 and 72 degrees north or south (the equivalent of northern Scandinavia), these glowing red, green, blue and yellow lights can usually be seen around the equinoxes in remote areas of the countryside, particularly when the sky is at its darkest. Aurora borealis is the trace of solar wind emitted from the sun when it gets excited by large amounts of energy being produced and released from its violent core. This energy flows outwards from the highest injections of the sun’s radioactive energy, or waves, and flow through our solar system and out into space where they are dispersed. When this energy hits strong atmospheres of the planets closest to the sun, they excite particles of light found in the magnetic layers of their atmospheres and excite nitrogen and oxygen atoms into releasing electrons.

The electrons are emitted in the form of photons (particles of light), which creates the amazing light spectacular that we call aurora borealis. These photons hit other nitrogen and oxygen atoms, and cause them to lose photons, and the night sky becomes ‘alive’ with the colourful bombardment of electrons. The higher in frequency this activity, the more photons are emitted and the less distance they ‘jump’ before colliding into another atom. They are therefore said to be less ‘red-shifted’ as they give off bluer and greener light.

The energy from the sun is not produced at a uniform rate, as the sun’s inner core comprises a series of complex and irregular chemical reactions, and thus once the core has been triggered, it produces increasing amounts of energy until the atoms used to produce this inner energy start to burn out, and the sun’s activity diminishes until it has stored up sufficient materials to start its cycle again. As 2011-2012 will be the culmination of three solar cycles, the power and force of energy emitted from the sun will be at a significantly high level, and thus the aurora borealis will be an event not to miss, with and the spark for stories to tell the grandchildren.