Aurora Borealis - visibility in Newcastle Upon Tyne
The Aurora Borealis is one of the most wonderful sights to be seen in the sky and it would be good to easily know when it might be seen.
The aurora is produced by charged particles ejected by the sun impacting on the upper atmosphere of the earth. Because they are charged they are deflected towards the earths magnetic poles. This means that aurora are most frequently seen in the high latitudes towards the poles.
The rate at which the sun throws off such charged particles runs with the 11 year cycle of sunspot activity. This peaks around the turn of the decade, so at present we are near the solar cycle minimum (in fact the official start of the current cycle ie: minimum is 2008), and activity will gradually increase toward the next peak around 2012.
The charged particles take around 2-3 days to cover the distance from the sun to the earth. The best aurora will be seen following a large sunspot group producing a coronal mass ejection travelling directly toward the earth. These may have enough energy to disrupt and damage earth orbiting satellites and distort the atmosphere disturbing radio communications.
I have found that the best way of determining whether you are likely to see an aurora if you go outside on a dark night (apart from the fact that the sky needs to be cloudless!) is to look at the Solar Terrestrial Dispatch auroral power chart visible at www.spacew.com and via the link on Beacon Themes.
The date and time of the chart is given in the top line. the second line indicates the energy impacting the earth from the solar wind, and the time it was valid. In this case it was 6GW or equivalent of 1/14th the total generating capacity of the United Kingdom ( 83GW ) at 19.47 UTC (ie: GMT not British Summer Time).
If the power figure on this chart rises to above 75GW there is a reasonable chance that you could see an aurora at the latitude of Newcastle Upon Tyne (ie. 55 degrees north)
Examples of Aurora - unfortunately not seen by me and not seen in Whitley Bay! At their best, the sky can be almost as bright as day. Most aurorae are green and red with light being produced from exited states of oxygen. Low level red and blue-violet are produced from nitrogen. Click on the images to see them enlarged.
This is the highest power input I have ever seen on the chart - 499GW, or 6 times the total generating capacity of the United Kingdom. This was 29th October 2003, and on that night the aurora was seen as far south as Italy.
