Aurora Borealis Visable
Credit: David Mark
The Aurora Borealis (often referred to as the Northern Lights) has been visable across much of the country recently and last night produced some stunning views over large parts of the UK.
However, if you were one of the unlucky ones who missed last night's spectacle, you may be interested in AuroraWatch UK. Run by Lancaster University, it offers free text alerts whenever there is a strong chance of the Aurora being visable from the UK.
So what causes the Aurora?
Aurora Borealis (and the southern hemisphere equivalent Aurora Australis) is caused when charged particles released by the Sun collide with gaseous particles in the Earth's atmosphere. Usually the charged particles are colliding with oxygen molecules at an altidude of around 60 miles, which produces the most common green glow. However, when the electrically charged particles from the Sun collide with higher altitude oxygen (around 200 miles) the Aurora produced has a red glow. Alternatively, the charged particles could collide with nitrogen and produce a blue/purple glow.