Yesterday afternoon, at 17h53 UTC, a vast sunspot erupted in an X-class flare, just as it directly facing Earth.  A powerful pulse of ultraviolet radiation lit up our upper atmosphere, briefly ionising it and disturbing the propogation of long-range radio transmissions.  The flare also threw off a Coronal Mass Ejection (CME) – a cloud of superheated plasma ejected from the outer layers of the Sun, which is now racing through space towards us.  It is expected to reach us sometime  on the 14th of July, around 10h20 UTC, give or take a few hours.

Fortunately, planet Earth is well equipped to deal with this – we have a strong magnetic field which will deflect most of the material, and our thick heavy atmosphere will soak up the rest long before it reaches the ground.  Most of what reaches the atmosphere will have been funnelled towards the poles, so anybody living at high latitudes should keep an eye out for bright displays of Corona Borealis (or Corona Australis, for those rare people far enough south) as the particles of solar material collide with air molecules and release their energy as light.

Our satellites are above the atmosphere and not so well protected, though.  Many will experience some effect, and there’s a chance of one or two being damaged or even destroyed.  But this is nothing new – that risk always exists.  After all, space is a very hostile environment.  The Sun has been doing this sort of thing for billions of years, and if it wasn’t for the Earth’s atmosphere and magnetic field, life could never have taken hold.  So rest easy: your GPS might struggle to get a fix tomorrow, but you yourself will be perfectly safe.