In space no-one can hear you scream

We depend on the Sun for life, but it an unpredictable master. Every now and again it flings out bundles of joy known as Coronal Mass Ejections (CMEs), which can do an awful lot of damage when they slam into our vulnerable little planet. The CMEs can produce magnetic storms that could have the power to knock our gadget-heavy lifestyle back into the dark ages. Most of the CMEs aren’t anything like that powerful, in fact they happen reasonably often and usually don’t do that damage. But they can do some damage, including messing with our satellites and electrical transmission lines. Which is why it’s interesting news that a team at SOHO (The Solar and Heloispheric Observatory) have discovered that the really big ones are preceded by radio ‘screams’ from the Sun. Here’s how it works:

Strong CME shocks accelerate electrons in the solar wind, which in turn produce the radio signal. The same strong shock must also accelerate atomic nuclei in the solar wind, which produce the radiation storm.

The radio signal moves at the speed of light, but the particles lag behind. So we can ‘hear’ the scream and know that the CME isn’t far behind. The article from the European Space Agency explains how the early warning system could be helpful (and has a nice clear explanation of the phenomenon) - if astronauts are showboating around on the outside of spacecrafts they could be told to get inside rightaway to be protected from the extra radiation. Handy indeed. But seeing as how the Sun is quite big and we are quite small, if a big ejection is on the way it’s not like we can say ‘Umbrellas up! CME a-coming’ just yet…

ETAC)