EIU Astro

Solar eruption aimed at Earth February 17, 2011

We are coming off the bottom of the 11 year sunspot cycle, so the sun is getting more active. As the internal magnetic field of the sun winds up, the field bursts out of the surface in regions known as sunspots.  Sunspots are cooler regions, hence they look darker, on the solar surface that have large magnetic fields. They can form in groups, and as part of their dynamics, they can release solar flares . Sunspot 1158 is a group of 4 sunspots that just had such a flare. The eruption can be seen in the video above taken by the SDO satillite and the optical image is below.

Sunspot 1158 in the lower right (OHO image from 2/17/2012)

Two forms of radiation come from an eruption, the electromagnetic radiation arrives first, just 500 seconds after the eruption. Then come the particles (mostly protons, with some Helium nuclei ) called the solar mass ejection. Since the particles travel much slower it can take up to several days to get to the Earth …and that is only if the spots are aimed at us.

The Chinese have reported some disruption in shortwave radio traffic. Very intense flares can cause damage to some satellites and power grids. This one however should just produce a light show, the aurora for people in more northern latitudes.

The NOAA space weather prediction site has aurora  maps to check if you can see the Northern lights.