September Aurora

There's a pretty good possibility of nights with Aurora Borealis in the next two weeks.

The Sun's rotation is bringing a very active sunspot area back into view. Yesterday that area, barely visible, coughed up a solar flare which caused a complete blackout of shortwave radio communication over the daylight side of the Earth -- impressive for a glancing blow. As the Sun brings that area round to face the Earth, things could get even more violent.

This was an "X-Class" flare: "X-class flares are big; they are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms." Their strength is measured on a scale of 1 to 9 (X-1 to X-9) -- yesterday's was an X-17. If another one of those explodes when that active region is central on the Sun (pointing at, or near, the Earth) in about a week's time, we should have quite a show! As some of us saw, the Moon was very new on Monday, so it'll be full and bright in about ten days and may spoil any show.

The all-time record is a flare in November 2003 which overloaded every X-ray detector on the satellites which monitor this stuff - it's estimated to have been in the X-30 to X-40 range, beating the previous record of about X-24. Luckily the material blown off the Sun by that one missed the earth. In March 1989 a X-15 solar storm took out the Quebec region's electrical power grid.

If anything happens SpaceWeather will have news ....