Bob Moler's Ephemeris Blog

Thursday, August 2nd.  The sun rises at 6:30.  It’ll be up for 14 hours and 35 minutes, setting at 9:05.   The moon, 1 day past full, will rise at 9:05 this evening.

With the sun really being active, there’s a good chance we’ll see several displays of the northern lights of aurora borealis.  Those south of the equator will see the southern equivalent, the aurora australis.  There’s an active group of sunspots rotating onto the earth-side face of the sun that should give us a chance to see the aurora in the next week or so.  Sunspots are caused by tremendous magnetic fields generated below the bright photosphere we rather improperly call the sun’s surface.  The sun has no solid surface, it’s all gas.  The magnetic fields cool the gas, making it darker.  The spots are maybe at a temperature 2,000 degrees cooler than the rest of the photosphere which is about 10,000 degrees Fahrenheit.  In  complex sunspot groups there is a potential for huge explosions.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Solar Dynamics Observatory white light image of the sun from Monday. Credits NASA / SDO. Click on image to enlarge.