Northern Lights

The Northern Lights (aurora borealis) are perhaps the thrill of the summer for the Black Oak Lake night sky watcher. They generate a number of very late night phone calls around the lake which infuriate your neighbors until they go out and look up! The dancing lights are caused by variations in the “Solar Wind” emanating from the sun. The sun goes through a cycle of activity which averages 10.7 years long. These cycles are numbered and we are currently (early 2020) very near “solar min” meaning we are at a very low level of activity. For daily updates on solar activity see www.solarcycle24.com.

Over recorded history the intensity of a late starting cycle has been less than normal so we may be in for a couple of decades of below normal solar activity. History has also shown that earth’s temperature varies with solar activity (see http://home.cern/about/experiments/cloud) so we may also be in for a return to below normal cold.  

YOU CAN FORECAST THE NORTHERN LIGHTS ….. SORT OF

Since the solar wind takes from 17 hours to 7 days to reach earth, the aurora borealis is somewhat predictable. Satellites positioned at the L1 Lagrange Point of equal gravitational attraction between the sun and the earth can give up to 48 hour warnings of an approaching Coronal Emission.  A good site for three day forecasts is: http://www.swpc.noaa.gov/products/3-day-forecast  

USEFUL LINKS

Excellent explanation of the aurora in video

Scroll down the left side of the below page for daily predictions of auroral activity. A world map is featured:

Shows the current auroral situation and gives an estimate of the accuracy of predictions:

Explains the physics of auroral bursts and flashes:

More Themis satellite system evidence on the causes of bursts and flashes:

Shows electronic video from the polar and THEMIS satellites of daytime aurorae:

Beautiful video and technical explanation of the phenomena:

Explanation of why aurorae are twice as frequent at the times of earth’s equinoxes: