Estimated to have released the energy equivalent to a 5 kiloton nuclear bomb when it exploded over the Central Valley of California, a minivan sized meteor was photographed (above) as it passed East to West over the Sierra Nevada mountains near Reno Nevada, around 8:00 AM Phoenix time last Sunday (1500 UTC).
The bolide, or extremely bright meteor, weighed around 70 tons, according to Bill Cooke of the Meteoroid Environments Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
With the Moon out of sight, the early morning of 22 April, will provide good seeing for the Lyrid meteor shower. These meteors are the result of the dusty tail of Comet Thatcher (C/1861 G1). Thatcher has an elliptical orbit, with a period of about 415 years. It will return in 2276. Space Weather has a good article about the Lyrids.
This year, the peak is expected on the evening of 21 April and the early morning of 22 April after midnight. The shower can last from 16 – 25 April. Typically, there are 10 to 20 meteors per hour. However, there is a large variation in the density of the shower. NASA has a long article (from the North American Meteor Network) concerning the shower and other events, and quotes an 1803 description from a newspaper in Richmond, Virginia on April 23rd, 1803:
For the techies on the audience, the radiant at maximum is at 271 degrees, i.e. RA 18h 04m, Dec +34, which is about halfway between theta and nu Hercules, and not actually in the constellation of Lyra at all.
6 May 2011, just before dawn.