When suitably aerodynamic porcine objects develop enough lift to move independently through a stream of air.
Sunday, September 19, 2010
Billion-Year Old "Black Widow" Pulsar Ripping Through Milky Way at 1 Million KPH (Weekend Most Popular)
The "Black Widow" pulsar is zipping through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent...