Wednesday, February 27, 2013

Relative Frequencies and Magnitudes of Bolide Explosions and Impact Events

The Great Daylight Fireball of 1972.

In light of the destructive bolide explosion over Chelyabinsk in Russia earlier this month, I have reviewed the recent history of meteoric events. From A.D. 1908 to 2013, there have been 11 confirmed events with potential explosive equivalencies greater than or equal to 10 kilotons of TNT. These are summarized below and suggest an observed frequency of such incidents that is somewhat higher than previous conservative predictions.

Eight of the observed explosions or impact events occurred over the greater Eurasian expanse. This continental zone includes just over 10.3 percent of the planet’s surface area. Extrapolating from these data yields an estimate of about seven such intermediate incidents per decade, which is not much lower than the number allegedly observed by military satellites. During the 105-year period bracketed by the Tunguska and Chelyabinsk explosions, there were also at least four bolides that exceeded 100kt equivalencies.

1908 Tunguska Event 15 Mt
1930 Curuçá River bolide explosion 5 Mt
1932 Arroyomolinos de León bolide 190 kt
1947 Sikhote-Alin impact 10 kt
1972 Great Daylight Fireball 80 kt
1993 Lugo bolide explosion 10 kt
1994 Marshall Islands Fireball 11 kt
2002 Eastern Mediterranean Event 20 kt
2004 Antarctic bolide explosion 12 kt
2009 Sulawesi bolide explosion 50 kt
2013 Chelyabinsk bolide explosion 500 kt
2016 South Atlantic fireball 13 kt

The Great Daylight Fireball of 1972 was caused by a near-Earth asteroid that passed harmlessly through the atmosphere over North America at least 35 miles above the surface. Estimates of its potential damage vary wildly, but I have selected a number in the upper range. Given the speed and luminosity of the bolide, had it grazed the planet at a more acute angle, I expect that the results would have been spectacular and potentially devastating.

As the Chelyabinsk explosion has proven, these intermediate objects present a very real danger. They are smaller, harder to detect, and much more common than the potential doomsday asteroids we can spot now. And we still lack the infrastructure to stop either of these threats.

Updated to include the South Atlantic fireball of 2016, which exploded several hundred miles southeast of Brazil (

Wednesday, February 13, 2013

Right-to-Carry Litigation in Summary

Map of the U.S. federal court system.

While the police finished murdering each other in southern California, and the President prepared “massive” proposals for the Congress, the case of Piszczatoski v. Maenza [now Drake v. Jerejian, 1/09/14] was argued before the U.S. Court of Appeals for the Third Circuit. With an en banc review of the decision in Moore v. Madigan looking unlikely, a victory in Piszczatoski would deepen the circuit split created by the loss in Kachalsky v. Cacace and thus make the conflicting jurisprudence even more difficult for the U.S. Supreme Court to avoid reviewing. Here is a summary of the major right-to-carry cases for those keeping score.

Kachalsky v. Cacace New York Lost on appeal at USCA2.
Moore v. Madigan Illinois Won on appeal at USCA7.
Palmer v. D.C. D.C. Won at U.S. District Court.
Drake v. Jerejian New Jersey Lost on appeal at USCA3.
Peruta v. San Diego California Petitioned to U.S. Supreme Court.
Richards v. Prieto California Lost on rehearing at USCA9.
Woollard v. Gallagher Maryland Lost on appeal at USCA4.

There is a host of other right-to-arms cases that are working their way through the federal court system, but this is the vanguard litigation. A historical turning point is at hand, though some people can’t or won’t see the important civil-rights implications at work here. Few people need to carry guns, they argue, but then very few people needed to abort pregnancies … or to marry the spouses of their choice … or to ride at the front of the bus.