This artist rendering provided by NASA shows the Van Allen radiation belts around Earth. A new study published Thursday Feb. 28, 2013, in the journal Science reports that NASA’s recently launched twin satellites to the region discovered a third, temporary ring. It appeared for a month before a shock wave from the sun destroyed it. Scientists are still trying to figure out how often this happens. (AP Photo/NASA)
This image provided by NASA shows an artist rendering of the newfound planet known as Kepler-37b. The planet is about the size of our moon and is the smallest known exoplanet, according to a study published in Thursday Feb. 21,2013 issue of the journal Nature. (AP Photo/NASA/Ames/JPL-Caltech)
In this photo provided by Chelyabinsk.ru a meteorite contrail is seen over Chelyabinsk on Friday, Feb. 15, 2013. A meteor streaked across the sky of Russia’s Ural Mountains on Friday morning, causing sharp explosions and reportedly injuring around 100 people, including many hurt by broken glass. (AP Photo/Chelyabinsk.ru)
FILE - In this 1953 file photo, trees lie strewn across the Siberian countryside 45 years after a meteorite struck the Earth near Tunguska, Russia. The 1908 explosion is generally estimated to have been about 10 megatons; it leveled some 80 million trees for miles near the impact site. The meteor that streaked across the Russian sky Friday, Feb. 15, 2013, is estimated to be about 10 tons. It exploded with the power of an atomic bomb over the Ural Mountains, about 5,000 kilometers (3,000 miles) west of Tunguska. (AP Photo, File)
SEFFNER, Fla. (AP) — Demolition work begins on Florida home atop huge sinkhole where man was swallowed by the earth.