Q: Why do meteors explode in the atmosphere?
— Mike Cooper, Atlanta
A: Meteors and other space debris travel through the vacuum of space at extremely high speeds. When a meteor enters the Earth’s atmosphere, it creates friction and pressure that cause the meteor to heat and glow before it explodes or shatters into smaller pieces, most often in the part of the atmosphere called the mesosphere. Most meteors disintegrate before they reach Earth. The meteor that exploded about 12 to 15 miles over Russia on Feb. 15 likely was 55 to 65 feet in diameter and weighed about 10,000 tons. NASA reported that the meteor exploded with the force of somewhere between 440 and 500 kilotons of TNT, or more than 30 to 40 times the energy of the atomic bomb dropped on Hiroshima in 1945. Only small pieces have been recovered.
Q: Did U.S. Sen. Lindsey Graham ever serve in any branch of the military?
— Marshall Reeves, Monroe
A: Graham, R-S.C., saw active duty with the U.S. Air Force for more than six years in the 1980s, serving a portion of that time at Rhein-Main Air Base in Germany, according to his Senate website (lgraham.senate.gov). He joined the South Carolina Air National Guard in 1989 and was recalled to active duty during the First Gulf War, serving stateside. He retains the rank of colonel in the U.S. Air Force Reserves and is one of two U.S. senators who serve in the Guard or the reserves. Graham saw reserve duty in Iraq in 2007.
Andy Johnston wrote this column. Do you have a question about the news? We’ll try to get the answer. Call 404-222-2002 or email firstname.lastname@example.org (include name, phone and city).