Q: What would be the consequences if an asteroid the size of an aircraft carrier hit the Earth, either in the ocean or on land?
-- Tom Brayton, Sharpsburg
A: An asteroid the size of 2005 YU55, which passed within 202,000 miles of Earth on Nov. 8, would destroy a city the size of Chicago, creating a crater 4 miles wide and 1,700 feet deep, according to scientists at Purdue University. The collision would be equivalent to a 4,000-megaton blast and a magnitude 7.0 earthquake if it hit land, Jay Melosh, an expert in impact cratering and a professor of earth and atmospheric sciences, physics and aerospace engineering at Purdue, said in an article on the university's website. The "heat from the fireball would cause extensive first-degree burns, the seismic shaking would knock down chimneys and the blast wave would shatter glass windows" at least 60 miles from the impact, the article stated. If the asteroid hit the ocean, it would cause a 70-foot-high tsunami within 60 miles of the crash. "Impacts from asteroids of this size are very rare," Melosh said. "They occur about once every 100,000 years, so the chances of an actual collision with an asteroid like YU55 is about 1 percent in the next thousand years."
Q: Why did President Barack Obama receive Secret Service protection 18 months before the previous election, which is the earliest a candidate has received protection?
-- Barbara Turner, Newnan
A: The Secret Service was concerned about the amount of "racially charged rhetoric" that was directed at Obama, long before he was elected, ABCNews.com reported. It began protecting him on May 3, 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 q&a@ajc.com (include name, phone and city).
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