Michigan meteor could have been meatier, scientists say

WASHINGTON — The fireball that streaked through the Michigan sky put on quite a show but as far as potentially killer space rocks, it was merely a flash in the pan. There are much bigger asteroids careening through our solar system.

Scientists who watch for them hope they spot them in time to get people out of the way if a truly dangerous one is heading straight to Earth.

So far, one isn’t coming.

Just as Tuesday’s meteor lit up the Michigan skies, about 30 scientists were gathered in California to discuss the biggest meteor hit in modern history — the 1908 explosion over Tunguska, Russia, that flattened 800 square miles of forest.

And that’s nothing compared to what happened 65 million years ago when a 6-mile-wide asteroid impact caused 70 percent of life on Earth to go extinct, including many dinosaurs.

“There are no Earth-crossing asteroids of that size in the solar system today,” said NASA senior scientist David Morrison, a space rock expert who organized the California workshop.

Since the 1990s, NASA has been conducting the Spaceguard survey looking for those large asteroids. So far, astronomers can rule out rocks bigger than 3 miles wide, Morrison said. 

Still, “something as small as 2 kilometers could really ruin your whole day for the whole Earth” and maybe kill three-quarters of the people but “wouldn’t be extinction,” he said. 

Tuesday’s 6-foot-wide Michigan rock was too small to be tracked. It exploded in the air with the power of 100 tons of TNT, said Bill Cooke of NASA’s Meteoroid Environment Office. Scientists will now try to figure out where it came from.

A meteoroid is a small chunk of asteroid or comet. When it enters Earth’s atmosphere it becomes a meteor or fireball or shooting star. The pieces of rock that hit the ground, valuable to collectors, are meteorites.

Doppler weather radar shows flashes that indicate meteorites are on the ground northwest of Detroit, Cooke said.

For comparison, the fireball that shook Chelyabinsk, Russia, in 2013…

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