(Cleveland) - A thick white contrail, an intense flash and sharp explosions marked the passage today of a meteor across the sky above Russia's Ural Mountains, where more than 500 people have reported injuries, many from broken glass.

The Emergency Ministry says fragments of the meteorite fell in a thinly populated area of the Chelyabinsk region. And about 6000 square feet of a roof at a zinc factory collapsed.

Cleveland State University research astronomer Jay Reynolds estimates that the meteor weighed about 10 tons and was made mostly of iron and precious metals.

Reynolds tells Newsradio WTAM 1100 that because it was so small, space watchers did not likely see the meteor until an hour before impact.

Jay Reynolds

Reynolds says the meteor entered the Earth's atmosphere at a speed of at least 33,000 mph and shattered about 18-to-32 miles above ground causing a very loud explosion. 

Meanwhile, experts will be closely watching a large asteroid set to pass by Earth this afternoon at 2:25pm.

Reynolds explains that the asteroid called 2012 DA 14 is expected to pass about 17,200 miles above the Earth at about 2:25 pm EST. It's about 150 feet across and scientists have been tracking it for nearly a year.

Reynolds maintains the only danger may be to low Earth orbiting satellites. He reports there are about 1,400 objects in space and scientists are closely watching at any given time.

Meteors are pieces of space rock, usually from larger comets or asteroids, which enter the earth's atmosphere. Many burn up by the heat of the atmosphere, but those that survive and strike the earth are called meteorites. They often hit the ground at tremendous speed, up to 18,642 mph.

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