On the same day that the world's scientists were polishing their telescopes in anticipation of asteroid 2012 DA124, a meteor broke apart over the Ural Mountains in Russia and rained down fire and debris -- reportedly injuring nearly 1,000 people. So why didn’t they see this one coming?

Apparently, size matters, explained Andrew Cheng of the Johns Hopkins Applied Physics Laboratory.

"It doesn’t take a very large object. A 10-meter size object already packs the same energy as a nuclear bomb," Cheng, who led a 2000-2001 mission for NASA to orbit and land on an asteroid, told FoxNews.com.


The Russian meteor -- estimated to be just 10 tons and about 15 meters or 49 feet wide -- entered the Earth's atmosphere at a hypersonic speed of at least 33,000 mph and shattered about 18-32 miles above the ground. It released the energy of several kilotons above the Chelyabinsk region.

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That’s relatively small compared with asteroid 2012 DA14, which will make the closest recorded pass of an asteroid to the Earth -- about 17,150 miles -- later today. And while NASA’s Near Earth Object Program and other skywatchers track thousands of larger asteroids like it, the countless smaller ones in the heavens are virtually impossible to locate.

“This thing is probably pretty small compared to DA14,” explained K.T. Ramesh, professor of science and engineering at Johns Hopkins Whiting School of Engineering and founding director of Hopkins Extreme Materials Institute.

“If you think about objects the size of the one that came into Russia, you’re probably looking at 100 million up there. Of those likely to intersect Earth, there’s less, maybe 100,000,” Ramesh told FoxNews.com. “Space is pretty big.”

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; those that strike are called meteorites. And the damage caused by even a small meteorite impact is significant, as seen by the events in Russia.


Chelyabinsk health chief Marina Moskvicheva, said Friday that 985 people in her city had asked for medical assistance. The Interfax news agency quoted her as saying 43 were hospitalized.

While scientists scan the heavens frequently and keep track of millions of objects, Cheng said, they don't keep watch continually.

"Extending the searches to objects as small as this thing was will require some serious investment. Is it possible? Yes," he told FoxNews.com. And doing so is clearly important. The impact of a larger asteroid, such as 2012 DA14, would be far worse.

“DA14 -- if that were made of iron, it would get to the ground and cause a significant crater, likely take out a city,” Ramsesh told FoxNews.com. “Major impact events have the potential to create global catastrophes,” he said.

Ramesh says that it is hard to predict exactly what would happen to life as we know it if an asteroid were to suddenly slam into the surface of the Earth; the destruction would depend on both the asteroid itself as well as where it hits -- sea, land or urban environment.

To prevent such an event, his team at the Hopkins Extreme Materials Institute has developed a computer model for the impact and disruption of asteroids to help protect against a planetary impact. And to start, we need to put more effort into tracking, especially smaller meteorites such as the Russian one.

“We’re getting reasonably good at the big objects. It’s the small ones we need to work on,” he told FoxNews.com.

And we need to know what they’re made of. Because the massive 2012 DA14 is made of stone, it would likely break up in the atmosphere rather than make it to Earth. Ramesh stressed the need for education as well. There’s a real risk that someone doesn’t recognize this as a natural event and sees it as an attack from another country, he warned.

“My great fear is that you have two countries on the brink of war and something like this happens … and someone reacts to it,” he said.

The Associated Press contributed to this report.