Large Asteroid to Fly Past Earth next week

SPACE.COM

By Jeanna Bryner
Staff Writer
posted: 24 January 2008
12:39 pm ET

Artist's representation of a rogue asteroid

An asteroid that's likely as big as several football fields will fly past Earth next week. Astronomers said the space rock will be visible the night of Jan. 29 to amateur astronomers with modest-sized telescopes.

Called 2007 TU24, the asteroid was discovered by NASA's Catalina Sky Survey on Oct. 11, 2007. It is estimated to be somewhere between 500 feet (150 meters) to 2,000 feet (610 meters) in diameter.

The asteroid makes its closest approach to Earth, 334,000 miles (537,500 kilometers), at 3:33 a.m. Eastern time (12:33 a.m. Pacific time). For comparison, the moon is an average of 239,228 miles (385,000 kilometers) away.

"This will be the closest approach by a known asteroid of this size or larger until 2027," said Don Yeomans, manager of the Near Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif.

However, that doesn't mean we won't hear about another flyby of this nature before then. With relatively small space rocks, like this one, astronomers sometimes don't know they're passing through until right before they do.

There is no danger of the asteroid striking Earth in the foreseeable future, the scientists said.

But if an asteroid with this size were to hit Earth, the results could be regionally devastating. The impact itself would release about 1,500 megatons of energy, creating a crater about three miles (nearly five kilometers) wide and kicking up loads of debris, according to Yeomans.

"If it hit in the ocean, which is more likely because two thirds of the Earth is ocean, it would create a tsunami, which would be devastating for the coastlines that happen to be nearby," Yeomans told SPACE.com. "It would be a huge local problem and the tsunami would be extraordinary if it hit in the ocean." Read More here.

The old Desert Gnome has a couple of physics related comments:

Remember that the energy resulting from such a collision is the kinetic energy of the moving body (the energy of motion of a body equals the product of half its mass and the square of its velocity) so it is dependent on the actual mass of the asteroid and its speed relative to the Earth.

The figure given in the article of 1500 megatons may not have a lot of meaning to many of the people reading this so, to put it into a more evocative form, it is helpful to know that the atomic bomb which destroyed Hiroshima in 1945 yielded an estimated 13 kilotons.

So, if I've done the math correctly, we're seeing an estimate of 100,000 times the energy of the Hiroshima bomb as being the product of a collision of the Earth and one of these rocks...

Oh, yeah, the Tunguska bolide is currently estimated to have been 70 meters in diameter and it flattened over 2000 square km of forest and incinerated a central region of 1000 square km.

We don't want to meet up with that 700 meter rock! And, here's the thing about this story that really makes the hair on your neck stand up, it was not discovered until 11 October 2007! That means that, if it were headed toward Earth impact, we would have had three months and eighteen days to prepare for the collision.

Does anybody believe that there is a well prepared plan out there to deal with such an emergency?

Here's a little more from SPACE.com about this issue