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."
"As
its closest approach is about one-and-a-half times the distance of Earth to the
moon, there is no reason for concern," Yeomans said. "On the
contrary, Mother Nature is providing us an excellent opportunity to perform
scientific observations."
At its
nearest, the asteroid will reach an approximate apparent magnitude 10.3, which
is about 50 times fainter than an object visible to the naked eye in a clear,
dark sky. Then, it will quickly become fainter as it moves away.
Like other asteroids,
this one orbits the sun. Most do so in the asteroid belt between Mars and Jupiter.
NASA pays particular attention to those whose orbits bring them so close to
Earth.
Given the
estimated number of near-Earth asteroids of this size (about 7,000 discovered
and undiscovered objects), astronomers would expect an object of this size to
pass this close to Earth every five years or so on average. And about every
37,000 years on average, an object this size would be expected to actually impact
Earth.
Astronomers
have catalogued hundreds of asteroids larger than a half-mile across that pass
in the vicinity of Earth's orbit. However, none of these are known to be on a
collision course with our planet.
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