Asteroid to squeak past Earth

In a near miss, an asteroid will be whizzing by Earth on a path that will bring it closer than the moon.
Written by Laura Shin, Contributor

An asteroid will slip by Earth in a near miss on Tuesday.

At 6:28pm Eastern Time, it will be at its closest point to Earth -- closer than the moon.

The asteroid, named YU55 (shown above) is the size of an aircraft carrier (1,300-feet wide) and will eventually be within 201,700 miles of Earth, though it won't be bright enough to be seen with naked eye.

The BBC quotes Lance Benner of Nasa's Jet Propulsion Laboratory: "This is the closest approach by an asteroid that large that we've ever known about in advance."

The roughly spherical asteroid is made of stone that is darker than charcoal, rotates once every 18 hours and has a gravity pull too weak to affect tides or earthquake activity. But it intrigues scientists for two reasons.

First, it is similar to asteroids that most likely collided with Earth in the distant past and brought to Earth the two ingredients that made life here possible: water and carbon. (Another asteroid that hit Earth 65 million years ago led to the extinction of the dinosaurs. It left a 110-mile-wide crater in Mexcio's Yucatan Peninsula that indicates it was about six miles or so across.)

Second, asteroids in general have the potential to play a major role in our future. The Los Angeles Times says:

In the future, scientists say, these asteroids may serve as watering holes and fueling stations for interplanetary travel. 'We may one day be able to mine asteroids, and if we start colonizing the solar system, they will be our fueling stations," scientist Marina Brozovic said in an interview. She's a member of the JPL Goldstone radar team tracking the asteroid.

There are about 19,500 asteroids of a similar size (between 330 feet and 3,300 feet wide) that have orbits around the sun that cross Earth's orbit, according to a tally NASA released in September.

The next time another asteroid comes so close to Earth will be 2028, when the asteroid 2001 WN5 is expected to pass by a mere 143,000 miles away.

photo: Asteroid YU55 shown on Nov. 7, 2011, at 2:45 p.m. EST, when the space rock was at 3.6 lunar distances, which is about 860,000 miles, or 1.38 million kilometers, from Earth. (NASA/JPL-Caltech)

via: Wall Street Journal

This post was originally published on Smartplanet.com

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