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Astronomers track asteroid's pass near Earth

The 1,300-foot space rock is drawing interest from around the world as scientists hope it will help unlock the secrets of the universe's origins.

November 07, 2011|By Phil Willon, Los Angeles Times
  • Scientists hope the asteroid will help answer questions about the origins of the universe.
Scientists hope the asteroid will help answer questions about the origins… (Gina Ferazzi/Los Angeles…)

Reporting from Goldstone, Calif. — Rising from the desert scrub and pointed toward the heavens, NASA's gargantuan radio telescope on Monday fired a beam of microwaves at the largest asteroid to pass near Earth in decades in an effort to map the craggy surface and, possibly, reveal the primordial ingredients of life.

The 1,300-foot-wide asteroid will be nearest Earth on Tuesday, close enough to be inside the moon's orbit but far enough away to be invisible to the naked eye and pose no danger.

The giant space rock's flyby is being tracked by amateur and professional astronomers across the globe, including a team of NASA scientists at the controls of the Deep Space Network antenna in the Mojave Desert outside of Barstow and the Arecibo Planetary Radar Facility in Puerto Rico.

"This is an important opportunity to observe a type of asteroid that could have provided Earth with the early building blocks of life.… Possibly carbon-based material; possibly water and organic material,'' said Donald Yeomans, head of the Near-Earth Object Observations Program at NASA's Jet Propulsion Laboratory in La Cañada Flintridge.

The surface of the space rock, named 2005 YU55, appears to be as reflective as charcoal, which will make it difficult to see even with an optical telescope. Scientists caught a glimpse of the asteroid in 2010 during the incoming leg of its orbit, when it passed within 1.4 million miles of Earth.

The asteroid's outgoing journey this week will bring it within an estimated 201,000 miles Tuesday afternoon, the closest a rock this big has flown by since 1976, when President Gerald Ford was in the White House and the Los Angeles Rams still were playing football in the Coliseum.

Lance Benner, JPL's lead scientist on the project, said the information that bounced back from the flying asteroid Monday revealed ridges, craters and boulders on the surface. The recent data also allows scientists to plot the asteroid's path until 2075, when it will have another close encounter with Earth.

"There's no risk of it hitting us, but we've got to continue to monitor it,'' Benner said, briefing reporters outside the 230-foot-wide dish antenna.

The flyby gives researchers a rare opportunity to study the physical characteristics of a massive asteroid, adding to our understanding of bodies floating in space and offering a glimpse, perhaps, of the forces that created the universe, Benner said. Studying the space rocks allows scientists to determine whether it's a solid chunk of rock, a porous powder puff or, perhaps, a collection of giant boulders held together by gravitational force.

A team of scientists at the Goldstone Deep Space Communications Complex started tracking the current leg of the asteroid's journey Friday, studying monitors inside the galactic telescope and a nearby building humming with computer servers. Benner said they will be poring over the data collected for months, enough to create a three-dimensional model of the asteroid and provide clues about forces affecting its path and rotation.

The asteroid's composition and landscape may provide valuable insight for the future of space travel, when astronauts on far-flung journeys may seek out asteroids as way stations for supplies of water, minerals or material that could be used for rocket fuel. Mining the resources already flying around the cosmos would be the most affordable and efficient way to build off-world settlements and space-docked ships, Yeomans said.

"It just makes sense to look around up there for raw materials," Yeomans said.

NASA has identified more than 8,000 "near Earth" asteroids flying around space, including more than 400 that are at least a half-mile wide. Thus far, none of them is classified as a threat.

If an asteroid the size of 2005 YU55 did slam into Earth, the impact would be powerful enough to wipe out a major city like Los Angeles or Chicago with a direct hit, leveling everything within a 60-mile radius. If it splashed into the sea, it could create a 200-foot-high wave 60 miles away, said geophysicist Jay Melosh of Purdue University in Indiana, an expert on impact cratering.

Still, 2005 YU55 is far smaller than the asteroid that smashed into the Yucatan peninsula 65 million years ago, the culprit sometimes blamed for wiping out the dinosaurs. That one was 10 miles wide and had 8,000 times the mass, Melosh said.

"This one would be a city-buster, but would not wipe out civilization,'' Melosh said.

A few options for such a doomsday scenario already have been sketched out, including exploding a nuclear weapon near the rock to alter its course. But given that NASA's tracking program would probably provide years of warning, a more likely solution would be to slam it with a large spacecraft, he said.

"NASA is doing a good job finding these asteroids, so we don't have to live in the blind shooting gallery where we don't know where the next bullet is coming from,'' Melosh said. "So far, there's nothing with our name on it.''

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