Mark your calendars - possible asteroid impact on Mars

**Skeptical**

By John Johnson Jr., Los Angeles Times Staff Writer
December 21, 2007
Talk about your cosmic pileups.

An asteroid similar to the one that flattened forests in Siberia in 1908
could plow into Mars next month, scientists said Thursday.

Researchers attached to NASA's Near-Earth Object Program, who sometimes
jokingly call themselves the Solar System Defense Team, have been tracking
the asteroid since its discovery in late November.

The scientists, at the Jet Propulsion Laboratory in La Cañada Flintridge,
put the chances that it will hit the Red Planet on Jan. 30 at about 1 in 75.

A 1-in-75 shot is "wildly unusual," said Steve Chesley, an astronomer with
the Near-Earth Object office, which routinely tracks about 5,000 objects in
Earth's neighborhood.

"We're used to dealing with odds like one-in-a-million," Chesley said.
"Something with a one-in-a-hundred chance makes us sit up straight in our
chairs."

The asteroid, designated 2007 WD5, is about 160 feet across, which puts it
in the range of the space rock that exploded over Siberia. That explosion,
the largest impact event in recent history, felled 80 million trees over
830 square miles.

The Tunguska object broke up in midair, but the Martian atmosphere is so
thin that an asteroid would probably plummet to the surface, digging a
crater half a mile wide, Chesley said.

The impact would probably send dust high into the atmosphere, scientists
said. Depending on where the asteroid hit, such a plume might be visible
through telescopes on Earth, Chesley said.

The Mars Reconnaissance Orbiter, which is mapping the planet, would have a
front-row seat. And NASA's two JPL-built rovers, Opportunity and Spirit,
might be able to take pictures from the ground.

Because scientists have never observed an asteroid impact -- the closest
thing being the 1994 collision of comet Shoemaker-Levy with Jupiter -- such
a collision on Mars would produce a "scientific bonanza," Chesley said.

The asteroid is now behind the moon, he said, so it will be almost two
weeks before observers can plot its course more accurately.

The possibility of an impact has the Solar System Defense Team excited.

"Normally, we're rooting against the asteroid," when it has Earth in its
cross hairs, Chesley said. "This time we're rooting for the asteroid to
hit."

This could be a once-in-a-lifetime event if it actually hits. So why do none of of Mars probes carry a video camera? Sad

S
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"A government big enough to give you everything you want, is strong enough to take everything you have." -- Thomas Jefferson

**Skeptical** · Posted: Sun Dec 30, 2007 2:47 pm Post subject:

They have upgraded the chances of January's Martian asteroid impact to 1 in 25. Place your bets!

S

LOS ANGELES (AP) — The chance of a football field-sized asteroid plowing into Mars next month has been increased to 4 percent, scientists said Friday after analyzing archival data.

Though still a long shot, some researchers are hoping for a cosmic smash.

"I think it'll be cool," said Don Yeomans, who heads the Near-Earth Object Program at NASA's Jet Propulsion Laboratory. "Usually when an asteroid is headed toward Earth, I'm not rooting for an impact."

The space rock, known as the nondescript 2007 WD5, was discovered in late November by the NASA-funded Catalina Sky Survey in Arizona. Based on the latest information available, scientists said last week there was a 1-in-75 chance the asteroid could hit Mars on Jan. 30.

The odds were increased to 1-in-25 this week after a Ph.D. student pored through the archives and plotted the asteroid's motions before its official discovery. The new information allowed scientists to improve their calculations of the asteroid's orbit and flight path.

Scientists will continue to monitor the asteroid to better predict the possibility of a Martian impact. Yeomans said he expects the odds to decrease with new observations gathered early next year.

The likelihood of an asteroid hit usually "peaks before plummeting to zero with additional data," he said.

The asteroid poses no threat to Earth and is closing in on the Red Planet at 27,900 mph.

Should a collision occur, it would likely blast a half-mile-wide crater north of where the rover Opportunity has been exploring since 2004.

The impact could release energy similar to the 1908 Tunguska object that exploded over remote central Siberia and wiped out 60 million trees.
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"A government big enough to give you everything you want, is strong enough to take everything you have." -- Thomas Jefferson

Will Sheephogan · Joined: 22 Sep 2007 Posts: 624 Location: Pahrump Nevada

**Carol Nistri** · Joined: 16 Jun 2007 Posts: 3352

well what happend,did it hit?

**Skeptical** · Posted: Mon Jan 21, 2008 1:20 pm Post subject:

It wasn't supposed to hit until January 30th, Carol, but I just checked a JPL website and the latest figures say the asteroid will miss Mars altogether. Shoot, I thought we were going to get to see sumpthin'! Sad

S
_________________
"A government big enough to give you everything you want, is strong enough to take everything you have." -- Thomas Jefferson