"Where's the Ka-Boom?"
Posted on 12/20/2007 6:27:00 PM PST by NormsRevenge
LOS ANGELES (Map, News) - Mars could be in for an asteroid hit.
A newly discovered hunk of space rock has a 1 in 75 chance of slamming into the Red Planet on Jan. 30, scientists said Thursday.
"These odds are extremely unusual. We frequently work with really long odds when we track ... threatening asteroids," said Steve Chesley, an astronomer with the Near Earth Object Program at NASA's Jet Propulsion Laboratory.
The asteroid, known as 2007 WD5, was discovered in late November and is similar in size to the Tunguska object that hit remote central Siberia in 1908, unleashing energy equivalent to a 15-megaton nuclear bomb that wiped out 60 million trees.
Scientists tracking the asteroid, which is halfway to Mars, initially put the odds of impact at 1 in 350 and increased the chances this week after analyzing the data. Scientists expect the odds to diminish again early next month after getting new observations of the asteroid's orbit, Chesley said.
"We know that it's going to fly by Mars and most likely going to miss, but there's a possibility of an impact," he said.
If the asteroid does smash into Mars, it'll likely aim near the equator close to where the rover Opportunity has been exploring the Martian plains since 2004. The robot is not in danger because it lies outside the impact zone. Speeding at 8 miles a second, a collision would carve a hole the size of the famed Meteor Crater in Arizona.
In 2004, fragments of the comet Shoemaker-Levy 9 smacked into Jupiter, creating a series of overlapping fireballs in space. Astronomers have yet to witness an asteroid impact with another planet.
"Unlike an Earth impact, we're not afraid, but we're excited," Chesley said.
I presume that the "impact zone" is the half of the planet facing where the asteroid is coming from, at the time the asteroid approaches the planet.
So I then presume they mean the rover will be on the back (far) side of the planet when the asteroid will either a) hit the planet, or b) pass by it.
It's relatively easy to predict the date and time the asteroid will be at the planet, and the rotational position of the planet at that date and time. But the actual trajectory of the asteroid (i.e. whether it will hit the planet) is a LOT tougher to predict.
Isn’t that the Vice President’s birthday?
However, that was a very good point and NASA is loosing their credibility.
When I first read the article I immediately thought of a Youtube shooting range video where the bullet hit a rock downrange and came back and plopped the shooter on the head. Ricochets can happen.
The sky is falling........ but on Mars! :-)
Ah, well we recently had Shoemaker-Levy crash into Jupiter, now this *may* happen to Mars, and yet, we are ASSURED that there is NO CHANCE anything like that could happen to the Earth.
Kinda like both neighors on your block winning the Lotto in the same week.
Sings in the Heavens anyone?
Huh? LOL
They just discovered this and it might hit in January. Reminds me that (either Shoemaker or Levy) said it is likely we will not spot an Earth threatening asteroid until after it enters our atmosphere.
"Where's the Ka-Boom?"
Halfway from where?
> However, that was a very good point and NASA is loosing their credibility.
No, it's not a good point. I think you misunderstood what I wrote.
The largest possible "impact zone" is the half of the planet facing the asteroid as it approaches the planet. By definition.
If the rover is on the OTHER side of the planet, it is "outside the impact zone".
So regardless of whether the asteroid hits the planet or not, if the rover is on the other side of the planet, the rover is safe.
They assign a 1 in 75 chance of the asteroid hitting Mars - which is fine, orbital uncertainties in a multi-body calculation are a given even this close to a (potential) impact date.
Then the writer claims that the on-ground Mars camera is “outside the impact zone” (of the crater). If they aren’t sure of any impact at all, how can they claim that any given spot below is away from the zone?
Are they placing it in an alternate hemisphere (possible north pole impact while the camera is at the equator?) Other side of the planet (day impact side/night lander side ?)
Neither case is implied.
Let us hope that the impact is on our visible side, and that the orbital cameras are usable that direction.
You're thinking only of the spacial dimension. Think time as well. They know the plane of the orbit pretty well I would imagine, but can't quite tell if Mars will be there when the object crosses Mars' orbit. But if it is, I imagine they can tell where the uncertainly in the orbit would cut across Mars, in latitude anyway.
Damn, beat me to it..
Well, technically speaking, it might only partially rock. Some asteroids are mostly iron.
Better steel yourself for the collision if you stear us wrong, lest we cow in fear and dread of the impact.
Speaking of which, would the EPA require an environmental impact statement for this crater?
Realized that as I thought about it more. The speed of the object is easer to pinpoint than the trajectory. Knowning that it will pass by at a certain time isn't the same as knowing exactly where it will pass.
Far easier to tell where the bullet is going from behind it. When it's passing in front of you the destination is a bit harder to figure out.
Here is the orbit viewer (recommend centering on Mars and then zooming in):
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007%20WD5;orb=1;cov=0;log=0#orb
not sure.. there was a recent report or study that said it was possibly a 60 meter wide object, nobody knows for sure,, it also made light of a lot of the forest being diseased so it may have been more easily blown away .. one of those mysteries that is hanging tough.
it may have been shockwaves preceding the thing that actually did the damage and the object itself pretty much went poof as it flew thru the atmosphere.. thus not much to find physically..
Jupiter is a lot different than the Earth. Almost anything that Jupiter reacts with will most likely be scattered out of the Solar System or it will impact Jupiter. Many objects that would safely fly by the Earth at a great distance would be pulled into Jupiter.
I know you often see the movies showing New York being hit by meteors and ice hurricanes and Los Angeles being hit by 10.0 earthquakes and volcanoes. This doesn't mean that these events are probable. Impact events are rare. The probability that humanity is going to be annihilated in the next 50 years is infinitesimal. The probability that Hollywood will make movies about meteors striking major American cities is one.
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