Scientists say asteroid may hit Mars in late January (1 in 75 chance on Jan. 30, 2008)

ap on Examiner.com ^ | 12/20/07 | Alicia Chang - ap

[dayglored]

> If they can't even say it will hit (75 to one?) how can they possibly say the rover is outside the impact zone if it does?

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.

[668 - Neighbor of the Beast]

Isn’t that the Vice President’s birthday?

[Hunble]

If they can't even say it will hit (75 to one?) how can they possibly say the rover is outside the impact zone if it does?

However, that was a very good point and NASA is loosing their credibility.

[steve86]

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.

[NotJustAnotherPrettyFace]

The sky is falling........ but on Mars! :-)

[BereanBrain]

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?

[verity]

"When it does happen, I hope my kinfolk are on the Moon, Mars..."

Huh? LOL

[Williams]

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.

[dfwgator]

"Where's the Ka-Boom?"

[El Gato]

Scientists tracking the asteroid, which is halfway to Mars,

Halfway from where?

[dayglored]

>> If they can't even say it will hit (75 to one?) how can they possibly say the rover is outside the impact zone if it does?

> 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.

[Robert A Cook PE]

OK, I’ve got a hard spot with this:

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.

[El Gato]

If they can't even say it will hit (75 to one?) how can they possibly say the rover is outside the impact zone if it does? I mean, the odds are good that it is, since the 'zone' is currently larger than the entire planet, but come on.

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.

[The Pack Knight]

Damn, beat me to it..

[Robert A Cook PE]

If it misses, we should seriously study the feasibility of being able to push it into a collision. That would create a bunch of tech, and scientific knowledge. And it would totally rock.

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?

[kAcknor]

You're thinking only of the spacial dimension. Think time as well

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.

[burzum]

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

[aruanan]

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.

Nobody really knows the size of the Tunguska object and wasn't it actually supposed to have been in the 3-5 megaton range?

[NormsRevenge]

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..

[burzum]

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.

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.