[meteorite-list] Deep Impact, Impact

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Mon Jul 4 03:03:17 2005
Message-ID: <42C8DF13.8A802D0B_at_bhil.com>

Steve,

    I'm betting the truck isn't two miles long!

Quote from NASA DEEP IMPACT website:
     "The nucleus of Comet 9P/Tempel 1 is elongated and irregular, so the closest example we currently have is the nucleus of Comet Borrelly, but even more elongated. The mean radius of Tempel 1 is 3.25 +/- 0.2 km, and the axial
ratio (a/b) is 3.2 +/- 0.4, giving an approximate prolate ellipsoidal shape with semi-major axes a=7.2 +/- 0.9 and b=c=2.2 +/- 0.3 (thus major axes of 14.4 x 4.4 x 4.4 km). The volume is then about 146 cubic kilometers, but could
be as low as 90 or as high as 210 cubic kilometers.
      Even more poorly known is the density. From studies of Comet Borrelly, we have a result of 0.49 grams per cubic centimeter, with a range of 0.29 to 0.83 (Farnham, Icarus 160, 398, 2002), but from further refinement through
studies of Wild 2, Tony Farnham would now expect that the most probable value is more in the range of 0.3 to 0.4.
      The mass is then calculated by multiplying the volume by the density, and considering the uncertainties. Thus we think we know the mass of the nucleus of Comet Tempel 1 to within about a factor of 3, or a range of a factor
of 9."

    Me, again:

COMET = VOL of 1.5 x 10^17 cc at 0.33 gm/cc = 0.5 x 10^17 gm = 5 x 10^10 mTons,
or
50,000,000,000 mTons

DEEP IMPACT GNAT = 3.72 x 10^5 gm,
or
0.372 mTons
or
RATIO 134,408,602,150 to 1


TRUCK = 2.5 X 10^7 gm = 25 mTons
REAL GNAT = 1 gram (FAT GNAT!)
RATIO 25,000,000 to 1.0

REAL GNAT GOING 50 m/sec
DEEP IMPACT GNAT GOING 11,000 m/sec
FORCE (mv) 220 times greater x 37,200 heavier = 8,184,000 greater force than real gnat

SCALED FOR RATIO OF
WEIGHT OF COMET TO
WEIGHT OF TRUCK,
IMPACT ON TRUCK IS
EQUIVALENT TO

30.5 GNATS!!!!

    I hear the screech of tires, the fracturing of king pins, rolling, tumbling, the bursting into flames, the last SQUAWK from the CB...

    Man, I wouldn't want to be in that 18-wheeler when it got hit with 31 gnats ALL AT ONCE, would you?


Sterling K. Webb

MeteorHntr_at_aol.com wrote:

> Sterling Said:
> "It's like the world's tiniest gnat smacking into the windshield of the world's biggest 18-wheeler, only even less so!"
>
> List,
>
> While I agree Deep Impact should not alter the Tempel 1 orbit, but I have to disagree with the gnat/18 wheeler example as most gnats don't create craters the size of football stadiums in the windshields of the trucks they hit.
>
> Now if the gnat would hit the truck taveling at 23,000 miles per hour, then maybe it would be a better comparison. Then again, at 23,000 mph the trucks "orbit" might indeed be altered.
>
> And if the truck is as fragile as Orgueil, then maybe that little gnat would cause some problems.
>
> Steve Arnold
> #1
> Arkansas
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Received on Mon 04 Jul 2005 03:02:43 AM PDT