And you thought you had a bad day at work

SgtWookie

Joined Jul 17, 2007
22,230
Many on the forums are too young (or weren't around yet) to remember the multiple Shoemaker-Levy 9 comet impacts on Jupiter in 1994. The comet broke into some 21 or so major fragments, and the impacts created tremendous fireballs in the Jovian atmosphere that were several times the diameter of Earth.

Had one of those fragments hit the Earth instead, it would've been sort of like shooting a plum with a high-powered rifle - except the "bullet" would have been travelling a LOT faster.

Here is a video of one of the fragments hitting Jupiter:
http://www.youtube.com/watch?v=7zNuT4dbdjU
The moon Io is the bright circle to the right.

The fragments of the comet were up to 1.2 miles in diameter, and were travelling at approximately 60km/sec (37.3miles/sec) when they impacted the surface.

A standard NATO-issue 5.56 round for the M16 rifle travels at approximately 3,250ft/sec, or 1km/sec - 1/60th the speed of the Shoemaker-Levy 9 comet fragments.

http://en.wikipedia.org/wiki/Comet_Shoemaker-Levy_9
 

magnet18

Joined Dec 22, 2010
1,227
Many on the forums are too young (or weren't around yet) to remember the multiple Shoemaker-Levy 9 comet impacts on Jupiter in 1994. The comet broke into some 21 or so major fragments, and the impacts created tremendous fireballs in the Jovian atmosphere that were several times the diameter of Earth.

Had one of those fragments hit the Earth instead, it would've been sort of like shooting a plum with a high-powered rifle - except the "bullet" would have been travelling a LOT faster.

Here is a video of one of the fragments hitting Jupiter:
http://www.youtube.com/watch?v=7zNuT4dbdjU
The moon Io is the bright circle to the right.

The fragments of the comet were up to 1.2 miles in diameter, and were travelling at approximately 60km/sec (37.3miles/sec) when they impacted the surface.

A standard NATO-issue 5.56 round for the M16 rifle travels at approximately 3,250ft/sec, or 1km/sec - 1/60th the speed of the Shoemaker-Levy 9 comet fragments.

http://en.wikipedia.org/wiki/Comet_Shoemaker-Levy_9
0.o
Do we have any sort of plan whatsoever for what to do if something like this is en-route to earth?
 

magnet18

Joined Dec 22, 2010
1,227
Since we have enough nukes to turn the planet into a glass parking lot then I would hope that we would at least have a method of destroying an asteroid... But I wouldn't be surprised if we didn't.
 

Thread Starter

someonesdad

Joined Jul 7, 2009
1,583
Per the Shoemaker-Levy impact -- I had a friend from work over that night for dinner and all of us went outside (it was a beautiful summer evening) and I set my telescope up to look at Jupiter. I of course didn't see any impacts, but you could see this big dark mark where one hit. It was a memorable event.

Speaking of that, I remember Halley's comet too. A friend from work and I were amateur astronomers and had been out the previous winter getting some nice views of it through the telescope. It wasn't quite as spectacular as I had hoped for. Anyway, the following summer I hadn't met my wife yet (it was another month or two) and she had won a trip to Australia from a local radio station -- to see the comet. She took her two kids and went there for a week and had a fabulous time. Unfortunately, it was clouded over and they never got to see the comet once!

Oh, and about doing something about a big asteroid heading for Earth. Unless it's detected a substantial distance away, there's basically little that can be done. We certainly know about the risk, but there's no collective effort to do anything about it. Maybe you kids reading this will be able to influence people in your time to organize a defense. I don't think many people realize how catastrophic a big impact would really be.
 

Wendy

Joined Mar 24, 2008
23,408
Or even a small impact for that matter. The asteriod they showed in the video was a bit smaller than our moon, so it would be more correct to call it a planetoid I think. But a asteriod half a mile in diameter will truly screw civilization as we know it.
 

strantor

Joined Oct 3, 2010
6,781
Since we have enough nukes to turn the planet into a glass parking lot then I would hope that we would at least have a method of destroying an asteroid... But I wouldn't be surprised if we didn't.
Like in the movie armageddon? Pretty sure that even a team of space-trained oilfield roughnecks couldn't do anything more than turn it into a big glass asteroid.
 

Wendy

Joined Mar 24, 2008
23,408
Personally I think we screwed if we needed it tomorrow, or even next year. The Russians have a heavy boost vehicle (the USA doesn't), so maybe they can do something.

The USA was better prepared during the Apollo era, but now no one in congress or the white house is willing to fund anything reasonable for the space program.

Personally I think that would be scary, the future of the human race dependent on Russian hardware.
 

ErnieM

Joined Apr 24, 2011
8,377
Watching it I was wondering what made the meteor so HOT before impact? Dang thing was glowing red.

Next, was it done in slow motion? It should have hit moving at near a good old "terminal velocity" equal to our (earth's) escape velocity. This thing was moving at a crawl.

Yes, it could "just touch" like that if it was moving in a conjoined orbit. But if it was doing that we would see it right now.

Third, why were there clouds? Anyone used to throwing rocks at the earth (Go read "The Moon is a Harsh Mistress" if need be) knows they make a big spark. That's gonna evaporate any clouds near by. Go youtube some vids of those Pacific islands we H bombed back in the 50's. The clouds are the first thing to go (well, right after ground zero is toast.)
 

Thread Starter

someonesdad

Joined Jul 7, 2009
1,583
And the nukes are pretty worthless -- that's the response of a kid with firecrackers. :p (yeah, I was one too)

Oh, don't believe me? The Ivy Mike shot was around 10 megatons. The crater was 2 km wide and 50 m deep. Let's assume that's a spherical cap. You can calculate that the volume is about 80 Mm3 (I use GNU units notation for units). Let's pick a Goldilocks-sized asteroid -- about 3 km in diameter (I estimated the middle size from the graph here); assume it's a sphere -- it's volume is 14 Gm3. Thus, vaporizing the asteroid will take 14000/80 or about 175 ten megaton bombs. I'd imagine an asteroid with e.g. a nickel-iron core will take a bit more energy than one of water, sand, and coral, so this may be a low estimate by a factor of 2 or more.

The pedants can quibble over the details if they want, but I'll be osculating my gluteus maximus. However, every cloud has a silver lining -- you can go fishing and say "screw the limit".
 

victorhugo289

Joined Aug 24, 2010
49
What are my plans...?
This would be great!

Ok, but where does a asteroid get its velocity from? Yeah it travels through space and gets pushed by the gravitational forces of other planets, then it goes...otherwise it would lie motionless wouldn't it?
...interesting.
 
Last edited:
Top