This is topic crater impact on the moon in forum Open Discussions About Writing at Hatrack River Writers Workshop.


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Posted by halogen (Member # 6494) on :
 
What would be the effects of a chunk of metal the size of a car hitting the moon at about 50 kilometers per second? Say an angle of 30 degrees

Would it create a shockwave? About how far do you think it would reach? What about a crater?

I assumed it would create a crater about 200 meters and a total shockwave of about 10 kilometers. How far off was I?

Is there any info available about this stuff? I'm having a real hard time trying to figure out what a shockwave on the moon would look and act like.

Any help would be appreciated
 


Posted by skadder (Member # 6757) on :
 
There are models (programs) for that sort of stuff. However I would just be a little vague about a few details and create the effect you want.

What you have done sounds good.


 


Posted by Bent Tree (Member # 7777) on :
 
I do not know much about velocity, but the surface regolith of the moon has a very thin layer of loose dust, Ie the footsteps. the rest is the same particles but very very compact. I would expect something so small travveling at such a high speed would enter like a bullet wound, releasing a large amount of particulate dust. I dont't think the shockwave would be that large. Perhaps similar to the small more recent pock mark craters on the moon that we see now.
 
Posted by snapper (Member # 7299) on :
 
The crater in Arizona was made by a meteor about the size you described, your crater would be a lot bigger than 200 meters. Increase it by ten-fold. As far as the shock wave goes, their is no atmoshpere so a heat/percussion wave wouldn't be a factor. A seismic shockwave is another matter, and that would depend on how close to the impact you are.
One thing you should consider is falling debris from the impact. The gravity is lighter so the fallout and range of falling rocks would be greater and a larger threat than a seismic shockwave.
 
Posted by Toby Western (Member # 7841) on :
 
This site lets you amuse yourself by throwing meteorites at the earth: http://www.lpl.arizona.edu/impacteffects/
It sounds sensible and authoritative, but information on the internet has been known to be incorrect

Folks seem less concerned by what happens when one hits the moon, but perhaps by playing with the parameters you might be able to come up with a fair approximation. The lack of atmosphere would probably make for some significant differences from this model, though.
 


Posted by halogen (Member # 6494) on :
 
Hey thanks everyone!

quote:
http://www.lpl.arizona.edu/impacteffects/

Yeah I found that url when doing research but the part that I'm really lost on is just the mechanics. What really happens when something hits the moon.

With no atmosphere and fine soil does an impact on the moon look more like an atomic explosion filled with vertical chaos or an expanding ring of dust that loses intensity as it spreads outwards?

I googled for about an hour last night and didn't find anything relevant. Argh!
 


Posted by annepin (Member # 5952) on :
 

NEWS RELEASES
NASA Astronomers Spot Rare Lunar Meteor Strike

There's cheesy video and an artist rendition, but it's a start, I guess.
 


Posted by skadder (Member # 6757) on :
 
I remember reading (don't know where, sorry) about a reference in the middle ages where there was a description of an impact on the moon that was visible (fireball) from earth with the naked eye--at least that is what I remember them saying.

Part of me thinks wasn't the Shoemaker-Levy Comet versus Jupiter the first recorded observation of a planetary strike? I think perhaps the moon thing was a modern interpretation of what someone described as a dragons on the moon or something.
 


Posted by Robert Nowall (Member # 2764) on :
 
As I recall, some of the Apollo gear detected lunar impacts soon after the astronauts left...nothing large, apparently, but detectable nonetheless...
 
Posted by TaleSpinner (Member # 5638) on :
 
Did you find this link?

http://www.geologyrocks.co.uk/tutorials/meteor_craters

Or: if Google doesn't know, nobody does, so you can write what you like!

Hope this helps,
Pat
 


Posted by skadder (Member # 6757) on :
 
I agree. Only one in 100,000 people may know what you are writing is b*ll*cks, although you can be sure they will write to you and tell you how wrong you are!
 
Posted by halogen (Member # 6494) on :
 
Nice article, thanks TS

Haha yeah normally I would just fudge it but this is for the return to luna contest and I have a feeling they'll be a little more critical.


 


Posted by JeanneT (Member # 5709) on :
 
quote:
agree. Only one in 100,000 people may know what you are writing is b*ll*cks, although you can be sure they will write to you and tell you how wrong you are!

I have to disagree here. A lot of sf writers, fans (and some editors) have a science background. Not only do a lot of them know if you're writing bs--they post it on every forum. Just the way it got around about a certain very, very famous fantasy writer saying you could stick a staff under a horse's girth.

He had a few hundred people tell him he was stupid and then they told everyone else they could find. SF people are worse, much worse.
 


Posted by TaleSpinner (Member # 5638) on :
 
quote:
SF people are worse, much worse.

I have to agree.

And yet, it's surprising how much one can find out about the latest thinking on a scientific subject using Google. Material on this particular topic, however, seems to be evasive. Maybe it's a military secret ;-)

I agree with halogen, I think the Return to Luna people will be critical. I imagine they'll know what the moon is made of and how that will impact, er, impact craters.

Mind, I don't know why I think they'll be critical--they want "Science Fiction stories that show the adventure of lunar settlement. We want to feel the romance of life there, the wonder of the lunar frontier, of its magnificent desolation." Sounds more like Fantasy than SF to me!

Good luck with this, halogen,
Pat
 


Posted by Rommel Fenrir Wolf II (Member # 4199) on :
 
HAY DONT BLOW UP THE MOON, ME AND OTHERS OF MY KIND STILL NEED IT.

anyway, there would be lots of fallout hitting the earth and many deaths. remember the moons surface is 90something% glass dust.

and the moon is the center of a lot of religons

RFW2nd
 




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