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Nonkers
2006-Jul-26, 11:57 PM
Films like "Meteor" and "Armageddon" depict H bombs on rockets destroying objects in space.

The Moon has a surface area equal to Africa.

WI a crazed world dictator, like a Hitler, Stalin or Pol Pot, got it into his head that the Moon is a threat to the Earth, and it had to be destroyed?! He orders every A and H bomb that can be made to be launched non-stop at the Moon.

Would it eventually blow apart if hit by 1000 50 Mt blasts? Or would it need much much more, or even be beyond our ability to destroy?

What would be the effects on Earth of suddenly no Moon, or a Moon with a 15% chunk of it blown off?

R.A.F.
2006-Jul-27, 12:18 AM
If we blew up the Moon.

Now why would "we" want to do that??

Bad jcsd
2006-Jul-27, 12:23 AM
Though the Moon landings proved the surface of the Moon was not made out of cheese I strongly suspect that the inner structure is dairy based.

As a source of food the Moon could be invaluabl, but the only way to get at this food would be to nuke it.

Lurker
2006-Jul-27, 12:23 AM
If we blew up the Moon.

Now why would "we" want to do that??
{shrugs} why not?? :think:

Van Rijn
2006-Jul-27, 12:49 AM
WI a crazed world dictator, like a Hitler, Stalin or Pol Pot, got it into his head that the Moon is a threat to the Earth, and it had to be destroyed?! He orders every A and H bomb that can be made to be launched non-stop at the Moon.

Would it eventually blow apart if hit by 1000 50 Mt blasts? Or would it need much much more, or even be beyond our ability to destroy? We certainly couldn't destroy it today.

Much more. This was previously discussed, see here:

http://www.bautforum.com/showthread.php?t=20361

50,000 megatons would barely make a scratch. Try more like 1013 megatons.

In the thread, it was suggested moving it to enter Earth's Roche limit, but the requirements would still be astronomical (pardon the pun). You might also redirect a large KBO to hit it, which might also help a bit, but the energy requirements would still be incredible, and we couldn't do it today.



What would be the effects on Earth of suddenly no Moon, or a Moon with a 15% chunk of it blown off?


If the moon just disappeared, it wouldn't be as big a deal, but cracking up the moon would lead to debris, and it wouldn't take much making it to earth to ruin your millenium. Actually, bacteria might be lucky to survive. Good thing it won't happen.

PhantomWolf
2006-Jul-27, 12:50 AM
I honestly doubt that we'd have all that much affect on it, even if we hit it with our entire planetary nuclear arsenal.

phaishazamkhan
2006-Jul-27, 01:37 AM
The impact would be great if the moon disappeared or was destroyed as hypothesized by the OP. Tides would become negligible, not vanish since the sun does affect the tides, which could impact the ecosystem for an extended period. The speed of Earth's rotation could stabilize in the long term rather than continuing to slow down.
Plus there wouldn't be anything left to take a hit for Earth. Having a large satellite like the moon surely prevented numerous impacts that would've set back life a couple of eons.
On a more pragmatic level, it'd be a waste of untapped natural resources and a base for performing outrageously dangerous and toxic experiments no one would consider on the surface of Earth.
Plus wouldn't a lack of our moon make L4 and L5 much less stable?

yuzuha
2006-Jul-27, 02:16 AM
Geeze, if the Yellowstone volcano goes off it could be »2 million megatons. Even that wouldn't make much of a dent on the moon (the world's arsenal is probably a paultry 12,000 megatons). 5 billion megatons would only make a crater about 260 miles in diameter. About all we can do is dig a hole and stir up some dust.

Ronald Brak
2006-Jul-27, 04:05 AM
Why do I have the feeling that soon I will hear somewhere that we don't need to worry about rising sea levels because we can just "blow up the moon" to get rid of tides?

Romanus
2006-Jul-27, 05:09 AM
I'm pretty sure blowing up the Moon is well beyond our current technological capability, let alone that of a hypothetical tin pot dictator. The world's entire arsenal would make a tidy crater, but I think it's safe to say that there isn't enough retrievable fission or fusion bomb material in the Earth's crust to come close to blowing up the Moon.

But, if it could be done, it would be the end of life on Earth. Those thousands of 1-100 km chunks of the Moon would have to go somewhere, and quite a bit would make their home here. We're talking the Late Heavy Bombardment all over again, and resetting the evolutionary clock.

Jens
2006-Jul-27, 05:21 AM
Actually, I don't think atom bombs is what you need, because the blast goes in all directions and so it's very wasteful. I don't think you'd get much of the material out of orbit, so it would just fall back down onto the moon and you've accomplished nothing.

What you would need to destroy the moon is a big ramp to launch material our of its orbit, and then mine it to death.

astromark
2006-Jul-27, 07:44 AM
This idea is interesting but, lets hope we have the brains not to try this. I do not think that we have the bang power to actually destroy the moon. I have often wondered what a substantial impact on the moon would look like. I sagest a 'feather' would appear as debris was ejected from the impacting objects crater. I think within just days of this it would settle and be showing off its new impact crater. Only a cosmic scale event would destroy the moon. We would need it to push away from Earth or the angular momentum could lead to big trouble for Earths inhabitance. If some thing bumped the moon into an elliptical path this could be big trouble also.
I like it the way it is, Its pretty. Lets leave it that way

max8166
2006-Jul-27, 08:14 AM
Yeah, but wouldn't it be cool to have a ring of moon dust surrounding the earth, like saturns rings. We could then use them to diminish sunlight falling on the equator and have a more temparate climate across the world.

astromark
2006-Jul-27, 09:08 AM
Oh dear me. We all die. . . . In order to disintegrate the moon. Blow it to smaller pieces. Create Earth rings. Unfortunately this would place an unrecoverable amount of debris into Earths atmosphere. This would change weather patterns so dramatically all most all life on planet Earth would perish. If we did not freeze to death we would starve. Back away from this destruction of the moon and just place it into a elliptical path. That would be trouble also. As the moon receded away from us the tidal effect would diminish. We would cope with this without any problems. Unfortunately 14 days later when the moon enters the closer orbital path that would bring it much closer to Earth the problems would be dramatic. massive tidal shifting, as the 'Roach' limit was reached the seismic upheaval would be catastrophic. Our atmosphere could be distorted by this event. Weather patterns would be equally disrupted. Mayheam. Not 'cool' unless you consider that its time to pass on the torch to the microbes and bacteria that might be all thats left alive on planet Earth.
Thankfully we do have a stable enough environment to allow the evolutionary process to weed out the weak and bread from the strong and thoughtful. When I see this sort of thinking I too wonder if we will survive this technical age. Yes I see that you might well be just asking. . . but its still a worry.

eburacum45
2006-Jul-27, 10:58 AM
Creating rings for the Earth is not recommended, not if we want to continue having access to space. A ring system would make the immediate vicinity of Earth a dangerous place to operate a spacecraft or to park a satellite or space station. And space elevators would be right out of the question.

Grey
2006-Jul-27, 06:31 PM
Here (http://qntm.org/destroy) are some ways that you could destroy the Earth. All of these should be applicable to the Moon, which might be a good warm-up project for any would-be Earth-destroyers. :)

Nonkers
2006-Jul-27, 07:24 PM
If the H bombs were dug in deep, as in "Armageddon", and managed to blow off 5-15% of the Moon's mass, ignoring debris problems, would there be any noticeable effect on the Earth's tides or anything else?

astromark
2006-Jul-27, 07:40 PM
Probably not. It is the mass of the Moon that has the gravitational effect on Earth. If you simply spread it out a bit. It would not change the mass., and would over time reform back onto the Moon.

Lurker
2006-Jul-27, 08:04 PM
Why do I have the feeling that soon I will hear somewhere that we don't need to worry about rising sea levels because we can just "blow up the moon" to get rid of tides?
Nope... but since we may be able to offset the next advance of the ice with global warming... :whistle:



Yeah, but wouldn't it be cool to have a ring of moon dust surrounding the earth, like saturns rings. We could then use them to diminish sunlight falling on the equator and have a more temparate climate across the world.
But of course!! We blow up the moon to stop global warming!! :)

Sticks
2006-Jul-27, 08:10 PM
All you need to get rid of the moon is to build a moonbase and staff it, store some nuclear waste, and let it go critical and explode, ripping the moon out of Earth orbit and send it wandering through the universe

Now why does this sound familiar :whistle: :shifty:

Lurker
2006-Jul-27, 08:14 PM
All you need to get rid of the moon is to build a moonbase and staff it, store some nuclear waste, and let it go critical and explode, ripping the moon out of Earth orbit and send it wandering through the universe

Now why does this sound familiar :whistle: :shifty:
NO! :neutral:

:)

mugaliens
2006-Jul-29, 03:31 PM
It's way beyond our ability to destroy. Essentually you'd have to impart enough energy to accelerate the entire mass of the moon to it's own escape velocity, which is relatively low at 2.4 km/s.

The problem is that there's too much mass: 7.35e22 kg.

A third problem is that even if one could drill, in a vaccuum, to the center of the moon, some 1,080 miles, all the nuclear fission and fusion weapons that have ever existed, past and present, if detonated simultaneously, wouldn't even make the moon burp.

Even a million times that amount would simply fracture the rock, lift it a bit, and most of it would fall back together, considerably hotter than before due to the energy.

A much more efficient mechanism would be to use linear drivers to accelerate bucketfulls of moon matter to just over escape velocity.

But you'd have to have a billion such devices hurtling one trashcan-sized load every second for more than 7,000 years in order to finish the job.

So, no - the Moon is here to stay.

Sticks
2006-Jul-29, 03:42 PM
NO! :neutral:

:)

Here is a big clue (http://en.wikipedia.org/wiki/Space:_1999)

Did Phil look into the physics of the premise of this show? :think:

Professor Marvel
2006-Jul-29, 10:22 PM
If it is true that launching the world's entire arsenal of nuclear weapons at the Moon would have little effect, then I am all for it. Few things would benefit humanity more than getting those awful devices off the planet.

_______________________________________________
"I had a rational thought this morning but I didn't like it."

WaxRubiks
2006-Jul-30, 01:13 AM
Isn't the Earth-Moon system the reason for Earth keeping its axis pointed in generally the same direction?
Doesn't this system act like one gyroscope?

I seem to remember something about, if it weren't for the moon the Earth's axis would wander until the north pole would be pointed right as the Sun(for some of the year anyway), this would be lethal for life on this planet.

Ronald Brak
2006-Jul-30, 04:28 AM
Isn't the Earth-Moon system the reason for Earth keeping its axis pointed in generally the same direction?
Doesn't this system act like one gyroscope?

I seem to remember something about, if it weren't for the moon the Earth's axis would wander until the north pole would be pointed right as the Sun(for some of the year anyway), this would be lethal for life on this planet.

The earth would wobble more, but it wouldn't do a uranus and bow to the sun. It wouldn't be lethal for life on this planet, but I'm not sure what the exact effects would be.

Sweety
2006-Aug-03, 06:03 AM
If moon is destroyed it won't be lost at all. its pieces will remain there and I am afraid that not as ring of saturn but as 2-3 or more sattelites of earth. What do you think we want remove one moon and we get more moons.

Jens
2006-Aug-03, 09:54 AM
If it is true that launching the world's entire arsenal of nuclear weapons at the Moon would have little effect, then I am all for it. Few things would benefit humanity more than getting those awful devices off the planet.


Umm, how about dismantling them? The problem's just getting rid of the enriched plutonium, and it is a serious problem. One option would be to launch it into space, into the sun if you want, but in any case there's no need to actually detonate a weapon.

flawedprefect
2008-Jul-25, 05:03 AM
New to this forum, and to this thread. I've been writing a story which at its heart requires the destruction of the moon (by accident - not by our hand!) I've been trying to get the physics right (or as right as fiction will allow). This thread, however, has provided me with many cool scenarios. Can I ask: is there a scenario which someone may believe will allow human life to survive?

cplradar
2008-Jul-25, 05:12 AM
Try this thread. (http://www.physicsforums.com/archive/index.php/t-106266.html)

Jeff Root
2008-Jul-25, 10:52 AM
Note to others: This thread has just been resurrected after two years!

Hello, flawedprefect!

Anything which doesn't send the debris hurtling to Earth should leave us
unscathed. However, crashing anything into the Moon hard enough to
take it out of Earth orbit will send bits flying in all directions, with a large
amount of material almost certainly hitting Earth and doing a lot of damage.
But it wouldn't be enough to kill everyone unless, by design or horribly bad
luck, the bulk of the Moon ended up on a trajectory to Earth.

However, I think that any plausible impact would leave most of the Moon
in pretty much the orbit it is in now, with a lot of debris going all over,
making for a real navigation hazard in Earth's vicinity, and an unpleasant
environment on Earth. Such an environment is sketchily described in
"The Scourge" (1981), a short story by James White. It can be found
in "The 1983 Annual World's Best SF", edited by Donald A. Wollheim.

-- Jeff, in Minneapolis

mugaliens
2008-Jul-25, 03:57 PM
Can I ask: is there a scenario which someone may believe will allow human life to survive?

Sure. A large mass coming near the Earth-Moon system could easily fling the Moon out of Earth's orbit while having little affect on the Earth. Mini-black hole, massive asteroid or comet, Planet X... Take your pick.

Jeff Root
2008-Jul-27, 02:48 AM
Asteroids and comets don't have enough mass to gravitationally fling
the Moon out of Earth's orbit. A mini black hole with mass comparable
to the Earth's mass could do it, but I think the extreme tide close to
the black hole would be as likely to rip the Moon apart as fling it away,
and such small black holes are not expected to exist. Planet X could
do the trick, but if it were going to arrive anytime in the next two or
three hundred years, it would already be easily visible by now.

-- Jeff, in Minneapolis

flawedprefect
2008-Jul-28, 01:19 AM
Note to others: This thread has just been resurrected after two years!

For this I apologize, Jeff, but I did not want to start another moon thread! lol. Consider me one of those clever noobs who actually use the search tool.


Anything which doesn't send the debris hurtling to Earth should leave us
unscathed. However, crashing anything into the Moon hard enough to
take it out of Earth orbit will send bits flying in all directions, with a large
amount of material almost certainly hitting Earth and doing a lot of damage.
But it wouldn't be enough to kill everyone unless, by design or horribly bad
luck, the bulk of the Moon ended up on a trajectory to Earth.

Yes, this is most likely the scenario I am after. Something that will wreak some destruction, but not anihilate the species(where's the fun in that?)

Ever read the Rober E Howard story, Bloodstar?


However, I think that any plausible impact would leave most of the Moon
in pretty much the orbit it is in now, with a lot of debris going all over,
making for a real navigation hazard in Earth's vicinity, and an unpleasant
environment on Earth. Such an environment is sketchily described in
"The Scourge" (1981), a short story by James White. It can be found
in "The 1983 Annual World's Best SF", edited by Donald A. Wollheim.

-- Jeff, in Minneapolis

I shall check this out.

Thanks for all replies, guys, and once again - sorry for dredging up an old thread. Great to be here, and enjoying the podcast and the community.

Neverfly
2008-Jul-28, 02:29 AM
For this I apologize, Jeff, but I did not want to start another moon thread! lol. Consider me one of those clever noobs who actually use the search tool.


I, for one, appreciate it. It introduces me to a lot of ideas and statements in a thread I had never seen before.

It helps keep things a tiny bit less cluttered... and it shows what you just said.

Because someone will come along and start a thread asking about such and such- and get chastised about "there are already threads on this topic..."
And another will post their question in an existing thread and they get chastised for thread necromancy.
Pretty much, wrong no matter what you do...:doh:

Welcome to BAUT!!:D

publiusr
2008-Aug-01, 07:34 PM
Because someone will come along and start a thread asking about such and such- and get chastised about "there are already threads on this topic..."
And another will post their question in an existing thread and they get chastised for thread necromancy.


People use this site different ways. I will often log onto this site only a few days a year--so an old thread is new to me. I will visit for a few weeks, then come back a few moths later.

I also seem to remember talk about blowing up the moon--but I also remember a study about blowing a hole to the moon's center using successive nukes.

In fact, there was a story just today about a proposed nuclear explosion on the moon

http://query.nytimes.com/gst/fullpage.html?res=9E0DE7DC113BF935A25756C0A9669C8B 63&sec=&spon=

Related links:

http://www.ctbto.org/glossary/?letter=o&cHash=361d6cd681
http://cedb.asce.org/cgi/WWWdisplay.cgi?9200021
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0610225
http://blog.modernmechanix.com/2008/01/28/blast-a-home-in-the-moon/