Moontanman

Quite the contrary you seem to fear a nuke worse than an asteroid strike, a nuke is not the end of the world, a major asteroid strike might very well be!

Mordred, lets set up a hypothetical, today NASA finds out a 250 meter asteroid is going to impact the Atlantic ocean near Bermuda in one year... what do you propose we do?

by the time we make a decision the impact has already occured

I would have to agree since that is exactly what I have been saying, given time (in our current state I would bet we would need 20 years lead time, probably take 5 years just to make a decision) we can use whatever method is best but we don't always get much warning in fact I would say we seldom do. All I have said is that nukes are the best if a quick but powerful method is necessary, if you have several years lead time then you can make different choices but to immediately say no nukes due to some exaggerated fear of nukes is not rational. a nuke or even several nukes would not be an existential threat to us. A significant asteroid impact could end us or at least have a significant impact on us, far more significant than a couple nukes. I know people who are terrified that a rogue state might detonate a single warhead as though it would kill us all, that is not a rational fear level. I agree time is the deciding factor but at some point a nuke is not just the best option it would be the only option. If we had a year lead time to deflect a 250 meter asteroid what would be the best method of deflection? Expend a few megatons of nuclear explosions or allow a 10,000 megaton explosion to devastate the earth... your choice.

Mordred, you are completely missing my point, the potential harm done by an asteroid strike is far worse than the damage that could be done by a little radiation from a nuke. A nuke or even a few nukes would not destroy life on earth or even have a significant impact on life on earth but a 10,000 megaton explosion and the dust and debris kicked up by such and iact would have a dire effect on the Earth, on our civilization, on humans in general. Not as foolish as allowing an unhinged fear of nukes to allow an asteroid strike.

I am sorry to me that is a given, I missed your point. Of if an asteroid lands on billions of people heads.

Protons can be defeated by a magnetic field, neutrons cannot, anti neutrons are even better when they contact matter, due to the half life of the neutrons it should create some interesting effects, like the beam being visible, and the the point of contact being a continuous multi megaton explosion. It should leave behind an expanding cloud of anti hydrogen if I understand neutron decay correctly. This would have to be a space weapon, no handheld anti neutron beam weapons! I am thinking of a beam that puts a microgram of antimatter on the target every micro second. Space operas illustrated by AI are becoming popular on you tube, I've already had one story published this way and I am hoping for others. No money in it but its still fun to hear your own words being narrated over AI images. I didn't know Vernor Vinge had died, his level of genius is a distant goal but it shines bright as a guiding star. BTW anyone who follows the erotic story (Slave girl Patty) on my blog I have two more chapters published!

Well first off the space shuttle is at least a couple orders of magnitude more debris than a single warhead would be and a single warhead is a lot stronger than the space shuttle for the same reason a Tonka truck is tougher that a real truck. The cube square law applies here, something as small as a war head would be much tougher than a space shuttle. But the fact remains that a few kilos of plutonium spread over such a large area isn't exactly the end of the world. If you were talking about a few kilos of cobalt 60 you'd have a point but the actual impact of the space shuttle, which broke up well before it impacted the ground and spread out before impact and a warhead that is designed to survive reentry with out breaking up or spreading out cannot really be compared. Plutonium is not some sort of magical poison that kills everyone and everything exposed to it. A few kilos of nerve gas would do far more damage. I lost my existential dread of nuclear power decades ago, its not magic and the risks can be mitigated. And again the amount of radioactive material is important here, the remnants of a nuke compared to the 507 already detonated is miniscule and would pose no realistic danger. Radioactivity is all around us and part of the natural world, the dose is important. I would like to propose that a small dose of radioactive material is far better than a large dose of asteroid. I disagree, in this case nukes are the best, easiest, and fastest method we currently have. Should we develop more than one method? Of course we should but currently I see nothing that even comes close to the potential effectiveness of a nuke. I am well aware of this, how does this change my assertion pointed out above? Again I am well aware of this, how does this change the assertion I have made above? Still the best we currently have, what we use has to be weighed against the time we have to react, the actual size of the asteroid, and the technology we have ready to use. I am not saying that nukes are our only hope, I am saying that currently they are our best hope until someone plans ahead and actually creates the technology to do this without nukes. I see no reason to take nukes off the table due to some exaggerated fear of radioactivity. If a 250 meter asteroid showed up that is going to hit within a year what would you do> Do we sit around arguing over how to do this without nukes or do we act as fast as possible to divert the asteroid away from our planet? How ever many nukes it takes wouldn't the goal of preventing a 10,000 megaton impact be worth the actual radioactive danger from a few nukes? I'm betting you guys won't like this at all!

And how many people died from operation star fish? How bad was the contamination, how long did people have to stay in fallout shelters? I was under the impression that we are planning on stopping the asteroid from impacting the earth and just how many nukes will it take to release enough radiation to be a realistic threat?

What would be your point here?

Obviously, if that plutonium wasn't encased in a reentry vehicle it would probably contaminate a few acres, the plutonium in the Cassini probe was in the form of a ceramic btw, the risk would have to be weighed against the risk of an asteroid strike. Just how dangerous do you think plutonium is, the amount in one warhead would certainly not threaten the planet significantly if 507 nukes can be detonated yet not have a significant affect and yes they leave behind plutonium.

No but the fail safes of the 1960's were robust enough to stop it from exploding on impact! Citation please, I have not read of any nukes falling from orbit.

Why hype the danger and wring your hands while a asteroid destroys a large area, the danger of a nuke has to be tempered with the danger of a asteroid strike. The 60 meter 12 megaton Tunguska event is quite telling to me and that was an air burst, imagine the chaos that would result from a actual ground strike by a 12 megaton strike in the Atlantic ocean near the East Coast of NA or in the middle of NYC. The difference between the danger of a nuke being launched into space vs an asteroid strike has to be determined outside any unreasonable fear of a nuclear explosion. A single nuke, even a Czar Bomba, would not destroy the earth or cause any more damage than the Czar Bomba. A 250 meter asteroid would be devastating to a continent sized area if not the entire planet. I guess it comes down to which is worse and history shows the detonation of even huge nuclear weapons is not a threat compared to the 250 meter asteroid. https://www.space.com/asteroid-launcher-earth-impact-simulator This site can show how much damage an asteroid could produce. For a 250 meter iron asteroid I get 1.90 x104 Megatons TNT Again, a nuke's reentry vehicle show this has been done already. This would make the danger non existent or at the very least highly limited. The nuke outside Charlotte NC shows this, nukes hitting the ground doesn't just vaporise and spread plutonium all over the planet. https://netspublic.grc.nasa.gov/main/HQ-0025-HQ-FEIS-Cassini-199506.pdf

Which part exactly, we make nukes in reentry vehicles that survive "falling to the ground" as part of our weapons and the bomb outside Charlotte NC is hardly a secret.

I understand that but the threat was mostly anti nuclear hype, the danger was almost nonexistent due to the fact that such a accident was anticipated and the nuclear material wouldn't been a threat for the same reason the nuke buried outside Charlotte NC is not a threat. A container can be easily designed that would prevent any wide spread contamination upon reentry.

I want to say that why I am asking this question is the idea of writing a story based on as few "magical" technologies as possible. One of my fav writers, Vernor Vinge, wrote a series called "Across Real Time" that is based on only one such technology called a "bobble" the sweep of the story is amazing and I want to stay as close to that ideal as possible in the story I am considering.

Thank you, that gives me room to play! I've figured out a "way" to get the beam and now I see it will have to be short range weapon, maybe a few might minutes. BTW, I am going to propose a antineutron beam that decays into antimatter protons assuming the antineutrons have a similar half life to matter neutrons. Now I just have to propose a "magic" to turn a coherent proton beam into antineutrons on the fly! I think I'll name it a gravitational reverse charge pinch! Thanks again!

??? Neither am I Again, a nuke falling from space wouldn't detonate, but even if it did the approximately 60 meter asteroid that produced the Tunguska event in 1908 was equal to about 12 megatons the biggest nuke in the arsenal of the US is supposed to be less than 3 megatons. So why fear it at all?

I was thinking more of neutrons freely moving around not neutrons bound together, I am thinking of a coherent beam of neutrons or even a cloud of neutrons, do they repel, attract or ignore each other. I am thinking of a weapon for a novel but I'd like to know how neutrons react to each other before I begin to speculate.

Ok, lets up the ante, how big an asteroid would justify using nukes? I agree if there is a viable option to a particular situation I would look for an option other than nukes but how far out would you have to intercept a 250 meter asteroid with various methods to effectively intercept it? From what I understand our current detection methods can give us very little time to decide. Should we just allow it to hit or should we prepare a possible nuclear strike and plan to use other means if we detect it early enough. The most powerful tool we currently have would have to be a nuclear strike, the fastest response we currently have would have to be a nuclear strike, where would you draw the line? As far as I know a 1/4 kilometer asteroid has never stuck the earth in modern times but 507 nukes have. You said a nuke falling, are you assuming a nuke falling would detonate? As far as I know no nuke has ever accidentally fallen the earth and detonated, while several have done this none have detonated accidentally. There is one several megaton nuke still burned deep in the ground outside Charlotte NC to this day.

Really, which is worse, a asteroid strike or a nuke falling to the ground? Falling to the ground would not mean detonation, nukes have many fail safes in place to prevent accidental detonation. Remember 507 have already been detonated and we are here alive and well. Again, compared to an asteroid strike how dangerous is the fallout from a few nukes even assuming all of the radiation would fall on the Earth? Remember we are currently living on a planet where 507 nukes have already been detonated above ground.

Do free neutrons attract, repel, or ignore each other?

My main problem is with people who say nukes are dangerous because of the radioactivity involved, unless you are exploding them in near earth orbit I think that radiation is no problem at all. Much like adding a chunk of rock salt to the ocean will cause it to be significantly saltier. Space is full of radiation, exploding a nuke is not going to be a problem and nuclear energy is the most powerful tool we have. People have an unreasonable fear of nukes not realizing how many actual nuclear explosions have actually taken place on the Earth... 507 actually in the atmosphere or above ground. I doubt several nukes used to steer an asteroid away from the earth pose more danger than the actual impact of a sizable asteroid.

Thank you but this is not what dim and me are discussing.