Nukes in space.

[Leader Bee]

I was thinking about the asteroid "Apophis" recently thats scheduled to be a NEO in 2036 and was wondering if it was actually going to hit us how could we prevent it?

 

I've heard a lot of mention that we might use nuclear devices to divert the course of a rock bound for earth, then it hit me. Space is a vacuum. How on earth would a nuclear explosion transmit it's energy into the asteroid efficiently enough to divert it? My only guess is we would have to land the device directly on the service.

 

I know there are other methods of diversion but I guess the real question is are what are the effects of nuclear weapons in the vacuum of space? An EM Pulse is going to be the most obvious.

 

What is the brissance of an explosion in space compared to at sea level on earth? is the explosion radius bigger or smaller? is there still a shockwave of some type? ( i find it difficult to comprehend without the prescence of a transmitting material )

[insane_alien]

one concept is a bunker buster nuke, the nuke travelsinto the rock a distance then detonates, the vapourised rock acts as reaction mass pushing the asteroid off course.

 

another relies solely on the radiation produced vapourising the surface again using the vapourised rock as reaction mass.

 

its either that or get enough nukes inside it to make sure there are no pieces left that are big enough to make it through the atmosphere.

[Leader Bee]

I imagine using a nuclear device at determined depth under the surface and possibly near fissures and geographical fractures on a sufficiently small 'roid would be effective, however , considering the estimated mass of this particular asteroid is 21,000,000,000 kilograms and the composition is partly iron ore it wouldnt leave sufficently small chunks for us to be left "in the clear".

 

You mention using the radiation produced instead of the thermal and kinetic energy to move the object off course. How does this process work? of course radioactive particles have some mass and therefore have a small possibility of thrust but the uncontrollable nature of an explosion means the majority of energy from the explosion ( including the radioactive materials are thrown away from the object, perhaps the use of a radiological weapon ( neutron bomb ) would be more appropriate, even still the majority of these particles would still be thrown anywhere other than the intended target.

 

Perhaps if scientists could come up with a robust enough shaped charge to direct this energy?

 

You see nukes used to destroy asteroids in most movies involving a collision with earth but now i've thought more about it it's highly innefficient cost wise, energy trasmitted to the roid wise and the danger of huge chunks of iron and lead you are risking it breaking apart into.

 

If we were to detect the object in enough time landing an ion engine on the rock to slowly move it out of earths orbit would work? This technology as far as I am aware is in it's infancy though and not sure how reliable it truly is.

[insane_alien]

I imagine using a nuclear device at determined depth under the surface and possibly near fissures and geographical fractures on a sufficiently small 'roid would be effective, however , considering the estimated mass of this particular asteroid is 21,000,000,000 kilograms and the composition is partly iron ore it wouldnt leave sufficently small chunks for us to be left "in the clear".

 

luckily, we have thousands of nukes to take care of that when brute force doesn't work, use more.

 

You mention using the radiation produced instead of the thermal and kinetic energy to move the object off course. How does this process work?

 

the radiation(both particle AND thermal radiation) heat up the surface of the asteroid facing the blast. they heat it up a LOT. to the point where the solid rock and ice vapourises.

 

as the rock vapour cannot go into the asteroid, if flies away. and thanks to newtons third law, this cause the asteroid to accelerate in the other direction.

 

Perhaps if scientists could come up with a robust enough shaped charge to direct this energy?

 

 

If we were to detect the object in enough time landing an ion engine on the rock to slowly move it out of earths orbit would work? This technology as far as I am aware is in it's infancy though and not sure how reliable it truly is.

 

yep, this is the current plan of action insofar as we have one. tiny tweaks long before it is a threat.

 

ion engines are actually quite well tested there have been whole deep space missions dedicated to the testing of them and some even exceeded performance requirements. they run fine for years at a time.

 

infact, we are getting ready for the second generation of ion engines that allow for much greater thrust and efficiency (VASIMR).

 

but in a pinch, nukes are good enough delivering huge amounts of energy quickly.

[Leader Bee]

Isn't the reason an ion engine runs for so long is due to their relatively low output?

 

Say we had an asteroid within 22,200 miles ( geostationary satellites are at this hight ) we wouldn't have time to use this method. What is an approximate minimum distance we could effectively use this plan?

 

Considering the energy output of Ion engines is more effective over time rather than lots of energy in one go wouldn't the object we'd be aiming for need to be as far out as Mars or something to be a useful method of deflection? Which also brings the question that if it does have to be out that far we wont be able to man a mission to deploy the engines so would robotics be sophisticated/reliable enough to deploy these on their own?

[insane_alien]

ion engines are really only useful if we have about a decades warning.

 

saying its at the orbit of mars doesn't really tell us much because pretty much all of the objects likely to hit the earth will take many many orbits to hit us and never actually get that far away from earth.

 

robotics are sophisticated enough to launch an automated mission already. including a land, drill and place a nuke in the middle mission.

[Airbrush]

luckily, we have thousands of nukes to take care of that when brute force doesn't work, use more.

 

but in a pinch, nukes are good enough delivering huge amounts of energy quickly.

 

Yeah, we need to think about "in a pinch". A quick and dirty method may be our only chance with the unannounced objects. Recently a Tunguska-sized object passed us by without us knowing it existed until a couple of days before closest approach. We can get blind-sided any day, with at best only a few days notice, if it comes "out of the Sun", the way fighter planes attack.

 

For short-notice objects we need to take advantage of high closing speed with the object. It will be headed, more or less, directly at us at a very high speed, 10 miles/second or faster. Our only hope will be kinetic impactors or nukes speeding towards it at a comparable speed, so the closing speed will be 20 miles/second or faster. If you can slam enough mass into it, you might divert it just enough. Or nukes timed to explode at the exactly proper moment just a short distance from it so you heat up one side to vaporize and push it just enough.

 

I don't know why we are not already practicing short-notice techniques on nearby asteroids.

Edited July 7, 2009 by Airbrush

[insane_alien]

could be the first peaceful nuclear missile launch.

[Tolmosoff]

I would be killed if a Rogue Moon sized asteroid headed to our earth and no nukes to stop it.

Imagin if penetrated our atmosfer and plunge into our earths mantel of an egg shell. The push of force on our other side to disrupt all earths Techtonic Plates.

Imagin our earths oceans to vaporize as steam and land masses ?. We will face a new earth Thanks to ( Neutons Forcast ) on gravity. But gravity will put our earth back together after we are gone into the rock like the Dinosaur for display to Alien specie in the future.

An the ocean water ?. it will cool our magma to become a new earth that we can walk on without a boat.

 

I think its written somewere about our future earth.

 

Just imagin !!! No usa, europe, north and south america, africa and etc:

 

Yes we can have a new earth without us.

[Sisyphus]

I would be killed if a Rogue Moon sized asteroid headed to our earth and no nukes to stop it.

 

Just you?

[Airbrush]

I don't believe there are any moon-sized asteroids around. So relax, all you need to worry about are Tunguska-sized asteroids and some bigger ones. No big deal.

Edited July 7, 2009 by Airbrush

[Xittenn]

When I saw 21,000,000,000Kg I thought wow that looks big! I then pondered about it, punched in the numbers going by density of water and that's like 275m in diameter assuming a spherical object. I Googled and Wiki says it's apx. dimensions are 270m(must be the rough diameter...) Wow that's not very huge at all...... How big is Tunguska?

[CaptainPanic]

The tunguska meteoroid or comet was believed to be "a few tens of metres across".

 

So, Apophis is quite a bit larger.

[Leader Bee]

I don't believe there are any moon-sized asteroids around. So relax, all you need to worry about are Tunguska-sized asteroids and some bigger ones. No big deal.

 

Tunguska destroyed everything within a 100 mile radius did it not and swept a few nomadic people from their feet? Amazingly this event wasnt investigated until around 20 years after it had happened either due to it's remoteness.

 

Arent there asteroids larger then pluto floating about? Pluto is only classed as a "Dwarf Planet" these days or not even that in some circles (the classification for what is a planet is pretty sketchy ) so even if there are no moon sized rocks floating around there are still some unimaginably huge asteroids out there. Infact a chicxulub sized object is something to worry about.

 

Airbrush:

I agree, why are we having talks with the Russian Federation about another START treaty and Non-Proliferation acts when we could be putting these nukes to good use?

Instead of just dismantling the devices we have in our arsenels, which I assume is a largely expensive procedure in removing/transporting/storing radioactive materials, we could be having target practice to see if these techniques will work.

 

Theory is all good and well but isn't Evolution just a theory? what I mean is what we think might work might not at all until proven fact.

 

Dislcaimer: Leader Bee supports the evolutions theory over God and or creationism and does not discredit this notion we evolved rather than just sprang from nothing.

Edited July 8, 2009 by Leader Bee

[insane_alien]

there are some kuiper belt objects larger than pluto but those are few and far between and just as likely to hit the earth as pluto is.

[Tolmosoff]

Airbrush :

 

I think that the Big Bang, Evolution, Creation was the God particle the scientists are pointing too or the anomoly particle in protecting its creation from an ever changing environment.

 

I seen astronomy theory on TV about the ( BRANES and STRING theory ) as male and female.

[Xittenn]

Tunguska destroyed everything within a 100 mile radius did it not and swept a few nomadic people from their feet? Amazingly this event wasnt investigated until around 20 years after it had happened either due to it's remoteness.

 

Well correct me if I'm wrong but this asteroid is carrying about 10exajoules or roughly 2.4GigaTons explosive energy. It may be somewhat dissipated in the atmosphere(as heat nonetheless) on entry but would still hit with an impact force of a couple dozen big fat nukes.

[insane_alien]

thats the thing though, it never hit the ground, it detonated in the air which lessened the force felt. if it had hit the ground the effects would likely have been more severe.

[Leader Bee]

thats the thing though, it never hit the ground, it detonated in the air which lessened the force felt. if it had hit the ground the effects would likely have been more severe.

 

Actually an Air burst explosion of that kind of yield would cause far more destruction then a ground impact. Most of the energy would be absorbed by the earth or reflected upwards and away from the area whereas an explosion above any objects that may diffuse the blast wave means the shockwave can travel further out.

 

Because of the high pressure of the wave it would create a vacuum or at least an area of lower pressure travelling outwards from the detonation point. There is also the possibility of second shockwave travelling inwards due to the atmosphere rushing back in to fill this low pressure area, hence the typical double flash you see with nuclear explosions ( the front of the shockwave obscures the light - once with the outward wave and once on the inward.

 

Directly underneath the explosion things might survive depending on their size and shape. Trees in the tunguska event being a prime example because the small profile they presented.... I assume they were still horribly charred.

anything perpendicular to the shockwave would be gone as this type of explosion damages through blast effects rather than thermal and kinetic energy and even though i say that the effects of these are still severe.

[insane_alien]

Actually an Air burst explosion of that kind of yield would cause far more destruction then a ground impact.

 

that depends on the altitude. there is an optimum altitude for airburst of a specific yield where it will do more damage than a ground burst. above or blow this altitude, the explosion does less damage than the optimum.

 

tunguska likely exploded WAAAAY above its optimum altitude where the atmosphere is still a pretty damn good vacuum which cause the atmosphere to be a poor transmitter for the shockwave.

 

much like how the high altitude nuclear blasts caused little more than a spectacular light show(ignoring the EM pulse effects) with no more blast than a loud noise.

 

just checked up, typical optimum airburst heights for nukes are several hundred meters maybe a kilometer for a really big one.

 

tunguska would have detonated at over 10 kilometers, probably about 30-50km. definitely not an optimum height.

Edited July 8, 2009 by insane_alien

[Sisyphus]

That's true for nuclear weapons, but "air burst" when we're talking about meteorites means in the upper atmosphere. 5-10m objects collide with the Earth about once a year with nuclear weapon-scale energies, but cause no damage because they explode in the upper atmosphere. Just a flash in the sky.

[Leader Bee]

that depends on the altitude. there is an optimum altitude for airburst of a specific yield where it will do more damage than a ground burst. above or blow this altitude, the explosion does less damage than the optimum.

 

tunguska likely exploded WAAAAY above its optimum altitude where the atmosphere is still a pretty damn good vacuum which cause the atmosphere to be a poor transmitter for the shockwave.

 

much like how the high altitude nuclear blasts caused little more than a spectacular light show(ignoring the EM pulse effects) with no more blast than a loud noise.

 

just checked up, typical optimum airburst heights for nukes are several hundred meters maybe a kilometer for a really big one.

 

tunguska would have detonated at over 10 kilometers, probably about 30-50km. definitely not an optimum height.

 

There shouldnt be any EMP to worry about with any kind of meteorite explosion should there? Isn't emp generated by particles specific to materials in nuclear weapons interacting with the van allen belts?

 

I don't really know how much radioactive material a given asteroid would contain but i wouldnt guess it to be much.

[insane_alien]

There shouldnt be any EMP to worry about with any kind of meteorite explosion should there? Isn't emp generated by particles specific to materials in nuclear weapons interacting with the van allen belts?

 

i never said there would be EMP with a metoerite strike. when i mentioned EMP i was reffering to nuclear weapons.

 

the EMP is caused by the intense heat generate at the moment of explosion in the nuclear blast which is several times the temperature of the suns core.

 

a meteorite explosion does not get hot enough and takes a longer time to complete(several seconds rather than a few microseconds). although if the meteorite was large enough i suppose it is possible there could be some EMP aspect to it.

 

I don't really know how much radioactive material a given asteroid would contain but i wouldnt guess it to be much.

 

about the same as you'd find in the earths crust. not sure what this has to do with it. not all radioactive materials are suitible for making a nuclear bomb.

[Leader Bee]

 

about the same as you'd find in the earths crust. not sure what this has to do with it. not all radioactive materials are suitible for making a nuclear bomb.

 

I was under the impression that EMP was generated through ionizing radiation in the upper atmosphere rather than intense heat. I don't see how heat interferes with electronics on such a large scale. The radiation had to come from somewhere and I assumed that it must have to do with the radioactives in a nuclear device considering we dont get random EMP every 1-2 years from asteroids colliding with the atmosphere

 

I'm well aware that radioactive materials need to be refined properly for weapons grade use.

[Airbrush]

Arent there asteroids larger then pluto floating about?.....

 

....Instead of just dismantling the devices we have in our arsenels, which I assume is a largely expensive procedure in removing/transporting/storing radioactive materials, we could be having target practice to see if these techniques will work.

 

The Kuiper Belt objects are so far away, they don't concern us as much as NEOs (Near Earth Objects) that cross our path.

 

Yeah, let's get some target practice on some dastardly NEOs!