World != Space
World free of nukes does not necessarily imply space free of nukes. That is one place where they may actually prove themselves useful.
Top American boffins have warned that the US government's efforts to prevent global apocalypse caused by meteor strike are inadequate. The scientists add that nuclear weapons are the only practical means of defence against large, planet-wrecker sized asteroids. In a new report, the US National Research Council says that so- …
I just have this nasty feeling that an orbital nuclear strike platform is more likely to be used for a military strike than against a catastrophic piece of space debris. Comparing the number of known catastrophic space debris strikes against the number of armed conflicts in human history doesn't leave you with favourable odds....
Hmm - maybe another task for an Orion/Daedalus class engine?
If caught in time anything from a solar sail to a ion drive would do the trick, the real secret is to get lots of time to do something effective.
Therefore lets start with NEOs and work our way out (not-Near Earth Objects, err Close Earth Objects?) and ideally have some wide-field telescopes checking out anything coming into the solar system.
Hopefully our bases on the asteroids will spot and deflect anything too massive iin time - what we don't have bases in the asteroids yet? but I was promised we would by 2000, as well as flying cars, supersonic/flying wing liners, hotels in space and lots of other really neat stuff.
flames - the later we leave it the bigger the flames we'll need to get rid of it.
I'm thinking there would be a difference between the ICBMs designed to level Russia and the kind of space-destined missiles designed to neutralise a flying cathedral. So perhaps Mr Obama McJesus' statement could be changed to say "no nukes aimed at this particular ball of rock."
"Nuclear explosions are the only current, practical means for dealing with large NEOs (diameters greater than 1 kilometer) or as a backup for smaller ones if other methods were to fail."
Er, and how big a nuke do you need to blast a kilometre-sized hole in a rock? I can certainly believe that nukes slightly increase the size of object we can deal with, but not by much in the woder scheme of things. I would also imagine that those sizes follow the usual rule with the population falling off with increasing scale, so the numbers of objects in this "window" is relatively small.
On the other hand, current rocket technology can't put much more than a few tons Up There, and a few tons of TNT isn't going to shift anything that the atmosphere wouldn't stop anyway.
So the boffins are correct that we need nukes, but have then driven a kilometre sized rock through their credibility. Pillocks.
Is there any particular reason for the ecclesiastical slant of your size scale for destruction raining down from the heavens... oh, I get it.
For Vatican read the Olympic village, for cathedral any Second Division football stadium, for church the open-topped double decker bus in which the triumphant athletes tour the city...
"Going to watch the Arsenal match this afternoon?" "No, no point." "Foregone conclusion, you reckon?" "No, the world's about to end." "Ah. Lucky escape for Arsenal if it did." "No, not really."
I guess by these figures, the Virginia doctors office meteorite was prayer book sized, i.e.
and that would make the famous Arizona Barringer impact crater (which was created by the Canyon Diablo meteorite) around probably about a church bus plus 300 prayer mats plus one golden candle stick holder in sized.
Just to clarify for those who didn't read the report, the idea isn't to destroy to object with nukes, and thus create lots of smaller objects, it's to detonate a nuke and change the objects course so that it misses us.
They're pretty much saying that even with this strategy we'd need decades of planning to avoid ending up as toast.
Dealing with NEOs by means other than nuclear demolition may well be possible. If we wanted to deliver large technical payloads in a timely manner, we might need a spacecraft with an engine delivering very high specific impulse, and to me that looks like the Orion engine -- pulsed nuclear fission with a very big shockabsorber between the drive plate and the rest of the spacecraft.
Of course we could just make a very big pointy DU ballistic impactor, and use an Orion engine to make it move fast enough...
Breaking an asteroid into pieces is not the right way to deal with it. Instead, one would dig a hole in the asteroid, put the nuke in there, so that it would vaporize part of the asteroid, ejecting the results out of the top of the hole. The principle is the same as a rocket engine, but with much more energy involved, since an asteroid is much heavier than your ordinary spaceship.
The trouble with 'nuking' an asteroid is that even if you do succeed in fragmenting it you end up with several smaller asteroids all in the same orbit and the same combined kinetic energy.
So you are not really any better off because it's the total energy released in the impact that causes the damage. 1big bang vs. several smaller bangs.
What you actually need to do is shift the orbit of the asteroid without breaking it up (too much) so it doesn't hit the earth in the first place, this could be done with a nuke if you vapourised a chunk off one side to give it a hard nudge. Trouble is some asteroids are actually more like piles of rubble than single solid rocks so giving the sharp nudge will just break the thing up without changing the orbit so much.
What you really need is a gentle push over a long period for the most reliable and predictable results. Hence "gravity tractors", ion engines and the like.
That's why you need to spot'em early, so you've got time to do the gentle push over, preferably years.
The level of risk coupled with the cost is why this sort of thing isn't heavily invested in. It simply isn't worth it.
Likewise radiation shielding in the event of a massive radiation burst from a nearby star, which would wipe us out before we even knew what was happening. You might as well offer insurance against total existence failiure. I mean, who's going to be around in any state to collect?
I think I prefer the idea of attaching (landing) a rocket engine onto the offending body and pushing it away that way. Much more controlled and actually possible and plausible. However the lead time to get it there remains large with all the planetary slingshots and stuff depending on the orbit. But if it's an NEO then surely the orbit is broadly similar to Earth so would not require too much manevering. I don't think we'd ever stop an Extinction Level Event*!
*not the Busta Rhymes album
If anyone here actually THINKS about the orbital mechanics necessary to land on a high-speed object _as it is approaching_ earth, you would quickly realise that it is IMPOSSIBLE. Most of these are moving faster than any human powered spacecraft has ever achieved, and worse, are headed FOR us (that is by definition, as otherwise the threat is very remote). That means that you have to catch-up to it, from behind, and match velocities to land - which (again remembering that we can't even fly that fast to begin with) means you have to fly outside of earth orbit, and then fly back in at a matching angle to the roid. Ummm, good luck with that - if you are REALLY lucky maybe the moon would be in the right position to whip around, but that is a remote possibility. With a great deal of warning you could accellerate to a point in the path of the roid, decellerate to a stop, and then re-acclellerate in the direction of the earth - but no chemical powered craft yet built (or close) could do that - too much fuel needed - an remember, you are carrying an engine and it's fuel, which is heavy.
Agree with the authors - you need to whack it from the front, and whack it hard. No need to approach it from behind.
Surely lots of small rocks are better than one big one. If you had the choice between getting shot in the chest with either a large calibre (.50) handgun or a shotgun I would assume the chances of survival favour the latter.
If a plus Vatican sized object was to hit then your looking at world wide destruction, extending the impact area with multiple catherdrals may only destory North America.
Actually you need to clarify your analogy and say at 200 yards or so. At point blank range any 12 gauge on up even with bird shot to the chest is likely to be as lethal as Desert Eagle (MW2 gets it right at close range, shotguns are fearsome weapons in close combat quarters, so much so the Germans tried to ban them in the trenches in WWI). At range your analogy works.
As when centuries later the object you deflected away from us hits something (ship, homeworld, colony etc) inhabited by some other developed species that it otherwise wouldnt have, if they work it out, they might be a tad disgruntled. Especially if they dont have the means to boot it on (or the morals not to).
Of course if they realise that it was only an accident, rather than a deliberat act of war, I'm sure they'll only pursue the matter in a civil court rather than travel back in time and obliterate us all from the timeline.
I suspect this really really could be heard in a US jurisdiction. That would be ironic and one could be smug and gloat about it being just desserts, but a bit like the French complaining about the US turning up in Haiti last week, it is really with the best of motives and the rest of us are just probably jealous of their capabilities.
Someone tell Lewis that the standard arbitrary illustrating units of measurements are:-
1. Beach ball.
3. Double Decker bus (UK type)
4. Football Pitch (also UK type)
5. Nelsons Column
6. Saint Paul's Cathedral or the Albert Hall
For negative numbers, there is the "GordonBrown"
For an event to have absolutely no chancing of happening there is the "NuLab"
Would be just our luck that some Dr Strangelove in the States gets yards and metres mixed up, and knocks a Double Decker sized rock into a collision course with the earth. But that would never happen would it?
Wonder if Apple have an App for that?
Dunderhead! You should know perfectly well that in the BVS (British Vernacular System) height units are unrelated to length units. Nelson's column is a height and a double decker bus is a length. A football pitch is an area : I think.
Actually a double decker bus can also be a weight (no such thing as Mass of course in the BVS). I've never heard of a beach ball.
For area you forgot pin-head, finger nail, postage stamp and Wales.
In the BVS the units deliberately bear no ratio relationship to eachother - they rise in quantum steps. ie we go straight from a finger nail to a postage stamp.
You can have a large object crash into the earth and wipe out half a continent, or you can blow it into small pieces so that it turns the upper atmosphere into a huge white hot radiator that fries/boils most of the surface of the planet.
@ravenviz - An NEO only has to be close to the earth once to be an NEO , its orbit can be completely different from earths. Space is big and it has some very big things in it. Our technology could just about say Doh! if we are very very lucky.
Everyone who's commenting that a fragmented asteroid isn't any better than a whole one is missing the point. The nuke is not to shatter the asteroid, it's to give it a good push so it misses the Earth - it doesn't really matter whether it fragments or not at that point. You could do the same with some kind of rocket attached to the asteroid, but it'd take a long time. The nuke's advantage is that it can deliver a whole lot of pressure really quickly.
...lots of smaller objects would actually be preferred to one big one for one big reason: SURFACE AREA. Once a space object starts to interact with the atmosphere, air friction (or drag) kicks in, and as any person involved with aerodynamics will point out, surface area plays a pretty significant role in drag. Break the big rock up into many smaller ones, and you've suddenly got a lot more surface area, which means a lot more drag, a lot more heat buildup...a lot less rock actually making impact. Furthermore, these impacts will be scattered (more like a long-range blast from a shotgun) rather than concentrated (say a slug from a 13mm rifle), which reduces the damages both from the immediate impact and from after effects (Try this experiment out; take a handful of gravel and throw it out over water, then take one big rock about as big as the combined gravel and give that a heave.)
WISE found it's first NEO the other day. This is the first of a long list.
Lots of other spacecraft and other automated surveys exist either dedicated to finding NEOs, or which will do so when one sails through it's field of view whilst it's staring at other targets. LINEAR is a good start if you're interested.
I think you're going to need a bigger tin-foil hat. Made out of many thousands of tons of bedrock.
It'd be little different from one made in atmosphere. The primary actions of a thermonuclear bomb work purely on a massive release of energy; this doesn't require any atmosphere to work (see the Sun; it's fusing like crazy even in a vacuum). Now, there won't be a secondary blast action due to no air to push, but that wouldn't be the action sought in an asteroid blast.
An atom bomb produces a lot of light and heat - which does wonders, when you have an atmosphere to react to it, and wreak havoc around the explosion - but in space, it's just so much light and heat. It might work well (if rather unpredictably) against an icy object, but you'd virtually have to attach the bomb to the surface of a dried up rock, in order to do any good. Most of these things will have seen far more radiation during their long life times, each time that passed near the Sun. One wonders how big a nuke you'd need to use, to cook through all those dried up layers of melted and frozen basalt (in which case, why not just attach something much more useful and controllable like a rocket engine - or even just an equivalent mass of chemical explosive, since it would probably be more effective?)
If vapourising rock was your means of deflecting the object, you'd be better off with some sort of 'geet big lasur in space', since you could maintain a steady burn on the target and control the redirection process more effectively and with much faster response times.
Really, we should stop looking at these things as a threat and maybe begin considering them as a potential resource. If you could steer one into a tame orbit, you could possibly think about landing things on it, mining it - even hollowing it out and using it as a long-haul, engine-less, means of getting to Mars and back.
Well, it won't have a shockwave like it does here but part of the energy release of the nuke is kinetic energy. But since they made a stupid treaty not to test weapons in space we have no way to check how EXACTLY will a nukulear weapon affect a rock in space.
That's how the Orion engine worked (if I read wiki's article correctly). A pusher plate received a hefty kick from mini nukes detonated 200 feet behind it.
With an election coming he has plans to make sure that we keep him in power.
He has (according his own rhetoric) already saved the world from financial disaster.
In recent days he has put the alert level up to severe to make us think about something else other than the election.
So if those nasty terrorists don't make us quake in our boots all he needs now is to raise the prospect of "we are all doomed" and he might still scrape in on May 6th.
And where's the Gordon Brown icon anyway? It'd be nice to pick a failure when posting a message on El Reg!
Fred Mbogo, since its lunchtime, I'll just chip in to observe that 'Project Orion' is a largely imaginary space ship of very dubious feasibility: the preservation of its memory serves to show that even smart people can be delusional. After all, most of the design principles behind these 'bomb-rockets' could be refuted using a basic application of 300 year-old physical laws, written by a man who devoted much of his own life to alchemy.
The existence of 'Project Orion's Wikipedia page (and the even more fanciful page on 'Nuclear pulse propulsion' in general) simply serves to reinforce the message that you shouldn't really believe everything you read in Wikipedia.
Either that, or we really COULD have gone to Mars and back, in under a month, in 1965, using a bill of materials to be found in Wallace and Grommet's tool shed... and JFK really DID conspire to prevent the USA from having a fleet of nuclear space battleships, because he thought that a futile and degrading war in Indochina would be a better way of projecting American military might. You take your pick, but on the whole, if deciding to believe in something, actually requires to to start not-believing, in a whole load of other things that most people take for granted, it's usually a good idea to check where your belief-system is heading you.
is, I suspect, rather less than that accruing to having them around to use on each other. No nukes, please - humanity might then just have a chance to get through this century without its own little extinction event !...
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