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Nukes Against Earth-Impacting Asteroids
TopSpin writes "Flight International reports that scientists at the Marshall Space Flight Center have developed designs for an array of asteroid interceptors wielding 1.2-megaton B83 nuclear warheads. The hypothetical mission for these designs is based on an Apophis-sized Earth impactor 2 to 5 years out. According to NASA, 'Nuclear standoff explosions are assessed to be 10-100 times more effective [at deflection] than the non-nuclear alternatives analyzed in this study." On April 13, 2029, Apophis will pass closer to earth than geosynchronous satellites orbit.
Shrapnel == Greater Cross Section
Greater Cross Section == Atmosphere has greater effect on projectile
Atmosphere has greater effect on projectile == Energy dissapated over wider area
Energy dissapated over wider area == No boom today. Boom tomorrow. Always boom tomorrow.
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Apophis is a perfect example of how flawed the current system for identifying potentially hazardous near-earth asteroids is. A two body analysis showed that it was on a collision course, but a more intensive three body analysis showed it would miss by a lot. Thing is, the opposite could potentially also be true - a two body analysis might show that an object is not a threat when, in fact, it is and a more heavy analysis would show that. We need more resources dedicated to this very real threat to our planet. Only with early detection do we have any chance of deflecting a planet killer.
How we know is more important than what we know.
They claim 10-100 times more effective than other methods. First of all they dont define more effective. Second of all, they seem to dismiss ideas like a gravity tug out of hand as not developed enough.
The idea of throwing nukes at an object of potentially unknown size bugs me, especially when much more controlled options exist. All that needs to be done is to nudge the NEO out of small zones known as "keyholes" that are small, finite portions of space where the pull of the Earth will push the object into a collision course on its next orbit rather than another random non-intersecting orbit.
A fairly massive object (something a Delta IV Heavy could launch) would be perfectly capable of handling an Apophis sized object with enough lead time (on the order of years, but certainly less than decades), by flying in formation with the object in the right location to shift its orbit slightly. This is a lot easier than Apollo, which we pulled off in less than 10 years, so to dismiss it as too difficult is ridiculous, and it seems a lot more responsible than launching nukes at an object we dont fully understand.
Just my thoughts anyway.
Nuke explosion high in the orbit was tested as a radiation shield in antibalistic missile experiments (Operation Argus, by Nick Christofilos of Lawrence Livermore fame) and it was found ineffective for the defense purpose. A side-product of these experiments with artificial radiation shields was discovery of Van Allen radiation belts.
It was later found by accident that multimegatonn explosion high in the orbit can dump lots of charged particles (mostly high-energy electrons) into Van Allen belts where they persist for many weeks during which time they gradually degrade solar panels and electronics of satelites - this happened in 60s (after operation Starfish Prime about 5 satelites went silent...)
I doubt that we will ever figure out - and I suspect that even if we did figure out we couldn't do much about it
I read a novel, I can't remember which, where the author made a great case for using enhanced radiation weapons against asteroids instead of conventional nuclear devices. His argument was that a non-impacting explosion using an enhanced radiation device might be able to divert even a fragile asteroid without necessarily breaking it up. The radiation from the weapon would transfer it's energy evenly to the surface of the asteroid. (Not exactly, but way better than a regular nuke) That would blow away the top layer of the asteroid on the side facing the blast, pushing the asteroid in the opposite direction. A series of such blasts might be able to divert the asteroid without causing it to break up.
I'm sure there are problems with the idea, but it seems logical to me.
-All that is gold does not glitter - Tolkien
www.ra
If you simply wanted to stop the Japanese, why didn't you simply drop the bomb on Fujiyama (for example)? I think that the sight of a giant volcano being blown to smithereens would have been just as effective as dropping the bomb on Hiroshima and Nagasaki.
The sad truth is you wanted to test the bomb as well as show to the Soviet Union that you have some big guns.
There is considerable debate on this issue as far as I know. Militarily the Soviet Union posed far more of a threat to the short and long term security of the civilians of Japan (it's not like what happened to Berlin was a secret, or what would happen to eastern Europe wasn't known). There is however one thing that is clear. The atomic bomb gave Emporer Hirohito (and to some extent Togo) the excuse he was looking for the push for an end to the war on all fronts. Civilians would understand surrender faced with this new terrifying weapon. The coup attempt that resulted from the repeated attempts to surrender was probably far smaller than it would have been without the bomb. The terms of the surrender were sufficient for the allies. The last one is the key. Without the bomb, would the Japanese have accepted unconditional surrender (with the exception of the retention of the Emporer) if the allies did not have the bomb? Maybe, but we know four of the big six wanted to reject the Potsdam declaration out of hand until the extent of the Soviet attacks became known, and the attack on Hiroshima and Nagasaki. Then it was split 3-3. Without the intervention of Emporer Hirohito (who certainly considered the bomb important) this deadlock may have lasted.
I don't know what the result would have been without the bomb. Perhaps the Japanese would have continued fighting until it was clear that the Soviets were preparing to invade Korea, or perhaps the Japanese islands themselves. It is possible that without the bomb the Japanese would have used losing territory to the Soviet Union as a bargaining chip against the Americans to get more favourable terms.
Your point about American B-17 raids on Japan is a good one. It is important to remember these were small nukes. The building directly under the bomb survived the explosion in Hiroshima. This does strongly suggest that the bomb was not, in the military leaderships mind, a deciding factor, considering that the death toll in Tokyo from fire bombing was higher than in Hiroshim or Nagasaki through the atomic bomb. However, the bomb is more than a incendiary weapon. I believe the Emporer said it best in his radio address to the Japanese people:
"The enemy now possesses a new and terrible weapon with the power to destroy many innocent lives and do incalculable damage."
The key word being terrible. The atomic bomb, more so than any other weapon, was terrifying. It is this terror that gave the Emporer the option of offering surrender (along with the Soviet invasion).