Largest possible nuke?

Gan

Banned
I saw a documentary on the Tsar Bomba, which mentioned someone thought of a 1,000 megaton bombs during the development process.

At any point between then and now could the Soviets or Americans have created and tested nukes in the gigaton range? How far could we go? What about teraton-range? The ability to deliver it by air is irrelevant.

Is there any place either government could test high-yield weapons without causing too much destruction? And what would the response be to the test?
 
Edward Teller reportedly designed a 10 Gigaton (10,000 Megaton) weapon, which he referred to
as the "backyard" bomb - you needn't deliver it to a target; just detonate it in your own backyard,
and destroy (or at least dump lethal amounts of fallout onto) any target in the world.

Fortunately, the Air Force chose not to fund this option.
 

katchen

Banned
I think the person to ask might be Elon Musk. But don't expect him to reveal his trade secrets.
When we're looking at teraton nuclear devices (notice I said devices, not weapons, we pass well out of the range of war weapons and into the field of technology for splitting or moving or altering the courses of asteroids both to protect the Earth and to exploit the minerals those asteroids hold.
As such, this discussion probably belongs on the Future History discussion board. A lot of very good hard science fiction (and now a lot of speculative investment prospecti) are being generated by the prospect of space industrialization, which will be a reality. The only question is, who will do it. And my guess is, those countries that need the resources the most rather than those countries that are currently first.
Of course if you can use teraton nuclear devices to nudge asteroids, you can use teraton or gigaton nuclear devices to nudge asteroid devices into trajectories that will send them crashing down onto one's national enemies. And anti-ballistic missiles are useless against teratons of rock once they get going in the gravity well. And meteorites have the blast effects without the radioactive fallout. Even George Friedman of Stratfor believes that as a war weapon, meteorites trump nukes.:eek:
 
Its theoretically possible but strategically not very wise, absurdly expensive to create, stripping the ability to make other bombs with the plutonium used thus also limiting tactical options, and it would be impossible to test on the planet so you wouldn't even be sure if the only bullet in your gun even worked.
 
I saw a documentary on the Tsar Bomba, which mentioned someone thought of a 1,000 megaton bombs during the development process.

At any point between then and now could the Soviets or Americans have created and tested nukes in the gigaton range? How far could we go? What about teraton-range? The ability to deliver it by air is irrelevant.

Is there any place either government could test high-yield weapons without causing too much destruction? And what would the response be to the test?

If I recall correctly, some rockets, like the Russian Proton, were actually built to deliver gigaton warheads. Improved guidance made that irrelevant--you could put a smaller bomb, or a lot of bombs, on a smaller rocket and do the same damage.

But such bombs would not realistically be developed. They'd be wildly inefficient compared to factory-production of smaller bombs--as bomb yield increases, the fraction of energy lost as heat radiated into space instead of a blast increases.

The only reason anyone might bother with a gigaton bomb is if, somehow, both computers and gyroscopes are retarded a few decades. If your missiles are inaccurate, then you'll want to put a big bomb on them. But even then, building a lot of missiles with smaller bombs and basically carpet-nuking a target is more cost-effective.
 
No problem in scaling up nuclear weapons if you make them fission-fusion-fission devices. That was the great thing about weapons using the fusion reaction, they were basically "infinitely" scaleable upwards in power.

IIRC, Teller's idea was for kind of "national doomsday devices". That is giant nuclear weapons put aboard big cargo ships and anchored in international waters as close to the U.S.S.R. and China as possible.

IIRC, again, a nuclear device can be built that generates about 6 megatons of explosive force for every 1 ton of bomb mass.

So theoretically today, you could put a 100,000 ton fusion device on a very large cargo ship and it could have an explosive yield of about 600,000 megatons. I guess that would be 600 gigatons.

That would be the power of 6,000 Tsar Bomba's (Tsar Bomba was capable of 100 megatons but only tested at 50 megatons for various practical reasons).
 
By the way, a study was done and at the time Tsar Bomba was built there were only THREE cities in the entire world that would require a 100 megaton device to effectively destroy.

And of course, it is much more efficient to hit a huge urban area with 5 or 6 500 kiloton warheads. That will gut any city in the world.
 
A teraton according to nukemap causes an explosion the size of the United States. I'm not sure anything we possess can generate that amount of energy nor would we be able to test such a weapon anywhere without casuing massive damage across the globe.

EDIT: Scratch that. It's actually about the size of Africa.
 

NothingNow

Banned
No problem in scaling up nuclear weapons if you make them fission-fusion-fission devices. That was the great thing about weapons using the fusion reaction, they were basically "infinitely" scaleable upwards in power.

Yeah, Tellar-Ulam cores don't really have an upper limit in terms of yield, although they do eventually reach absurd sizes.

A teraton according to nukemap causes an explosion the size of the United States. I'm not sure anything we possess can generate that amount of energy nor would we be able to test such a weapon anywhere without casuing massive damage across the globe.

EDIT: Scratch that. It's actually about the size of Africa.
We can probably make a Tellar-Ulam device big enough to do that, with sufficient materials. Problem is, it'd have no real use outside of powering the biggest Nuclear shaped charge ever, for a planetary defense system or something.

Or if we want to utterly wreck another planet.
 
For the situation in that movie, even teraton would probably be ludicrously inadequate.

A device the size of Manhattan would probably have a higher yield than a Teraton though, it was mentioned that the bomb was made up of about half of the worlds fissile material.
 
I saw a documentary on the Tsar Bomba, which mentioned someone thought of a 1,000 megaton bombs during the development process.

At any point between then and now could the Soviets or Americans have created and tested nukes in the gigaton range? How far could we go? What about teraton-range? The ability to deliver it by air is irrelevant.

In a memoir by a weapons physicist, I read that several hundred megatons is actually the largest possible size, because if you try to chain too many fusion stages together the light from the first stage blows the later stages apart before they can actually ignite. However, I know that Teller, among others, did investigate multi-gigaton-range weapons, so I'm not sure what to make of that. If there really is an upper limit on yield, it's probably classified.

In practice, if you're detonating the device inside the atmosphere, once you hit a few hundred megatons there's little point to going bigger because you're limited by the horizon. At that kind of yield you're basically blowing a large chunk of the atmosphere into space; going to a higher yield just means you're blowing it into space faster.

I have seen some speculation on uses for such devices. These ultimately all either proved to be impractical or unnecessary, but they're kind of interesting:

  • Destroying extremely deeply buried military facililities, something like the DUCC.
  • Area effect sea mines. Create a tsunami that wipes out enemy submarines over a wide area.
  • Burst the device in orbit, to start fires over a wide area.
  • And, as others have mentioned, a suicide weapon to produce enormous amounts of fallout that would render the human race extinct as an ultimate form of MAD.

Is there any place either government could test high-yield weapons without causing too much destruction? And what would the response be to the test?

High Earth orbit or further is the only place you could test one of these things.
 
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Yeah, Tellar-Ulam cores don't really have an upper limit in terms of yield, although they do eventually reach absurd sizes.


We can probably make a Tellar-Ulam device big enough to do that, with sufficient materials. Problem is, it'd have no real use outside of powering the biggest Nuclear shaped charge ever, for a planetary defense system or something.

Or if we want to utterly wreck another planet.

It would be a literal planet killer :eek:
 
A teraton according to nukemap causes an explosion the size of the United States. I'm not sure anything we possess can generate that amount of energy nor would we be able to test such a weapon anywhere without casuing massive damage across the globe.

EDIT: Scratch that. It's actually about the size of Africa.

Nitpick: the scaling laws Nukemap runs on break down at that kind of yield due to horizon limits and other effects (Nukemap assumes a constant altitude airburst). Not that it matters much when you're throwing that kind of yield around.
 
Nitpick: the scaling laws Nukemap runs on break down at that kind of yield due to horizon limits and other effects (Nukemap assumes a constant altitude airburst). Not that it matters much when you're throwing that kind of yield around.

Oh okay but like you said we are dealing with a ridiculous ammount of energy.
 
I think for a practical deliverable nuclear weapon, the limit would probably be in the 40-50 MT range. My guess is that the Russians did look at a true multi-stage thermonuclear warhead for the R-36M (NATO code name SS-18 Satan) with a yield around 50 MT, but probably kept it around 20 MT due to lower cost of producing the 20 MT warhead. There was consideration for a 35 MT version of the B41 gravity-dropped bomb for the B-52, but only the 25 MT version ever made it to the USAF inventory.
 

Delta Force

Banned
What is the most powerful gravity bomb a strategic bomber could carry without being damaged or destroyed by its own weapon? Apparently the B-36 was very close to the limit for a piston aircraft with its 25 megaton bombs. How would subsonic turboprops/jets (B-47, B-52), Mach 2 jets (B-58), and Mach 3 jets (B-70) fare? The higher yield weapons can only be practically carried by bombers so it is worth knowing what they can safely handle. It would be very costly to field Saturn V and N-1 size nuclear missiles, especially since they would take so long to prepare for launch that they would require incredibly expensive blast and EMP protection to avoid destruction by bombers and solid fueled missiles.
 
According to wikipedia, the theoretical maximum yield of a nuclear weapon is about 6 kilotons per kilogram (or 6 megatons per metric ton). For larger warheads, the practical efficiency seems to come pretty close (5.2 megatons per metric ton for the 25 MT Mk-41, the highest-yield US weapon).

Using those figures, a hypothetical bomb that uses the full bomb load of B52 (32 metric tons) could yield a theoretical maximum of 192 MT or a practical maximum of about 166 MT. That's just getting it to the target -- no idea if a B52 could lift it high enough for an efficient airburst (does optimal airburst height vary with yield?) or get far enough away before detonation to survive the blast.
 
Well, it was a modified TU-95 Bear that dropped the Tsar Bomba (its Bomb bay was modified because part of Tsar Bomba had to stick out under the airplane). Reportedly one reason they restricted Tsar Bomba to 50 megatons by not firing the third stage was to give the Bear crew a better chance at escaping.

Note, when Tsar Bomba was dropped over Nova Zemyla, it didn't even cause a crater IIRC because the shockwave from the bomb reflected off the ground and kept the fireball suspended in the air.

Amazing.

Even more amazing is that hundreds of people live on Nova Zemyla despite it being the most nuked location in world history.
 
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