Either Little Boy or Fat Man (The Gadget was never intended to be deployed as a weapon). Alien space bats alter history so that Berlin is a target for nuclear weapons in 1945. Hitler’s in his famed bunker - does he survive?
Hiroshima still had buildings standing after the detonation of Little Boy - but would the radiation have offed the Führer and his pals?
Not sure. The first two nukes were not very powerful as nukes go.
I have read (sorry, no cite) that even Cheyenne Mountain Operations Center could not withstand a direct hit from a modern nuke (it might survive a near miss though).
Indeed, which is why I included both bombs - according to wiki Fat Man was a little more powerful than Little Boy with a blast yield of 21 kilotons to Little Boy’s 13-18. Whether this difference would make killing Hitler in his bunker significantly easier or not I don’t know.
The atomic bombs dropped on Japanese cities detonated at altitude in order to maximize the area of destruction, so the fact that not all buildings were flattened should not be taken to mean they would have survived a ground level detonation.
At the Nevada test site, underground detonations were contained by blast doors in side tunnels that slammed shut between the time of detonation, and the arrival of the shock wave. From this I infer that it is far from impossible to build structures that will survive nearby nuclear detonations.
“Bunker buster” munitions rely on maraging steel armor to penetrate deeply into the bunker or surrounding ground prior to detonation.
Opinion only: Reading the wiki description of the bunker, it sounds like the structure (4 meters of concrete, 8 meters of earth) could withstand a Hiroshima style attack (airburst), but I doubt the squishy folks inside would be unaffected (heat? does the fireball consume all the local oxygen? etc).
I think there were even a few survivors fairly close to ground zero at Hiroshima. I apologize for not having time to look it up.
You really want earth penetrating weapons so that the shockwave couples to the ground for buried targets. If Hitler was the main target rather than the city I imagine they wouldn’t have gone with an air burst.
I remember an engineering analysis of the famous domed observatory at ground zero in Hiroshima. Apparently the initial flash vaporised the (thin) copper dome. The buidling was almost directly under the blast, so the later shockwave pummelled it from directly above, while further away buildings got side blasts and were knocked over. Similarly, the vaporised dome skin was fortuitous (?) because the iron/steel(?) struts of the dome were not buckled, as they would have been if the blast had pushed on the full dome.
Whether something survives today depends on the warhead. At the height of the cold war, the best bombs (“we use only the best”) were in the 100 megaton range. Set one of those off over a major city, and the blast would like start fires in the structures and forests 50 to 100 miles away. (Firestorms in Hiroshima and Nagasaki were attributed as much to knocked-over cookstoves as nuclear flash) The crater would probably create a new lake. Remains of the Führerbunker and anything within a hundred feet of the surface would be found in the vapour deposits around the world.
OTOH, as the cold war wound down, the weapons (at least USA ones) tended to smaller size. Computerized target accuracy substituted for brute force. Ultimately, Hiroshima-strength warheads delivered within 30 feet of the intended target (at altitudes less that 100 feet) probably would have also done in the bunker, either as a small crater or a very very thin Führer sandwich.
(I remember the first gulf war, as the Baghdad gunners claimed to have shot down an impossible number of American aircraft. “This thing came flying down the main street and we kept firing at it until it finally blew up right over the Ministry of Defence”)
An additional factor you’re going to want to take into account is how the device is going to be delivered to the F-Bunker. The only way to feasibly do it in 1945 was to drop it out of a B-29. Depending on a variety of factors (if the B-29 is getting shot at or not, weather, visibility) this can either be quite accurate or miss by several miles. At Hiroshima, the bomb missed the aiming point by 800 feet; at Nagasaki, the Fat Man bomb missed its planned aiming point by nearly 2 miles. As already noted, both bombs were airbursts, in order to maximize their destruction of the lightly constructed buildings typical of the area. To destroy hardened targets such as missile silos and C3I bunkers like the F-bunker, you’d typically use a groundburst, Given that the Fat Man bomb was not a hardened, armor-piercing design (OTOH, the Little Boy design was, IIRC, supposed to be very robust, if extremely inefficient), you’d probably set the bomb to detonate as close to the ground as practical without actually striking the ground.
We have data for the effects of prompt radiation on animals within bunkers from tests like Crossroads and others at the Nevada test site. During the Able test at Bikini atoll, a bomb very similar to Fat Man was detonated over a collection of ships. Animals were caged within the ships to serve as test subjects for bomb effects. Within one of the ships, the decommissioned battleship U.S.S. Nevada, animals were caged within the battleship’s turrets. The turret was protected by 18 inches of armor plate. The Able bomb detonated roughly 700 yards away, and 520 feet above the water. Despite the large distance and 18 inches of steel shielding, a goat within the turret still received enough radiation to die of radiation sickness 4 days later. The distance was far enough away, that the crew of the bomber which dropped the Able bomb had a board of inquiry convened against them for negligence.
From The Nuclear Weapon Archive comes a set of equations for roughly scaling the effects of nuclear weapons. For the Able bomb of 23 kilotons (or, roughly the same yield as Fat Man) plugged into those equations yields a distance for receiving 500 rem (5 Sv)of prompt bomb radiation of ~1500 meters. This is if you were standing in the open air. The wiki for radiation shielding gives some figures for “halving distances”: the thickness of material needed to reduce radiation by 1/2. As different types of radiation penetrate different materials more readily than others, this is necessarily a gross estimate. Still, from the linked chart under radiation shielding, the figure for steel is 1 inch. So, if the goat on the Nevada was sitting behind 18 inches of steel (which seems awfully high, but that’s what the wiki for Nevada had listed for turret protection), then the radiation reaching the goat was attenuated by 1/(2^18), or nearly 250,000 times. My guess is that there wasn’t 18 inches protecting the goat and that armor steel’s halving distance for Able’s radiation is greater than one inch. If we take the chart at face value, then plugging in 4 meters of concrete and 8 meters of dirt gives a total of roughly 150 halving distances. Or attenuation of 1/(2^150). Taking the linked radiation protection chart at face value, I don’t think they’re going to take too much damage from prompt radiation in the F-Bunker, unless you dropped the bomb directly on top of the bunker.
From the nuclear weapon archive’s discussion of the Buster-Jangle series of U.S. surface nuclear weapons tests, it was extrapolated from the “Uncle” test of a 1.2 kT sub-surface device that a 23 kT gun-type penetrating device would leave a crater 700 feet in diameter and 140 feet deep. Naturally, the size of the crater would depend greatly on the nature of the excavated soil, as well as how deep the weapon buried itself before detonating.
So, my guess as to what would happen if the Allies nuked Berlin is that the Allies would use an airburst and the F-Bunker inhabitants would survive, absent a firestorm being created by the device. (Not that there was a great deal left to burn in the Berlin of May 1945) If the Allies tried to kill the F-Bunker, then they’d use a near-groundburst and hideously contaminate most of downtown Berlin with radiation. Not to mention splattering the Soviets with a lot of downwind fallout. Your guess is as good as mine as to how close they’d have to drop the device to kill the F-Bunker with a ground burst. I think a drop with Hiroshima accuracy would do it.
The Tsara Bomba was supposed to have had a maximum yield that high, but it was never tested at full strength. Nothing else came particularly close.
Did they Allies even know the Führerbunker existed and where it was located?
Superheated air & breathing is an issue, people.
Did the bunker have an independent air supply? Even if it wasn’t planned for nuclear strikes, surely the architects would have considered poison gas?
The yield of the crippled version of the Tsara bomb was 57 Megatons. The crippling came from substituting lead rather than depleted Uranium for the tertiary stage. But the sucker was too large and heavy to be considered a usable weapon. The largest yield weapon in the US arsenal was the B-41 with a yield of 25 Megatons (FWIW, I’ve read that it could have souped up to 35 MT mounted on an ICBM). The Russians fielded a 8F675 model which was mounted on an ICBM with a yield of 20 MT.
Expanding on md2000’s comment, if you increased the accuracy of the warhead to hit within 1/2 the distance of the earlier version (CEP - circular error of probable), you can reduce the yield of the weapon by a factor of eight. A smaller weapon means a smaller mass; this allows one to use a smaller ICBM, or using the same icbm, carry more warheads. You also increase the reliability of destroying the target (redundancy).
Pretty much what folks above have said: As a practical matter they’d probably have missed dropping either Fat Man or Little Boy close enough to dig up the bunker. Had they planned a near-ground burst and gotten within 50-100 ft, either bomb was plenty powerful enough to dig up a mere 8 meters of dirt & 4 meters of concrete. The heat & radiation flux would have been promptly lethal out aways beyond that, WAG 200ft through that shielding material.
Ref a comment above, the “fireball” isn’t fire. It’s incandescent air & (for ground bursts) incandescent vaporized rock. Since it isn’t combusting, it doesn’t preferentially consume oxygen like a conventional fire would. To be sure, pretty soon all (like in a matter of seconds) that radiant & conductive heat will set surrounding stuff on fire. And from there that conventional fire may well develop into a fire storm which will lead to a low oxygen environment near the center.
If you’re bored of reading the internets, read Le Carre’s “Russia House”. The crux of the story was that a soviet dissident provides the west with material suggesting the soviet arsenal is totally incapable of delivering nuclear weapons accurately enough to be effective (i.e. to take out hardened missile silos reliably). Then the human factors take over - is it real, is it a plant to lull the west into relaxing their weapons development, etc. So what do you do… ?
It had a filtered air suppy.
What does that do to help with superheated air?
Cite?
There were two long-term survivors within about 400 meters of they hypocenter at Hiroshima; Eizo Nomura and Akiko Takakura. Mr. Nomura was in the basement of the concrete Fuel Cooperative Building (now the rest house) and Ms. Takakura was in a heavily-built bank building. Both noted other immediate survivors in the area who later died of radiation effects or in the following firestorm. The speculation I’ve seen was that Ms Takakura was in just the right place in the bank building to be properly shielded from radiation - a foot or two in another direction and she might not have made it.
“Bank Row” was quite close to the hypocenter and many of those buildings were left damaged but still standing. The actual hypocenter was over the Shima Hospital, a brick building which was completely destroyed. Survivors in any of those buildings were the very rare exception and not the rule.
Nope, not a clue. We know for certain that the Western Allies didn’t know, and can infer from various statements that the Russians didn’t know, even though they had a much better intelligence network. (The West mainly relied on decrypts.)
The British had Tallboy bombs and such that could have roughed it up with a direct hit. Which is a purely theoretical statement given the tech of the time.
