The ending to me makes no sense.

Batman put his plane on auto pilot that was carrying the bomb away from the city, but they should be affected for many years to come just like Hiroshima.

How come there is no mention of people in Gotham city suffering from radiation poisoning due to the explosion?

7 Answers 7


This is an interview with Edwin Lyman, PhD, scientific director for the Nuclear Control Institute, in November 2001.

Member Question: What are the levels of radiation risk at 10 miles, 100 miles, 100,000 miles from ground zero? How far can the radiation travel? Is that based solely on wind direction?
Edwin Lyman: Well, again one should distinguish between a nuclear weapon attack and an attack on a nuclear plant.
For a nuclear power plant accident, the acute effects I described -- acute radiation sickness with a high chance of death -- would be limited to within 10 miles or less of the accident. This is partly the basis for the choice of 10 miles as the size of the emergency planning for U.S. plants. However, the plume would be carried by the wind and depending on atmospheric conditions could contaminate a large area and even hundreds of miles downwind there would be some significant contamination. This was seen after the Chernobyl accident, where large sections of Northern Europe did receive significant contamination and the aftermath was detectable all around the northern hemisphere.
The range of effects from a nuclear weapon is very strongly dependent on its yield and whether it was detonated on the ground or at some height above the ground. If we take the example of a terrorist crude nuclear device, let's say one-tenth or one-fifteenth of the Hiroshima yield (which would be about a 1,000 tons of TNT equivalent), the blast affects would be fairly limited in range, probably to less than one mile.
The direct radiation effects would be felt considerably farther and fallout would travel hundreds of miles, and that would be directly related to atmospheric conditions and wind direction. So, the extent does depend on a lot of factors, but the ultimate effect could be felt tens or hundreds of miles away. However, the farther one is from the site of detonation, the more time there is to take countermeasures.

The bomb in The Dark Knight Rises was not a 'bomb' exactly. It was a nuclear core built for a reactor, converted to be used as a bomb by Bane and his followers.
Bruce Wayne has 2 minutes to fly 'The Bat' away from Gotham. Though there were words said between this and when he actually got in the cockpit, let's just assume he had the 2 minutes.

BATMAN: Two minutes. I can fly it out over the bay...

This article says that 'The Bat' flight sequences were done by helicopters, so we can estimate the speed of The Bat with that.

According to Wikipedia, the fastest helicopter(checked 11/28/2012) reached 250 mph in 1986, or a little over 4 miles per minute. With modern engineering and the resources of Wayne Enterprises and with the goal of building one aircraft, not a large fleet of cost-effective aircraft, I think the speed would be able to get a little further.

I am not convinced that Batman was able to carry the nuclear core far enough in the time provided to prevent the damage. We don't really have enough information about the capabilities of "The Bat" or the specifics of the nuclear core depicted in the film. There are also other factors that decide how far the radiation will travel (and over what period of time), and I don't know how heavily nuclear fallout has been researched. I think this is just something we have to accept as a 'given' for the purposes of the film.

Also, the film ended right afterwards, so there may very well be some radiation poisoning that was just not shown.

  • 5
    We do have some information of the bomb, Pavel states in the stadium that it is ..a fully primed Neutron Bomb, with a blast radius of 6 miles. Upon finishing the conversions he states: It is done...this is now a 4-megaton nuclear bomb. Hope those specifics help.
    – Tablemaker
    Commented Nov 28, 2012 at 21:36
  • 2
    Hiroshima was 5.2 megaton.
    – Reactgular
    Commented Nov 28, 2012 at 22:01
  • 8
    Now the real question: Will the radiation poisoning spawn a whole new crop of supervillains?
    – Kyralessa
    Commented Nov 29, 2012 at 2:59
  • 2
    @Kyralessa Super-villains that Batman created!
    – Reactgular
    Commented Nov 29, 2012 at 3:20
  • 4
    @MathewFoscarini - the Hiroshima weapon was 16 kilotons - 325 times smaller than you state here.
    – iandotkelly
    Commented Nov 6, 2013 at 19:26

I think the ultimate answer to this question is: movie magic. Movies are known to bend the laws of physics to meet their needs, Batman is no exception.

For instance, look at how hard it was for the bat to even lift the bomb up, let alone fly fast with it. He couldn't have gotten the bomb much more than a couple of miles out into the water before it blew up.


The film mentions that it is a 4 megaton NEUTRON bomb. My understanding is that in a typical fission nuclear device, approx. 95% of the released energy is kinetic (blast) and 5% radiative (high energy neutrons). In a neutron device, it is more like 50% for each. In other words, a neutron bomb of the same yield will emit more of its energy in the form of lethal radiation and less as blast potential compared to its fission counterpart. Note that these types of bombs were flirted with decades ago due to their ability to kill living organisms while doing a lot less damage to infrastructure.

Anyway... if we assume that Batman programmed the Bat to go out to sea and explode at a low altitude, this would have resulted in a smaller blast radius. And, if we assume he was lucky and the prevailing winds were directed off-shore, the overall effect on Gotham could have been minimal or nonexistent.

Add to this a shot of "suspension of disbelief" and I can enjoy what we saw in TDKR... :-)

  • A lot of dead fish, though... Aquaman won't be happy. Commented May 16, 2016 at 16:02

Because it was a neutron bomb, not a nuclear bomb. Neutron bombs release less of their energy in an explosion than nuclear bombs, so while the explosion and radiation levels are significantly less than a nuke, neutron bombs release a greater percentage of their energy in the form of radiation and over a much smaller area.

That is why, in Batman, Gotham is not harmed by the explosion: as a neutron bomb, it had a smaller blast and radiation area than a nuclear bomb of equivalent tonnage. From a few miles away, the effects of a neutron bomb would be minimal. Hell, that's what they were designed for, the ability to damage with radiation without spreading the effects too far and wide.


It is a fusion reactor, which means that it simply fuses different hydrogen ions to create helium. This is of course, a layman's explanation, but what this means is that there is no nuclear fallout. Search nuclear fusion for more information, specifically the difference between fusion and fission.


Well, at one point he claims it's a 4 Megaton nuclear bomb, that bomb should be able to destroy buildings with a 15 mile radius, even outside of that there would be a blast wave. The Bat is supposed to be for an urban environment, not designed for speed, but assuming it can match the best helicopter (as Padenton said) it could get 6 miles away (he only had a minute and a half) 6 miles from the 59th st. bridge is just past the tip of the island. The bomb would take everything from Richmond to the Bronx to Essex. 10 million+ dead.


Here's my take, based on information from the Wikia.

The bomb seems to be a pure fusion bomb. These release less radioactive products, and in fact, this one is a repurposed fusion power plant, presumably containing no fissile material at all - the initial burst of radiation is everything, and there is no radioactive fallout.

The neutron radiation would alter the nuclear composition of nearby particles, causing buildings, soil etc to become radioactive; however, this is nowhere near the effects of a traditional uranium or plutonium fission weapon. Since the bomb is detonated 10 miles offshore, and has a stated blast radius of 6 miles, neutron activation would affect little more than atmospheric nitrogen and oxygen, and oceanic oxygen and hydrogen; this would create only stable isotopes or isotopes with a half-life of less than an hour, with the exception of a small amount of tritium, which would increase local background radiation by a barely measurable amount. Even with adverse wind directions, the citizens of Gotham are going to be fine.

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