I'm not experienced in physics yet (if it helps I've covered as much as acceleration, momentum and energy transfer/chemistry ionic and covalent bonding) but I've heard that the way people compare destructive force of nuclear weapons by megatonnes or kilotonnes is wrong. This does seem to make some sense because the energy will turn into a mix of gamma (?) radiation, light radiation, heat radiation and other things, but is there an accurate way to compare nuclear weapon destructive force? Say, I wanted to compare today's weapons to Little Boy.

  • 3
    $\begingroup$ What people? The people who are building nuclear weapons for a living? They have quite sophisticated ways of defining what such a weapon does. "tons of TNT equivalent" is just a crude energy measure. $\endgroup$
    – CuriousOne
    Jun 11, 2016 at 8:07
  • $\begingroup$ You might find this interesting: atomicarchive.com/Effects/effects1.shtml $\endgroup$
    – userLTK
    Jun 11, 2016 at 8:10
  • 1
    $\begingroup$ The 1980s grim book "Nuclear War: The Facts on our Survival" and its appositely stark white on black forerunner, "Nuclear War: The Facts" will tell you more than you EVER wanted to know about these matters. $\endgroup$ Jun 11, 2016 at 9:01
  • 1
    $\begingroup$ Which weapon do you want to compare? The B61 en.wikipedia.org/wiki/B61_nuclear_bomb has a variable yield. It can be "programmed" to be a fraction of Little Boy or a multiple. Even the smallest yield would give you and a million people a really bad day if it was to explode close to you. $\endgroup$
    – CuriousOne
    Jun 11, 2016 at 13:06

2 Answers 2


The so-called TNT equivalent of a nuclear weapon is an unambiguous way of quantifying how much energy is released by the nuclear weapon. There's nothing 'wrong' about it.

The only caveat is that the damage caused by, say, Little Boy versus 15 kilotons of TNT would not be identical despite having an equivalent yield (for various practical reasons).

Generally, 10-20% of nuclear yield is emitted in the form of ionizing or residual radiation, unlike conventional weapons. Related: effects of nuclear explosions.

  • $\begingroup$ okay, thank you. i think what i mustve read was refering to the destructive power of the nuclear weapons. this has cleared it up in my head a little. thanks! $\endgroup$
    – user120774
    Jun 11, 2016 at 8:08
  • 1
    $\begingroup$ Also, spreading out a bunch of small bombs in a carpet will do more damage to the city than one big bomb. $\endgroup$
    – JDługosz
    Jun 11, 2016 at 17:46
  • $\begingroup$ @JDługosz Not necessarily - if the bombs are small enough, they will do no damage at all! $\endgroup$
    – MikeB
    Aug 8, 2023 at 11:54

Since no nuclear bomb has been used since since Nagasaki we can and indeed do only infer "applications" if you are talking about dropping a nuclear weapon on a human population. These estimates based upon the criteria you have given appear very effective as no theronuclear weapon has been detonated on a population center since Nagasaki, Japan in 1945.

I would read up on Edward Teller and his work on the Hydrogen Bomb and its controversies which were legion since a hydrogen bomb is an order of magnitude more destructive than the two atomic bombs dropped in World War 2 on Japan.

  • 17
    $\begingroup$ Downvoted because nuclear bombs have been used many times since Nagasaki. The US, for example, conducted 23 tests of nuclear weapons at Bikini Atoll alone, and almost 1000 in Nevada. $\endgroup$ Jun 11, 2016 at 10:47
  • 4
    $\begingroup$ @DavidHammen I think the user is talking about population centers $\endgroup$
    – anna v
    Jun 11, 2016 at 11:17
  • 4
    $\begingroup$ @Jelly -- What exactly do you mean by "used"? They most certainly have been "used" in the sense that they were detonated and the effects of those detonations were very carefully measured. Those detonations were much larger than the small nuclear weapons used at Hiroshima and Nagasaki. Just because they were only used in wartime twice does not mean they have not been used since then. $\endgroup$ Jun 11, 2016 at 14:51
  • 2
    $\begingroup$ The bomb detonated at Nagasaki was a plutonium fission bomb, not a thermonuclear weapon. $\endgroup$ Jun 11, 2016 at 15:08
  • 5
    $\begingroup$ You're wrong. Fission bombs are nuclear weapons. Thermonuclear weapons are fusion bombs, aka hydrogen bombs. $\endgroup$ Jun 11, 2016 at 16:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.