Hacker News Reader

Hacker News

Comment by myrryr | Hacker News Reader

Full thread

myrryr

ok... here is the deal.... the Tsar Bomba was ^#%$ing huge.

No seriously... MUCH MUCH bigger then you think.

it was 10 times the combined power of all the conventional explosives used in World War II

it was 10% of the combined yield of all nuclear tests to date.

and mostly.... It was the equivalent of over 1kg of antimatter going up. 1 ^#%$ing kg.... of ^#%$ing antimatter.

It broke windows in Norway and Finland and its shock wave was VISIBLE in the air 700 km away.

It is impossible to get people to understand how much of a monster it was. AND.... and this was it dialed down to 1/2 its maximum yield.

No one has been crazy enough to test another nuke of its size. Even in the height of the cold war no one was crazy enough to test something like that again.

View on HN

If you want to see the effects of various nukes there is a simulator here: http://nuclearsecrecy.com/nukemap/ (I have no idea if it will get you on some sort of list if you access it).

The takeaway is that, as long as it is just a single nuke, the damages are rather underwelming, except for the Tsar bomba.

Those rings show the area of near total destruction and death.

The area of severe damage and less instant fatality is maybe twice as wide.

Outside of that there's another ring of significant damage, but the probability of survival increases (as long as you're not near a window when the shockwave hits.)

The map also doesn't show fall out or the effects of a possible firestorms.

"The map also doesn't show fall out"

It's an option you can select - you can also set wind speed and direction (drag the windsock icon about). You also need to make sure it is a ground burst as an air burst won't produce much fallout.

"the damages are rather underwelming"

Not sure I would agree with that - a single 800kt detonation over Manhattan looks pretty bad to me and a realistic attack would probably have had many tens of warheads used.

Here is a rather jolly 1980's BBC documentary that spends a lot of time looking at the effects of a single 1Mt warhead on London:

https://www.youtube.com/watch?v=vejorfkdgwU

Of course, it does finish by noting that a real attack would have multiple ground and air bursts.

[NB UK("pretty bad") == NonUK("utterly appalling")]

Well when I mean pretty underwhelming I mean that I kinda expected a nuke to take out the entirety of New York + a big chunk of the east coast. I mean these are the weapons of doom, right? The weapons that will end the world?

And yet if you are just 30 miles from the target the first time you are going to notice is when you turn on the TV.

I have a 90 minute commute and my living room is just barely 30 miles from the target.

Keep in mind that at the height of the Cold War, both the US and USSR had thousands of nuclear warheads. A single nuke might not be a civilization-destroying weapon, but a carpet bombing of nukes sure is.

Well, with a single 25Mt ground burst in New York and the wind in the right direction Boston would be getting 1000 rads/hour - which is not going to be good if you are not in some kind of protected area.

Mind you, although the Soviets did have 25Mt warheads on ICBMs they were targeted on key bunkers - Cheyenne Mountain, Raven Rock Mountain etc.

One missing piece to the puzzle from that page is accuracy and hardened targets.

These days you can just about crush an individual ant with a missile fired from the other side of the planet, but it wasn't always like that. Accuracy used to be much worse, especially on the Soviet side. At the time the Tsar Bomba was developed, you might be lucky to get your bomb within a mile or two of your target. Even bombers were frequently way off target.

Then consider that a lot of the targets are hardened military targets, not cities. Destroying cities was always either incidental (they contained or were near military/political targets) or a last resort (convince the enemy not to attack by threatening his population in retaliation). Primary targets were (still are!) things like airbases, missile silos, and command centers. Many of these are hardened targets. A more normal-sized nuke going off a mile or two away from the intended ground zero will still wreck a city, but a missile silo can take it. If you want to be sure of getting targets like that, you either need to be a lot more accurate or you need much more powerful bombs. Accuracy wasn't possible at the time, thus huge bombs.

If you look at the evolution of nuclear arsenals, it was a race to bigger and bigger bombs until sometime in the 60s, at which point accuracy started improving greatly and the bombs got smaller again. For example, the US fielded lots of 9 megaton bombs in the 60s, but now the typical weapon in the US arsenal is under one megaton.

> I have no idea if it will get you on some sort of list if you access it

I guess it will get you on a list of nuclear history enthusiasts. Apart from that, this sort of thinking is really just mild paranoia. While I recognise that the NSA monitoring is a big deal, I don't think that it can be extended to mean that ordinary people accessing sites like this will become targets.

So, don't worry, and go ahead and access the site, and also read the guy's blog - it's very interesting.

The takeaway is that, as long as it is just a single nuke, the damages are rather underwelming

No—no it's not. See "What would happen if an 800-kiloton nuclear warhead detonated above midtown Manhattan?" (http://thebulletin.org/what-would-happen-if-800-kiloton-nucl...). Notice this:

No survivors. Within tens of minutes, everything within approximately five to seven miles of Midtown Manhattan would be engulfed by a gigantic firestorm

Furthermore:

The fire would extinguish all life and destroy almost everything else. Tens of miles downwind of the area of immediate destruction, radioactive fallout would begin to arrive within a few hours of the detonation.

Manhattan has a daytime population of more than two million people.

Not when you set it to ground burst and look at the fallout. A nuke in Florida can leave fallout up the entire east coast.

When nukes stop being about the M.A.D. concept and more about being a propaganda tool... It was designed to shock. And it surely did. Soon after the detonation, Andrei Sakharov himself (behind the Soviet "Third Idea" nuclear weapon design) began speaking out against nuclear weapons and became a Soviet dissident.

It's not crazy. It's pretty horrifyingly logical. Why have one 100Mt nuke, when you can have a hundred 1Mt nukes?

http://en.wikipedia.org/wiki/Multiple_independently_targetab...

Here are a couple videos of MIRV re-entry tests - basically what it'd look like before having a really bad day. http://m.youtube.com/watch?v=1dDTnszCQC0 http://theaviationist.com/2013/12/27/russia-icbm-test-kura/

Indeed. I can confirm that after having played Missle Command on the Atari 800 in 1983!

that's the part that boggles my mind.. it's as phenomenally big as everyone mentions, but it was only 50% yield because the Soviets were scared.

my head cannot fathom what 100% yield would look like.

It would also have been far more terrible even in the 50% yield if it had been let to touch the ground for the energy to turn into seismic waves. The energy corresponded to a 8.1 on the Richter scale.

The trouble with the 100% yield version that was originally planned is it would have dumped a lot of radioactive fallout on Russia. The 50% version was not so much dialled back as a different design with some of the uranium components replaced with lead.

Thank goodness. I'm also glad they tested it high enough up to prevent the fireball from touching the ground. With a modern bomb you get fallout from the primary stage but the vast majority from an air burst is going to be from the outer uranium-238 shell which absorbs all the extra neutrons from the fusion and splits without emitting any neutrons itself. This isn't a problem with lead for reasons I don't understand and with the air near the bomb you're just doing stuff like turning nitrogen into carbon-14. The results either decay immediately or last for a thousand years and so aren't particularly radioactive. If a bomb goes off near the ground or sea water then there's plenty of stuff possible products with those nasty intermediate half-lives.

Well, lead is a very stable element from what I understand. Radioactive elements like Uranium are radioactive because they're inherently unstable, such that fission is 'easily' doable and releases a lot of surplus energy.

Yeah. I just don't understand why lead can't be turned into an unstable element by bombarding it with neutrons.

Looking it up in a reference, natural lead is about 1% Pb-204, 24% Pb-206, 22% Pb-207, and 53% Pb-208. These are all of the stable isotopes.

If Pb-204 absorbs a neutron it turns into Pb-205, which isn't stable but its half life is ten million years so it's only very weakly radioactive. The -206 and -207 turn into other stable isotopes, of course. So those don't matter so much: about half of your neutrons enter lead nuclei which can safely absorb a neutron.

The other half, the Pb-208, turns into Pb-209. Pb-209 is radioactive with a surprisingly short half-life of 3.25 hours, so that's gone in a matter of weeks.

The nasty stuff is the lead atoms which happen to absorb two different neutrons during the explosion. This becomes Pb-210, which has a half life of 22 years: short enough that it's going to be emitting a bunch of radiation, long enough that it won't be gone after a few weeks.

So the answer is probably "it's very rare in these sorts of explosions to have two neutrons hitting a single lead nucleus." There are other possibilities (maybe they got the lead from spent nuclear fuel or centrifuges or something and it's all Pb-206) but that sounds like it's the most plausible.

Ok, I did a bit of research. It seems that Pb-208 has a very small absorption cross section for neutrons so you'll probably see very little Pb-209.

http://en.wikipedia.org/wiki/Neutron_cross_section

http://www.ncnr.nist.gov/resources/n-lengths/elements/pb.htm...

A 1-Megaton explosion has the same energy as 46.55 grams of matter. 50-Megatons is thus about 2.32 kilograms, or 1.16 kg each of matter and anti-matter.

A kilton of TNT is said [0] to be equivalent to a cube 27.8 feet on a side. 50-Megatons would be a cube over 1000 feet on a side.

[0] http://en.wikipedia.org/wiki/TNT_equivalent

>No one has been crazy enough to test another nuke of its size. Even in the height of the cold war no one was crazy enough to test something like that again.

and thanks to the test we know for sure that ignition of the atmosphere with even such a bomb still wouldn't happen :)

Whenever the Tsar Bomba comes up, the potential for it to have ignited the atmosphere is always brought up. What exactly, however, does that mean? (Apologies if that sounds sarcastic; it's a genuine question!)

My guess is that the heat/EM could induce a state change in atmospheric gasses into plasma. Would this be a chain reaction that ultimately encircles the world? Also, what are the implications of that (locally or globally)?...

It might get brought up because before the first atomic bomb was detonated, one of the physicists who worked on it (Edward Teller) suggested the possibility that detonating the bomb would ignite Earth's atmosphere. There's a bit more information here: http://www.sciencemusings.com/2005/10/what-didnt-happen.html

I assume it's similar to fear that fusion bomb detonated under the sea would cause a chain reaction with the hydrogen, turning all water into plasma.

Every transformation (chemical, nuclear) has an activation energy.

When you're exploding bombs using a new principle you might cross the activation energy of stuff that you'd rather keep around.

This is only a problem if it's possible for the transformation to be self-sustaining. That is, the act of transforming atmosphere causes yet more atmosphere to transform. Only in that situation would the whole planet's atmosphere burn.

Is that possible?

Let's make an analogy with trees. You can't burn a living tree outright. Or so you'd think. But once there is enough energy around a forest fire can jump from crown to crown faster than you'd imagine possible outrunning the ground fire. This will continue until the fire runs out of fuel or the conditions change enough to put it out.

http://www.thefreedictionary.com/crown+fire

There is so much energy in the system that the burning crown of one tree dries out the matter in the crown of the next to the point where it can be combusted in an extremely short time, contrary to ordinary conditions when lighting 'wet wood' appears not to work.

The whole point was that Teller thought that the reaction might be self sustaining once the activation energy was reached.

Think about it: someone made the call to ignore that possibility and pull the trigger on deployment even if they weren't sure about the outcome. Possibly the single most irresponsible deed in the history of man.

> someone made the call to ignore that possibility

Actually, they did the calculations and verified that it wouldn't happen. It was Richard Hamming who did the calculations. https://en.wikipedia.org/wiki/Richard_Hamming#Manhattan_Proj...

I said to myself, "What have you done, Hamming, you are involved in risking all of life that is known in the Universe, and you do not know much of an essential part? [uncertain variable]" I was pacing up and down the corridor when a friend asked me what was bothering me. I told him. His reply was, "Never mind, Hamming, no one will ever blame you."

Fission of atmospheric hydrogen.

You mean fusion.

Share of hydrogen in the atmosphere is almost negligible; nuclear fusion of ocean water is a bit more likely, although it still has to meet too many conditions.

My understanding was you can actually get a chain reaction in the world’s oceans, but it would take significantly more energy to kickstart than any atomic bomb designed.

PS: Fusion is one of the few equations where you will see X^4th power so you vary quickly go from it's fine to big boom. However, igniting the world’s oceans would take enough energy to kick off that we would be dead either way.

There is an old Soviet sci-fi book from 50s by Alexandr Kazantsev, "The Burning Island", where he depicted an island in the Pacific Ocean producing some catalyst that made self-sustaining exothermal reaction between nitrogen and oxygen possible; the reaction had sucked out all oxygen from Earth atmosphere. The book has several scientific discussions, but the essence of the catalyst is avoided.

There is another sci-fi book by the same author, "Faetians", where he depicts the fifth planet of the Solar System, Faeton (a hypothetical planet between Mars and Jupiter that could be the source of the asteroid belt), destroyed by nuclear fusion of its ocean hydrogen after several powerful nuclear explosions. The author gives even less explanations there.

So, I think the atmosphere explosion is a myth rooted in sci-fi books, at least in Soviet culture (I have not yet encountered such plots in American literature/movies of that time, but maybe I'm just not familiar enough with it).

> There is an old Soviet sci-fi book from 50s by Alexandr Kazantsev, "The Burning Island"

Hah! I remember reading this as a kid and absolutely loving it.

Of course, most of the geopolitical stuff whooshed right over my head.

None that i can think of, but i recall one or two stories that poke at the concept of a nuclear winter.

Not just crazy--there was no military utility for a bomb that large, even in the twisted logic of cold war doomsday planning.

Reply on news.ycombinator.com