Gauging safe distance from nuclear explosion with your thumb?

[RainDreamer]

Was checking reddit and saw this: https://www.reddit.com/r/FanTheories/comments/1os3ve/fallout_fallout_vault_guy_is_not_actually_giving/

It is a fan theory about how the fallout vault guy in some images is not actually giving you a thumbs up - he is measuring his distance from a nearby nuclear explosion by lining up his thumb with the mushroom cloud. How possible is this?

According to the wikipedia chart below, we can gauge the average height of a nuclear detonation if we can somehow recognize shape of the mushroom cloud, and figure out the yield of the bomb.

This information, along with knowing how long your thumb is, does seem like something that can help you figure out the distance between you and the detonation.

[TheCanadianVendingMachine]

I remember hearing somewhere that this is false. I think it was from Mythbusters, or something like that

[Gaarst]

If your thumb catches fire, you're too close.

[NuclearNut]

If you see the flash... you are probably blinded.

Anyway, no, the big concern is the prevailing wind conditions, the height of burst, and the distance. If you were to be at say twenty kilometers upwind from a nuclear detonation of around two megatons (which is really large for modern nuclear weapons) your primary concern would be fire, not fallout (again, assuming the wind continues away from you).

It should also be noted that mushroom clouds can and do end up being quite tall, tens of thousands of meters, thus making that method extremely inaccurate. The best solution would be to either move out of the area, or preferably get to shelter underground. The latter takes less time than the former and thus is best.

[RainDreamer]

Well, the whole idea about doing this to see whether you are safe is silly at best. If you see a nuclear detonation, you better run either way. If the blast didn't get you, the fallout will. But I just wonder if it is actually possible to measure distance with this very kerbal method.

[NuclearNut]

Well, the whole idea about doing this to see whether you are safe is silly at best. If you see a nuclear detonation, you better run either way. If the blast didn't get you, the fallout will. But I just wonder if it is actually possible to measure distance with this very kerbal method.

Just measure the time between everything becoming very bright or you becoming very blind and the shockwave. From those you should get your answer, kind of like measuring your distance from lightning.

[MaverickSawyer]

Honestly, if you can see the mushroom cloud, you're safe for the next few minutes. Best get into your shelter ASAP, though: Fallout is NOT your friend.

[NuclearNut]

Honestly, if you can see the mushroom cloud, you're safe for the next few minutes. Best get into your shelter ASAP, though: Fallout is NOT your friend.

Plus, if you saw the detonation directly and without welding glasses or blinking, and can see the mushroom cloud forming you probably have quite some time (a few hours) in which to do that.

[Jovus]

That said, while observing a ground detonation test, Fermi ripped out a page from his notebook, tore it into pieces, and did an order-of-magnitude calculation of the energy released based on how far they were blown by the overpressure. http://www.dannen.com/decision/fermi.html

[Shpaget]

If you know how big the mushroom is, then yes, you can estimate the distance. If you don't know how big it is nor how far it is, this approach will not be helpful.

In a hypothetical world where all the nukes are of approximately same yield, this could be a viable technique.

However, if I were the guy in the logo, I would orient my thumb horizontally to get more resolution for the mushroom cloud height (in vertical position he's measuring width).

[Hcube]

I would get the hell out either way...

[Nibb31]

It's probably false, but then the 1950's propaganda (on which the Fallout universe is based) was a wierd period with promises of a brighter future thanks to the atom. Remember the overly optimistic "Duck and cover" educational films, the projects for using nukes to make artificial lakes, or the wacky ideas like nuclear planes, Orion propulsion, and the Ford Nucleon.

[p1t1o]

It doesn't just depend on knowing how long your thumb is, you also need to know how big the cloud is at the same time, to judge its distance. So yeah, this would be pretty hard to do.

An alternative explanation would be he's super-imposing his thumb over the bright fireball of distant explosion so that he can look at it/in that direction more clearly.

[KSK]

Or you could use the nuclear fireball to light your cigarette:

http://modernnotion.com/man-lit-a-cigarette-with-a-nuclear-bomb/

[p1t1o]

Or you could use the nuclear fireball to light your cigarette:

http://modernnotion.com/man-lit-a-cigarette-with-a-nuclear-bomb/

I...I'm speechless...that is THE most BadS thing I have read in a very, very long time.

[RainDreamer]

Or you could use the nuclear fireball to light your cigarette:

http://modernnotion.com/man-lit-a-cigarette-with-a-nuclear-bomb/

Well, it is cancer either way, right? XD

[tomf]

But is the size of the mushroom proportional to the size of the blast? Could you draw up a rule of thumb like if the cloud is bigger than your thumb you are in a lot of trouble, if it is smaller you are probably ok for (for some level of ok) that would hold for large nukes and smaller ones?

[GreenWolf]

I think we're all missing the real problem here.

If you see a mushroom cloud, it doesn't matter how far away you are, you're probably going to die. Because WW3 has started.

[p1t1o]

But is the size of the mushroom proportional to the size of the blast? Could you draw up a rule of thumb like if the cloud is bigger than your thumb you are in a lot of trouble, if it is smaller you are probably ok for (for some level of ok) that would hold for large nukes and smaller ones?

Well as a weapon of a given yield will produce different clouds depending on the nature of the surface and the height of the burst. Also, the mushroom cloud is not a static object, its size is constantly changing, so to make any estimate about anything you either need to know a) the size of the cloud you are looking at, or how far away it is. Either way, measuring against your thumb is pointless.

A better measure is the duration of the flash. Nuclear weapons actually produce 2 flashes (this is a unique characteristic and how early warning sattelites distinguish nuclear detonations from other phenomena such as lightning). The first flash is very brief, and comes from the immediate detonation effects in the first few fractions of a second. The second flash is the thermal/optical radiation from the fireball. The longer the second flash, the larger the yield. Very short for yields in the low kilotons, can be several tens of seconds for multi-megaton bursts.

To be honest, estimating the yield of ANY nuke is already quite hard, even if you *already know everything you possibly could about the weapon*.

[WestAir]

I think we're all missing the real problem here.

If you see a mushroom cloud, it doesn't matter how far away you are, you're probably going to die. Because WW3 has started.

I just want to hear someone use the phrase Winter is coming. It would make WW3 worth it.

[wx7]

I think we're all missing the real problem here.

If you see a mushroom cloud, it doesn't matter how far away you are, you're probably going to die. Because WW3 has started.

We're just 1 nuke away from WW3.

What could keep it from happening...

[problemecium]

I dunno if you can measure distance too well, but the above post about "if it's smaller than your thumb, you're probably okay" seems useful enough.

Or perhaps Fallout Guy is just blocking the center of the blast so he can ogle it without getting blinded. Sort of like blocking the Sun when taking a coronagraph.

[Jovus]

I think we're all missing the real problem here.

If you see a mushroom cloud, it doesn't matter how far away you are, you're probably going to die. Because WW3 has started.

I just want to hear someone use the phrase Winter is coming. It would make WW3 worth it.

Like this?

[CptRichardson]

Was checking reddit and saw this: https://www.reddit.com/r/FanTheories/comments/1os3ve/fallout_fallout_vault_guy_is_not_actually_giving/

It is a fan theory about how the fallout vault guy in some images is not actually giving you a thumbs up - he is measuring his distance from a nearby nuclear explosion by lining up his thumb with the mushroom cloud. How possible is this?

According to the wikipedia chart below, we can gauge the average height of a nuclear detonation if we can somehow recognize shape of the mushroom cloud, and figure out the yield of the bomb.

https://upload.wikimedia.org/wikipedia/commons/6/66/Nukecloud.png

This information, along with knowing how long your thumb is, does seem like something that can help you figure out the distance between you and the detonation.

This is actually true. (Confirmed by my grandfather, who was a nuclear weapon technician who worked with some of the test detonations). It was a literal rule of thumb (and maybe THE rule of thumb the concept is named after). Well, true after a fashion. You can't gauge the exact yield, but it's 'if the cloud cannot be fully obscured by your thumb held up at arm's length, you're too close and need to be running from the fallout'. It's an informal measurement for grunts to decide what they need to do in case of battlefield nukes.

[PB666]

Like this?

http://weknowmemes.com/generator/uploads/generated/g1365364981185832085.jpg

cool meme, but still a meme