Power of the Atom

Factual Questions
1

While in principle I kind of understand Eintein’s E-mcSquared, I’ve never really understood how so much energy can be stored in something with mass. Forgive me, my math skills are virtually zero, and although I love reading about physics and math-like stuff, my brain just refuses to process it, no matter how simply it’s explained.

I think it was Bill Bryson who said that one single atom, if exploded, has the power to make a grain of sand visibly jump – and when one considers how many atoms there are in a single grain of sand – again, the mind boggles and I can’t comprehend the numbers, but it goes something along the lines of “if each atom were the size of a green pea, their bulk would fill the Albert Hall,” which by itself is almost as meaningless as trying to grasp the latest description of The Laniakea Supercluster of galaxies.

But WHY does an atom possess so much potential energy? It just makes no sense to me that Fat Boy’s payload weighed something like 20 lbs. yet demolished miles of territory.

And a last question: just exactly how difficult would it realistically be for a group such as say, ISIS to come into possession of a nuclear weapon that they themselves could deploy in a Western city?

Sorry, I know those are two separate questions, but I’d imagine one leads to the other – obviously if it were easy to make grains of sand jump as parlor tricks a lot more people would be doing it.

2

Because as Al said, cSquared is a big number, so it doesn’t take a whole lotta m to yield a shitload of E.

But, yeah, it does boggle. I hear ya.

3

Boggle is damn right.

It’s kind of like imagining being a creature that lives in the open ocean at a depth of, say, four miles. No light, eternal cold – how on God’s earth does such a thing find anything to eat? And I’ve heard they can go for years without touching anything solid.

But that’s for another day.

Jeez, just the thought of being suspended in eternal blackness with no sound and nothing tangible for miles around . . . that gives me the crawlies.

Which leads me to: what if a bomb like Tsar Bomba were detonated at the bottom of the Mariana Trench (or as some inept British narrator called it, the "Marinara Trench!)

Would anything happen at the surface, seven miles above?

4

(bolding mine)
10,300 pounds (4,670 kg) (source: wiki)

Now most of that was the structure of the thing, and the TNT needed to start the reaction.

5

[quote=“Kamakiri, post:1, topic:697748”]

But WHY does an atom possess so much potential energy? /QUOTE]

Imagine a mouse trap. When you open up the spring, you give it the energy to make it work.
Now take two atoms of around 115 AMU each.

Now squash them together… well they didn’t actually want to get squashed together, as the nucleii are positively charged, so there was work done to squash them together. The work done to squash them together is the potential energy.

6

Sorry, I meant just the plutonium core, not the whole assembly. You know, that actual part with all the atoms in it that were designed to fission (or fusion – I never know which).

7

First question: we don’t know. It is in the nature of matter to be convertible to a vast amount of energy, and vice versa, but to the best of my knowledge nobody understands why that is.

Second question: quite difficult indeed. These things aren’t small, they aren’t cheap, they require significant skill to handle, store and use. Plus I don’t think they’re that stupid.

8

On the topic of ISIS, etc. …

It will be more or less impossible for them or any other non-state actor to build their own A- or H-bomb. But it isn’t too hard for them to steal one or buy one or be given one. My personal take is that it’s a virtual certainty some non-state actor will obtain & detonate a nuke someplace in the next 20 years.
On the topic of mass and energy & why they tradeoff between them is so lopsided …

What follows is pure arm-waving metaphor, not science & certainly not math. But it may give you a feel for why things are the way they are.

Energy is pretty evanescent stuff. Lots and lots of it can flow through a small area of space without having any impact on the space. Like millions of watts through a single cubic inch of space with no effect on it.

If you consider matter to simply be space that’s been so stuffed with energy that it coagulates into something solid, you can see that there had to be a huge amount of energy stuffed into that space to get it to coagulate.

And once there is all that energy stuffed into a small-enough space to coagulate, then it’s like a very, very, very strongly coiled spring. If something releases the tension, all the tremendous energy comes bursting out.

Radioactivity is the behavior of space that’s been stuffed just a little too full. Or stuffed in the wrong configuration. And so the mass wants to convert at least part of itself back into energy. The spring wants to uncoil a bit.

Theory has it that all mass decays over time. Eventually even protons decay into energy. Space wants to relax into being nothing but energy. It’s matter which is “unnatural”. A universe of pure energy is the “natural” state. It’ll take an unimaginable number of years to get there, but eventually all the matter decays back into energy.

Until that time, we have matter available which we can coax into de-coagulating & releasing that stored energy either slowly, as in a nuclear reactor, or quickly as in a nuclear weapon or star.

Like I said, this isn’t scientifically accurate, but it captures some of the qualitative features of theory which may make some sense to you.

9

Obligatory xkcd link. Short answer: not much.

10

You can’t turn a small amount of matter into a huge amount of energy. You can release the energy, but it’s still exactly the same amount that it always was. It’s exactly the same amount because c isn’t a large number at all, it’s exactly 1.

The real question here isn’t why the amount of energy released is so much larger than the amount of matter, because it isn’t. The real question is why do we think it’s so much larger. Or, equivalently, why do we think that the speed of light is huge, despite being just 1. And that’s just due to how we developed knowledge of measurement of space and time, or of matter and energy, before we realized that they were the same thing. We got used to using sticks to measure some things and clocks to measure others, when we could have been measuring them both with clocks to begin with.

11

Everything is relative. Relative to the amounts of matter we deal with every day, and relative to the amounts of matter we have to send to chemical reactions to get similar amounts of energy, the matter used for a nuclear reaction is small and the energies are huge.

If our alien creators* back in ancient Egypt had said to us: “The distance of this rod is how far light travels in this fraction of a day, you should use this period of time to measure distances, and this weight is the equivalent of the energy needed to lift it against gravity the length of the aforementioned rod, so you should use that unit of mass to describe energy” we’d still consider nuclear energy to be a lot of energy in a small amount of matter, and the speed of light would still be hella fast.

You’re right of course that accepting mass-energy equivalence in strict terms means they are … equivalent, but that doesn’t really do much to help the OPs understanding.

*I’m kidding here of course.

12

I know this is really 10th-grade hypothesizing – even though I’ve read the literature and watched the videos hundreds, if not thousands of times (I should have by now – I’m 56) and it’s all very fascinating, I still have a hard time grasping it. More like, an impossible time grasping it.

When I die, all the atoms that made up my human self are going to go off to wherever atoms go – but truly, what will happen to them? Will they just circulate in the universe, drifting from role to role, for the length of the universe, whatever THAT might be? WHY are they so full of energy, and if they ARE, why don’t they just all spontaneously combust? What is stopping them from just all fissioning right there and then?

Do I truly have one or two atoms of Jesus in me, or is that just a trope? When something, like a fetus, grows, where do the atoms that make it grow come from? Are they just randomly harvested from whatever’s nearby . . . or what?

I do realize that not even theoretical physicists fully understand all this stuff – if they did, they’d all be small gods, wouldn’t they? So why do they even bother to try to explain things that no human mind – not even Albert Einstein’s – is able to grasp?

I realize that a lot of it is through mathematics – and proofs, and hypotheses like Higgs’s brainstorm, but why don’t physicists just come right out and admit that they have no idea what’s going on except in the most incredibly crude terms (iron is hard because it’s just . . . very, very hard. Steel is harder because, well, there are more atoms in it than iron) etc. until madness and insanity just turn their brains to mush?

Like when they talk about the “age of the universe,” and come up with some impossibly improbably accurate figures such as “14.3 billion years,” who are they trying to fool? How on EARTH would anyone be able to prove that?

I realise that “Man” must struggle for answers, but when does “Man” just throw up his hands and say, “We give up. We don’t know and we probably never will know.” Why do they find it so hard to just out and out SAY that, instead of coming up with hallucinogenic concepts such as “branes” and “strings,” which, even to a math fail like me, sound suspiciously like “Make-work projects for people who are immensely talented at math but have really nothing better to do.”

And, as is my wont, I’ll throw in another huge puzzler that has really not much to do with my original question, but begs an answer: if graphene can be made in sheets only one atom thick, wouldn’t they just either just pass through a human hand like butter, as each atom bypasses the atoms in one’s hand, or be completely invisible to anything but extremely powerful scanning-tunneling electron microscopes? And if such sheets could actually be manufactured in sufficiently large sizes, wouldn’t they be the ultimate Star-Trekkian force field that anyone could ever come up with?

(if you imagine that these so-called sheets of graphene could be assembled, two at a time, so that one sheets’s atoms neatly blocked the gaps in the other sheet’s hexagonal matrix, wouldn’t that be an impenetrable substance that no explosion on earth could penetrate?)

Ah, I doth think too much. God doesn’t play dice – He watches porn all day.

13

Yeah, I know when smart people are kidding . . . and I also know when my brain just stops trying to understand stuff that physicists (or even chemists) come up with. I mean, it’s just so unutterably huge – and tiny at the same time. Attoseconds. Planck lengths. Where does it end?

I MUST find a way, at least in my own mind, to reconcile these things – and that path is NOT through that most bogus of constructs, “spirituality.” I mean, I can SEE why people want to use a god to explain all things, but that’s so easy.

Yet sometimes I envy them, their smug, self-satisfied answers to Everything . . . they seem so . . .placid and finished with any further questions.

“You, in the back row . . . what is the speed of light?” “Well, jeez, Doc, everyone knows it’s the speed God made it to be.”

Do they still officially have sanatariums where they house the clinically insane? Because I’d like a free pass into one of them. I could listen to Mantovani piped through the grounds-wide PA system, take my thorazine at my appointed hour, and play checkers with Doctor Wilhelm whenever I liked.

14

To some extent the question is circular. Waving hands here a lot.
I await a real physicist to tear this apart. :smiley:

The mass we are made of is built out of two things, electrons and quarks. The vast majority of the mass in us is in the nucleus of our atoms, which are made of quarks - quarks that organise themselves to build protons and neutrons. The big surprise is that the mass of the constituent quarks themselves is much smaller than the mass of the proton or neutron. Most of the mass, and that means most of the mass we are built of, is in the form of energy in the force that binds the quarks together. So the majority of the mass that makes us up is already energy, held like a very strong taught spring holding our quarks together.

A nucleus is made of protons and neutrons; the protons have a positive charge - which means a nucleus should simply fly apart. So there is some other force that stops this. This turns out to be related to the quarks again, and a constant dance where protons and neutrons exchange particles also built out of quarks. Now, depending upon your particular atom’s element (determined by how many protons you have) you will need a similar number of neutrons to make it stable. Too many or too few neutrons and it won’t stay together. The exact layout of protons and neutrons you end up with will need a slightly varying amount of binding force to hold it all together. Turns out that elements either bigger or smaller than iron need a tiny bit more to hold together. You can measure this because, although we know the mass of a proton and the mass of a neutron, the various elements don’t end up being perfect multiples of these masses.

So what happens if you take a big heavy element and split it into two smaller atoms? There is a bit of mass left over - mass that was in the energy that held the nucleus together. This energy is the energy from a fission reaction. Same thing happens the other way. Somehow slam two light elements together to make a bigger element, and there is mass left over, mass that was sitting around as energy that held the two individual nuclei together. So you have a fusion reaction.

The question about why there is so much energy is perhaps one of the puzzles of the universe. Not that the the forces that hold atoms together are so strong, but rather that the other forces are so weak. For almost all useful purposes, the only forces that an ordinary person directly experiences in life are gravity and electromagnetic. Chemical reactions are fully covered by a full theory of electromagnetic forces (quantum electrodynamics.) A ton of TNT exploding is chemical, and thus the energy of the blast is determined by the strength of the electromagnetic force. A fission bomb is releasing energy from the nuclear force, which is about a million times stronger, and has a huge amount of energy sitting in it just holding the nucleus together. If you drop a rock on something the energy is held in the gravitational attraction. Dropping a ton of TNT onto something is going to do a lot less damage than exploding the TNT. The gravitation force is 10[sup]33[/sup] times weaker than the electrical force. So your everyday experience of energy is of forces vastly weaker than the nuclear force. Now, why is there such a disparity in the strength of the forces? Answer that and you will almost certainly get a free trip to Stockholm.

15

Matter is condensed energy.

At least, that’s the way to think about it. We all understand condensing things. Take something large and squeeze it into a tiny space. Then release the pressure and it blows up, usually violently. If matter is the solid form and energy is the liquid form the relationship corresponds to something we get from ordinary experience. It’s not accurate, it’s just a metaphor, but it’s as good a metaphor as gravity being a rubber sheet.

16

I thought that over unimaginable time, everything would decay into the smallest bits of matter; not energy. Eventually, atoms would ‘evaporate’ into protons, neutrons, and electrons. Those would ‘evaporate’ into quarks and leptons. These would/might degenerate further into preons (or not). Eventually, anyway, you’ll get down to the smallest thing that composes things, which we call a particle. ISTM that a ‘particle’ would be matter, and so eventually the universe would be filled with cold matter.

Except ‘energy cannot be created or destroyed; it can only be converted’. So it must be in these indivisible particles. But if these indivisible particles have energy, then wouldn’t that mean they could be divided? Or if matter is energy and energy is matter, does it matter?

OK, I’ve only had one cuppa joe. My mind is boggled. I’ll just wait for Stranger On A Train to pop in. :wink:

17

There a thread running through your recent post that suggests that you think scientists are just guessing or taking stabs in the dark when they say things like “The universe is 14.3 billion years old.” They’re not. But understanding why they’re not requires some explanation about how science works.

Scientists don’t start out by saying “Hey, I think the universe is 14.3 billion years ago, how can I prove that?” Instead, they start by saying “Hmmm … can I put an upper or lower bound on the age of the universe?” And then they start making observations: “Could the universe be less than a million years old? No, that doesn’t make sense with the geological record on Earth. Could the universe be more than a trillion years old? Not, that doesn’t make sense with how the light from distant galaxies is red-shifted.” Over several hundred years they’ve made millions of observations that push the upper and lower bounds closer together. And once you know the rough age of the universe, you can construct experiments that specifically target that range of dates: “Hmmmm … if we see X then the universe must be older than 14.3 billion years. But if we see Y then the universe must be younger than 14.3 billion years.”

The result is a huge body of data that gives pretty tight bounds on what the possible age of the universe is. There’s no one experiment that “proves” a particular age. Instead there are thousands of experiments that SUPPORT a particular age.

Now imagine this process taking place all across science. No one is proving anything. They’re just gradually establishing tighter and tighter bounds on what could possibly be true.

18

Rfrttrrr

19

When a fetus grows where do you think the atoms (really in the form of molecules) come from? It should be obvious they come from the “food” the fetus gets via the mother. Similarly as kids grown into adults or adults get fatter, those atoms come from the food they eat. But that is not so say that there is a constant set of atoms that make up you. Everyone is constantly sloughing dead skin and hair and otherwise losing atoms they are made of.

Fission and combustion are completely different things. The former is nuclear, the latter is chemical. Generally nuclei lighter than iron don’t fission at all as they are energetically more stable than the fission results. They are not full of energy. Things that are “full of energy” had to get put together using energy. Generally things that were living burn and those that weren’t don’t because the process of living used energy to put the stuff together. The nuclei that fission were put together using the energy in supernovae.

20

Thank you. Very nice - a terrific response and would seem to be exactly the type of thing that the OP was asking for.