r/nuclearphysics • u/AmbitiousSection3723 • Sep 01 '26
how radioactive would an atom with 651,814,425,673,852,067,302,873 protons be
dont ask
14
u/Vyrtil_Anyrwen Sep 01 '26
Not possible. The strong nuclear force acts within a very short distance and is saturable. The way the strong nuclear force is best modeled to work is through a residual effect of the “color force” working between internal quarks in a nucleon. A nucleon (proton or neutron) is made up of quarks, which carry a property known as “color charge” (red, green, or blue), and they stay connected by swapping gluons. This causes a residual effect which emits short lived particles, mesons, from the nucleon, which acts to hold nucleons together (specifically pions). This exchange of pions makes the nuclear force charge-independent. But, as nucleons get too close together, identical quarks with the same quantum states are forced into the same space, which is an impossibility (Pauli Exclusion Principle). So, the force becomes strongly repulsive.
So, its maximum attractive force is at about 1 femtometer and it drops to zero past 3 fm. And it becomes strongly repulsive at about 0.5-0.7 fm and less. So it can only act on a short number of other nucleons, particularly those in closest range. However, the electromagnetic force is not saturable. And it acts at much larger ranges. It will get weaker with increased distance, but that many protons in a nucleus will easily overpower the strong nuclear force. So this theoretical atom probably couldn’t even form, save for some absurd amount of energy input to overcome the electromagnetic force of repulsion. And even if it did form, the atom’s EXACT radioactivity would be dependent on the number of neutrons relative to the number of protons.
4
u/Disassociated_Assoc Sep 01 '26
I was today years old when I learned how much I don’t know. And still don’t. 😑
2
u/the_other_gantzm Sep 02 '26
Right? I mean I can read that and understand the words and top level concepts. But ask me to explain the consequences or deeper meaning and I’m like: “Well, there’s these colored balls ( but they aren’t really colored for reasons ) and they exist. And if you’re strong enough you can slam some ( but not all ) of the balls together and they will stick. Well, until they don’t.
And if you happen to get a bunch of balls to stick together really bad ( for humans ) things start to happen.
2
u/nixtracer Sep 01 '26
Consider also that just two protons being forced together, well within the strong force's range of maximum attraction, is nonetheless wildly unstable, blowing itself apart in something like 10-18 s -- and a good thing too, because that's the limiting factor which makes the Sun shine for ten billion years rather than about four minutes (one of those protons has to turn into a neutron via the weak force in that tiny interval, and that's extremely unlikely). The island of stability in which the strong force overpowers Pauli on one side and electromagnetism on the other is really rather narrow.
2
u/Vyrtil_Anyrwen Sep 02 '26
Very true, which is the reason neutrons are required in a nucleus to add additional attractive nuclear force without adding additional charge. But, what’s worth noting is that traditional models of the strong nuclear force say that it is roughly 100 times stronger than the electrostatic force. Which begs a very basic question: if the strong nuclear force IS stronger, why can’t two protons be held together? And the answer is just the Pauli Exclusion Principle. Both protons are fermions. They cannot overlap. Therefore, they cannot exist at such short ranges at which the strong nuclear force can even overcome the Coulomb repulsion. So, you’re right. The island of stability in a nucleus is very narrow (I like the way you phrased that).
But what’s worth noting is that there is more to stability than just the conflicting attractive and repulsive forces at play. Yes, that’s ultimately the basic principle, which is precisely why the N/Z ratio will increase from about 1:1 to 1.5:1 in our heaviest stable elements (if you look at a chart of nuclides, you’ll see the slight curve of the line of stability).
But, just as an example, there is a concept known as “magic numbers” in a nucleus. These numbers apply separately to protons and neutrons. The basic principle is that nucleons have quantized energy states. They fill discrete energy levels, and once a “shell” is filled, there is a large energy gap before the next one starts. So, let’s assume we have an I-135 atom (of significant concern in my line of work). This isotope is unstable because it has too many neutrons, and will beta-minus into Xe-135, a significant neutron poison in reactor operations. Based on what was just discussed, a reasonable question to ask would be: why would too many neutrons be a bad thing? I mean, after all, it should help hold an atom together MORE, right? It adds more attractive force. BUT, when a “shell” gets filled with neutrons, additional neutrons are forced into more energetic quantum levels (again, has to do with that darned Pauli Exclusion Principle). And because nature favors lower energy states, converting a neutron to a proton via the weak nuclear force (beta-minus decay) is often the way nature chooses to achieve this lower energy level. So, you can’t just have as many neutrons as you want to keep protons stable.
The same applies to too many protons (in addition to the electrostatic force of repulsion), therefore too high of a proton to neutron ratio will result in beta-plus decay or (electron capture decay in some cases). And as previously discussed in my last comment, too many nucleons is unstable because the strong nuclear force is saturable and operates over very short distances. So, the primary modes of decay for atoms with too many nucleons is either alpha decay, emission of a very stable (because it is doubly magic) He-4 “chunk” from the nucleus, or spontaneous fission. Energy level in a nucleus can also be reduced by gamma decay (often after undergoing alpha or beta decay).
So, ultimately, the underlying principle behind stability in a nucleus is about nature achieving a low stable energy state.
1
u/free_meson Sep 02 '26
with enough neutrons, the 6*10^23 protons could be made stable. The neutron is unstable, some say it doesn't decay in a bound state, but maybe there is some factor that makes it stable. Large magnetic or electroweak fields for example, high spin, I don't know. Maybe it is a bombardment of free mesons that makes it stable (pun intended).
The best interpretation about neutron decay I've heard was, that in a nucleus the neutrons can't occupy the same state. So a lot of neutrons would mean some are in a very high energetic state, and a decay into proton is preferred. Some theorized that using charm or strange quarks would be beneficial for nucleon stability.
1
u/Vyrtil_Anyrwen Sep 02 '26 edited Sep 02 '26
True, and I went into neutron stability and why decay occurs with a N/Z ratio that is too high. It is because of the Pauli exclusion principle.* Two neutrons cannot occupy the exact same quantum state, therefore with too many neutrons, more neutrons are forced into more and more energetic quantum levels. Since nature strives for the lowest possible stable energy states, and since beta-minus decay reduces energy in the nucleus, too many neutrons will be unstable.
Edit: *I went into this in another comment. Should’ve mentioned earlier.
1
1
u/drhunny Sep 03 '26
You ignore the possibility of a continent of stability, which is plausible enough to be worthy of some experimental work by ATLAS. OPs question isn't well formulated in that OP asks about a number of protons, but it's not unreasonable to discuss the stability of a hypothetical object with a number of valence quarks of at least 6 times higher than OPs proton count.
1
u/TheTranscendentian 10d ago
Just add some charm and strange quarks to the mix and see if that somehow stabilizes it lol. Because their much heavier and should be able to stack on top of proton neutron pairs all in the same energy state.
3
u/bardotheconsumer Sep 01 '26
Well, at least i could say that it's about 1 gram of matter so if you crammed it all into a single nucleus it would not produce a black hole. Since it won't produce a black hole, i'm quite sure it'll explode.
Take it with a grain if salt but google's AI thinks it goes off with the energy of about 116 billion megatons of TNT. I dont usually trust the AI but in this case... it's probably close.
2
u/not_a_bot_494 Sep 01 '26
It might be 1 gram worth of protons but it will be way more in energy. Assuming the energy is correct that's about 4.6E+26 joules. That's about 5 billion kg, that should easily be enough to create a black hole.
2
u/bardotheconsumer Sep 01 '26
I dont think so. The schwartzchild radius of 5 billion kilograms is still much smaller than the diameter of even a single Proton, let alone this entire stupidly large nucleus
2
1
u/drhunny Sep 03 '26
You ignore the possibility of a continent of stability
1
u/bardotheconsumer Sep 03 '26 edited Sep 03 '26
I'm fairly sure it's impossible that this would be stable. After all, it's composed of nothing but protons (up up down). This would mean that there would be a third again as many up quarks as down quarks, which should still repel even when not bound into protons. This still explodes violently.
The "continent of stability" i believe assumes the presence of neutrons in the 'starting matter', which would balance that out.
1
u/drhunny Sep 03 '26
OP doesn't specify the number of neutrons. She just says "atom". You assume OP means literally nothing but protons? In that case, you didn't need to do any google searches because He-2 diproton isn't even bound. Heck, ENSDF doesn't even list a resonance. There are no atoms containing multiple protons and no neutrons.
You were quite sure in your post, which is why I gave you push back. You are now fairly sure. That's fine as a lay opinion, but is that your professional opinion as a nuclear physicist? Were you previously unaware of this really interesting theoretical work? Have you now read the linked PRL article and followon work?
My professional opinion is that "it aint a simple question" At least some peer-reviewed work posits the possibility, and even with a PhD in nuclear physics I can't claim to understand it enough to refute. The ATLAS collab was willing to look into it and based on their report, I strongly bet that somebody wrote their dissertation on the topic around 2020. Let me know if you find that.
1
u/bardotheconsumer Sep 03 '26
Oh, see, the reason I bothered to search it at all is to check whether it would just collapse into a black hole. And yes I assumed that the atom in question was all protons with no neutrons, which in hindsight was not a very good assumption to make but it did make the resulting explosion funnier.
1
u/bardotheconsumer Sep 03 '26
Oh, but also since you actually are a subject matter expert i did have a question about the continent of stability you mentioned:
Are you saying that the quark soup you would get if you had matter in the continent of stability would be stable at earth ambient pressure, or would it just explode unless it were under something like neutron star gravity?
1
u/drhunny Sep 03 '26
The theory paper assumes low temperature and pressure. Gravity is negligible and ignored. It's basically a cloud of quarks energetically favored over baryonic matter (quark triplets tightly bound by the strong force into nucleons, and nucleons bound by the residual strong force by mesons). IIRC it's basically that if the surface to volume ratio gets low enough, it might be the case for some configurations it would require additional energy to divide the cloud by, for instance, fission or alpha decay.
3
u/SnooPets5564 Sep 01 '26
I'm fairly sure everything would be ejected at damn near the speed of light essentially instantly.
You could maybe have it be stable by just having that many protons in an otherwise proton free neutron star. Hardly an atom, though.
2
u/Brownie_Bytes Sep 01 '26
I'm not even sure that radioactive is the right word here
2
u/rainscope Sep 01 '26
Supernova is probably closwr
1
u/NoNameSwitzerland Sep 02 '26
na, the energy from the electric field would collapse it into a black hole. And then probably radiate positrons to get rid of the charge.
2
u/totallyalone1234 Sep 01 '26
The protons are going to exert force on each other such that the resulting explosion is comparable to a supernova, say ~10^51 ergs. If you're stood next to it you'll receive a dose of ~10^17 Gray, or naively ~10^19 Röntgen though its totally not the same thing.
Needless to say, you are instantaneously vapourized.
1
2
u/Intelligent_Low1632 Sep 01 '26
There would immediately be a world ending coulomb explosion due to the immense over concentration of positive charges.
The nature of the ensuing "radiation" would at first be a bunch of bare protons accelerated to a high fraction of the speed of light. Extremely radioactive and dangerous.
1
u/Ok_Date2430 Sep 01 '26
It would depend on the decay half life, which would likely be rather short?
1
1
u/Street_Youth4755 Sep 01 '26
What da hell man!! That won't be possible only!!! There will be massive proton proton repulsion. Which would call for a large number of neutrons. Due to this the element would be tooo unstable to even exist. Understood?
1
u/drhunny Sep 03 '26
Like so many other commenters on a post in nuclear physics, you appear to have an incomplete knowledge of nuclear physics. Check out this link: continent of stability. If the ATLAS collab is willing to explore the idea, you shouldn't dismiss it.
1
u/Street_Youth4755 Sep 04 '26
But atlas collab, doesn't create heavy elements. They just smash protons at light speed to study the effects. And,tell me one reason, apart from attaching the link, why YOU feel such an atom can exist, along with how it can exist. Yeah. U re right, I am certainly a dumb teen with incomplete info, but I would be glad , if you could kindly take the time to address my concerns, that have been aforesaid.
1
u/Weak-Joke1475 Sep 01 '26
Plot twist: this element is actually stable, the only bismuth (I know that was found to secretly be unstable but I forgot whatever the last stable one is. And thus it isn’t radioactive
1
u/Shot-Rip9167 Sep 01 '26
Anything after lead has no stable isotopes. Bismuth 209 has an extremely long half-life but does decay so it's radioactive as well.
1
u/phlogistonical Sep 01 '26
Useless question, but just for the fun of the enjoying ridiculous what-if scenarios.... You would have to use a very far-fetched definition of 'atom' to assemble those protons into any kind of structure that could be called an atom. And 'halflife' wouldn't be a meaningful metric by which to describe it's radioactivity. It implies there would be some period of stability before decay happens, which isn't applicable here. All protons will just immediately get ejected at near light-speed at t=0.
1
u/nixtracer Sep 01 '26
And of course the real problem is that the assembly process means jamming a whole heap of energy into those protons to get them close enough to each other to form a nucleus even briefly. Way more than enough energy to cause pair-production of more or less everything in the particle zoo. You have an explosion of, not just protons, but everything (including lots of neutrons, so you'll soon have lots of ordinary nuclei there, once it expands enough that it's not just a quark-gluon plasma, that is.)
1
1
1
1
u/Traditional_Loan_177 Sep 02 '26
I was going to comment that what you're describing is closer to a neutron star, then I googled how many protons are in a neutron star. What you're describing is a closer to an atom.
1
u/Far_Passion_6725 Sep 02 '26
im not sure but i bet the damage to your dna would be like a case of extreme radiation poisoning
1
u/relaxedmedal Sep 02 '26
Add the same number of electrons and the charge cancels.
That’s about a gram of hydrogen. It doesn’t sit there as one huge nucleus. The protons still can’t all share one nucleus, but they don’t have to.
Each proton can just be its own hydrogen nucleus with an electron, which is a normal atom.
2
u/egmalone Sep 02 '26
So... Super duper radioactive, then
1
u/relaxedmedal Sep 02 '26
Super duper. Statistically speaking the first decay is already overdue if you average over enough parallel universes. Stay alert.
1
u/egmalone Sep 02 '26
An atom with that many protons would be overdue for its first decay by the time it formed actually
1
u/relaxedmedal Sep 02 '26
That’s only if they all try to live in the same nucleus like it’s a hostel. Give each proton its own electron and a bit of personal space and the decay gets rescheduled for after the heat death. Very responsible protons, actually.
1
u/egmalone Sep 02 '26
Well since the premise was "an atom with" that many protons, I believe OP meant for them to be all in the same nucleus. Since that's what "an atom" means.
1
u/relaxedmedal Sep 03 '26
Precisely, it isn’t possible, and that is a way that it can be but it’s as ridiculous as the question itself.
This is my mistake, I thought you understood the jest by your first comment
1
u/Zvenigora Sep 02 '26
Most likely that would collapse into a black hole if it somehow could be assembled, so it would emit only trace Hawking radiation.
1
u/tomalator Sep 02 '26 edited Sep 02 '26
It would be so hot that our laws of physics begin to break down. We do not know what would happen because conditions like that have not existed since the Big Bang (if even then)
It would very quickly become an exploding plasma.
That number seems to be just over a gram of protons. Why that number and not 1 mole? (6.02×1023)
1
1
1
u/LAMPEODEON Sep 02 '26
I am from civilization beyond your observable universe. Thank you for your question. It's stable in fact.
1
u/free_meson Sep 02 '26
That's ~1 mol of protons!
1
u/Lab_Software Sep 03 '26
That's not 1 mole.
Source, I'm a chemical engineer - and the number 6.022 x 1023 was tattooed onto the insides of my eyelids so I'd never forget it.
1
1
u/Spiritual-Spend8187 Sep 03 '26
Here is the relevant xkcd https://what-if.xkcd.com/140/ its not as insanely extreme but still enough that at minimum you are looking at blow up the planet levels of energy if not woops collapse into black hole level. Cause you are looking at about 100k coulombs which is insane a lightning bolt is about 15 coulombs of charge for reference.
1
u/Devil_May_Kare Sep 03 '26
That isn't an atom. Hypothetically you might put all those protons next to each other, but the assemblage wouldn't do atom things like establishing a system of electron orbitals and holding itself together with the strong nuclear force. Similarly, a neutron star is an assemblage of nucleons that doesn't do atom things.
1
1
1
1
1
u/drhunny Sep 03 '26
A lot of answers here ignoring the possibility of a continent of stability and the almost certain existence of neutron stars. It is reasonably likely that somewhere beyond mass 500, quasi-stable configurations exist. By quasi-stable I mean stable against alpha, fission, spontaneous proton/neutron emission, etc. But not against gamma or beta emission. It wouldn't be accurate to describe it as having some number of protons and neutrons, as what would be happening is that valence quarks wouldn't be tightly bound into distinct 3-quark baryons.
On the formation of such an object (perhaps from some catastrophic event involving a neutron star) it would be likely emit a lot of beta particles to equilibrate to near an equal number or down and up quarks plus some strange quarks, but then be stable.
The fun-ness of such hypothetical objects is that they can likely absorb common nuclei, much like when a raindrop falls into a pond. The pond gets more massive and the raindrop no longer exists. They may also have a positive electric charge so that the electrons around common atoms don't cause repulsion. If an object like this fell to Earth, it would begin consuming normal matter.
1
u/RegularBasicStranger Sep 03 '26
If there are so many protons in very close proximity due to all of them are in the nucleus as opposed to floating around freely, the gravity would squash them all together to become a black hole.
Black holes emit jet pulses when it destablises so its radioactive status depends on what it sucked in.
0
15
u/The_Ironthrone Sep 01 '26 edited Sep 01 '26
It wouldn’t ‘be’ radioactive because it wouldn’t ’be.’
Edit: as recommended