Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.
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Why is there a scarcity of lithium?
One of the major impediments to the widespread adoption of electric cars is a shortage of lithium for the batteries. I read an article a while back that says that there is simply not enough lithium ...
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Can the solar system really fit in a thimble?
Almost every time somebody talks about atoms, at some point they mention something like this:
If we remove the spaces between the atoms and atomic components, we can fit the solar system in a ...
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What practical issues remain for the adoption of Thorium reactors?
From what I've read on thorium reactors, there's enormous benefit to them. Their fuel is abundant enough to power human civilization for centuries, their fission products are relatively short-lived, ...
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Why don't electrons crash into the nuclei they “orbit”?
I'm having trouble understanding the simple "planetary" model of the atom that I'm being taught in my basic chemistry course.
In particular,
I can't see how a negatively charged electron can stay ...
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Why can Hiroshima be inhabited when Chernobyl cannot?
In Hiroshima, atomic bomb was dropped, but today, there are residents in Hiroshima. However, in Chernobyl, there is no resident living today (or very few). What made the difference?
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How does Positronium exist?
I've just recently heard of Positronium, an "element" with interesting properties formed by an electron and positron, and I was shocked to hear that physicists were actually working with this element, ...
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Why is the nucleus of an Iron atom so stable?
Lighter nuclei liberate energy when undergoing fusion, heavier nuclei when undergoing fission.
What is it about the nucleus of an Iron atom that makes it so stable?
Alternatively: Iron has the ...
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Turned to steel in the great magnetic field
This is obviously a "fun" question, but I'm sure it still has valid physics in it, so bear with me.
How great of a magnetic field would you need to transmute other elements into iron/nickel, if ...
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How come random matrices can predict energy spectra of heavy atoms?
Some of the applications of random matrices is to find the spectra of heavy atoms in nuclear physics which are usually difficult to find otherwise.
How can starting from randomness of some kind, ...
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Why do electrons occupy the space around nuclei, and not collide with them?
We all learn in grade school that electrons are negatively-charged particles that inhabit the space around the nucleus of an atom, that protons are positively-charged and are embedded within the ...
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Protons' repulsion within a nucleus
Do the protons inside the nucleus repel each other by the electrostatic force? If they do, why doesn't the repulsion drive the protons apart so that the nuclei get disintegrated?
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Hydrogen as a fuel in Sun
The source of Sun's incessant energy is hydrogen; which is continuously converting to helium through nuclear fusion reaction releasing energy. Why does not all hydrogen convert into helium in one big ...
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How many times has the “stuff” in our solar system been recycled from previous stars?
Is there a cosmologist in the house? I've got a basic understanding (with some degree of error) of some simple facts:
The Universe is a little over 13 billion years old. Our galaxy is almost that ...
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Why is technetium unstable?
Is there a simple account of why technetium is unstable?
From the Isotopes section of Wikipedia's article on Technetium:
Technetium, with atomic number (denoted Z) 43, is the lowest-numbered ...
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How do we know that the nucleus isn't a quark-gluon plasma?
The standard picture of the nucleus of atom is that is several distinct nucleons, which themselves are composed of quarks. However, it seems to me like a much simpler picture is that the nucleus is ...
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Age of the Earth and the star that preceded the Sun
One of the great unheralded advances made in the history of science was the ability to determine the age of Earth based on the decay of isotopic uranium. Based on the apparent abundance of uranium in ...
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Why some nuclei with “magic” numbers of neutrons have a half-life less than their neighbor isotopes?
It's easy to find the "magic" numbers of neutrons on the diagrams of alpha-decay energy: 82, 126, 152, 162. Such "magic" nuclei should be more stable than their neighbors.
But why some nuclei ...
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Pictures of nuclear explosions some milli/nano seconds after detonation
Where I can find photos of nuclear explosions just after detonation (before 5-10 ms, the shorter the better)?
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Is there any thing other than time that “triggers” a radioactive atom to decay?
Say you have a vial of tritium and monitor their atomic decay with a geiger counter. How does an atom "know" when it's time to decay? It seems odd that all the tritium atoms are identical except with ...
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Nuclear physics from perturbative QFT
Is there a renormalizable QFT that can produce a reasonably accurate description of nuclear physics in perturbation theory? Obviously the Standard Model cannot since QCD is strongly coupled at nuclear ...
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Why does nuclear fuel not form a critical mass in the course of a meltdown?
A BWR reactor core may contain up to 146 tons of uranium. Why does it not form a critical mass when molten? Are there any estimates of the critical mass of the resulting zirconium alloy, steel, ...
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Why are alpha particles made of 2 protons and neutrons?
When experiencing alpha decay, atoms shed alpha particles made of 2 protons and 2 neutrons. Why can't we have other types of particles made of more or less protons?
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What does a nucleus look like?
It's a Christmas time and so I hope I'll be pardoned for asking a question which probably doesn't make much sense :-)
In standard undergraduate nuclear physics course one learns about models such as ...
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Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?
It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy (~28.3 MeV) is higher than for $Z$-neighboring stable isotopes. But ...
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Are the protons and neutrons in the nucleus arranged in any particular way?
I was wondering this: suppose you have two oxygen atoms. They will both have 8 protons and 8 neutrons in the nucleus (at least if they are the most common isotope). Now, will all those particles be ...
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Island of Stability
When I was much younger, I remember being fascinated by the thought of an Island of Stability at very high atomic numbers. However, I have not heard much on this and I was wondering
Did this idea ...
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Is ultradense deuterium real?
I've found several articles discussing experimental evidence of a deuterium state of densities over $140 \textrm{ kg}/\textrm{cm}^3$:
F. Winterberg. Ultradense Deuterium. arXiv.
Shahriar Badiei, ...
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How do we know that C14 decay is exponential and not linear?
In my previous question I asked Please explain C14 half-life The OP mentioned that I was thinking of linear decay and C14 was measured in exponential decay.
As I understand it, C14 is always in a ...
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How do we know that some radioactive materials have a half life of millions or even billions of years?
If a radioactive material takes a very long time to decay, how is its half life measured or calculated? Do we have to actually observe the radioactive material for a very long time to extrapolate its ...
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Having the same number of neutrons
Sorry if this is a silly question.
If I understand correctly, for two atoms "having the same number of protons" is equivalent to "being of the same element", while "having the same number of protons ...
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Why is storage of spent nuclear fuel dangerous?
Just what the title states; there's a good deal of noise made about transport, and storage of spent nuclear fuel. Why all the hullabaloo when the fuel is all spent?
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Nuclear fusion: what causes this “resonance” peak?
Can anyone explain why the $^{11}\mathrm{B}\mathrm{H}$ fusion cross-section has a peak near 150 keV, and why $\mathrm{D}\mathrm{D}$ and $\mathrm{D}\mathrm{T}$ have no such sharp peaks?
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How would nucleosynthesis be different if the neutron were stable?
If the strong nuclear force were just 2% stronger, the neutron would be a stable particle instead of having a half life of about 13 minutes. What difference would that have made to Big Bang ...
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Nuclear fusion : ion vs atom fusion cross section?
I've read critique on ITER project (in Russian), and one of points was that cross section of ion-ion fusion is much lower than ion-atom and atom-atom, and that's the reason why it likely to not work.
...
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How can such a high exponent arise in this physics equation?
This site http://what-if.xkcd.com/14/ states that during a helium flash, "the reaction rate is proportional to the 40th power of the temperature".
Taking for granted that this is true, how can ...
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Where does the energy from a nuclear bomb come from?
I'll break this down to two related questions:
With a fission bomb, Uranium or Plutonium atoms are split by a high energy neutron, thus releasing energy (and more neutrons). Where does the energy ...
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What is so special about iron?
I remember reading something about how iron was a highly stable element. Ever since then, I have looked at iron fry pans with new-found respect. However, in a recent discussion I was unable to ...
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References on the non-compositeness of the known elementary particles
What paper(s) or theory(s) describe or prove that the elementary particles that we have determined today cannot be made up of smaller more fundamental particles?
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What stabilizes neutorns against beta decay in a neutron star?
Free neutrons are known to undergo beta decay with a half-life of slightly above 10 minutes. Binding with other nucleons stabilizes the neutrons in an atomic nucleus, but only if the fraction of ...
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Why doesn't orbital electron fall into the nucleus of Rb85, but falls into the nucleus of Rb83?
Rb83 is unstable and decays to Kr-83. Mode of the decay is electron capture. Rb85 is stable.
The nuclei Rb83 and Rb85 have the same charge. Rb85 is heavier than Rb85, but gravitation is too weak to ...
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Does neutron radiation form clouds?
I've heard a couple of scary stories from experienced accellerator physiscists about something called neutron clouds. Apparently, if you have an experiment like a fixed-target experiment that produces ...
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Radioactive nuclear fuel?
I suppose this is a not-too-bright question but, in a nutshell: why are nuclear fuels radioactive?
With this I mean, which is the connection between being a fissile (or fertile, for that matter) ...
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Weak contribution to nuclear binding
Does the weak nuclear force play a role (positive or negative) in nuclear binding?
Normally you only see discussions about weak decay and flavour changing physics, but is there a contribution to ...
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Radioactive Decay
Problem:Nuclei of a radioactive element $\Bbb X$ having decay constant $\lambda$ , ( decays into another stable nuclei $\Bbb Y$ ) is being produced by some external process at a constant rate ...
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Is the speed of sound almost as high as the speed of light in neutron stars?
Have you ever wondered about the elastic properties of neutron stars?
Such stars, being immensely dense, in which neutrons are bound together by the strong nuclear force on top of the strong gravity ...
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Does quark color contribute to “spin degeneracy” for QGP calculations?
Like the title say, does quark color matter in counting contributions in a early universe plasma (QGP), as when adding up the total plasma energy density, or is it just spin? The book I have (Pathria) ...
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Is it possible to obtain gold through nuclear decay?
Is there a series of transmutations through nuclear decay that will result in the stable gold isotope ${}^{197}\mathrm{Au}$ ? How long will the process take?
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“Dear radioactive ladies and gentlemen” - Letter by Wolfgang Pauli
In 1930, Wolfgang Pauli wrote a letter to Lise Meitner for a convention in Tübingen, considering the problem of beta decay.
Does anybody know, where to find the original letter online ?
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Do some half-lives change over time?
I was recently doing some physics tuition on radioactivity and the student claimed her chemistry teacher had said that radioactive substances can be grouped into two divisions: those whose half-life ...
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Nomenclature of hadronic resonances
I have the Particles Physics Booklet and I noticed that the resonances that decay into a nucleon and pion are indicated by an abbreviation. For example $P_{33}$ is associated to the $\Delta (1232)$ ...
