Physicists may now have a way to make element 120
newscientist.com
newscientist.com
"IUPAC defines an element to exist if its lifetime is longer than 10^−14 second, which is the time it takes for the atom to form an electron cloud.[7]"
https://en.m.wikipedia.org/wiki/Island_of_stability
https://en.m.wikipedia.org/wiki/Superheavy_element
(Edit: this was intended in response to ssijak's question about the theoretical limits)
More importantly, I think that the Coulomb's Law repulsion effect would more than cancel out the gravitational attraction effect - both laws work as Force = (constant x particle1 x particle2) / distance^2, and the electromagnetic force is much, much stronger than gravity at all distances.
(Edit because we got a little confused in the replies: If it were all protons, they would repel and overcome gravity. But real matter isn't that, it's always protons and neutrons and electrons with close to no net repulsion so gravity wins.)
Similarly, radioactive nuclei (alpha emitters and spontaneous fission) happen because the electromagnetic repulsion exceeds the strong force, which has a very short range and doesn't reach across those large nuclei.
Is that true? All of the protons repel all other protons with the electric force and attract with the gravitational force, and it seems like gravity is just much weaker at all distances...
I haven't thought about this very hard though.
Now think of 10^50 protons in a line. They're all experiencing net gravity towards the middle.
With gravity, A is attracted inward, B is not attracted, C is attracted inward.
Of course, in practice, we don't know what the inside of a black hole is like, as quantum gravity is very much unsolved.
So the conclusion is any proton star would just explode? That's what I already thought.
Even if you make the argument that the energy complicit in the strong/weak forces is cumutavily much greater than the energy due to gravity, I'm still not sure "weak" is the right word for the job...
Gravity onstensibly runs at infinite speed over infinite area (the effect of gravity waves non-withstanding).
Protons can generate neutrons through beta decay. I suspect something like this happens in neutron stars, which don't spontaneously fly apart into a proton cloud, so far as we've observed.
This SE comment explains why neutron stars don't contain (many) protons:
<https://physics.stackexchange.com/a/149656>
(The ratio seems to be ~100:1 neutron:proton.)
They're ... both big (by atomic scales) and massive (atomic and astronomical).
I'm struggling to find a strong source, but this page, by M. Coleman Miller at the University of Maryland, describes properties suggesting modelling over observation. Specifically it describes "the guts of a neutron star":
Even further down, you mainly have free neutrons, with a 5%-10% sprinkling of protons and electrons.
With an subsequent 'graph:
Yes, you may say, that's all very well for keeping nuclear theorists employed, but how can we possibly tell if it works out in reality? Well, believe it or not, these things may actually have an effect on the cooling history of the star and their spin behavior!
What follows is more description of theory with a few points based in what is directly observable, largely spin (via radio astronomy) and some temperature observations largely in X-ray observations, and the occasional gamma-ray burst.
<https://www.astro.umd.edu/~miller/nstar.html>
Miller's bio at UMD emphasizes his theoretical work:
Cole Miller's research in the last few years has focused on theory and modeling of high-energy radiation from neutron stars and black holes.
The conceptualisation of elements is useful to us because physical characteristics of atoms are (mostly) stable over time, with atoms having distinctive masses, atomic numbers, and most importantly, electron shells. The latter account for most of what we consider to be "chemistry", along with some other effects, most notably the van der Waals force.
Neutron stars ... lack most of this. They're in constant flux, they (probably) don't have stable masses (if only due to constant accretion) or atomic numbers, they probably don't have anything resembling an electron shell, and in interactions with other objects any electromagnetic forces would probably be overwhelmed by gravity or, say, spin-induced magnetism. If a measure of a concept or model's usefulness is how much it explains behaviours, "neutron-star-as-element" doesn't buy you much.
Though there's possibly some truth or conceptual validity to it.
I subscribe strongly to a pragmatic approach to knowledge and understanding. That is, knowledge isn't so much true as it is useful, in that it provides a useful mental model of the world. There are cases where multiple truths are possible, as with wave-particle duality, or mass-energy. Either classification may be useful, that is, provide predictive, understanding, or manipulative power, depending on contexts and circumstances. Some of the classic philosophical paradoxes (Sorites, Ship of Thesus, falling tree in a forest) resolve at least somewhat under this view. What is often called "truth" I think of as "useful mental models". The distinction is that whilst both are grounded in observation and empiricism, "truth" is an absolute, whilst "usefulness" is a bit like evolutionary fitness: changing over time, dependent on circumstance, not entirely arbitrary, but also not perpetually fixed.
So, is a neutron star a gigantic nucleus? Yes, in a sense, in that it's primarily made of what we'd otherwise consider nuclear material. Does this give us useful insights on neutron star behavior above and beyond those given by gravitational, thermodynamic, and electromagnetic descriptions? No, not really, because the attendant characteristics and properties of much smaller nuclei (from atomic number 1 to the low 100s or so) simply don't apply. There's not much behaviour that is explained, predicted, or controlled by applying that knowledge.
The GR vs Standard Model breakdown occurs at the extreme limits of GR, for example Planck scale regions of space and black hole singularities. A heavy nucleus is way too big to probe these limits and is well within the domain of physics where we don't see a conflict between the two theories.
String theory may well be wrong/currently untestable, however failure to invalidate the null hypothesis is not proof that somehow we don't have a meaningful understanding of other, proven theories/laws.
Put a different way, if an apple falls from a tree on earth, I don't panic because I don't understand quarks or electron orbitals. I calculate the point/speed/force of impact to acceptable margins of error.
And then 1.4 Solar masses is the upper limit. [1]
[0] https://physics.stackexchange.com/a/143174/43351 [1] https://en.wikipedia.org/wiki/Chandrasekhar_limit
[0] https://en.wikipedia.org/wiki/Tolman%E2%80%93Oppenheimer%E2%...
I was thinking of neutron stars all along - which, correct me if I’m wrong, look like they have similar density to an atomic nucleus and for which the upper limit is apparently 3 Sols. [0]
[0] https://en.m.wikipedia.org/wiki/Neutron_star#:~:text=Neutron....
P.S. Quote from the link:
> Would this black hole cause the universe to collapse? Hard to say.
There's also the whole menagerie of nuclear pasta [1] where gnocchi and spaghetti you could maybe consider "nuclei" unto themselves. There's also waffles & lasagna, but when you get into the anti-spaghetti and anti-gnocchi realms, then you're into the "one nucleus" region.
[On The Way To Super Elements](https://archive.org/details/FlerovIlyinovOnTheWayToSuperElem...)
I don't know much about chemistry since I haven't done anything with it in the last 20ish years. What need is there to be able to accurately predict it before attempting to synthesize it?
Drugs are also the same with many, if not the majority of drugs having come from things that were initially intended to treat something else, only to find out what you created has stronger effects elsewhere. The most obvious and amusing one being that Viagra was meant to be a heart medicine. It turned out to have little effect on heart disease, but had a rather pronounced side effect in half the participants!
That's also something of the paradox at work at something like this: you sometimes can't have models that strongly predict interesting or "good" outcomes (such as the "island of stability") without a lot more data from experiments and maybe you aren't running the right experiments because you don't have the right model, but you won't have the right model until you run more experiments.
Water is kind of like ash. Technically full combustion of any hydrocarbon outputs CO2 and Water. Since water isn’t a greenhouse gas it’s not mentioned when discussing combustion usually.
This is one of the reasons why methane leaks are so impactful - not only is methane a terrible green house gas, when it decays in the upper atmosphere, it decays into water vapour and CO2)
https://science.nasa.gov/earth/climate-change/steamy-relatio...
You could say that about the constituent elements of pretty much any chemical necessary for life.
A boulder balanced 40m above your head is lethally dangerous; vs. if mostly-embedded in the dirt next to you it's perfectly safe.
But yes, in general it's interesting how little difference there is from "essential nutrient" and "human poison"
And why it is yummy, well they are pretty useful atoms in lot of chemistry and in general balancing things that happens in body. Thus it is nice to have sufficient amount around... Best way to encourage this is to make it taste good like sugar does too.
An example I like is with nitrogen. Nitrogen atoms really want to form nitrogen gas (N2), a form that is really stable and therefore unreactive and generally harmless. However, if the nitrogen atoms are not in this form, and they have the opportunity to turn into it, they will, and they want it so much that it can be violent. That's why a lot of explosives are nitrogen-based, they are made of nitrogen atoms that have been separated from their N2 form by giving them a lot of energy, and when they come back together as the explosive is detonated, all that stored energy is released.
Elemental sodium in the air spontaneously oxidises to sodium hydroxide which is nasty and caustic but the hydroxide layer spontaneously forms bicarb which is comparatively harmless. At a best guess, I'm not convinced a block of sodium not swallowed is lethal... (it will be extremely harmful)
If we ignore the dynamics of the explosion that seems enough to cause a maybe lethal explosion. It would also release 120dm^3 of hydrogen.
I would imagine in conditions of high heat, plasma, RF energy and pressure many things "exist" but I don't see that as quite the same. I guess if their spectral line emissions from stars says they are a continuum of existence then thats something, but I wondered if there were wierd islands of stability e.g. inside crystal lattices under pressure, or in solution in some wierd, non-plasma state. Absent an observer round that star we can't know but can we hypotheise physical states which would let it be?
https://englishatlc.com/wp-content/uploads/2016/03/randall-m...
1. Are nuclear isomers a thing?
2. Corollary: Could it be the case that some nuclei are stable and others are unstable, even though they have the same numbers of protons and neutrons?
The difficulty here is that such a collision leaves the result very "hot", so it tends to decompose. This tendency is minimized by reducing the energy of the incoming ion, but that reduces the rate of fusion.
Needless to say, this doesn't present much in the way of practical benefit from producing some new science fictional material. It's purely of scientific interest.
The discovery of Fluorine...elemental, killed 8 and rendered 3 disabled.
I have been following this for 40 years. Congratulations on the attempt.
Titanium is a pita to work with.
But also... the 'island of stability' is fascinating, and I think we have to assume that we don't know enough about the Strong Force until we either prove it exists and is reachable, or doesn't/isn't.
It's spin dependent, and not just involving interactions of pairs of nucleons. There are at least three-nucleon terms in the potential. It looks like something accidental, not elegant or designed. It just "happens" to give stable nuclei that end up allowing something like us to have come into existence. I get the feeling of anthropic effects on display.
At the scale of the nucleus, gravity is many, MANY orders of magnitude weaker.
Or in this case 4) oh no your country and my country don't get along anymore! time to asset scientific dominance by "re entering the super heavy race" (https://www.science.org/content/article/u-s-back-race-forge-...) and getting the department of energy to start funding this again so we're back on top.
I would assign the noun- royal pita.
I read every article I come across about this, and I would strongly encourage you to write more. What upsets me is politics getting in the way of science.
However, in each island of stability the most stable element is much less stable than the most stable element of the previous island of stability. Therefore in most higher islands of stability the decay times will become too short.
It is possible and rather likely that only the first undiscovered island of stability may contain relatively long-lived elements, e.g. with half-lives over one second.
An island of stability finishes at bismuth, which is radioactive, but which has a huge half-life. The next island of stability contains the long-lived thorium and uranium and the still relatively long-lived neptunium and plutonium, after which the half-lives decrease very quickly.
Whichever will be the longest-lived elements of the next island of stability, their half-lives will be many orders of magnitude smaller than those of thorium and uranium.
Nevertheless, it was usually supposed that 126 is the next magic number for protons, in which case it has not been reached yet. Other possible values, from more recent computations, are 122 and 124, also not reached yet.
Moreover, the isotopes that are the most stable for the already synthesized elements are expected to have more neutrons than in the isotopes that have been successfully produced. So it is not impossible that an "island of stability" might have already been reached, but only with isotopes that have so few neutrons that they remain outside the zone of stability.
If the nucleus disintegrates before electrons can cluster around it, you're not really in the realm of chemistry any more. Chemistry is all about those electrons.
It belongs in the group of noble gases, together with helium, neon, argon, krypton, xenon and radon. Like radon, it is unstable, but also like radon it is widespread in nature as a product of radioactive decays.
The element with Z=0 has multiple isotopes, like any other chemical element. Unlike for any other element, the possibility of gravitational stabilization makes the number of its stable isotopes potentially infinite.
The neutron stars can be seen as belonging to the isotopes of the chemical element with Z=0.
Their concentration is the result of the equilibrium between neutrons that decay into proton and electron pairs and proton-electron pairs that recombine into neutrons.
The complete neutron star still behaves like a giant nucleus with null electric charge, i.e. with Z=0.
From a big enough distance, there is no essential difference between neutrons and the neutral atoms of any noble gas. They all are neutral particles which do not react chemically.
The weak van der Waals forces between the atoms of the noble gases decrease from radon to helium and neutron fits in this progression. At extremely small distances between neutrons, weak attraction forces appear between them, which are analogous to the van der Waals forces generated by residual electromagnetic interactions, but they are generated by residual strong nuclear interactions.
A positive hydrogen ion has 0 electrons too, the same as a doubly-ionized helium atom, triple-ionized lithium atom, etc.
The relationship between neutrons and these ions is the same as for instance between helium and lithium ions, beryllium ions, boron ions, etc.
Calling a neutron as the limit case of an atom is a choice, but this choice simplifies many descriptions of things related to atoms and ions, in the same way as including zero in the cardinal numbers simplifies the descriptions of many things related to numbers, because there is no longer any need to describe separately some special cases.
The operating definition has been "a list of all elements that humans have discovered and/or made". By that definition, it is not currently infinite, nor will it ever be.
If instead you define it to mean "all elements that might theoretically exist under all theories of physics that are not currently definitively ruled out", then it may be it infinite. But that's not the normal definition.
We give too much importance to the "Periodic Table". It's just a man-made microlang. Nature is unconcerned with it. There is much more beyond it.
P.S. While I'm criticizing the PT, might as well mention that I think we've probably done people a diservice by giving misnomer names like "Hydrogen" and "Oxygen" to these elements, which is completely disconnected from the mathematical beauty and patterns that those names represent.
Wikipedia: Oxygen
> Lavoisier renamed 'vital air' to oxygène in 1777 from the Greek roots ὀξύς (oxys) (acid, literally 'sharp', from the taste of acids) and -γενής (-genēs) (producer, literally begetter), because he mistakenly believed that oxygen was a constituent of all acids.
Hydrogen comes from ‘water’, which contains hydrogen and oxygen.
So, since all acids must have Hydrogen, Oxygen is actually a better name for Hydrogen. This then leaves the name Hydrogen free for Oxygen.
Singtium and Octium, perhaps.
I think it is clear what question is being asked here. There will be a limit on the maximum size of a nucleus stable enough to count as an element, as there are a couple of effects which, at some point, will be insurmountable (and which are also responsible for an isotope of lead being the largest stable element.)
One is that the electrical repulsion of the protons is long-range, while the strong nuclear force binding the nucleons together is short-range. To simplify quite a bit, in a large nucleus, each proton is being repelled by every other one, while it is being bound only by its neighboring nucleons.
The second effect prevents this being worked around by adding more neutrons, as one reaches a point where it is energetically favorable for a neutron to convert to a proton via beta decay.
As mentioned by others, there is likely an 'island of stability' around the largest elements created so far, but this is, at best, only a brief respite from the inexorable effects described above.
The estimates of the half-live of any given element on the island of stability ranges over several orders of magnitude. That being so, it seems unlikely that there is any clear idea which isotope is the largest possible in this universe.
Neutron stars are, of course, very large agglomerations of nucleons, but it seems pointless to call them elements (and there is an upper limit on their size, anyway.)
[1]: https://en.wikipedia.org/wiki/Relativistic_quantum_chemistry
(It's not as if the speed of electrons would *exceed* c above Z=137; it just approaches it asymptotically. The 1/137 factor comes from the non-relativistic approximation (simply, the plain Bohr model [0])).
Imagine 500 years in the future when we have laptop particle accelerators... We may have whole diffent reality around 'strange'.
The line from the remake of 'the man who fell to earth.' "He has miscalculated the chirality."
The macro stars and the micro. I for sure thought that 118 was the limit, and again, this has been a life long interest of mine.
I have the isotope chxart on the wall at home.
P.s. kudos for paying attention in school.
P.p.s extra thanks the people who kept the Laurence hall of science going, and it's periodic table working.
So clearly there is a limit. Either bounded by the point where gravity becomes dominant or when you get a black hole.
What happens in neutron stars is somewhere between nuclear reactions and quantum effects. Both of which are decidedly not "chemistry" in the way most people use that word.
More generally, only normal atoms can undergo chemistry. All of chemistry depends on the arrangement of electron orbitals. Once you leave that domain, you're in an entirely different field of physics.
There is a theoretical upper bound on the mass of an elementary particle at which it will collapse into a black hole. Fundamental particles can not be heavier than the Planck Mass, and Atoms should have a corresponding value at which they will likewise collapse into a black hole.
Black holes do not satisfy even the loosest definition of an element.
It may be difficult to predict just how far we can go in a lab, but the existence of black holes means there must be some limit.
[1] https://en.wikipedia.org/wiki/File:Binding_energy_curve_-_co...
In other words, energy required to break them apart.
At some point it becomes "quark matter" and might exist in collapsed stars.
Atoms are much bigger than subatomic particles, so they have to live even longer in order to exist.
The 121st element would end up in the G block, which isn't in any of these locations but rather gets its own special location.
That said, these extreme elements are great tests of the understanding of mechanics of atomic nuclei. Personally, I expect this improved understanding to become important in nanofabrication/nanotechnology as we are getting individual atoms to stick to each other.
There are other implications I'm sure for those studying the early superhot universe.
There is also the chance this is a stepping stone to the Island of Stability: https://en.wikipedia.org/wiki/Island_of_stability
They typically try to honor someone or something relevant to particle physics or nuclear physics. So, no fun allowed, unless you are a physicist in which case you probably find naming things after historical physics figures fun.
besides learning about them briefly in chem classes as the "man made elements", haven't heard much from them otherwise