As a non-scientist this sounds pretty huge to me, but what actually are these new elements? The article doesn't elaborate.
They're all in a similar numeric range, but are these entirely new elements, or other elements recategorised?
They're all in a similar numeric range, but are these entirely new elements, or other elements recategorised?
They are as different from other elements as gold is different from carbon. Each is unique and unlike any other element, with unknown properties (they don't last long enough to study, although some guesses can be made).
We are hoping there is a "magic" number, that if we reach can make elements that actually last long enough to study (because certain numbers of particles are extra stable because they "fit" together very nicely - like how you can fit 6 coins around another coin much nicer than 7). That's called the Island of Stability if you want to look it up.
These elements are on the path to that, so it's important to study them. As of right now we don't know how to make anything heavier.
I find limits like these interesting (absolute zero, the plank temperature which may or may not be absolute hot, the speed of light, etc.)
Yes, see: https://en.wikipedia.org/wiki/Nuclear_drip_line
In particular the Neutron drip line is not known, so we don't know how large an atom can be. But there is such a number.
It's easy to understand why protons drip: Their electric repulsion pushes them out. For neutrons it's more complicated, but basically you need energy to force a neutron to attach to a nucleus, and at some point the energy released in falling off is high enough that they will no longer stay attached (this is a simplification BTW).
Think of the nuclei as big, quivering blobs of jelly. They are too big to hold together and really want to split into other stuff. But studying them while they're still in one piece tests our understanding of a lot of basic physics, and lets us compare predictions to reality.
For example, element 118 was called "Ununoctium" and abbreviated "Uno". Now it has a real name, "Oganesson" (Og) after one of the discoverers.
> the conditions in our accelerators are singular in the universe.
Most likely they are. A supernova is a random event, an accelerator is directed. It's quite possible we could make lots of something in an accelerator that would never happen in the random conditions of a supernova (for example if some other more common effect consumed the raw material needed for the rare thing to happen).
The r-process starts with something fairly stable and relatively light, like iron. Then you start throwing phenomenal amounts of neutrons at it. Outside of a nucleus, neutrons are unstable, and decay to protons in about 15 minute, so this can only happen if something is producing lots and lots of neutrons, all at once. Anyways, the iron catching those neutrons, becoming heavier and heavier.
Eventually, the nucleus becomes heavy enough that beta decay, in which a neutron inside the nucleus changes into a proton, starts happening at the same rate as neutron capture. At this point, it is a competition. In the table of isotopes [2], neutron capture moves to the right, and beta decay moves diagonally up and to the left. Between the two, the nuclei get heavier and heavier, with more and more protons and neutrons. The general path is known [3], zig-zagging through the isotopes, becoming more and more unstable.
The process stops when the source of neutrons runs out. At that point, everything beta-decays back to stability. Everything is finished, and the heavy elements of the universe have been produced.
There is a theorized "island of stability" [4]. We have enough protons, but not enough neutrons. Remember how the r-process adds one neutron at a time? Well, if the island of stability is as stable as predicted (half-lives of a few hours are typically predicted), then we might be able to produce those isotopes by careful selection of the input nuclei. Nature is limited to what exists in stellar environments, and can't choose. So (and here I'm stepping out of my area of expertise), since this selection wouldn't happen in nature, it is entirely possible that we are creating conditions that haven't existed in large quantities elsewhere.
[1] https://en.wikipedia.org/wiki/R-process [2] http://cdn.iopscience.com/images/0034-4885/76/5/056301/Full/... [3] http://www.onafarawayday.com/Radiogenic/Ch1/Ch1-2_files/imag... [4] https://en.wikipedia.org/wiki/Island_of_stability
For example, the neutron decays to a proton, because a proton+electron system has less energy than a neutron. Bind the neutron with a proton, forming deuterium, and suddenly it is stable. The neutron is unstable by only a free MeV, and so the binding to a proton can stabilize it.
All matter is made of up and down quarks. The next lightest quark, the strange quark, is about 100 MeV. It order to stabilize it, there would need to be some binding effect that would bind a strange quark 100 MeV more strongly than an up or down quark. That would be the only way to make the strange quark system be the most stable.
And here we run into the problem that, of the four fundamental forces, none of strong enough and specific enough to the strange quark to do so. The strong nuclear force, which stabilizes the neutron, is the strongest, and only provides that few MeV of binding, not the 100 or so that would be necessary.
Getting at that energy after it is stored would require a bit more handwavium, since you don't want it to destabilize (read: catastrophically explode) on common use. I could imagine using a gamma-ray laser (same principle as regular laser, but they don't currently exist) to destabilize the strange carbon.