Question: tachyons. the hypothetical particle that travels faster than light. no-one's seen them, many people don't believe in them, and yet they have a name. what other particles/phenomenon have been named but not discovered?
Lots of different particles have been predicted to exist, based on other observations of atoms, and when you think something exists, it’s best to give it a name so other people know what you’re talking about. They’re too small to see normally though, so scientists are designing lots of experiments to try and find them.
The tachyons are a special case though, because most scientists don’t think they exist, because they don’t fit with the things we can see in the universe. Its still useful to give them a name though, so people can say: “Haha the idea of Tachyons is ridiculous!”
The Higgs boson would be a good one. Theory predicts its properties, but we have never ‘seen’ one. Antimatter was predicted from theory well before it was every actually discovered. Paul Dirac’s particle mathematics predicted particles opposite to the normal ones. He thought it was a mistake in his maths, but it turned out that he was totally right and there was just these weird things.
But a tachyon is a bit different. No theory predicts that it should exist, and in fact most scientific theories would say that it can’t exist. In fact, the name just means “quick particle” so you shouldn’t put too much faith in the fact it has a name.
There’s other stuff that has been predicted before they were actually discovered. Neutrinos is a good one, but things other than particles too.
People predicted there was another planet beyond Neptune just using Newton’s laws well before Pluto was discovered, but when we eventually saw that pluto was really small, it meant there must have been other stuff too, and eventually this was proved right when we discovered there’s a whole /cloud/ of pluto sized bodies out there.
A lot of different elements were predicted before they were found. Especially nowadays, where we actually have to go and /make/ the elements, we can predict their properties before anyone goes and does the hard job of making them.
Just thought of another one (from another question) – we predicted black holes mathematically way before anyone saw the evidence for them.
Well perhaps the most famous is the Higgs Bosun – the particle which is supposed to tell other particles how much they should weigh.
Theoretical physicists seem to like to invent cool names for particles. My favourite particle names are the quarks (which have been discovered). There are six “flavours” of them called “up”, “down”, “bottom”, “top”, “strange” and “charmed”. They were named by physicists in the 60s. When I first learnt about them as an undergraduate I suddenly realised physicists are just normal people too who sometimes have funny ideas!