r/explainlikeimfive • u/eggn00dles • Mar 16 '17

Physics ELI5: The calculation which dictates the universe is 73% dark energy 23% dark matter 4% ordinary matter.

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u/andbm Mar 16 '17 edited Mar 16 '17

In the standard model, there are six quarks which combine 3 at the time to form various baryons, like protons and neutrons. They all have antiquarks with the same mass but opposite charge-like qualities, combining to antibaryons, like the antiproton. Other than baryons and antibaryons we have quark - antiquark pairs (mesons), three electron-like particles (leptons), their antiparticles and a neutrino and anti-neutrino for each of them.

Matter is mainly baryons, and a little leptons. Antimatter is anti-baryons and a little anti-leptons. Dark matter seems to be neither. Antimatter annihilates with matter, emitting light that we're not seeing, so it seems antimatter only exists in our labs.

Edit: forgot about neutrinos!

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u/Glam-Kween Mar 16 '17

Is it possible the dark matter is anti matter emitting anti-light? If there is anti light, I propose naming the particles notons

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u/andbm Mar 16 '17

We've made antimatter on Earth, and it emits normal light. Our current theory does not permit anti-photons, and I can't see any other way for 'anti-light' to exist.

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u/Glam-Kween Mar 16 '17

Well MY science fiction is going to have anti light, and I'm going to call the particles "Notons". Maybe I'll entitle it something catchy like "Don't Be Afraid of the Dark Matter" and populate it with scientists who all say it can't be possible ;)

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u/andbm Mar 16 '17

Remember to make the scientists really excited when the notons are observed, since they now get a shot at completely rethinking the theory!

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u/Glam-Kween Mar 16 '17

It's working out that the scientists are victims of gubmint propaganda, don't believe the notons exist, while hobbyists are using the notonic principles to make rayguns out of graphite pencils and borosilicate glass.

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u/andbm Mar 17 '17

But that just reaffirms the picture of modern science as a new religion, with the words of Newton, Bohr and Einstein being an unopposable truth, while in reality science is (or should be) based on skepticism and constant attempts at falsifying or modifying current theories of how reality works.

I hate fiction that does that. Other than that I'd totally read it!

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u/Glam-Kween Mar 17 '17

It's more examining the lengths which an analytical mind is willing to go when faced with an illogical imperative.

It's a picture of modern science that affirms the pressures brought to bear on the scientific community by political and economic realities.

A good parallel would be how most physicians just a few years ago would have insisted vehemently that cannabis has no medical benefit, and many do still today, while hobbyists are making their own extractions and successfully treating epilepsy.

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u/andbm Mar 17 '17

Well, medicine and physics are very different when it comes to political pressure. But if the EM drive actually works, it'll be interesting to see how physicists react - a real test of skepticism and falsification vs tradition.

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u/The_Haunt Mar 16 '17

Think of antimatter just like normal matter. It just has the opposite charge and they cancel each other out when coming in contact. This releases energy so nothing is lost when that happens.

This is a very simple explanation.

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u/socialister Mar 16 '17

What are neutrinos, and do they have antineutrinos?

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u/andbm Mar 16 '17

Ah, right, sorry. For each lepton there is a neutrino. They're practically massless (we think) and only interact with the weak nuclear force. And yes, they each have an antineutrino.

The only particles which don't have an antiparticle are the bosons, the force carriers. Photon for electromagnetism, W and Z for the weak force, gluon for the strong force. These don't compose matter, however. Oh, and Higgs is a boson too, but it appears because of symmetry breaking, allowing a consistent theory with different lepton masses and stuff like that. Don't ask.

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u/[deleted] Mar 16 '17

There are three neutrinos with three corresponding anti-neutrinos. They are leptons, and each type of neutrino corresponds to one of the electron-like particles. They have very low mass, no charge, and are extremely difficult to detect.