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Expert considers dark matter

| Wednesday, February 4, 2015

Theoretical particle physicist Patrick Fox from Fermilab served as the keynote speaker for a physics department colloquium that focused on evidence for dark matter’s existence and the means by which the scientific community could learn more about its properties in the future.

“I’m a theorist in particular,” Fox said. “I am beyond the standard model theorist, so my day-to-day job is to think up extensions of the standard model that experiments can look for, or if experimenters have seen things that don’t make sense, I can try to interpret it and build models that explain those observations.”

Fox said the standard model remains a powerful tool that explains most natural phenomena by defining the elementary particles of matter, but it is far from perfect or all-encompassing. Although this model explains things observed at the sub-nuclear level, Fox said these particles should all be massless, a very different world from the one present.

20150204, Emmet Farnan, Lecture, Looking For Dark Matter, NieuwlandEmmet Farnan | The Observer

“There’s an explanation for that problem,” he said. “There’s a particle that is responsible for giving the other particles their mass, and that is the Higgs-Boson particle. The Higgs Boson was the last piece of the Standard Model to be discovered, and with it’s discovery, all the phenomenon in the natural world could seemingly be explained.”

Even after the discovery of the Higgs-Boson particle, Fox said a lot of exciting physics remains to be done, such as research on the mysterious dark sector.

“We like to think we’re doing a good job of explaining the phenomenon that can be observed,” he said. “It turns out, once you dig into it, that we can only explain roughly 5 percent of everything.

“This other 95 percent is broken up into two categories. There’s stuff that behaves with respect to gravity just like the matter that makes up you and me, known as dark matter, and then there’s dark energy, which is very different than matter and dark matter in that it is not affected by gravity. Dark energy is what’s responsible for the expansion of the universe speeding up.”

Fox said the explanation for dark matter’s mysterious name is intuitive in comparison to the rest of the dark sector.

“Dark matter gravitates and attracts matter in the same way that you or I do, but more importantly, they don’t feel the affects of photons,” he said. “Light does not reflect off them, and dark matter and photons do not interact.”

Although dark matter certainly exists, Fox said modern physicists still have questions to answer.

“We know that everyone in this room is made out of matter and not antimatter, but the laws that govern the standard model are symmetric,” he said. “If you replaced everything in this room with antimatter, it would behave in exactly the same way. We don’t know why there’s only matter inside us and zero antimatter.”

The evidence for and against explanations of dark matter can be confusing, and Fox said this means it’s time to start working to make the evidence more consistent.

“Dark matter is one thing we know for sure that is not explained by the standard model, but we know for sure it’s out there,” he said. “We don’t know more than that, but we have some good ideas that we are working on to try and squeeze all the information out of all the avenues of attack that we have.

“There have been a lot of recent advances both on the theoretical front and the experimental front. The coming decade will be a very exciting time for particle physics.”

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  • Bee Farms

    We can’t see dark matter because we aren’t able to “think” about it. If we thought about it, we would see it. What you have to realize is == all the world depends on us observing it === without that it has no certain place. therefore thought itself is a force — and has parts to it === one part of it is gravity and space and time -=== maybe i dont know . good luck with it.

  • mpc755

    There is evidence of dark matter every time a double slit experiment is performed; it’s what waves.

    Dark matter has mass. Dark matter physically occupies three dimensional space. Dark matter is physically displaced by the particles of matter which exist in it and move through it.

    The Milky Way’s halo is not a clump of dark matter anchored to the Milky Way. The Milky Way is moving through and displacing the dark matter.

    The Milky Way’s halo is the state of displacement of the dark matter.

    The Milky Way’s halo is the deformation of spacetime.

    What is referred to geometrically as the deformation of spacetime physically exists in nature as the state of displacement of the dark matter.

    A moving particle has an associated dark matter displacement wave. In a double slit experiment the particle travels through a single slit and the associated wave in the dark matter passes through both.

    Q. Why is the particle always detected traveling through a single slit in a double slit experiment?
    A. The particle always travels through a single slit. It is the associated wave in the dark matter which passes through both.

    What ripples when galaxy clusters collide is what waves in a double slit experiment; the dark matter.

    Einstein’s gravitational wave is de Broglie’s wave of wave-particle duality; both are waves in the dark matter.

    Dark matter displaced by matter relates general relativity and quantum mechanics.