interaction of dark matter with regular matter
20 Feb 2016 20:05:56 UTC
Topic 198450
(moderation:
Is it known if dark matter and regular matter interact in such a way that gravitational waves are emitted?
merle
What is freedom of expression? Without the freedom to offend, it ceases to exist.
— Salman Rushdie
interaction of dark matter with regular matter
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Hallo Merle!
I would think so. But as there is 5 times (26,8%/4,9%) more dark matter than our ordinary, baryonic matter, you will see more or less only the movements of the dark matter. On the other hand dark matter doesn´t clump together as baryonic matter do.
They hope to find in future gravitational waves from the time, the matter build up after the big bang. The BICEP2 experiment was such an experiment, searching for polarization effects in the microwave background radiation due to gravitational waves. But it has been shown, that the effect they found is due to polarization effects from dust in our milky way. It´s planed to search for this also in future with the LISA experiment.
Kind regards and happy crunching
Martin
RE: Hallo Merle! I would
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Thanks for your response. It was all very interesting. I was surprised at your comment re. 'the matter build up after the big bang'. That we will be able, one day, to sense that far back is just amazing.
merle
What is freedom of expression? Without the freedom to offend, it ceases to exist.
— Salman Rushdie
RE: On the other hand dark
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Now that is interesting. Does that mean that dark matter has a repulsive force, in addition to its gravitational force? Or that it is moving too fast to clump together? What are the possibilities?
RE: RE: On the other hand
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The best evidence indicates, for galaxies at least, that the pizza/spiral shape typical of most is surrounded by an extended halo of something else that is unseen but has a gravitational influence ie. dark matter. So it is all still attractive but DM would seem to have a different history of evolution of it's distribution. However DM is also relevant more cosmically in matching the models that include it for the developing universe with respect to the observations now. If you don't account for something like it with non-relativistic properties - so that's cold DM then - you won't get agreement.
There is the hypothesis that all the lost pens and pencils in the world go to a planet of their very own to live. I disagree. We have our CDM candidates right there. :-)
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
There are multiple
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There are multiple ingredients that can make ordinary matter clump:
* Self-interaction. An exploding star's shockwave (or just collision of 2 gas clouds) can compress thin gas in galaxies to the point that it get dense enough to collapse to form stars.
* Radiation of converted potential energy. A gas cloud that compresses under its own gravity will convert most of the potential (gravitational binding) energy into heat and radiate it away as long as it is still transparent enough - and that energy is now lost for the gas cloud, it won't be able to expand again on its own.
* Segregation. Plays a role for massive bodies clumping (such as star clusters) - upon close encounters sometimes one of the involved stars gets more than enough energy to leave the cluster, removing potential energy from the cluster which gets even tighter.
* Magnetic fields - these probably play a big role in newly forming stars + planetary systems.
None of these mechanisms would really work for Dark Matter from our theory books - heavy and barely interacting particles.