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Daddy Limster
2012-Aug-27, 07:52 AM
What of the current speculations of the nature of dark matter seem to be best supported by current research? Are there any current mainstream speculations that dark matter could be made up of a significant number of different particles? As a thought exercise, if an intelligence lived in the dark matter world and saw that approximately 4.6% of the mass/energy content of the universe were made of baryonic material that they could not easily interact with, it would not seem reasonable to assume there would be such a variety to the visible universe that we live in. Is it possible that the 23% of the mass/energy content created by dark matter is also as varied as our 4.6%?

Thanks.

antoniseb
2012-Aug-27, 12:13 PM
All ideas about dark matter is that it is made of things which are very weakly interacting *with each other* and with baryonic matter. This is a requirement to get the shape and distribution of cold dark matter that we see (neutrinos are hot dark matter). It is possible that it is made up of a mixture of weakly interacting species. Because of that, your idea about dark-matter based thinking life forms is pretty unlikely.

The most frequently discussed possibilities include the lowest mass particle from a supersymmetric family of particles that were around when the universe was very dense, but have all decayed down to this last holder of the supersymmetric quantum numbers.

Some other people are looking at:
- tiny black holes left over from inflation coming to a halt.
- axions
- other previously undetected particles.
- ways to explain it using small variations in the distance relationship of gravity

Daddy Limster
2012-Aug-28, 07:33 AM
So, basically, even though dark matter is only weakly interacting with baryonic matter, and even though we can primarily only detect it and measure it through gravitational effects, we can deduce enough from that to conclude that dark matter is not as intrinsically varied as baryonic matter?

(And just in case it wasn't clear, I wasn't advocating for dark matter lifeforms - it was probably a poor way to try and explain the visualization I had.)

antoniseb
2012-Aug-28, 01:40 PM
... we can deduce enough from that to conclude that dark matter is not as intrinsically varied as baryonic matter? ...
Well, we haven't ruled out the possibility that it is made up of hundreds of different types of particles, but if so, none of them interact with each other to any great degree, and they don't bind together in any way (such as making dusty clumps). On a macroscopic scale, the distribution in any dark matter halo is relatively smooth.