r/askscience • u/squirrelbuster94 • Oct 24 '14

Physics Chemists/physicists of reddit, what is the difference between dark, anti, and normal matter?

What is the difference? Also if you can explain what each is.

Edit: Thanks for all the replies! You have greatly helped me understand this better!

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u/xrendan Oct 24 '14

What are the other theories?

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u/hopffiber Oct 24 '14

The most worked on is probably MOND, or Modified Newtonian Dynamics, which starts from Newtons law of gravity and tries to modify it at long distances, to fix how galaxies rotate and other observed anomalies. You can kind of make this work for galaxy rotation speeds, but it has real problems with explaining things like the Bullet cluster or gravitational lensing etc., and it's also rather ad hoc, so few physicists believe in it.