Percent Ordinary Matter
What percentage of the universe is made of ordinary matter?
I am not exactly sure what you are trying to ask, so I will take a couple
Are you asking what percentage of the volume of the universe contains
The answer to that question is not well understood by scientists. The rate
of expansion of the universe indicates there should be more mass than we
observe through telescopes. Thus, some scientists have predicted 'dark
matter' that we cannot see, or other solutions, to explain this apparent
contradiction. So, we are not really sure how much matter there is, and if
this dark matter exists, where it is or how much space it takes up. However,
there is a lot more 'empty space' (it is not really empty, but ...) where we
do not see stars and galaxies than where we do see them.
Are you asking what is the ratio between the matter we can see and the
matter we think should be there (e.g. dark matter)?
If this is your question, estimates range up to 95% of the matter in the
universe being 'dark' matter. There is also 'dark energy' which could be
three times more than that as well. Scientists do not have a great grasp on
this yet -- they are working on it though.
I hope these are helpful. If you're asking something else, reply back and
let me know what you meant.
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Update: June 2012