Expert: Tom Whiting - 11/25/2009

Question
How large is the volume of matter in the universe?Say we take containers each holding inside 1 cubic metre of the universe's volume(size),and of the same form as a cubic metre too.Now we proceed to pack the matter,the universe contains inside of itself(star,black holes,planets,etc material)densely into those containers,just as water is used to fill bottles,up to their very limits(by the limits I mean the final density of matter,the  densest state before ignition,not like"in each place of the universe some atoms fly around".So humidity is also always around,but not the H2O densest state of WATER).Ok,so we have put finally all of the universe's material(atoms & other elementary particles in their forms of black holes,stars,planets,etc) into the containers each sized 1 cubic metre exactly.Now,just how many of those containers with matter would face how many empty now cubic metres of universe's vacuum?I mean I know the universe is unclear by its final size,matter too;but what would be the ratio(relation)between the 2 types of containers in numeral calculation?I heard a version that presumably averagely 1 cubic metre of vacuum contains throughout the universe 3 atoms of matter.Is it true?Or which IS the ratio?I come personally to the conclusion that matter is weirdly too rare in the universe;just like the Sun of our solar system,is making over 99% of the entire mass of the solar system's matter;JUST SO,vacuum,I assume,is making up over 99% of the universe's entire volume(the ratio between the 2 types of containers I mentioned above)True?Please comment.Tnank You  

Answer
Hi Dima,
Yes, regular matter is scarce... I've read where it's density is more like one atom (mainly hydrogen) per cubic meter.  The stuff we're made of...atoms, people, stars and planets, only constitutes 4% of the matter and energy of the Universe; The rest is dark energy (73%?) and dark matter (23%?)which we have no idea what they are, as yet.  (Read the word dark, as unknown).

The spacial part of the Universe could be at least 50 billion lightyears (and maybe more) in diameter due to inflation and accelerating expansion of space... if this seems to contradict Einstein and light speed, it doesn't.  Only matter is bound by velocities just under light speed; spacial expansion (or shadows of objects) are not bound by light speed. Regular matter only constitutes a small volume, 13.7 billion lightyears, of the total Universe.

So none of your "Earthly" analogies can be used on the description of the Universe...like putting things in containers and such.
Plus, the spacial component is not only expanding, it's accelerating it's expansion as time goes by, and perhaps the acceleration is even accelerating... we just don't know as yet. That's where
it stands now.  So the "Big Crunch" is out. It's either the Big Rip, or a heat death in the end.
Clear Skies,
Tom Whiting
Erie, PA

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For composition of the Universe, see
http://www.infoplease.com/ipa/A0908644.html
Tom