Expert: James Gort - 7/21/2005

Question
Do we have a hypothesis or deduction with regard to what could be a void (something that lacks energy and mass)?

If there is, what would be the most respected scientific and mathematical perspective, and what is the best source of information on this subject?


Answer
Hello Pja,

First, I'll give you my view (based solely on an opinion and not much research), but then I'll give you two excellent sources that discuss the issue at considerable length.

First, the universe (in a large scale - on the order of 300 million light years) is very uniform.  Matter and energy appears uniformly distributed at that scale.  But as you look closer (on a shorter scale), there are considerable irregularities, and even regions that may qualify as "voids".  They seem to be a result of random motions and the combined effects of gravitational fields from nearby bodies.  These regions are pretty good vacuums (much better than we can create on earth) - and contain perhaps 1 atom (usually, atomic hydrogen) per cubic meter.  Between those atoms (which are moving around, since space is at an average temperature of about 3 degrees K), it can qualify as a "matter void".  But an energy void is another question.  Energy transport mechanisms, principally in the form of photons and neutrinos, permeate space.  As long as stars and galaxies are visible from the void region, there's energy being transported through the region.  So I'm not sure if there any regions that comes close to an "energy void".

But for more (and certainly more authoritative) reading, check out:

"Bubbles, Voids, and Bumps in Time:  The New Cosmology".  Ed. by James Cornell.  Paperback published by the Cambridge University Press.  Each chapter written by an expert.

"The Book of Nothing - Vacuums, Voids, and the Latest Ideas about the Origins of the Universe".  By John D. Barrow.  Published by Pantheon Books.

Both these sources will certainly give you the latest background and theories concerning voids.

Good luck!

Prof. James Gort