Wednesday, February 13, 2008

Physics Factoid: Composition of the Universe

This pie chart shows what makes up the Universe.  Amazingly, about 96% of all the mass-energy  in the Universe is invisible in the form of dark matter or dark energy.  I'll do posts on each of them, but briefly, dark matter is related to ordinary matter except it doesn't interact with light, so it is invisible and doesn't clump into planets and stars (unless you count these); dark energy is a mysterious energy which is causing the Universe to expand faster and faster, and may well be the inherent energy of space itself.

Of the 4% of the Universe that is in "normal" matter, most is in interstellar and intergalactic gas--only about 1/10 (0.4%) of the total is in stars like our Sun.  Finally, all the elements other than hydrogen and helium make up less than 1/10 of that slice (0.03%--not shown).

[Image credit: NASA] 

No comments: