Constituents

[FUNKER]

What is the constituent material of the universe? Is the material all exists on tangiable?
please any answers will aid me thanks

[mathman]

Current estimates are that the universe is about 5% baryonic (ordinary) matter, about 25% non-baryonic matter, and 70% dark energy. Physicist and astronomers have proposed various theories to describe the two latter components, but nothing has yet been verified by observation.

[FUNKER]

What is dark energy? do you have any links that would be able to help me out in understanding it?
thanks

[mathman]

For the latest on non-baryonic (dark) matter, hep-ph/0312013 from arXiv (use google to get arXiv). In this article are references to dark energy as well. The most favored explanation for dark energy is the presence of a small cosmological constant in Einstein's general relativity. However, there are some serious problems relating to the size of the constant. For dark energy, it is about 50-60 orders of magnitude smaller than other theory expects.