What would you consider to be the 5 or 10 most important/fundamental questions physicists are trying to answer currently?

Asked by: Peter Sullivan

That's a subjective question, but here is my vote for the most important questions science currently has before it:

What is the so-called 'dark matter', known by its gravitational influence in the Universe, composed of?
If the Universe is really expanding at an ever increasing rate, as observations seem to indicate, what force is responsible?
Ongoing theoretical research into a 'theory of everything', attempting to explain why fundamental particles and forces have the relative masses and strengths that they do. Is string theory a valid basis for this, or just a blind alley?
The ongoing search for the Higgs boson, a subatomic particle believed to be the source of all mass.
Continuing study of the the origins and nature of life, and the search for life beyond the Earth.

Answered by: Paul Walorski, B.A. Physics, Part-time Physics Instructor