Open Questions in Physics
While for the most part a FAQ covers the answers to frequently asked questions whose answers are known, in physics there are also plenty of simple and interesting questions whose answers are not known. Here we list some of these. We could have called this section Frequently Unanswered Questions, but the resulting acronym would have been rather rude.
Before you set about answering these questions on your own, it's worth noting that while nobody knows what the answers are, a great deal of of work has already been done on most of these subjects. So, do plenty of research and ask around before you try to cook up a theory that'll answer one of these and win you the Nobel prize! You'll probably need to really know physics inside and out before you make any progress on these.
The following partial list of open questions is divided into five groups:
Condensed Matter and Nonlinear Dynamics
Quantum Mechanics
Cosmology and Astrophysics
Particle Physics
The Big Question™
However, given the implications of particle physics and nonlinear dynamics on cosmology, and other connections between the groups, the division is somewhat artificial, so the classification here is somewhat arbitrary.
There are many other interesting and fundamental questions in other fields, and many more in these fields besides those listed here. Their omission is not a judgement about importance, but merely a decision about the scope of this article.
Since this article was last updated in 1997, a lot of progress has been made in answering some big open questions in physics. We include references on some of these questions. There is also a lot to read about the other open questions--especially the last one, which we call The Big Question™. But, we haven't had the energy to list it. [continued]
