What is dark matter?
What is dark energy?
How were the heavy elements from iron to uranium made?
Do neutrinos have mass?
Where do ultrahigh-energy particles come from?
Is a new theory of light and matter needed to explain what happens at very high energies and temperatures?
Are there new states of matter at ultrahigh temperatures and densities?
Are protons unstable?
Are there additional dimensions?
How did the universe begin?