Today, particle physics learns from astronomy, and astronomy learns from physics. For example, astronomical observations predict that there are only three generations of elementary particles, a prediction confirmed by accelerator experiments. And physics experiments imply a mass for the particles called neutrinos, a finding with profound implications for the way the universe is put together.
Why is there more matter than antimatter in the universe? Will the universe expand forever? How fast is it expanding? What is dark matter? How did a smooth universe become a "lumpy" one, filled with stars, galaxies and quasars? Exploring these critical questions will deepen the powerful connection between particle physics and astronomy.