What Don't We Know About The Universe?

While you are reading this text, our universe is expanding. As it does so, it separates galaxies and cools down its own temperature. We have known this for over a hundred years, but we are still trying to figure out its exact expansion rate. In this talk, you will join me in exploring the history of this problem, which takes us from Einstein’s time to ours.

In the dating game of the cosmos, neutrinos are the ultimate tease. These subatomic particles zip through the universe, playing hard to get by barely interacting with anything else. With a wink and a nod, they pass through planets, stars, and even you and me, leaving physicists sending flirty glances and expensive equipment just to catch a glimpse. Join us on a whimsical journey to understand these elusive particles that could swipe right on the secrets of the universe but choose to ghost us instead. From their solar escapades and cosmic voyages to their identity-swapping shenanigans known as oscillations, we'll explore how neutrinos might just be the key to unlocking the mysteries of the Big Bang, supernovae, and why the sun shines so bright. No need to update your particle physics profile; just bring your curiosity and a readiness to mingle with the most elusive particles in the universe. Let's decode the mixed signals of neutrinos together and find out why they're playing hard to get.

Dark matter is a strange and elusive substance. Despite making up ~85% of the mass in the Universe, we have yet to directly observe it. Our most prevailing theory predicts dark matter to be “cold” (slow-moving) and “collisionless” (non-interacting). However, observations of dwarf galaxies—galaxies that are much less massive that our own Milky Way—seem to be at odds with this theory. In this talk, we will explore why low-mass galaxies serve as natural laboratories to probe this otherwise invisible form of matter using both observations and simulations.