Events at Physics |
Events on Thursday, April 11th, 2024
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Mysteries of the High-Energy Sky
- Time: 9:00 am - 10:00 am
- Place: 5280 Chamberlin Hall and
- Speaker: Dan Hooper, Fermilab
- Abstract: It has been more than a century since the discovery of cosmic rays, and yet there remains much that we do not know about these mysterious particles. In particular, it is an open question as to where many of the cosmic rays come from and how they are accelerated to such incredible energies. The resolution to these puzzles will require not only measurements of the cosmic rays themselves, but also information provided by gamma-ray, X-ray, optical, infrared, and radio telescopes, gravitational wave detectors, and high-energy neutrino telescopes. It will be through this program of multi-messenger astronomy that we will finally be able to identify the sources of the cosmic rays and cosmic neutrinos, and begin to understand the physics behind these naturally occurring engines of high-energy particle acceleration. This observational program will also provide exciting opportunities for the field of particle physics, allowing us to test a variety of new physics scenarios, to search for the particle nature of dark matter, and to further probe the physics of neutrino oscillations.
- Host: Francis Halzen
- Astronomy Colloquium
- Water under X-ray Vision - A Molecular Look at Life’s Mysterious Elixir
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Uwe Bergmann, UW-Madison
- Abstract: Every life form on earth requires liquid water to function and when we look for life in space, we often look for water signatures. Yet, we still don’t know precisely how the water molecules are arranged in the liquid. We also don’t know how exactly plants and algae split the water molecules to form molecular oxygen during photosynthesis. This over three-billion-year-old process has created essentially all the oxygen in our atmosphere and therefore enabled the evolution of all lifeforms relying on respiration. Understanding this mechanism can also help us to create new fuels based on sunlight.
Powerful new synchrotron X-ray sources have enabled detailed atomic level investigation of the structure of water and the photosynthetic water splitting. We will first describe these amazing X-ray sources and the various techniques that have been used to carry out these studies. We will then review our current understanding and the most recent progress of solving these two compelling mysteries, which have critically shaped the existence of life on earth. - Host: Ke Zhang