Events at Physics
Events on Thursday, September 29th, 2022
- Physics Department Colloquium
- Justin Kasper: Nuclear Power (fusion and fission), Galactic Radiation, and Space Exploration
- Time: 12:00 pm
- Place: Orchard View Room, Discovery Building
- Speaker: Justin Kasper, PhD, BWX Technologies, Inc. and University of Michigan Climate & Space
- Abstract: Special joint colloquium between Physics, Engineering Physics, and Astronomy:
Nuclear Power is about to Transform our Presence in Space.
We are a decade into a revolution in our ability to access, explore, and use space. The cost of rockets and spacecraft and the time between launches have dropped by orders of magnitude. Advanced technologies allow us to send probes into harsh environments like the atmosphere of the Sun, the frozen craters of the lunar poles and the icy moons of the outer planets. Our ambitions are limited by the amount of energy we can carry into space, or more precisely the density of that energy. We need heat and electricity to operate on the moon at night or in permanently shadowed craters, and more efficient rockets to transport humans and cargo to Mars, and nuclear power is the solution. A small fission reactor can continuously power a base on the moon or Mars for a decade, and nuclear propulsion is several times more efficient than chemical rockets, halving the duration of a crewed mission. This talk will review the amazing work in nuclear technology and design under way right now to deploy nuclear power and propulsion in space.
- Host: Cary Forest
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Tau appearance and quantum gravity with high-energy neutrinos
- Time: 2:30 pm
- Place: Chamberlin 4274
- Speaker: Alfonso Garcia , Harvard University
- Abstract: In this seminar, we will discuss two studies in the context of the high-energy neutrino detection. First, we address the impact of tau appearance from high-energy muon and electron neutrinos interaction as they propagate through Earth. This component is predicted to be significantly larger than the atmospheric background, and it alters current and future neutrino telescopes’ capabilities to discover a cosmic tau-neutrino flux. Second, we explore the capabilities to detect neutrino-nucleon soft interactions induced by TeV-scale gravity with the next generation of radio telescopes. In this elastic regime, the commonly used method to measure the total cross section breaks down, so we explore new proxies.
- Host: Lu Lu
- Astronomy Colloquium
- Galactic HII Regions and Structure in the Milky Way
- Time: 3:30 pm
- Place: Sterling Hall 4421; or via Zoom:
- Speaker: Trey Wenger, NSF Astronomy & Astrophysics Postdoctoral Fellow
- Abstract: Radio recombination lines (RRLs) are an unobscured tracer of ionized gas in both the diffuse interstellar medium (ISM) as well as high-mass star forming regions. The Green Bank Telescope HII Region Discovery Survey (HRDS) and its successors have more than doubled the number of known high-mass star forming regions in the Milky Way by detecting RRL emission toward infrared-identified HII region candidates. HII regions are the classic tracer of structure in galaxies, and their physical conditions (e.g., metallicity, internal kinematics) inform models of high-mass star formation and Galactic chemodynamical evolution. I will give a brief overview of our latest HRDS project, the Southern HII Region Discovery Survey, and some preliminary results with the first Galaxy-wide flux-limited HII region sample, including a novel technique to constrain Milky Way spiral structure. In the SHRDS, we serendipitously discovered a population of HII regions with ionized gas velocity gradients. I will discuss both the origin and implications of this discovery on models of high-mass star formation as well the future of Galactic structure and HII region science (both Galactic and extragalactic) in the era of ALMA and ngVLA.