Physics & Astronomy Colloquium

Thursdays, 4:00-5:00 pm

Virtual Colloquium Meetings are held via Zoom, in-person events in PAB 1-434. Meeting information will be sent in email. You may watch past presentations by clicking the title link when available.

For more information, contact Katsushi Arisaka.

Click here for the 2022-2023 archived Physics & Astronomy Colloquium.

Click here for the 2021-2022 archived Physics & Astronomy Colloquium.

Click here for the 2020-2021 archived Physics & Astronomy Colloquium.

Click here for the 2019-2020 archived Physics & Astronomy Colloquium.

Spring 2023

Thursday, April 6, 2023

Thermal Infrared and Cosmological Observations from Space
Edward (Ned) Wright
University of California, Los Angeles

Abstract: Thermal IR spans the range of wavelengths from 2.3 to 300 microns. In this broad range, radiation from room temperature optics overwhelms the radiation from the night sky, producing a much as 26 million photons/second of telescope background at 10 microns in a diffraction-limited beam. Goingtospaceallowscoldtelescopetoreducethisbya factor of 3 million. Objects that radiate primarily in the IR include very high redshift galaxies, cold brown dwarfs or free floating planets planets, and very dusty protostars: "the old, the cold and the dusty". I will discuss COBE, WMAP, the Spitzer Space Telescope and WISE which are already in space. Finally, I will discuss NEO Surveyor, a Planetary Defense Mission to locate potentially hazardous asteroids which is scheduled for 2027.

Thursday, April 20, 2023

Developing New Windows Into the Secret Lives of Cells
Eric Betzig
University of California, Berkeley

Abstract: The hallmark of life is that it is animate. To gain a better understanding of how inanimate molecules assemble to create animate life, it is necessary to image the dynamics of living organisms noninvasively at high resolution in both space and time. Beginning in the 1980's, the widespread availability of computers, lasers, sensitive detectors, and fluorescence labeling techniques has allowed physicists and engineers to develop new microscopes with the ability to understand the findings of genetics and biochemistry in the context of spatially complex and dynamic living systems. I will discuss the role of my lab in this developing story, and show how an increasingly detailed look at life has increasingly revealed an intricate and beautiful world.

Thursday, April 27, 2023

Membranes, RNA World and the Origin of Life
Robijn Bruinsma
University of California, Los Angeles

Abstract: Molecular self-assembly and self-replication are central in attempts to reproduce the earliest biological systems in a laboratory setting. The colloquium will discuss these concepts and then focus on the proto-cells that were developed in the laboratory of Nobel laureate Jack Szostak. Interplay between the physics of membranes and the self-replication of nucleic acids produces new physical phenomena that allow the proto-cells to assemble, grow, divide, and acquire increased complexity. A second focus of the colloquium will be on the question how proto-cells can capture free energy from the environment required to power these processes, and why ion concentration gradients across membranes are believed to play the central role in this context.