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Stargazing Lecture

Friday, April 10, 2020
7:00pm to 9:00pm
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Online Event
The Circumgalactic Medium: The Gas Around Galaxies
Yuguang Chen, PhD Candidiate, Department of Astronomy, Caltech,
  • Public Event

This event, originally scheduled for April 3, is being moved online in light of the impact of COVID-19. Because this is an online event, the in-person stargazing that normally follows events in this series will not be possible.


7:00–7:30 p.m. - Virtual Lecture
7:30–9:00 p.m. - Virtual Panel Discussion


The galaxies that we are familiar with are only a tiny tip of a giant iceberg. In 1969, astronomers John Bahcall and Lyman Spitzer proposed that all galaxies are embedded in massive, enormous gas clouds. It is only in the last decade that we have developed efficient tools to detect and probe the details of these clouds, which are now known as the "circumgalactic medium". But what is the nature of this gas? How do we study it? And how does it affect how galaxies like our Milky Way form and evolve over cosmic time? I will address these questions and introduce you to this exciting frontier in astronomy.

About the Series

Stargazing Lectures are free lectures at a public level followed by a Q&A panel and guided stargazing with telescopes (weather permitting). All events are held at the Cahill Center for Astronomy and Astrophysics at Caltech. No reservations are needed. Lectures are 30 minutes; stargazing and panel Q&A last 90 minutes. Stay only as long as you want.

Stargazing is only possible with clear skies, but the lecture and panel Q&A takes place regardless of weather.

For directions, weather updates, and more information, please visit:

Download the series flyer (PDF)

For more information, please contact Cameron Hummels by email at [email protected].