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Friday, April 16, 2021
7:00 PM - 9:00 PM
Online Event

Stargazing Lecture

Endless Hunt for Black Holes
Wenbin Lu, David and Ellen Lee Postdoctoral Scholar Research Associate, Department of Theoretical Astrophysics, Caltech,

Because this is an online event, the in-person stargazing that normally follows events in this series will not be possible.

Join the YouTube Livestream here:

7:00–7:30 p.m. - Virtual Lecture
7:30–9:00 p.m. - Virtual Panel Q&A and Discussion

The existence of black holes is one of the most striking predictions of Einstein's theory of general relativity, but it has been a century-long journey to test whether these bizarre objects are actually formed in our universe. This question has been investigated in several different ways: by considering the evolution and eventual collapse of massive stars; by observing stellar motion around a "dark mass concentration" at the center of our own galaxy; by examining X-ray and radio emission from gas falling into "dense massive objects"; by viewing light bent by the gravitational potential of free-floating "invisible objects"; and most recently, by collecting gravitational waves from colliding "compact massive binaries". I will show that black holes predicted by general relativity have passed all these checks with scrutiny, and then I will discuss what additional ways astronomers can further test the existence of black holes.

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:

For more information, please contact Cameron Hummels by email at