Abstract: What does a black hole look like? The first images of the supermassive black hole M87* display a bright ring encircling the event horizon, which appears as a dark patch in its surrounding emission. But Einstein's theory of general relativity predicts that within this image there also lies a thin "photon ring" consisting of multiple mirror images of the main emission. These images arise from photons that orbited around the black hole multiple times, probing the warped space-time geometry just outside its horizon. The photon ring carries an imprint of the strong gravity in this region and encodes fundamental properties of the black hole. A measurement of this predicted (but not yet observed) ring could provide a precise test of general relativity and will be the target of a NASA mission proposed to fly within the next decade.
***Join before the Colloquium at 3:00 pm for discussion with speaker, Dr. Sasha Philippov, in Wilder 103, for coffee and cookies!***
Hosted by Rufus Boyack
Please click the link below to join the webinar:
https://dartmouth.zoom.us/j/92598910992?pwd=TzE5Qlg0TW1CTGczTnhVZmVkMVo1QT09
Passcode: Physics