Cornell University

Cornell Department of Astronomy & Space Sciences Fall 2021 Colloquium Series. Gold Lecture:

Thursday, October 21, 2021 at 4:00pm to 5:00pm

Space Sciences Building, 105

Gold Lecture: "Comets, unseen planets, and the outer fringes of the solar

This lecture is primarily in-person. Zoom access is available, but the effect may not be optimal.

Abstract: Comets have inspired awe since prehistoric times, but even today there are only a few thousand comets with well-determined orbits. Nevertheless, the analysis of this limited sample yields a compelling model for the formation, evolution and present distribution of comets. This model implies that the primary source of comets is the Oort cloud, containing over 100 billion comets at 5,000 to 100,000 times the Earth-Sun distance. I will review our current understanding of the history and structure of the Oort cloud, and what comets can tell us about possible undiscovered planets beyond Neptune.


Contact for Zoom link: or

Dial-In Information

The colloquia are held every Thursday afternoon 4-5 pm. The public is welcome. To view via Zoom, please contact Jill Tarbell or Jason Jennings ( for the link.

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Contact Name

Monica Carpenter

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Scott Tremaine

Speaker Affiliation

Institute for Advanced Study

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