‘Oumuamua: A Mysterious Interstellar Interloper

Amaya Moro-Martin, Space Telescope Science Institute

During the formation of our solar system, a tremendous number of asteroids, comets, and planetesimals were ejected into interstellar space by gravitational encounters. If extrasolar planetary systems, which are now known to be quite common, experienced a similar development, then our galaxy should be teeming with these expelled objects. Astronomers were perplexed that none had been found passing through our solar system.

Then, in 2017, the discovery of ‘Oumuamua transformed the situation from puzzlement to bewilderment. Observations with a wide range of telescopes followed the brightness and trajectory of this first interstellar interloper but left important questions about its origin and composition unanswered. Further, what process was responsible for the non-gravitational acceleration found in its unbound orbit?

This cosmic visitor will not return to provide explanations. Thus, the intriguing inquiries ‘Oumuamua left behind will remain as we seek out and study other guests from beyond our solar system.

Host: Frank Summers, Space Telescope Science Institute
Recorded live on Tuesday, July 7, 2020
More information: www.stsci.edu/public-lectures