Today in the history of astronomy, we meet our first interstellar visitor.

| Published: October 19, 2026

‘Oumuamua, the first-known interstellar visitor, is seen venting gas and dust in this artist’s concept. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

Sometime around the year 1837, a strange object passed an invisible cosmic mile marker: 1,000 astronomical units from the Sun. (One astronomical unit, or AU, is the average Earth-Sun distance.) For more than a century, it continued undetected toward our star. Finally, on Oct. 19, 2017, humans noticed the visitor.

That night, a faint, thin streak appeared in a 45-second-long image snapped by the University of Hawai’i’s Pan-STARRS1 Telescope on Maui. The next morning, postdoctoral researcher Robert Weryk spotted the streak and compared it to an image taken the day before. The object was there, too. It was moving steadily across the sky, covering about 6.2° each day.

By Oct.…