Quirks & Quarks

Close Encounter with a Star

70,000 years ago a wandering star brushed by our solar system.
Artist's conception of Scholz's star and its brown dwarf companion (foreground) during its flyby of the solar system 70,000 years ago. The Sun is left, background. (Michael Osadciw/University of Rochester.)
70,000 years ago, a tiny Red Dwarf star visited our solar system, brushing by the outer reaches of the Oort Cloud, a mere 7.6 trillion kilometres from the sun.

That might not seem like such a close visit, but according to Dr. Eric Mamajek, an astronomer and professor at the University of Rochester, who traced the star's path, in astronomical terms that's a very close call.

Dr. Mamajek and his colleagues saw the star receding from us and traced its course backwards to discover that it was the closest known encounter of a star with our solar system. These events are relatively rare, but are important, as a close flyby can potentially disturb the orbits of comets and the outer planets, and lead to cosmic collisions.

Related Links

- Paper in The Astrophysical Journal Letters
- Dr. Mamajek's FAQ on the encounter
- University of Rochester release
Sky and Telescope story
BBC News story