Pair of stars buzzed the solar system 70,000 years ago

A pair of dim red stars, shown in an illustration, passed within 0.8 light-years of the sun (left) roughly 70,000 years ago.

Michael Osadciw/Univ. of Rochester

Most stars keep their distance from the sun. Scholz’s star, about 20 light-years away in the constellation Monoceros, is an exception. Roughly 70,000 years ago, the binary star system came within about 0.8 light-years of the sun, researchers report in the February 12 Astrophysical Journal Letters. It’s the closest known flyby of another star.

When Scholz’s star buzzed the solar system, it probably slipped inside the Oort cloud, a shell of trillions of comets that envelops the solar system. While such close encounters can hurl a barrage of comets toward the sun, Scholz’s star’s flyby apparently spared the inner solar system.