We're light-years away from the closest stars, but in the billions of years of history in the Milky Way, our Sun has come much closer to other stars. For example, a star passes within 0.8 light-years every millions years and 0.16 light-years every 20 million years. These close passes have had a collective effect on the planets, shifting their orbits and helping to explain some of the eccentricities of the planets. Some of these might even have affected Earth's climate.

Astronomers still aren't entirely sure what causes fast radio bursts, which can briefly release a galaxy's worth of energy. However, they might have figured out how to use them to measure distances in the Universe. In a new paper, astronomers propose that fast radio bursts could be detected as they're magnified by stellar microlenses. With about 30 microlensing events, they should be able to measure cosmic distances precisely.