'Intruder' stars have changed Earth's climate over the eons. Here's how.

Illustration showing earth in the foreground, with the sun and a more distant intruding star in the background.

Stars intruding into the sun's cosmic backyard could have shifted Earth's orbit in the distant past, triggering major climate events in our planet's history.  

The gravitational influence of these intruder stars has also impacted the orbit of other planets in the solar system, causing minor deviations called perturbations.