The study centers around an effect called gravitational microlensing. And the idea is that supermassive objects, such as stars, can bend light that passes by them. The object’s gravity actually works as a sort of lens, warping the direction of the passing light. Einstein predicted this in his theory of general relativity, but because observing that effect requires a very specific set of parameters to line up perfectly, he thought we’d never be able to observe it directly.
But pessimism got the better of Einstein here and because our technology is way better than what it was during his time, these microlensing effects are now detectable.
Researchers using NASA’s Hubble Space Telescope watched a white dwarf star — the leftover core of a star nearing the end of its life — pass in front of another distant star. When it did, the white dwarf appeared to push the other star out of its way. It didn’t actually do that, though. The white dwarf’s gravity just warped the light of the background star, making it look like the light jumped out of the way. It’s the first time this effect has been seen from stars other than the Sun.
In addition to just being really cool, this new technique also allows astronomers to measure the mass of the star doing the warping. The intensity of the light-deflection can help scientists determine the object’s mass and gravity. In the study, they were able to get the mass of the white dwarf based on this effect, which they hadn’t been able to successfully do before.
Watch the video below for more information on the study and what the findings mean for future research.