"They're saying that there's as much light outside of galaxies as there is inside of galaxies, which is a pretty tough pill to swallow, frankly," notes Michael Zemcov, an astrophysicist at Rochester Institute of Technology, who was not part of the research team.
A few years ago, Zemcov and some colleagues analyzed New Horizons data in a similar way. Using fewer images, they made a less precise measurement, but it was still compatible with the current results.
He says for 400 years, astronomers have been studying visible light and the sky in a serious way and yet somehow apparently "missed half the light in the universe."
"It's very difficult to turn around and say to the astronomical community, like, 'Hey, guys, we're missing half of the stuff out there,'" says Zemcov. Still, he buys the results: "I think the work is really solid."
"Or perhaps there's a more exotic explanation"some unknown phenomenon out in the universe that creates visible light. It's even possible it's something associated with dark matter, a mysterious form of matter that exerts a gravitational pull on visible matter but has never been seen directly.
"As a person who studies the universe, I really want to know what the universe is made of and what are all the components of the universe," says Postman.
"We would like to think that the components that give off light are something that we can really get a good sense of and understand why there is that much light." - excerpts