The universe can be frustrating. Roughly two-thirds of everything in the universe appears to consist of dark energy. Despite decades of study, though, scientists haven’t been able to explain what dark energy is.

Astronomers discovered dark energy by studying a type of supernova – exploding stars. The supernovas brighten and fade in a predictable way. That allows astronomers to measure their distance and their motion away from us. Stars that are farther were moving away faster than expected. That suggested that something was causing the universe to expand faster over time: dark energy.

But a recent study said that dark energy might not exist. Instead, the researchers proposed a new model to explain what we see, called timescape.

The model notes that matter clumps together in clusters of galaxies, with huge “voids” between them. Time passes more slowly in the presence of stronger gravity – like that exerted in the denser regions. So the voids, with less gravity, could be billions of years older than the clusters – creating “bubbles” of spacetime.

If that’s correct, then it would be tough to know just when the supernovas in different parts of the universe exploded. And that makes it tough to know how fast they’re moving away from us. So the study says we don’t need dark energy to explain what we see in the universe.

But there’s still a lot of work to be done to understand dark energy – including whether it even exists.

Script by Damond Benningfield