In what could be a huge new breakthrough in our understanding of the universe, scientists have put together the most precise measurements to date of the expansion of the universe thanks to a new “yardstick” they developed. And by using these measurements, thanks to the Hubble Space Telescope, they were able to determine the universe is expanding at a much different rate than we thought.

It is such a big new discovery that it could require a new understanding of physics, and challenges old ways of measuring the universe’s expansion, first described in a Nobel Prize-winning paper in 1998. The research indicates we have a lot to learn about the increasing expansion of the universe, and therefore about its origins.

Researchers are calling the new yardstick the “Hubble constant,” and it took years of developing better measurements to arrive at it. They combined ancient Greek geometry with modern and sophisticated techniques to create the new measuring system.

“The community is really grappling with understanding the meaning of this discrepancy,” said lead researcher and Nobel Laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, both in Baltimore, Maryland.

“Both results have been tested multiple ways, so barring a series of unrelated mistakes,” Riess explained, “it is increasingly likely that this is not a bug but a feature of the universe.”