A study with ties to Utah Valley University is helping fuel a controversy over the age of the universe
Jul 30, 2025, 7:00 AM
Utah Valley University Dr. Joe Jensen poses for a portrait in the Planetarium on the UVU Campus in Orem, Utah on Wednesday, July 16, 2025. He is among a group of scientists and students revealing new information about how the universe expands. (August Miller, UVU Marketing)
(August Miller, UVU Marketing)
SALT LAKE CITY — For many years scientists have agreed that the age of the universe is 13.8 billion years. But for the last 20 years or so, scientists have made observations that indicate that age may be wrong.
Utah Valley University Physics Professor Joseph Jensen is one of those people. Jensen, one of his students and a few other scientists around the world recently published a study that challenges a key part of the theory that fuels the 13.8-billion-year prediction.
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“Maybe 20 years ago, we discovered that the universe was accelerating, that the expansion of the universe was getting faster with time,” Jensen said. “And as that expansion accelerates, it implies something about both the age of the universe and also what the universe is made of.
“If the universe has a lot of matter in it, that matter pulls things together and slows down the expansion. So, if it’s not slowing down, it’s speeding up, it means that the universe must be dominated not by stars, not by galaxies, not by dust, not by planets, or any of the things we’re used to seeing, [it] must be dominated by something that is causing that expansion to accelerate.
“We don’t know what that is, but we call it dark energy as kind of a a placeholder for our our lack of understanding. It could be almost anything that causes that expansion to accelerate,” Jensen said.
The current model suggests that the universe accelerates at a rate of 67.5 kilometers per second per megaparsec, a unit of length that measures the large distances to astronomical objects outside the solar system.
By using the Hubble Telescope as well as other methods, Jensen and the other study authors say they’ve calculated the universe’s expansion at 73.8 kilometers per second per megaparsec. Jensen said that while that isn’t a large gap numerically, since a megaparsec is 3.2 million light years, the difference represents a very large gap.
“That represents a difference of of what we call five sigma or five standard deviations,” Jensen said. “Whenever a theory makes a prediction and the observations don’t match by five sigma, then you know that there’s something missing. Either there’s some major error that you’ve made in your measurements, or there’s something about that theory that’s incomplete.”
How expansion is measured
Jensen said theorists believe there’s currently a problem with the way universe expansion is being measured.
“If you’re using the wrong length ruler to start with, it won’t matter how many times you measure it, you’ll always be wrong. So in this case, what you need to do is get a new ruler, and that’s the work that we did.”
Jensen said his team used a different distance measurement technique that doesn’t rely on the previous version.
“And we came up with the same answer. So that indicates that we’re probably using a good ruler, and it’s the theory that requires a second look,” he said.
The scientific method
The opportunity to to learn new things and apply new information to existing databases is valuable to scientists. It’s a part of the scientific method.
“We value … the opportunity to learn new things when the theories and the observations don’t quite match up. It’s when there are these disagreements that we that we get excited.”
