The rate of expansion of the universe appears to vary depending on the objects used to measure it. A new model could resolve this discrepancy by suggesting that the universe rotates very, very slowly. (Image credit: Digital Art via Getty Images)
In 1929, astronomer Edwin Hubble published a paper demonstrating that the universe was expanding. This discovery led to the creation of the Hubble constant, a value that describes the rate at which the universe is expanding.
However, this has created a mystery known as the Hubble tension, as the rate of cosmic expansion varies depending on the cosmic objects used to measure it.
A new mathematical model could help resolve the Hubble contradiction by assuming that the universe is rotating.
A recent study published in March in the journal Monthly Notices of the Royal Astronomical Society suggests that our universe rotates once every 500 billion years. This extremely slow rotation could eliminate the discrepancy between different measurements of the Hubble constant.
“The standard cosmological model has its flaws,” study co-author Istvan Sapudi, an astronomer at the University of Hawaii at Manoa’s Institute for Astronomy, told Live Science via email. “A slow-rotating universe could help solve Hubble’s puzzle.”
Astronomers use several methods to measure the expansion rate of the universe. One involves observing supernovae — explosions of giant stars — and determining how fast these supernovae are moving away from each other. Another method relies on the cosmic microwave background, radiation that existed 380,000 years after the Big Bang. However, the two methods produce results that differ by about 10%.
The idea of a rotating universe is not new; mathematician Kurt Gödel proposed the concept in a 1949 paper published in the journal Reviews of Modern Physics. Other scientists, such as Stephen Hawking, have also explored the theory. In the new study, the team applied the concept of rotation to the Hubble voltage. Since all celestial bodies — from planets to stars, galaxies, and black holes — rotate, this behavior could naturally extend to the universe as a whole, the study authors suggested.
“To our great surprise, we found that our rotational model resolves the paradox without contradicting current astronomical data,” Chapudi said.
The supposed rotation speed of the Universe is too slow to detect, but it still affects the expansion rate and does not require the introduction of new physics.
However, the model only took into account some of the physics that was thought to be involved. “We are using Newtonian physics with some aspects of general relativity,” Chapudy said. “It would be desirable to fully integrate [general relativity].”
He also added that their work suggests that the universe is homogeneous and has not changed its density throughout its evolution. In future studies, the team plans to compare the rotating universe model with other cosmological models.
Elana SpivakNavigation via social linksLive Science Contributor
Elana Spivak is a science writer based in New York City. She holds an M.A. in science journalism from New York University and a B.A. in
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