Nasa telescope shows universe is expanding at an unexpected rate

The universe appears to be expanding faster than initially thought possible, according to new observations from NASA’s James Webb Space Telescope.

There is an unexplained discrepancy between the observed expansion rate of the universe and the rate scientists thought was possible based on our knowledge of the cosmos - known as the Hubble tension. But, according to new research in The Astrophysical Journal, new measurements from the James Webb Space Telescope (JWST) have confirmed that the Hubble tension is not down to a flaw in our observations but potentially due to the influence of dark matter and dark energy - a hypothetical form of energy proposed by physicists to explain the accelerating expansion rate.

For the study, the research team analysed data from the JWST's first two years in space to calculate the rate at which galaxies were moving away from each other. This new data confirmed the findings of the Hubble Space Telescope, that the universe is expanding faster today than it did during its first few billion years.

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Study co-author Adam Riess, a Nobel laureate and professor of physics and astronomy at Johns Hopkins University, said in a statement: "The discrepancy between the observed expansion rate of the universe and the predictions of the standard model suggests that our understanding of the universe may be incomplete.

"With two NASA flagship telescopes now confirming each other's findings, we must take this [Hubble tension] problem very seriously - it's a challenge but also an incredible opportunity to learn more about our universe."

Today’s rate of expansion of the universe is a figure known as the Hubble constant. This is measured in units of kilometres per second per megaparsec (km/s/Mpc), where a megaparsec (Mpc) is around 3.26 million light-years.

Based on scientific knowledge of the universe, the Hubble constant should be lower than the value observed by the Hubble Space Telescope by around 5 km/s/Mpc. This difference, which cannot easily be explained, is the Hubble tension.

The JWST measurements were found to closely match those of the Hubble, meaning the tension was not due to Hubble instrument error. Therefore, the new study concludes that Hubble tension must be due to unknown gaps in our knowledge of the physics of the universe.

Marc Kamionkowski, a Johns Hopkins cosmologist who helped calculate the Hubble constant but was not involved in the new study, said: "One possible explanation for the Hubble tension would be if there was something missing in our understanding of the early universe, such as a new component of matter - early dark energy - that gave the universe an unexpected kick after the big bang.

"And there are other ideas, like funny dark matter properties, exotic particles, changing electron mass, or primordial magnetic fields that may do the trick. Theorists have licence to get pretty creative."

The James Webb Space Telescope, a collaborative project between NASA, ESA (European Space Agency), and CSA (Canadian Space Agency), was launched on 25 December, 2021 from the Guiana Space Centre in French Guiana. It was sent to its operational location at the second Lagrange point (L2), approximately 1 million miles from Earth, and became operational for scientific observations in July 2022.