The universe is expanding faster than expected

Data collected over two years by NASA's James Webb Space Telescope have confirmed earlier Hubble findings that the universe is expanding about eight percent faster than expected based on astrophysicists' knowledge of initial conditions. of the universe and its evolution over billions of years.

This new confirmation of a surprising observation has scientists thinking about a cause – perhaps an unknown factor involving mysterious components of energy and dark matter.

Observations by the Webb, the most powerful space telescope to date, appear to rule out the idea that the data from its predecessor, the Hubble, may have been inaccurate due to a flaw in its instruments.

"This is the largest sample of data from the Webb telescope in its first two years in space and confirms Hubble's puzzling discovery, which we've been grappling with for a decade - that the universe is expanding faster than our best theories can explain," said astrophysicist Adam Riess of Johns Hopkins University in Maryland, lead author of the study published Monday in the scientific journal Nature. Astrophysical Journal.

"Yes, it seems that something is missing in our understanding of the universe," added Riess, winner of the 2011 Nobel Prize in Physics for co-discovering the accelerating expansion of the universe.

"Our understanding of the universe lacks knowledge of two elements – dark matter and dark energy – which make up 96 percent of the universe. So this is no small thing," he said.

"Webb's results could be interpreted as suggesting that a revision of our model of the universe may be necessary, although at this point it's very difficult to define exactly what that is," said Siyang Li, a doctoral student in astronomy and astrophysics at Johns Hopkins University and co-author of the study.

Dark matter, which is thought to make up about 27 percent of the universe, is a hypothetical form of matter that is invisible but assumed to exist based on the gravitational effects it has on ordinary matter—stars, planets, moons, and all things on Earth, which make up about five percent of the universe.

Dark energy, believed to make up approximately 69 percent of the universe, is a hypothetical form of energy that permeates vast space, defies gravity, and drives the universe's accelerated expansion.

"There are many hypotheses involving dark matter, dark energy, dark radiation – for example, neutrinos (a type of elementary particle with very little mass) – or gravity itself that might have some exotic properties. All of these appear as possible explanations," Riess said.

The researchers used three different methods to measure a specific metric – the distance from Earth to galaxies where special pulsating stars called Cepheids have been documented. Webb's and Hubble's measurements matched.

The Big Bang that occurred 13 to 14 billion years ago started the universe that has been expanding ever since. Scientists in 1998 discovered that this expansion is actually accelerating and hypothesized that dark energy may be the reason.

For the new study, scientists analyzed Webb data covering about one-third of Hubble's full list of relevant galaxies. In 2023, they published that Webb's interim data confirmed Hubble's findings. /Telegraph/