“Are we living in a giant vacuum?”

How fast the universe expanded remains controversial today because measurements contradict each other. A research team is now applying an external theory.

Bonn – Research has known for many decades that the universe is expanding. The Hubble-Lemaitre constant shows how quickly this expansion is occurring. But there is a problem with this: a constant is not a constant – it gives a different value depending on how you define it. This so-called “Hubble tension” is one of the biggest mysteries in cosmology.

However, an international research team now claims to have solved the mystery. The study presenting the potential solution was published in the journal Monthly Notices of the Royal Astronomical Society (MNRAS) published.

“In our new work, we offer a possible explanation: that we live in the vast vacuum of space,” study co-author Indranil Panik wrote in a guest post. On the platform Conversation. There are two ways to calculate the Hubble-Lemaitre constant: One method uses cosmic background radiation – cosmology uses this to calculate a speed of approximately 244,000 km/h for every megaparsec of distance between two celestial bodies (a megaparsec is equivalent to about three million light-years). ).

How fast is the universe expanding? The Hubble-Lomaitre constant is not a constant

However, if you use Type 1a supernovae to calculate the expansion speed, you get approximately 264,000 km/h per distance of one million parsecs – a great mystery to date in cosmology. “The universe appears to be expanding faster in our surroundings — a distance of about three billion light-years — than in its entirety,” says Pavel Krupa of the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn. “This should not actually be the case,” the expert said.

The Standard Model of cosmology does not recognize “bubbles” in the “cookie dough” of the universe

However, there has been a recent observation that could explain this, according to the research team. Therefore, the Earth is located in a region of space that contains a relatively small amount of matter. In one Communicate about the study It is compared to an air bubble in a cake. The density of matter is higher around the bubble. Gravitational forces emerge from this surrounding matter, which pulls the galaxies in the bubble toward the edge of the cavity.

“As a result, they are moving away from us faster than expected,” explains Panek (University of St Andrews), who speaks of a “vast void” or “an area of ​​below-average density.” The Standard Model of cosmology does not allow such faint densities to exist; they should not exist in reality, but matter should be evenly distributed in space.

“The Standard Model is based on a theory about the nature of gravity put forward by Albert Einstein,” Krupa asserts. “Gravity forces may behave differently than Einstein predicted.” To get to the bottom of the puzzle, the team around Krupa and Panek used modified gravity theory in the simulation. Modified Newtonian Dynamics (MOND) is still considered a strange theory to this day, but it is Used repeatedly in studieswhen it comes to the Hubble effort, for example.

MOND intruder theory could solve the mystery of cosmology

“In our calculations, MOND accurately predicts the existence of such bubbles,” Krupa says. The new study shows that if gravity actually behaved as MOND theory suggests, the Hubble jitter would disappear. Then there would be only one constant for the expansion of the universe – and the observed deviations would be due to irregular matter distribution.

“Einstein is said to have said that we cannot solve problems using the same thinking that led to the problems,” Panek wrote in his op-ed. “Even if the changes required are not radical, we may be witnessing the first reliable solution,” he continued. Evidence in more than a century We need to change our theory of gravity. (unpaid bill)