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A possible explanation for one of cosmology’s greatest mysteries has arrived

A possible explanation for one of cosmology’s greatest mysteries has arrived

A study from the Universities of Bonn and St Andrews proposes a solution to what is called “Hubble jitter.”

The universe is expanding. The speed at which this is done is described by what is called Hubble-Lameter constant. But there is controversy about how large this constant actually is: different measurement methods provide contradictory values. This “Hubble tension” is a mystery to cosmologists. Researchers from the Universities of Bonn and St Andrews propose a new solution: using an alternative theory of gravity, the discrepancy in the measured values ​​can be easily explained. The Hubble effort disappears.

What is Hubble tension?

Credit: University of Bonn

The expansion of the universe causes galaxies to move away from each other. The speed at which they do it Proportional to the distance between them. For example, if Galaxy A is twice as far from Earth as Galaxy B, then its distance from us is also increasing twice as fast. American astronomer Edwin Hubble was one of the first to recognize this connection.

How is the expansion of the universe calculated?

In order to calculate the speed at which two galaxies are moving away from each other, it is necessary to know How far apart they are. However, this also requires a constant by which this distance must be multiplied. This is the so-called Hubble-Lameter constant, which is a fundamental parameter in cosmology. Its value can be determined, for example, by observing the most remote regions of the universe. This gives a speed of approximately 244,000 kilometers per hour per megaparsec distance (a megaparsec is equivalent to just over three million light-years).

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Was Einstein wrong?

About the Hubble constant. According to scientists, matter should be evenly distributed in space. However, if this were the case, it would be difficult to explain the forces that push galaxies to their high velocities. The study’s authors say: “The Standard Model is based on the theory of gravity proposed by Albert Einstein.” “However, gravitational forces may behave differently than Einstein predicted.”

– Irregularities in the distribution of the material

Teams from the Universities of Bonn and St Andrews used a modified theory of gravity in a computer simulation. This “modified Newtonian dynamics” (abbreviation: MOND) was proposed four decades ago Written by Israeli physicist Professor Dr. Mordechai Milgrom. If gravity behaved according to Milgrom’s postulates, the Hubble tension would disappear: in fact there would be only one constant for the expansion of the universe and the observed deviations would be due to irregular matter distribution.

References: University of Bonn