Why is the universe expanding

Hubble measures space Our universe is expanding faster

Where is the problem?

With their studies of 70 stars in our neighboring galaxy, the Large Magellanic Cloud, Riess and his team have refined the so-called Hubble constant and thus calculated that the universe is expanding at a speed of 74.03 kilometers per second per megaparsec. In other words, the universe grows 74.03 kilometers every second at a distance of one megaparsec (about 3.26 million light years).

This is around 10 percent faster than previous observations and calculations suggest. They come from the Planck satellite of the European Space Agency ESA. He examined the cosmic background radiation that arose around 380,000 years after the Big Bang.

These are not just two experiments that mismatch.

Adam Riess, Nobel Prize Winner

Because in this case, according to Riess, fundamentally different things are involved. “One is a measure of how fast the universe is expanding from today's perspective. The other is a prediction based on the physics of the early universe and measurements of how fast it should expand. If those values ​​don't match, then one exists very high probability that something is missing in the cosmological model that connects the two epochs. "

What is missing in the model of the universe?

Is our model of the cosmos correct? So that's the big question that researchers now have to answer. So far, dark matter or dark energy have been seen as possible candidates that interact more strongly than expected with the part of the universe that we can observe.

Regardless of these theoretical questions, Riess and his team want to use their observations to continue working on the refinement of the Hubble constant.

The results of the current study are in The Astrophysical Journal published.