What do we know about the age and expansion of the universe

With the new cosmological telescope, scientists studied “the oldest light in the observable universe” and concluded that the Big Bang occurred 13.77 billion years ago, plus or minus 40 million years. But why would they think that?

How many years is our universe?

The deeper we look into the cosmic ocean, the faster galaxies move away from us. The eminent American astronomer Edwin Hubble discovered this in 1929, and since then researchers have been scrupulously trying to put this speed into figures – the Hubble constant. Today, there are two leading approaches to determining the age of the universe. One compares the distance to local variables (cepheid) and exploding (supernovae) stars, the other suggests looking at the state of the cosmos shortly after the Big Bang and using an understanding of the laws of early universe physics to predict the Hubble Constant.

Max Planck, a German theoretical physicist and pioneer of quantum physics, also took the second approach. He studied relict radiation (cosmic ultra-high-frequency background radiation), the first light to travel through space after the universe had cooled down sufficiently to form neutral hydrogen atoms – about 380,000 years of cosmic life.

Light washes the Earth almost uniformly at microwave frequencies and its temperature profile is only 2.7 degrees above absolute zero. But in this signal you can find the tiniest deviations and how light becomes curved or polarized when it approaches us. One of the particles of information obtained is the value of the Hubble constant.

The work, in which astronomers from all over the world took part, was published on the server of preprints arXiv (there are published works, not fully peer-reviewed). According to the obtained results, the Hubble Constant equals 67.6 kilometers per second per megaparsek – megaparsek is 3.26 million light years.

The expansion of the Universe increases by 67.6 kilometers per second for every 3.26 million light years. It is noteworthy that the number obtained using the plank method is 67.5. But shouldn’t such approaches produce similar results? According to BBC News, the experiments were quite different, but in what way?

The expansion of the universe.

Planck’s calculations are sort of “happening” in space, but you and I are on Earth, which means that we observe smaller angular scales and our calculations simply cannot be the same. Over time, due to the uncertainty in measurement, the gap between the two methods has become insurmountable. At the same time, we cannot exclude the fact that both methods are erroneous in something, or perhaps there is some new physics that neither side has not understood.

There may be small offsets in datasets obtained from the study of relict radiation or supernovae explosions (or both) that are not fully accounted for. But as the tools and methods of observation become better, it becomes increasingly difficult for us to understand what is really going on. The alternative is that there is something fundamental about the universe that we do not understand.

Professor Isobel Hook of Lancaster University, UK.

There are several theories that try to explain this discrepancy – according to one of them, additional early expansion in the universe makes relict radiation a ‘yardstick’ of other physical quantities. But there are problems with these theories, too. The authors of the research admit that they don’t know whose side they’re on, but the argument is very fascinating.