General, Research, Technology

What do scientists know about the age and expansion of the universe?

The data obtained with the newThe Atacama Cosmological Telescope in Chile is further fueling an already heated debate in the astronomical community about the age and rate of expansion of the universe. This topic is the subject of active discussion among researchers using various astronomical instruments and methods. So, with the help of a new cosmological telescope, scientists studied "the oldest light in the observable Universe" and came to the conclusion that the Big Bang occurred 13.77 billion years ago, plus or minus 40 million years. But why did they decide that?

Before you is the Milky Way revolving abovea Tasmanian lake, in the still waters of which shining stars were reflected. Measurements of small variations in the polarization properties of the CMB (red and blue in the image) show the age of the Universe. The image covers an area of ​​the sky 50 times the width of the moon

How old is our universe?

The deeper we look into the cosmic oceanthe faster the galaxies move away from us. The eminent American astronomer Edwin Hubble discovered this in 1929 and since then, researchers have scrupulously tried to clothe this speed in numbers - the Hubble constant. Today there are two leadingapproach to determining the age of the universe. One of them compares the distance to local variables (Cepheids) 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 physics of the early Universe to predict the Hubble constant.

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Max Planck, the German theoretical physicist and founder of quantum physics, also took the second approach. He studied relict radiation (cosmic microwave backgroundradiation) - the first light that swept through space after the Universe had cooled down enough and neutral hydrogen atoms began to form in it - which is about 380,000 years of the life of space.

Light washes the Earth with an almost uniform glow formicrowave frequencies, and its temperature profile is only 2.7 degrees above absolute zero - read more about what it is in our material. But in this signal, you can detect the smallest deviations, as well as how the light becomes curved or polarized when it approaches us. One of the bits of information received is the value of the Hubble constant.

The 6-meter Atacama telescope in Chile examines the relic radiation

Work in which astronomers fromdifferent countries of the world, published on the arXiv preprint server (there are published works that have not completely passed the peer review). According to the results obtained, the Hubble constant is equal to 67.6 kilometers per second per megaparsec - megaparsec is 3.26 million light years.

The expansion of the universe is increasing by 67.6 km per second every 3.26 million light years. It is noteworthy that the number obtained withusing the Planck method, is 67.5. But shouldn't similar approaches give similar results? According to BBC News, the experiments were quite different, but in what exactly?

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Expansion of the universe

Planck's calculations seem to "take place" in space,but we 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 the measurements, the gap between the two methods became insurmountable. At the same time, it cannot be ruled out that both methods are somewhat erroneous, or, perhaps, there is some new physics that neither of the parties understood.

Every time we look at the stars we see the past

There may be slight offsets in the setsdata obtained from the study of relic radiation or supernova explosions (or both), which are not fully taken into account. But as the tools and methods of observation become better, to understand, it becomes more difficult for us to understand what is really going on. The alternative is that there is something fundamental in the universe that we don't understand.

Professor Isobel Hook from Lancaster University, UK.

There are several theories that tryto explain this discrepancy - according to one of them, the additional early expansion in the Universe makes the relic radiation a “measure” of other physical quantities. But there are also problems with these theories. The study authors admit they don't know which side they are on, but the argument is very exciting.