In July 2020, astronomers discovered that the universe looks a little “unusual”, with galaxies, gas and other matter not clumping together as they should – the universe is thinner than we previously thought. It instantly became one of the hottest topics of discussion among cosmologists.
The difficulty with studying the modern universe is that it is almost invisible. Astronomers have described the universe as we know it now based on observed luminous star clusters, etc. In addition to these luminous objects, there are many other “dark gases” in the universe (such as dark matter, gas clouds, etc.), which astronomers are still unable to perceive.
To make matters worse, most people believe that most of the universe is made of these “dark gases”, which are the big frame of the entire universe, and the galaxies, nebulae, etc. we see are just hanging on this frame. decorations.
The July 2020 measurement was the most precise method yet, and it’s perfect for revealing the unseen. When light from distant galaxies reaches Earth, it passes through dark matter and faint clouds of gas. These “thick spots” pull light rays under the force of gravity, distorting their paths. By the time the light from distant galaxies reaches our ground-based telescopes, it’s already distorted — possibly squeezed into exaggerated ellipses. So, by measuring the shape distortions of a large number of distant galaxies, astronomers have attempted to map the invisible dim matter in the universe.
In this measurement, the surveyors observed about 31 million galaxies at distances up to 10 billion light-years away. They then used these observations to calculate the average distribution of dark matter and hidden gas in the universe. The cosmic “clump” they found was nearly 10 percent thinner than predicted by currently established models of the universe.
Another independent measurement also supports the finding that the modern universe is thinner than previously thought. In this measurement, the researchers created a map of the universe’s hidden matter by watching galaxies drift through the universe. In this image, the clumps in the modern universe are almost as small and thinner than previously thought, as recently measured clumps.
Additionally, at least 12 measurements over the past eight years (all using different techniques) have found that the universe today is thinner than thought. This has made some cosmologists increasingly skeptical that the universe is really thin, after all, when we start seeing the same thing in a ton of different data sets, we usually think it’s really telling us something.
How does it fit with the model of the universe?
Why are actual observations of the universe thinner than theoretically predicted?
First of all, the Standard Model of cosmology is a model made to be suitable for observing and explaining the universe. Therefore, in order to keep the model consistent with newly observed cosmic phenomena, cosmologists continue to add and delete this model. For example, some theorists have tried adding “dark radiation” to the early universe in order to explain why the universe is expanding so rapidly. But adding dark radiation would have to balance it out with extra matter, and adding matter would make the universe “thick.”
And now, new measurements have found that the universe is not as thick as the Standard Model says it is. To explain why the universe is the way it was recently measured, cosmologists are getting busy again. They must create new explanations and revise the Standard Model of the universe again to match the new observations.
Some cosmologists speculate that some dark matter in the universe is converted into dark energy, which makes the universe expand rapidly, so the universe becomes thinner. Or, the Earth happens to be in a huge void in the universe, and what we observe is the result of distortion. Alternatively, the two anomalies may not be related in any way.
Of course, the discrepancy between the observations and the model of the universe can still be resolved with more data. Currently, increasingly sophisticated measurements of the universe are underway. Among them, the Chilean International Dark Energy Measurement Project covers an area of 5 times the sky of this measurement project in July 2020, and its measurement results are likely to change some of our views of the universe. Obviously, a lot of people are waiting for it, and it will be the next big thing in cosmology.
However, it must be noted that at distances of billions of light-years, galaxies appear only as pixels, complicating analyzing their shapes. Researchers also need to know how far each galaxy is, and how they deal with the uncertainties that come with those distances can have profound implications for our understanding of the universe.