How complicated is the cosmos?

How complicated is the cosmos?

Humans still have difficulty understanding the universe. © den-belitsky/Istock

One foundation of the Standard Model of cosmology is in question: Is the universe, on the whole, not as simply structured as thought? In the December issue, Bild der Wissenschaft reports on how newly discovered giant structures and mysterious dynamics in space could change fundamental ideas about the universe.

We want to know! Human curiosity has always been focused on the “big picture”. As is well known, the initially religious and mythical ideas about the cosmos were increasingly replaced by scientific approaches. The current ideas about the universe then developed from the combination of astronomical observations and calculations. The so-called standard model of cosmology is based on the assumption that the universe has a complex structure in detail, but on a large scale it is rather simple. Averaged over hundreds of millions of light years, it is the same everywhere and in every direction and a few parameters are sufficient to describe its development from the Big Bang into the future.

In the first article on the title topic, “How simple is our universe?”, bdw editor for astronomy and physics Rüdiger Vaas first describes how the idea of ​​a spatially similar universe developed: from the approaches of Giordano Bruno in the 16th century to the relativistic one Albert Einstein’s world model and the following further developments. The uniformity of the cosmic background radiation, the distribution of galaxies and the expansion history of the universe indicate a homogeneity of the cosmos. But can cosmic complexity really be simplified in such a way? Einstein already emphasized that astronomical observations that show a less uniform distribution of stellar matter could question the assumptions, the author reports in the article “The Cosmological Principle”.

About mysterious giant structures and dynamics

Vaas then reports on evidence of enormous structures in space that do not seem to fit with the assumptions of a homogeneous structure of the universe. Accordingly, there is increasing evidence that there are extremely large superclusters of galaxies in space that appear like huge “walls”. Astronomers are also worried about discoveries of huge groups of distant quasars – luminous centers of active galaxies. The author explains why the formations are so huge that they go beyond the scale of cosmic homogeneity. They therefore also question the cosmological standard model, according to the article “The largest structures in space”.

In the third part of the title topic, Vaas focuses on another aspect that shakes previous ideas about space: there are increasing indications of cosmic dynamics that do not seem to fit into the picture. Distant galaxies and entire clusters of galaxies are moving faster than permitted and in similar directions. It appears as if space is expanding at different speeds or has an axis. However, this contradicts the assumption about the so-called isotropy of the universe, explains the author in the article “An asymmetrical universe?”

The bottom line is that the numerous observations show that we still have significant difficulties in understanding our universe. This is what Jenny Wagner from the Helsinki Institute of Physics says in an interview that rounds off the cover story. The physicist comes to the conclusion: “The standard model of cosmology must be corrected.”

You can read the articles on the title topic “How simple is our universe?” online as part of a bdw+ subscription https://www.forschung.de/bdwplus/, or you can find them in the December issue of bild der forschung, ab will be available in stores on November 22nd.

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