The elephant in the universe occupies scientists

It gives astronomers and physicists a headache. But one of the most obvious problems with astronomy now also results in a beautiful book that makes it even more curious about exactly what’s going on.

In recent years, scientists armed with powerful (space) telescopes with the help of exciting expeditions to other celestial bodies have discovered many secrets of the universe. But some secrets, despite repeated urging from researchers, the universe refuses to release. Dark matter is such a secret. Science journalist Geoffert Schelling has now written a book on the subject: Elephant in the universe.

frustrated
The title refers to a phenomenon that physicists cannot ignore, but at the same time they cannot properly explain. And with that, this proverbial elephant in the universe is very frustrating. This becomes clear when Schilling takes us by the hand in his book and explains where and how the idea of ​​dark matter was born. He introduces us to the scientists who played an important role in it and who all died before a solution was in sight. We are now nine decades past and the elephant is still resilient.

Puzzle
There are many fundamental questions and problems for astronomers and physicists to consider. But the dark matter in its midst is undoubtedly File Headache No. 1. “This problem is the most annoying,” Physicist Ivo van Volpen told me a few years ago Scientias. nl. It all comes down to the fact that we find evidence of dark matter in many places in the universe. For example, the velocities of stars in the Milky Way reveal that our galaxy contains more mass than we can see. Half of our galaxy appears to be made up of invisible (or dark) matter. It also turns out that other galaxies were heavier in the past than you’d expect based on visible matter. So dark matter is everywhere. In fact, about 85% of all the mass of the universe can be classified as dark matter. But what kind of thing is this?

Which leads us to the proverbial elephant in the universe. Because scientists do not know. It’s not that they haven’t looked into it; We read in Schilling’s book about many (thought) experiments that attempted to reveal the nature of dark matter. But there has been no breakthrough all these years.

doubts
And then you can start to doubt. Schilling sometimes does it himself, as he already admitted in Chapter One. Does dark matter really exist? After all, we can’t see it. We have had to infer its existence from what we can see. But do we understand visible matter well enough to conclude that invisible matter exists? Or is it possible that our theories with which we have been able to describe the universe so well have been skewed and contained a false assumption, forcing us to create dark matter, even though this is not the case at all? Schilling is in good company with his doubts. Because there are also plenty of scientists who don’t take the existence of dark matter for granted. Dutch researcher Eric Verlind It is a fairly well-known example of that. “He doesn’t believe in an elephant at all,” Schilling says in his book. “According to his theory of emerging gravity, dark matter does not exist. Instead, what we consider to be the gravitational effect of mysterious dark things is actually the interaction between ordinary matter and ubiquitous dark energy (another mysterious and hypothetical form of energy that will be responsible for the accelerating expansion of the universe, ed.).” However, not everyone was convinced; Ferlind’s theory still has some loose ends. Thus the question “what is the physical universe made of” remains unanswered for the time being.

to persevere
The fact that we still cannot change such a fundamental question in 2021 clearly nibbles at the many researchers whom Schelling gives the floor to in his book. But at the same time, it does not deter them. The elephant takes up a lot of space for it. “Dark matter governs our universe,” Schilling says. “Without it, we probably wouldn’t be here to admire the nature of the universe.”

It remains to be seen whether this marvel will in the future give way to a full understanding of the physical universe. Many scholars are working on it and aspire to it. Uncovering the nature of dark matter would be a breakthrough. He deserves a Nobel Prize. But what Schelling shows very well in his book is that not only are the breakthroughs remarkable; The path to it—with ideas, experiments, hypotheses, necessarily revised theories, and trial and error—is equally fascinating.

“Elephant in the universePublished by Fontaine Publishers. The science journalism book was written by Govert Schilling and presented by Vincent Eike, Professor of Theoretical Astronomy at Leiden University and Professor of Cosmology at the University of Amsterdam by special appointment. The book costs €25 (paperback) or 12.99 (e-book) and it is Here Available.