Why is there something rather than nothing

Origin of the universe : Everything out of nothing

If you turn the pages of the newspaper in the morning, you will find that the air does not offer you any significant resistance. The air molecules only take up a small part of the volume of space around you. Molecules and atoms are scattered much less frequently in space. But even far from stars and galaxies there is nowhere a complete nothing. Where there are no atoms and molecules floating around, the room is filled with electromagnetic radiation or exotic elementary particles such as neutrinos.

A complete nothing is hardly imaginable - and yet our universe, all galaxies, stars, planets and the whole animated diversity in our cosmos should have emerged from it. At least that's what physicists like Lawrence Krauss from Arizona State University claim. “A universe out of nowhere” is the title of his latest book, which sparked heated discussions in the USA. No wonder. "Even the theologian's last remaining trump card, the question of why there is something instead of nothing, withers before our eyes when we read these pages," writes the evolutionary biologist, critical of religion, Richard Dawkins in the afterword.

In the modern natural sciences, there could be nothing more interesting than nothing, emphasizes Krauss. However, its nothingness is difficult to grasp. The vacuum of the theoretical physicist is not that of the philosophers, i.e. not a complete emptiness, but rather corresponds to what remains when one removes from a given volume everything that can be removed from it.

Krauss refers in particular to findings from quantum physics. Accordingly, nothing is a highly unstable state. When physicists try to remove all particles from a container, new particles and their antiparticles appear in it in a flash and then disappear again shortly afterwards. In a similar way, bubbles or entire universes could emerge from a cosmic vacuum and then plunge back into nothingness. Would it be possible that such a bubble could have lasted billions of years and transformed into the world we are familiar with? And all from nowhere?

“Creation has spread so much that nothing is empty, everything is full of swarm,” wrote the German poet Georg Büchner. For thousands of years this has been the conviction of many natural philosophers: a complete nothing is impossible. Nature shies away from the vacuum.

Scholars have found numerous pieces of evidence for this “horror vacui”. For example, if you immerse a tube in a liquid and hold it closed at the top with your finger while you pull it out again, the water cannot drain away. Otherwise, there would be a blank space. A vessel called “Klepshydra” or “Water Thief” in ancient Greece is based on this effect. Only when you release the upper opening and air flows in can the water run off. It is therefore conceivable that a force corresponding to the “horror vacui” ensures that matter is penetrated into every space.

Modern research gave new impetus to the ancient theory of the atomists: that there should be the smallest particles or atoms in nature that move in an otherwise empty space. Naturalists like Otto von Guericke pursued this question in the 17th century with new experimental means.

As mayor of the city of Magdeburg, which had been reduced to rubble during the Thirty Years War, von Guericke knew his way around water pumps. At first he tried to pump the liquid out of wine and beer barrels. When he noticed that the barrels weren't airtight, he tried copper kettles, which collapsed, "crumpled up like a linen cloth in his hand".

Von Guericke was not deterred, ordered kettles with thicker walls in the shape of hemispheres, had seals and valves improved in order to counter the enormous forces that were created when the liquid was sucked out. After he had joined two hemispheres and pumped out the air between them, even two teams with initially six, later eight, then ten horses on each side failed to separate the halves again. His interpretation of the experiments: The air has a weight that weighs on all bodies and compresses the evacuated hemispheres.

Von Guericke's experiments aroused the ambition of the researchers to penetrate ever deeper into the vacuum. But is a void created in this way just an effect of technology? A phantasm?

According to modern quantum theory, every otherwise empty room is seething. "In quantum mechanics, the vacuum represents the state of the lowest energy," says Dieter Lüst, Director at the Max Planck Institute for Physics in Munich. “In the quantum mechanical vacuum, the particles are in constant restlessness and constant movement.” In particular, pairs of particles and their antiparticles can knock on the gate to existence for a fraction of a second and then immediately radiate again. In principle, these particles cannot be removed from the world.

The physicist Henning Genz has illustrated this as follows: “Let's take a poor swallower who has nothing gross or net because all his accounts are empty at all times, and let's compare him to a pumping genius, whose accounts in total and always also result in total assets zero , individually but sometimes here and sometimes there show large positive and negative amounts. ”The empty space of our imagination is empty like the poor swallower's accounts. In contrast, the empty space of quantum physics resembled the accounts of the pumping genius.

Nothing always creates something, even if only for a tiny moment, writes Krauss. And these vacuum fluctuations would have measurable consequences. Because of them, for example, two parallel, very close together electrically conductive plates attract each other in a vacuum.

The effect is tiny. It is only detectable for distances of less than a thousandth of a millimeter. Similar to a violin string, only certain vibrations are possible when it is clamped between two ends, only certain fluctuations of electromagnetic waves fit between the two plates, since these waves have a vibration node on the surfaces of the plates. Outside the plates, on the other hand, all waves can propagate unhindered. This difference between inside and outside creates an attractive force.

Quantum fluctuations may also have shaped the early phase of our world. Krauss believes that nothing is so unstable that sooner or later universes must emerge from it. He is an advocate of a theory jointly developed by physicists Andrei Linde and Alexander Vilenkin, and he assumes that cosmic bubbles are constantly forming and disappearing in space-time foam. In the midst of these parallel universes, the universe observable for us would be a comparatively rare case. It would only have assumed such dimensions because at times it went through a phase of extremely rapid expansion.

“Our participation in being deprives us of the possibility of recognizing the first reasons that come from nothing, and the little of this participation obscures the vision of the infinite”, wrote the French natural philosopher Blaise Pascal once. Krauss is more optimistic. He and other researchers would like to answer unanswered questions by merging quantum and general relativity to form a quantum gravity theory in the near future. Such a theory would mean, among other things, applying the rules of quantum mechanics to space itself and not just to the properties of objects present in space, according to Krauss.

His conclusion from all of this is a strange mixture of personal conviction and sheer speculation: “The lesson is clear: Quantum gravity does not just seem to allow universes to emerge from nothing - which I emphasize as the absence of space and time understanding is - it might even require it. The nothing - in this case no space, no time, no nothing at all! - is actually unstable. "

The book “A Universe from Nowhere” (252 pages, 19 Euro 99) has been published by Knaus Verlag.

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