What if the big bang happens again

How it all started What came after the big bang?

Nobody has the slightest idea how the Big Bang could have happened. However, astro and quantum physicists believe that they understood the processes that followed. According to Junior Professor Martin Ammon from the Theoretical-Physical Institute at the University of Jena, the first are to this day 10 to the minus 43 seconds also hidden with the general theory of relativity. In other words, scientists calculate the state of the universe 0, ... and then there are 42 zeros and one 1 second after the big bang. And yet there is something that researchers agree on: namely that it must have been extremely hot from the start, says Martin Ammon and explains:

We're talking about trillions, quadrillions and even more Kelvin or degrees Celsius. After about a thousandth of a second, the elementary particles, like protons and neutrons, have formed.

Martin Ammon

You can still imagine something under very hot. But what must have happened within the first second, that sounds - like the Big Bang itself - like magic again. Scientists speak of the "inflationary phase of the universe". As the hot plasma breaks its path, the space around this plasma suddenly expands. From one split second to the next we have an extremely small, invisible universe for the human eye that suddenly takes on the dimension of infinite space. You can't understand that. After that, everything is rather boring in comparison. The primordial soup is sorting itself out, says cosmologist Bruno Leibundgut:

The very first elements hydrogen, helium, lithium and boron were formed in the first three minutes after the Big Bang. There we have a first consistent picture of the Big Bang that fits together very nicely at the moment.

Cosmologist Bruno Leibundgut

It goes well together because the calculations about the formation of the elements match the current observations perfectly, i.e. how matter is distributed in space and how often or rarely certain elements occur.

It will take a long time before something happens

The plasma spreads in the suddenly infinite universe. The density becomes lower and it continues to cool. The swarm of particles is still so dense that the hot pulp doesn't let any light out. Light hits particles and is absorbed. Until about 380,000 years after the Big Bang, the temperature cools down to such an extent that more and more protons bind electrons and light escapes: This is how quantum physicist Christian Rödel from the Helmholz Institute in Jena describes a phase in the universe that is crucial for us.

That means nothing less than that from this point on we can see and observe the universe. The oldest light that reaches us comes from around 380,000 years after the Big Bang. What happened before remains in the dark. At the plasma border, our telescopes simply end the workday. All we know about the time before that are calculations and theories that were created at the desk.

Big Bang shines to this day

Back then, the primordial soup had cooled to 3,000 degrees Kelvin in the endless space. Today the residual rumble, the background radiation of the Big Bang is ice cold: 2.7 degrees Kelvin. Wherever astrophysicists measure the background radiation - everywhere it is 2.7 degrees Kelvin - apart from the smallest deviations, many places after the decimal point that show slightly warmer and colder areas. These temperature differences are the first indications that the irregular clumping of matter began at that time and that structure later emerges in space - galaxies, stars, plaents, says cosmologist Bruno Leibundgut.

So much for the story of shortly after the Big Bang, as science understands it today. The hopes of getting information straight from the Big Bang, from the very beginning, are very high. With the detection of gravitational waves, one can theoretically listen directly to the Big Bang. Every particle creates gravitational waves differently than light. And unlike light, gravitational waves penetrate even the thickest primordial soup. Bruno Leibundgut assumes, however, that our theory of the Big Bang from the beginning of the universe is not yet the last.