The first seconds of the Big Bang are what we know and what we don't know

The first seconds of the Big Bang are what we know and what we don't know

Misconsidered as an initial explosion, the Big Explosion is not a starting point, but a line of the horizon beyond which we cannot come out and from which concepts of space and time were born. What do we know about this early era?

The discovery by Hubble in 1929 of the fact that the universe is expanding has had terrible consequences for cosmology. In fact, if the universe is expanding, it was once much more concentrated.

Extension and first elements

13.77 billion years ago, we knew that our universe was incredibly hot. It was also incredibly small. Astronomers suspect that when it was less than a second away, space experienced a period of incredibly rapid growth known as inflation. Less than a moment, our universe expanded by at least 10'52 times.

As soon as this expansion phase ended, what caused this inflation flooded the universe with matter and radiation.

At this point, the universe was too hot and too dense to make anything stable. Space was nothing more than a soup of elementary particles of matter and antimatter, born of pure energy consisting of quarks and antiques, electrons and positrons, neutrinos and antineutrinos, which annigated each other as soon as they met.

Also during this first second, the nuclear force made the quarks come together to form protons or neutrons, which in turn form the nucleus of hydrogen atoms.

After the first second, the universe continued to expand and slowly cool, bringing together protons and neutrons, and after three minutes the first nuclei of atoms, a little more complex than hydrogen atoms, could see light.

Nucleosynthesis will naturally continue for a few minutes and then have to wait for thermonuclear fusion machines, which are the first stars, to enrich the image of the elements.

All this is known only by calculation, because none of these initial phases will ever be seen by our instruments; our world will remain indistinct until it is 380,000 years old when the first stars are lit.

Dark matter and inflation

While some details are indeed out, there is also much that we do not know, especially in the period leading up to the formation of the first elements.

For example, the question of dark matter arises. We don't know what it's made of, but we know that it accounts for more than 80% of the matter in the universe. We also don't know when and how dark matter appeared. It appeared in the first few seconds or much later? Did it affect the primitive chemistry that led to the formation of the first elements, or did it remain in the background? We don't know.


Matter / Antimatter

Another problem, not least,

However, we know that during this famous "first second" of matter that we were created from, we dominated antimatter, so these two forms of matter were different, and the causes of this imbalance are still unknown.

If we can't see directly the state of the universe when it's only a few seconds away, for example, we can try to recreate these conditions in our powerful particle accelerators.

This chaotic hell must have caused a wave of raspberry in the fabric of space-time, and with technical means we can try to capture gravitational waves from this famous Big Bang.