Table of contents:
- What happened before the start of time?
- The big bang was not an explosion
- Return to the past
- Quantum cosmology does not answer the question
What caused the universe to arise? The root cause must be special, scientists say. But if we attribute the beginning of everything to the Big Bang, the question arises: what happened before that? The author offers a fascinating reasoning about the beginning of time.
Asking science what was before time is like asking "Who were you before you were born?"
“Science allows us to determine what happened in one trillionth of a second after the Big Bang.
“But we’ll hardly ever know what caused the Big Bang.
“It’s disappointing, but some things are completely unknowable. And this is good.
Let's be honest: it's rather strange to think that the history of the Universe began with a kind of birthday 13.8 billion years ago. This is in line with many religious tenets, according to which the cosmos was created through intervention from above, although science says nothing about it.
What happened before the start of time?
If everything that happened has a causal relationship, then what caused the emergence of the universe? To answer a very difficult question about the First Cause, religious myths about the creation of the world use what cultural anthropologists sometimes call "positive being" or a supernatural phenomenon. Since time had a beginning at some point in the distant past, the First Cause must be special. It must be a causeless reason, a phenomenon that just happened, and nothing preceded it.
But if we attribute the beginning of everything to the Big Bang, the question arises: what happened before that? When we are dealing with immortal gods, this is a completely different matter, since for them timelessness is not a question. Gods exist outside of time, and we do not. For us, there is no such thing as "before time." Therefore, if we ask the question of what happened before the Big Bang, it will be somewhat pointless, even if we need to find the meaning. Stephen Hawking once equated it with the question "What is north of the North Pole?" And I like the phrase "Who were you before you were born?"
Aurelius Augustine hypothesized that time and space appeared along with the creation of the world. For him, it was, of course, divine providence. And for science?
In science, in order to understand how the universe originated, developed and matured, we go back in time, trying to reconstruct what was happening. Like paleontologists, we identify "fossils", that is, the remnants of matter from days gone by, and then with their help we learn about various physical phenomena that existed at that time.
We confidently assume that the Universe has been expanding for billions of years, and that this process continues now. In this case, "expansion" means that the distances between galaxies are increasing; galaxies move away from each other at a speed that depends on what was inside the universe in different epochs, that is, what matter filled space.
The big bang was not an explosion
When we talk about the Big Bang and the expansion, we imagine the explosion that started everything. That is why we named it that way. But this is a misconception. The galaxies are moving away from each other, because they are literally separated by the stretching of space itself. Like elastic fabric, space stretches and carries galaxies with it, as the current of a river carries away logs with it. So galaxies cannot be called debris flying from an explosion. There was no central explosion. The universe is expanding in all directions, and it is completely democratic. Each point is equally important.Someone in a distant galaxy sees the removal of other galaxies the same way we do.
(Note: Nearby galaxies have deviations from this cosmic flow called “local motion.” This is caused by gravity. For example, the Andromeda Nebula is approaching us.)
Return to the past
If we spin the cosmic movie backwards, we will see how matter is being squeezed more and more in the shrinking space. The temperature rises, the pressure rises, and decay begins. Molecules break down into atoms, atoms into nuclei and electrons, atomic nuclei into protons and neutrons, and then protons and neutrons into quarks. This sequential decomposition of matter into its most basic and elementary constituents occurs as the clock ticks in the opposite direction towards the explosion.
For example, hydrogen atoms decay about 400,000 years before the Big Bang, atomic nuclei in about one minute, and protons with neutrons in a hundredth of a second (when viewed in reverse, of course). How do we know this? We found the remnants of radiation from the time when the first atoms formed (relic microwave background radiation), and figured out how the first nuclei of light atoms appeared when the universe was only a few minutes old. These are precisely the cosmic fossils that show us the way in the opposite direction.
Currently, we can experimentally simulate the conditions that existed when the universe was one trillionth of a second. It may seem to us a negligible value, but for a light particle of a photon, this is a long time, allowing it to fly a distance that is a trillion times the diameter of a proton. When we talk about the early Universe, we should forget about human standards and ideas about time.
Of course, we want to get as close as possible to the moment when the time was equal to 0. But at some point we bump into the wall of ignorance and can only extrapolate our current theories in the hope that they will give us at least some hints of happening at the beginning of time, at such energies and temperatures that we cannot create in the laboratory. But we know one thing for sure. When time is close to zero, our current theory of the properties of space and time, which is Einstein's general theory of relativity, does not work.
This is the realm of quantum mechanics, in which the distances are so small that we have to imagine space not as a continuous sheet, but as a granular structure. Unfortunately, we do not have a qualitative theory describing such granularity of space, as there are no physical laws of gravity on a quantum scale (known as quantum gravity). Candidates, of course, are, for example, superstring theory and loop quantum gravity. But there is currently no evidence that they correctly describe physical phenomena.
Quantum cosmology does not answer the question
Nevertheless, a person's curiosity requires that the boundaries be brought closer to the zero value of time. What can you say? In the 1980s, Alexander Vilenkin, Andrei Linde, and James Hartl and Stephen Hawking proposed three models of quantum cosmology, in which the universe exists as an atom and the equation is similar to that used in quantum mechanics.
In this equation, the universe is a wave of probability, which, in essence, connects the timeless quantum region with the classical one, where there is time, that is, with the universe in which we inhabit, and which is now expanding. The transition from quantum to classics literally means the emergence of space, what we call the Big Bang. Thus, the Big Bang is a causeless quantum fluctuation, as random as radioactive decay: from the absence of time to its presence.
Assuming that one of these simple models is correct, would it be a scientific explanation of the First Cause? Can we get rid of the necessity for a cause altogether by using the probabilities of quantum physics?
Unfortunately no. Of course, such a model would be an astounding intellectual feat. It would be a colossal step forward in understanding the origin of everything. But this is not enough. Science cannot exist in a vacuum. She needs a conceptual apparatus, such concepts as space, time, matter, energy. She needs calculations, she needs laws of conservation of such quantities as energy and momentum. You cannot build a skyscraper out of ideas, just as you cannot create a model without concepts and laws. Asking science to "explain" the First Cause is like asking science to explain its own structure. This is a request to provide a scientific model that does not use precedents, there are no earlier concepts to operate on. Science cannot do this, just as a person cannot think without a brain.
The riddle of the Root Cause remains unsolved. As an answer, you can choose religion and faith, and you can also assume that science will figure everything out over time. We can also, like the ancient Greek skeptic Pyrrho, humbly acknowledge that there are limits to our knowledge. We can rejoice at what we have achieved and continue to comprehend, while realizing that there is no need to know everything and understand everything. It is enough that we continue to be inquisitively interested.
Curiosity without a riddle is blind, and a riddle without curiosity is flawed.