There are a lot of things we have learnt about the universe over the last millennium. But some things are still unknown to us, and these unsolved mysteries seem suspicious to us.
Let’s take a quick look at some of the puzzling mysteries we have no knowledge about to this day.
1. What is the universe made of?
Just ninety years ago, we had no problem describing what the universe consisted of atoms, which in turn consisted of (insert the words here you may have previously been taught about). But a lot of knowledge leads to a lot of disappointments, and according to recent views, the universe is 96% made of unknown dark matter (this phrase was first used in 1933), comprising about 22% of the mass of the universe, and even less defined dark energy (~1998), which accounts for 74%. And while the 4% is tangible, the other 96% is quite unfathomable, because “dark particles”, whatever they may be, must come into contact with ordinary matter very inconspicuously. Reliable detection of these particles, dark matter for example, (the dark energy will be even more difficult!) has failed, but the list of possible candidates is too long: ultra-light, heavy, and even ultra-heavy. The knowledge regarding the properties of dark matter, however, is still very, very, very out of reach.
Half a century of attempts to imagine the interior of black holes and whether they have connecting tunnels between them did not produce any logical findings.
2. Why do we need these pathetic four per cent of ordinary matter, all these atoms that make up stars, all that sand and other people?
And the truth is that they do not exist. The standard model does not suggest that matter and antimatter at the birth of the universe had different quantities. But back then, after they have appeared, the anti-hydrogen was annihilated, counteracting with hydrogen, and so on. The final picture must have been tragic: all atoms are annihilated, and the universe has photons with different energies scrambling around, only the light, and nothing but the light. In such a scenario, even this light was not to be seen by anyone.
And yet we are still here. So there is something that we are missing in this picture, there is an obvious mystery regarding asymmetry of matter and antimatter. There have been many attempts to explain it this way: say, for some reason, antimatter decayed faster than matter, and so on. But even with some promising mechanisms of transformation of one kind of neutrino to another, may not give the correct or generally-accepted answer to this question…
3. Are there other universes other than our own?
This is a very awkward question because the whole picture of the world will need to be reconsidered with this answer. If there is more than one universe, they are indefinitely abundant and varying with a high degree of probability. Other physicists like to refer to their numerical infinity saying that it is silly to ask why the observed physical laws and values of the fundamental physical constants are what they are. There is no fine-tuning of the universe they say. No configuration exists, and all of us are a product of solving complex problems by the brute force of enormous proportions, the result of going through an infinite number of options for every conceivable physical law.
In one of the outcomes (among different universes) nature had its luck, and as a result, life has appeared, with a pair of eyes to look around. And was even endowed with the brains, that’s why it is now asking all kinds of silly questions. But there is no fine tuning (we attest to that!), only the blind but predictable game of chances. Take the number of letters that make up the word “Hamlet”, and with an infinite number of reordering the letters, you will certainly come up with “Hamlet” at a Shakespeare’s level if not even better.
In short, in the majority of parallel universes no life is present. Which is indeed, very frustrating.
But there are other opinions out there. Some physicists claim that all of the so-called random processes are actually quite quantum in their nature, and therefore cannot occur until the moment when they have been looked at by an observer. And even after that, there will be only one possibility in which the observer still exists, and “cat” is either dead or alive, that is there is only one reality which is our own world.
But how can we find out exactly which of the two approaches is correct ? ..
4. Oops. We still need to mention the word “universe” one more time. Are we the only ones in it?
A million variants of this problem have occupied inquiring minds for a long time. We will not go into details, but no aliens on the streets mean that we will either perish before becoming able to travel to other stars (how is it that we have not been visited by extraterrestrials yet?), or something else.
There is a couple of original explanations. The first, suggested by Stanislaw Lem, explains that our understanding about alien life is limited. We have initially separated all things in space into natural and artificially made, while many natural objects and phenomena can be a by-product of the process or the ultimate goal of some activity by highly advanced civilizations.
According to this concept, some black holes may be energy generators and, at the same time, means to dispose of space debris, the stars can be a means of dispersion of the gas clouds, somehow interfering with this super-advanced civilization, and so on. In this case, our attempts to find alien life are doomed to fail. “The ability to distinguish between artificial and natural phenomena is a function of knowledge of those who establish such difference … The presence of the energy “star’s” concentration of its influence, how far it can be detected, as well as its variations, all of these can only be known when we have a comparable energy level to operate with… “
The second option, which was not seriously described in science fiction even 60 years ago, may seem even more bizarre. There are no alien space travel, because at some point they have learnt to change the laws of physics at will, quickly and easily, allowing infinitely expand their living space without the need to travel far distances, or able to find wormholes into other worlds that enable them to “colonize” space without traveling by spaceships.
5. What is inside a black hole?
The trouble is not that we do not know this, but the fact that we do not even have an idea about a theory or an experiment that would allow us to find this out. General theory of relativity fails to work under conditions of singularity, which is hypothetically present inside a black hole. Maybe this is where quantum physics should step in, but decades of attempts to use it for these explanations, and in conjunction with the theory of relativity have not yet led to any success. We need a theory of quantum gravitation concept, but it is, unfortunately, still cannot be devised. String theory and looping quantum gravitation concept, which criticize and juxtapose each other, have not yielded any unambiguous answers yet.