Our Universe is almost ideally adapted for the emergence of man and other intelligent beings. What is behind this - higher powers or some random factors? Bernard Carr, friend and student of Stephen Hawking, tells how this issue is related to parallel worlds and whether we can be sure of their existence.
Black "ship of eternity"
Professor Carr recently visited Moscow and gave a lecture at the Physics Institute of the Russian Academy of Sciences about how black holes could have appeared in the first moments of the life of the Universe and what role they played in its evolution. The scientist explained to RIA Novosti why he came to the conclusion that parallel worlds exist and our Universe is one of them.
“We still have a poor idea of what happened before the Big Bang. On the other hand, string theory predicts that we will be able, through observations of primordial gravitational waves, to understand what the universe looked like in the first moments of its existence. And on the basis of this to present a picture of the world before the beginning of time, - said Carr, answering the questions of RIA Novosti.
For example, if our Universe arose not from a void, but inside the remains of another Universe, which ended its life in the course of a sharp compression of space, then its "embryo" should contain many black holes. They, as Carr explains, can survive the Big Bang and be present in the universe even today, although we are unlikely to determine which of the modern holes have such an exotic origin.
“These black holes, in fact, should be the only objects capable of surviving the end of one universe. Everything else - you and me, planets, stars and galaxies - will be grinded in a “big bang”. If such objects exist, then they played an important role in the evolution of the Universe, serving as embryos, a kind of "DNA" of supermassive black holes in the centers of galaxies. They, in turn, “orchestrated” the formation of the stars and govern their lives today,”says the professor.
To verify this, he admits, is extremely difficult - many scientists doubt that it is possible in principle. On the other hand, according to him, gravitational wave detectors are able to see another important thing, potentially explaining the emergence of humanity in a "convenient" universe for us.
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The fact is that many astronomers and cosmologists today believe that our Universe has a number of unique characteristics, including the ratio of the proportion of visible, dark matter and energy, thanks to which stars, planets and suitable conditions for the origin of life exist in it.
Bernard Carr within the walls of the Physical Institute of the Russian Academy of Sciences in Moscow / Photo: FIAN.
The slightest deviations in the values of these and some other physical constants, as supporters of this idea, called the "anthropic principle", believe, will make the Universe lifeless or shorten its life span so much that neither humanity nor "brothers in mind" will simply have time to appear in it. …
At the same time, modern cosmological theories say that the Universe does not necessarily have to possess such a set of properties. Accordingly, the question arises - why do we exist and how did our world arise?
“This question has two answers, of which we have to choose only one. First, the unique properties of the Universe could be set “from above”, which I personally, unlike many colleagues, do not completely rule out. On the other hand, the existence of the so-called Multiverse is also possible. To this, as I constantly have to emphasize, I am inclined more than to the presence of some supernatural forces,”explains the cosmologist.
Carr and many other cosmologists think that our universe is just one of countless parallel worlds that make up a larger structure, the Multiverse. These "other spaces" can have very different sets of properties, which eliminates the need for scientists to explain the unique features of our universe.
The possibility of their existence follows from string theory and a number of other mathematical concepts that assume the presence of a large number of dimensions, some of which are "rolled up" in our Universe, but "unrolled" in the Multiverse.
“It seems to me that we will definitely find traces of other dimensions and parallel worlds, pointing to the Multiverse. The only question is what properties they will have. In some cases, the extra dimensions will be large enough to influence our Universe, in particular, the formation of black holes,”the scientist says.
Key to the Multiverse
This idea can be tested if astronomers calculate how many black holes appeared in our Universe at the moment when its boundaries began to rapidly expand in the first seconds after the Big Bang.
“The number of primordial or primordial black holes cannot be random. With their abundance, the Universe simply will not have enough matter to form galaxies, stars and planets, and with their small amount, the properties of dark matter will not be the same as current observations of relatively young galaxies show,”continues Professor Carr.
Almost all primordial black holes are believed by astronomers to have relatively low masses. For this reason, they should have long since evaporated and exploded in the distant past, as Stephen Hawking's theory predicts. Large primordial holes evaporate more slowly and may therefore survive to this day.
“I have long wanted to ask Stephen what would be more interesting - the discovery of traces of explosions of primordial black holes (this would confirm the existence of Hawking radiation) or the discovery of unusually large objects of this type in the modern universe. Their discovery, in turn, would mean that we found dark matter - the physicist recalls. - Stephen would have liked the first option better, but personally, I lean towards the second. It is not only more interesting to me, but also more likely in reality. This would be another great discovery."
The smallest black holes, whose diameter is less than the so-called Planck length, will, according to Carr, behave not like singularities, but like "wormholes", tunnels in the structure of space-time. They can connect not only different universes, but also different times - past, present and future.
A cosmic web of ordinary and dark matter / Photo: Volker Springel, Virgo Consortium.
Traces of primordial black holes, according to Carr, could already be found by humanity. The fact is that virtually all bursts of gravitational waves discovered by the LIGO and VIRGO telescopes are generated by unusually large black holes, whose existence and pairing are difficult to explain.
Another possible trail is the recently discovered mysterious fast radio signals (FRB bursts) emanating from distant corners of the universe, as well as some faint gamma-ray bursts like the event that was recorded last August with a burst of gravitational waves.
If primary black holes are ever discovered, then, as the scientist suggests, they can become a window into the world of the Multiverse and one of the keys to the answer to the main question of astronomy - how gravity works.
“Lee Smolin, Peter Voight and other skeptics constantly insist that string theory has a purely mathematical, abstract nature, in no way connected with the real world or physics. For the same reasons, they criticize the theory of the Multiverse, which is supported not only by me, but also by many eminent physicists such as Leonard Susskind and Martin Rees. Yes, we have problems with the fact that traces of these worlds are almost impossible to find, but we cannot say for sure that we will never be able to do this. We've spent 100 years discovering gravitational waves. It will likely take the same amount of time to discover parallel dimensions and validate string theory. And primordial black holes, I believe, will hold the key to their discovery,”concludes Carr.