Time flows differently in different regions of the Universe – 07/19/2023 – Science

In “Time: The Dream of Killing Chronos”, the Italian physicist Guido Tonelli starts from the observation of the reality immediately around us, the visible to our eyes, to the exploration of worlds of colossal astronomical objects, as well as that of what is very, very small, in the search to understand how the flow of the past, the present and the future works.

“We consider time an abstract concept because we are macroscopic objects, living in a kind of ‘middle world’, in which the clock seems to flow perfectly and the same for everyone”, says Tonelli, in an interview with BBC Brasil.

“Very peculiar phenomena occur close to large masses, such as stars and black holes, in the surroundings of which space-time is deformed and one can have the impression that time passes much more slowly, just as everything is different in the microscopic world, of photons, electrons and muons”.

Reading leads the reader to imagine himself in these realities in which the same natural laws we are used to, those of classical physics founded by Isaac Newton from the pioneering studies of the force of gravity, do not seem to apply.

When observing both the gigantic bodies that populate the Universe and the phenomena that occur on subnuclear scales, the harmonious passage from the past to the present and to the future is distorted, shattered and liquefied.

“Space and time appear to us as an inseparable pair; not an abstract concept, but a material substance”, writes the author.

Tonelli’s speech takes the side of quantum mechanics and relativity, sciences founded at the beginning of the last century by names that are now iconic, such as the German Albert Einstein (1879-1955), the Danish Niels Bohr (1885-1962) and the Austrian Erwin Schrödinger (1887-1961), three Nobel laureates for contributions in the field that led to changes in the way we perceive time.

This means that Tonelli defends, through the exhibition of discoveries and scientific experiments, the theory that time is, in his words, a material element that “occupies the entire universe, that vibrates, oscillates and deforms”.

That is, it is not a concept created by us humans when we formulate calendars and the like. Space-time, for modern Physics, corresponds to a kind of field that permeates the entire cosmos.

Where time goes slower

In the book, the Italian physicist, professor at the University of Pisa, does not present brand new theories.

As in his previous work, “Genesis: the history of the universe in seven days”, released in 2019, Tonelli’s ability lies in leading the reader through the evolution of our understanding of a fundamental question of our existence, not in revolutionizing the sciences with disruptive theoretical proposals.

If in “Genesis” he presented the most modern concepts of physics to answer the question “How did it all start?”, in “Tempo”, which arrived at Brazilian bookstores in June, by Zahar, the reflection revolves around the seminal questions: “What is time?”, “Will we manage to defeat it one day?”, “Does it really exist, or is it just an illusion?”.

“Time is a substance, a material element”, says the scientist.

“In our day-to-day life, we don’t see space-time oscillating. But the truth is that time flows differently, in different regions of the Universe, as it depends on the location, in particular the amount of mass around.”

Tonelli is a fan of allegories. In the book, he imagines physicists traveling toward a supermassive black hole.

One of them, in a ship at a safe distance from the phenomenon. The other spacecraft, however, has the audacity to venture, crossing the boundary of the black hole, known by the term “event horizon”. This second, therefore, enters the cosmic event.

When crossing the event horizon, time seems to continue to pass normally for those inside the explorers’ ship. However, if these scientists broadcast a radio signal to their colleagues on the other spacecraft, an eternity would pass before the message was received.

In reference to the outside world, while a few seconds pass inside the black hole, centuries and even millennia could pass for someone who is, for example, on Earth.

“Next to supermass bodies, time travels proportionally well, much slower”, explains Tonelli to BBC Brasil.

“In theory, only technicalities prevent us from bending time in our favor. I’m sure we’ll do that one day.”

He rescues how the public perceived the physicists who inaugurated the studies of quantum mechanics, such as Einstein: “In that era of the first decade of the last century, these scientists asked themselves questions that, in the eyes of common sense, seemed useless, such as ‘why does the photon travel at the speed of light, but not faster?’

However, Tonelli defends how these scientific bases led to the development of innovations such as cell phones, satellites, X-rays and nuclear energy.

As a researcher, the Italian physicist has experience leading teams at the Large Hadron Collider, the particle accelerator located underground on the Swiss-French border.

He was one of the main scientists in the laboratory when the discovery of the Higgs boson was announced, detected by the equipment’s plates in 2012.

“When there is a scientific discovery of weight, our world does not change immediately. Decades later, however, that same finding usually leads to technological revolutions”, assesses Tornelli.

“With the confirmation of the Higgs boson, we are now sure that the mass of objects, whether stars or our human bodies, are not absolute certainties. They depend on the existence of a field, formed by bosons, and which in theory can be manipulated”, adds the physicist.

“I imagine this discovery could lead to incredible progress.”

NASA, the United States space agency, maintains a website, Nasa Spinoff, which compiles technological advances present in everyday life and that originated in space science carried out in its laboratories, this direct result of the evolution of quantum physics.

More than 2,000 products are listed, developed since 1976, in areas such as agronomy, transport, power generation, medicine, information technology, among others.

the origin of time

The ancient Greeks viewed Chronos (a deity personifying “time”) as a titan.

The giant devoured his own children, for fear of a prophecy that one of them would depose him. Until Zeus deceived his father, who ate a poisoned stone in his place. Thus, Zeus killed Chronos, time, and became immortal.

“In the past, human beings saw themselves as fragile beings in the midst of an eternal cosmos, made up of the Sun, stars, planets, immortal divinities”, says the author of “Tempo”.

“Today, we know that everything has an end. The Sun’s energy, for example, will run out in a few billion years, and our star will thus die”.

Centuries ago, we didn’t have the tools to accurately measure distances and passages of time that were too small, or too large. Civilization thus resorted to mythology and religiosity.

According to the narrative in the Bible, for example, the creation of the world would have taken place on October 6, 3761 BC.

Today, Science has concluded that our species, the human, emerged in Africa around 300,000 years ago, as descendants of other primates.

We live on Earth, a planet that emerged 4.5 billion years ago in the Solar System.

We all inhabit the same Universe, which began in a great expansion, the Big Bang, 13.8 billion years ago.

“Space-time, like field and substance, would have been born together with the emergence of mass and energy in the cosmos”, adds Tonelli.

What is time?

In his new book, the Italian physicist does not attempt a precise definition of what time is, apart from pointing it out as a substance and as part of an omnipresent field.

However, he makes references to scientists who explore the most modern theories of quantum mechanics on the subject, like his fellow countryman, and also a physicist, Carlo Rovelli.

Author of bestsellers in science communication, such as “Seven Brief Lessons in Physics”, from 2015, in academia, Rovelli, now 66 years old, is revered for his seminal research on the existence of what he calls “quantum gravity in loop“.

“Quantum theories will become part of our basic understanding of the world. However, it will take time for this to happen, as it took more than a century for them to accept Copernicus’ heliocentric model”, he said in an interview in December last year, on the occasion of the launch in Brazil of his latest book, “O Abismo Vertiginoso”..

Rovelli, often compared by press vehicles to the English physicist Stephen Hawking (1942-2018), due to the success of his scientific dissemination works around his own studies and those of colleagues in quantum mechanics, was also known for his unique view on the properties of time.

In 2012, he gained fame for opening a TEDx event talk with the statement “time does not exist”.

But he claims to believe, yes, in the existence of time. It’s just not the one we’re used to, the days, weeks and months of the calendar.

“What we call time doesn’t work as a real feature of the Universe,” he said in the interview.

In another of his books, “The Order of Time”, from 2017, Rovelli explores the conceptions that humanity has had about this crucial element of reality: from Newton, who theorized two forms of time, and Einstein, for whom space-time would result from deformations of the gravitational field, to the current stage of research.

For scientists of the Rovelli line, whose theories echo in the final chapters of “Time”, in which issues about the entropy of the Universe are addressed, time is a thermal element.

Instead of a chronological measure, as calculated in calendars, it would be a variable resulting from the increasing entropy of the cosmos, throughout its 13.8 billion years of existence.

the end of everything

The subtitle of Tonelli’s book, “The Dream of Killing Chronos”, refers to the desire to overcome mortality, by analogy with the Greek myth that narrates how Zeus achieved divinity by poisoning the titan, his father.

However, despite believing in the possibility of bending and manipulating the field of space-time, the author does not see any possibility of overcoming mortality, as Zeus did.

“Nothing is eternal, every structure of matter, be it a human being, a star, a galaxy, is intrinsically fragile”, states the author. “Sooner or later, it all ends”.

While elementary particles, such as the Higgs boson, have a very short duration, of tiny fractions of microseconds, stars, planets and galaxies remain in the cosmos for billions of years.

But in the end, as modern physics theorizes, even the universe will one day come to an end.

Guido Tonelli defends a theory of modern physics that indicates the cosmos closing in total darkness and cold.

According to this thesis, the cosmic expansion, started with the Big Bang, will not be interrupted until it breaks the field of space-time itself.

“If the structure of the Universe no longer supports space-time, then it will be the true end of times, an Apocalypse, but as told by quantum physics”, he concludes.