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Time is elastic: why does time go faster at the top of a mountain than at the beach?

Gravity, as we know today, hasthe ability to bend space and time. As Einstein argued in General Relativity (GTR), time goes slower as it approaches the Earth. This is due to the fact that the gravity of a large mass, such as our planet, bends space and time around it. This effect is called the "time dilation effect" and it appears even at low levels. However, outside of physical laws, we perceive time differently, more precisely, distorted. So, if you put one clock on the top of the mountain, and leave the other on the beach, then in the end you will see that all clocks show different times. Scientists first observed the effect of time dilation on a cosmic scale when a star passed next to a black hole. Then the same effect was recorded on a smaller scale - the researchers used a pair of extremely accurate atomic clock mechanisms, with some clocks located 33 centimeters higher than others. The results showed that time slowed down again on clocks closer to Earth.

Time is not uniform: it flows at different speeds depending on where you are and how fast you are moving.

Atomic clock - a device for measuring time. Natural vibrations associated with processes occurring at the level of atoms or molecules are used as a periodic process.

Time dilation effect

Time dilation goes back to the Special theoryEinstein's relativity (SRT), according to which movement in space actually creates changes over time. The faster you move through the three dimensions that define physical space, the slower you move through the fourth dimension - time, at least relative to another object. Thus, a clock in motion will tick slower than a clock on the ground. If you move at a speed close to the speed of light, the effect will be much more pronounced.

It is important to understand that time dilation is not a thought experiment or hypothetical concept, but reality. The experiments of Hafele-Keating proved this,carried out in 1971, when two atomic clock mechanisms were installed on planes flying in opposite directions. The relative movement actually had a measurable impact and created the time difference between the two hours. This has also been confirmed in other physics experiments.

Why do we remember the past and not the future?

But there is one more remarkable detail: time dilation due to gravitational effects. You may have seen the Christopher Nolan movieInterstellar, where the proximity of a black hole causes time on another planet to slow down extremely (one hour on this planet is equal to seven Earth years). This form of time dilation is also real. It's all about Einstein's General Theory of Relativity, which was written about at the beginning of the article - gravity can bend space-time, and, consequently, time itself. This means that absolute time does not exist.

The closer the watch is to the source of gravity, the slower time passes; the farther the clock is from the source of gravity, the faster time will go.

It turns out, for all watches in the world and for each oftime passes us a little differently. But even if time flows at constantly changing speeds throughout the universe, time still flows in some objective sense, right? Or not?

Physics without time

In his book The Order of Time, the Italiantheoretical physicist Carlo Rovelli has suggested that our perception of time - our feeling that time flows eternally forward - may be a highly subjective projection. After all, when you look at reality at its smallest scale (using the equations of quantum gravity, for example), time disappears.

So why do we perceive time as moving forward? Rovelli notes that although time disappears on an extremely small scale, we observe entropy: order turns into disorder; the egg breaks and becomes scrambled eggs. Rovelli writes that key aspects of time are described in the second law of thermodynamics, which states that heat always goes from hot to cold, like a one-way street. For example, an ice cube melts in a cup of hot tea, not the other way around. Rovelli suggests that a similar phenomenon may explain why we are only able to perceive the past and not the future.

See also: How Much Has Time Affected People's Expressions?

"Every time the future is definitely different from the past, there is a kind of warmth," Rovelli wrote in an article for the Financial Times.

Thermodynamics traces the direction of time tosomething called 'low entropy of the past', a still mysterious phenomenon that is raging about. " “The growth of entropy orients time and allows for the existence of traces of the past, and they allow for the possibility of memories that cement our sense of identity. I suspect that what we call the "passage" of time must be understood by studying the structure of our brains rather than studying physics: evolution has turned our brains into a machine that feeds on memory to anticipate the future. This is what we listen to when we listen to the passage of time. Thus, understanding the "flow" of time may have more to do with neuroscience than with fundamental physics. Finding an explanation for the sensation of flow in physics can be a mistake.

Scientists still have a lot to learn about how wewe perceive time and why it acts differently depending on the scale. But what is certain is that outside of physics, our individual perception of time is also surprisingly elastic.

For even more fascinating articles on the latest scientific discoveries in the field of physics, read our channel in Yandex.Zen. There are regularly published articles that are not on the site.

Strange subjectivity of time

At the top of the mountain, time moves differently than atthe beach. But to experience the distortion of the perception of time, you do not need to go to the mountains or the sea. So, in moments of intense fear, the brain releases a large amount of adrenaline, which speeds up the internal clock, forcing to perceive the external world as moving very slowly.

Rovelli notes that working in the field of quantum gravity will have to face questions about the nature of time.

Another common distortion arises.when we focus our attention in a certain way. As Aaron Sackett, associate professor of marketing at St.Thomas University points out in an interview with Gizmodo, if you think about how time is currently going, attention is the most important factor affecting your perception of time.

The more attention you pay to the passage of time, the slower it flows.

When you are distracted from the passage of time -maybe something interesting happening nearby makes you more likely to lose track of time. There is a persistent feeling that it is slipping away faster than before. There is a well-known saying, "Time flies when you are having fun," but reality is more like "time flies when you think about other things."

In turn, Rovelli believes that what wewe call time - it is a rich, stratified concept that has many layers. Some layers of time are applicable only on a limited scale in limited areas, but this does not make them illusions; the illusion is the idea that time flows at absolute speed. The river of time may flow forever forward, but it moves at different speeds, between people and even within your own mind.