- Part one -
The essence of relativity is that space and time are not absolute, but relate to a specific observer and the observed object, and the faster they move, the more pronounced the effect becomes. We will never be able to accelerate to the speed of light, but the more we try (and the faster we move), the more we deform in the eyes of an outside observer. Almost immediately, popularizers of science began to look for ways to make these ideas accessible to a wide range of people. One of the most successful attempts - at least commercially - was The ABC of Relativity by mathematician and philosopher Bertrand Russell. Russell gives an image in the book that has been resorted to many times since then. He asks the reader to imagine a train 100 meters long traveling at 60 percent the speed of light. To manstanding on a platform, the train would appear to be only 80 meters long, and everything inside it would be similarly compressed. If the voices of the passengers were heard, they would sound indistinct and stretched, like on a plate rotating too slowly, and the movements of passengers would seem to be just as slow. Even the train clock seemed to run at only four-fifths of its normal speed, but - and that's the point - the people inside the train would not have felt these distortions. For them, everything on the train would look completely normal.and passenger movements would appear to be equally slow. Even the train clock seemed to run at only four-fifths of its normal speed, but - and that's the point - the people inside the train would not have felt these distortions. For them, everything on the train would look completely normal.and passenger movements would appear to be just as slow. Even the train clock seemed to run at only four-fifths of its normal speed, but - and that's the point - the people inside the train would not have felt these distortions. For them, everything on the train would look completely normal.
But we on the platform would seem to them unnaturally flattened and slow in movement. Everything, as you can see, is determined by your position relative to the moving object.
In fact, this effect occurs whenever you move. By flying the United States from end to end, you will get off the plane about one hundred millionth of a second younger than those you left. Even walking around the room, you slightly change your perception of time and space. It is estimated that a baseball launched at 160 kilometers per hour increases its mass by 0.000000000002 grams on its way to base115. So the effects of the theory of relativity are real and have been measured. The difficulty is that such changes are too small to have any tangible effect on us. But for other things in the Universe - light, gravity, the Universe itself - they lead to serious consequences. So if the concepts of the theory of relativity seem incomprehensible to us, it is only becausethat we do not encounter such interactions in our daily life. However, if we turn to Bodanis again, we usually all encounter manifestations of relativity of a different kind, for example, with regard to sound. If you are walking in the park and there is annoying music somewhere, then, as you know, if you move somewhere further, the music will not be so audible. Of course, this is not due to the fact that the music itself becomes quieter, just your position relative to its source will change. For someone too small or too slow to make this experience - say, a snail - the thought of two different listeners playing a drum at the same time at a different volume may seem incredible.we all usually encounter manifestations of relativity of a different kind, for example with regard to sound. If you are walking in the park and there is annoying music somewhere, then, as you know, if you move somewhere further, the music will not be so audible. Of course, this is not due to the fact that the music itself becomes quieter, just your position relative to its source will change. For someone too small or too slow to make this experience - say, a snail - the thought of two different listeners playing a drum at the same time at a different volume may seem incredible.we all usually encounter manifestations of relativity of a different kind, for example with regard to sound. If you are walking in the park and there is annoying music somewhere, then, as you know, if you move somewhere further, the music will not be so audible. Of course, this is not due to the fact that the music itself becomes quieter, just your position relative to its source will change. For someone too small or too slow to make this experience - say, a snail - the thought of two different listeners playing a drum at the same time at a different volume may seem incredible.it will simply change your position relative to its source. For someone too small or too slow to make this experience - say, a snail - the thought of two different listeners playing a drum at the same time at a different volume may seem incredible.it will simply change your position relative to its source. For someone too small or too slow to make this experience - say, a snail - the thought of two different listeners playing a drum at the same time at a different volume may seem incredible.
The most challenging and incomprehensible of all the concepts of general relativity is the idea that time is part of space. We initially consider time as infinite, absolute, unchanging; we are accustomed to the fact that nothing can disturb its steady course. In fact, according to Einstein, time is constantly changing. It even has a shape. In the words of Stephen Hawking, 117 it is “inextricably intertwined” with the three dimensions of space, forming an amazing structure known as space-time. What is space-time is usually explained by proposing to imagine something flat but plastic - say, a mattress or a sheet of rubber, - on which a heavy round object, such as an iron ball, lies. Under the weight of the ball, the material on which it lies slightly stretches and bends. This is vaguely reminiscent of the impact on space-time (material) of a massive object, such as the sun (metal ball): it stretches, bends and bends space-time. Now, if you roll a smaller ball on the sheet, then, according to Newton's laws of motion, it will tend to move in a straight line, but when approaching a massive object and the slope of a bending material, it rolls downward, inevitably attracted to a more massive object. This gravity is the result of the curvature of space-time. Every object with mass leaves a small dent in the structure of the cosmos. So the universe is, as Dennis Overbye put it, "an endlessly crumpled mattress."if you roll a smaller ball on the sheet, then, according to Newton's laws of motion, it will tend to move in a straight line, but when approaching a massive object and the slope of a bending material, it rolls downward, inevitably attracted to a more massive object. This gravity is the result of the curvature of space-time. Every object with mass leaves a small dent in the structure of the cosmos. So the universe is, as Dennis Overbye put it, "an endlessly crumpled mattress."if you roll a smaller ball on the sheet, then, according to Newton's laws of motion, it will tend to move in a straight line, but when approaching a massive object and the slope of a bending material, it rolls downward, inevitably attracted to a more massive object. This gravity is the result of the curvature of space-time. Every object with mass leaves a small dent in the structure of the cosmos. So the universe is, as Dennis Overbye put it, "an endlessly crumpled mattress."Every object with mass leaves a small dent in the structure of the cosmos. So the universe is, as Dennis Overbye put it, "an endlessly crumpled mattress."Every object with mass leaves a small dent in the structure of the cosmos. So the universe is, as Dennis Overbye put it, "an endlessly crumpled mattress."
From this point of view, gravity is not so much an independent entity as a property of space, it is “not a“force”, but a by-product of the curvature of space-time,” writes physicist Michio Kaku118 and continues: “In a sense, gravity does not exist; what drives the planets and stars is the curvature of space and time.”Of course, the analogy with the crumpled mattress is only true within certain limits, because it does not include time-related effects. But in this case, our brain is only capable of it, because it is almost impossible to imagine a structure consisting of three quarters of space and one quarter of time, and everything in it is intertwined like the threads of a Scottish plaid. Anyway, I think we can agree that it was a stunning idea for a young man,staring out of the window of a patent office in the capital of Switzerland. Among many other things, Einstein's general theory of relativity said that the universe must either expand or contract. But Einstein was not a cosmologist and shared the conventional wisdom that the universe is eternal and unchanging. Largely in order to reflect this view, he introduced into his equations an element called the cosmological constant, which played the role of an arbitrarily chosen counterweight to the action of gravity, a kind of mathematical pause button. Authors of books on the history of science always forgive Einstein for this lapse, but, in essence, it was a huge scientific blunder. He knew this and called it “the biggest mistake in his life.” 119 It just so happens that at about the same time when Einstein added the cosmological constant to his theory,At the Lowell Observatory in Arizona, an astronomer named Vesto Slipher (actually from Indiana), taking spectra of distant galaxies, found that they appeared to be receding from us120. The universe was not stationary.
The galaxies that Slipher looked at showed clear signs of Doppler shift - the same mechanism is behind the characteristic sound: and-and-il-zhu-u-u, which is produced by racing cars flying past us on the track. The effect is named after the Austrian physicist Johann Christian Doppler, who first predicted this effect theoretically in 1842. In short, what happens is that when a moving source approaches a stationary object, the sound waves are condensed, crowding in front of the receiver (say, your ears). This is similar to how any objects propped up from behind are piled up on a stationary object. This heap is perceived by the listener as a higher sound (and-and-izh). When the sound source passes by and begins to move away, the sound waves stretch and lengthen, and the pitch suddenly drops (zhu-u-u).
The phenomenon is also characteristic of light, and in the case of receding galaxies, it is known as redshift (because a source of light moving away from us looks reddened, and an approaching one turns blue). Slipher was the first to discover this effect in the radiation of galaxies and realized its potential significance for understanding movements in space. Unfortunately, no one paid attention to this. The Lowell Observatory, as you remember, was treated as a bit of a strange institution due to Percival Lowell's obsession with the Martian canals, although in the 1910s it became an outstanding astronomical center in every way. Slipher was not aware of Einstein's theory of relativity, and the world, in turn, had not heard of Slipher. So his discovery had no repercussions; instead, fame went largely to a very proud man named Edwin Hubble. Hubble was born in 1889, ten years after Einstein, in a small town in Missouri on the edge of the Ozark Plateau, and grew up there and in the Chicago suburb of Wheaton, Illinois. His father was the director of a successful insurance firm, so life was always secure, and Edwin enjoyed generous financial support. He was a physically strong, gifted athlete, a charming, witty handsome man - according to the description of William G. Cropper, he was "perhaps too handsome"; "Adonis," according to another fan. According to his own stories, in life, he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches.in a small town in Missouri on the edge of the Ozark Plateau, and grew up there and in the Chicago suburb of Wheaton, Illinois. His father was the director of a successful insurance firm, so life was always secure, and Edwin enjoyed generous financial support. He was a physically strong, gifted athlete, a charming, witty handsome man - according to the description of William G. Cropper, he was "perhaps too handsome"; “Adonis,” according to another fan. According to his own stories, in life he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches.in a small town in Missouri on the edge of the Ozark Plateau, and grew up there and in the Chicago suburb of Wheaton, Illinois. His father was the director of a successful insurance firm, so life was always secure, and Edwin enjoyed generous financial support. He was a physically strong, gifted athlete, a charming, witty handsome man - according to the description of William G. Cropper, he was "perhaps too handsome"; "Adonis," according to another fan. According to his own stories, in life, he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches. Illinois His father was the director of a successful insurance firm, so life was always secure, and Edwin enjoyed generous financial support. He was a physically strong, gifted athlete, a charming, witty handsome man - according to the description of William G. Cropper, he was "perhaps too handsome"; "Adonis," according to another fan. According to his own stories, in life, he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches. Illinois His father was the director of a successful insurance firm, so life was always secure, and Edwin enjoyed generous financial support. He was a physically strong, gifted athlete, a charming, witty handsome man - according to the description of William G. Cropper, he was "perhaps too handsome"; “Adonis,” according to another fan. According to his own stories, in life he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches.a charming, witty handsome man - as described by William G. Cropper, he was "perhaps too handsome"; “Adonis,” according to another fan. According to his own stories, in life he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches.a charming, witty handsome man - as described by William G. Cropper, he was "perhaps too handsome"; “Adonis,” according to another fan. According to his own stories, in life he more or less constantly managed to perform heroic deeds - to save drowning people, to take frightened people to safety on the battlefields in France, to confuse world boxing champions with knockdowns in exhibition matches.confuse world boxing champions with knockdowns in exhibition matches.confuse world boxing champions with knockdowns in exhibition matches.
Promotional video:
It all looked too good to be believed. Yes … For all his talents and abilities, Hubble was also an incorrigible liar. It was more than strange, because from an early age Hubble's life was rich in real differences, sometimes surprisingly abundant. In 1906, for one school athletics competition, he won the pole vault, shot put, discus and hammer throw, high jump and running, and was part of the team that won the one mile relay - in short, seven first places in one competition, and in addition he was third in the long jump. In the same year, he set the Illinois high jump record, excelled academically and easily entered the University of Chicago, where he studied physics and astronomy (coincidentally, the faculty was headed by Albert Michelson at the time). Here he was included among the first Rhodes Fellows at Oxford. His three years in England clearly turned his head, because when he returned to Wheaton in 1913, he began to wear an Inverness hooded cloak, smoke a pipe, and use a strangely pompous language - not quite British, but something like that - which has kept for life. He later claimed to have practiced law in Kentucky for much of his twenties, although he actually worked as a school teacher and basketball coach in New Albany, Indiana, before earning his doctorate and serving briefly in the military. (He arrived in France a month before the armistice and almost certainly did not hear a single live fire.) In 1919, at the age of thirty, he moved to California and received a position at the Mount Wilson Observatory near Los Angeles. Quickly and more than unexpectedly, he becomes the most prominent astronomer of the twentieth century. It is worth stopping for a moment and imagine how little was known about space at that time.
Astronomers today estimate that there are about 140 billion galaxies in the visible universe121. This is a huge number, much more than you might imagine. If galaxies were frozen peas, that would be enough to fill a large concert hall, say, Boston Garden or Royal Albert Hall. (This was actually calculated by astrophysicist Bruce Gregory.) In 1919, when Hubble brought his eye closer to the eyepiece, the number of known galaxies was exactly one piece - the Milky Way. Everything else was thought to be either part of the Milky Way, or one of many distant, minor accumulations of gas. Hubble soon demonstrated just how erroneous this belief was, and for the next decade, Hubble tackled two of the most fundamental questions about our universe: determining its age and size. To get an answer, it was necessary to know two things: how far are certain galaxies and how quickly they are moving away from us (i.e., the speed of recession). The redshift gives us the speed at which galaxies are receding, but says nothing about the distances to them. To determine distances, so-called "reference candles" are required - stars whose luminosity can be reliably calculated and used as a standard for measuring the brightness of other stars (and hence the relative distance to them).the luminosity of which can be reliably calculated and used as a standard for measuring the brightness of other stars (and hence the relative distance to them).the luminosity of which can be reliably calculated and used as a standard for measuring the brightness of other stars (and hence the relative distance to them).
Fortune came to Hubble shortly after an outstanding woman named Henrietta Swann Levitt figured out how to find such stars. Levitt worked as a calculator at the Harvard College Observatory122. Calculators have studied photographic plates with captured stars all their lives and made calculations - hence the name. It was more than a tedious task, but there was no other astronomy job in those days for women at Harvard - as well as in other places. This arrangement, while unfair, had unexpected advantages: it meant that half of the best minds went to activities that would otherwise attract little attention, and created conditions in which women ultimately managed to understand the details of the structure of the cosmos, which often eluded attention of their male colleagues.
One Harvard calculator, Annie Jump Cannon, through constant work with the stars, created their classification so convenient that it is still used today. Levitt's contributions to science were even more solid. She noticed that variable stars of a certain type, namely the Cepheids (named after the constellation Cepheus, where the first one was discovered), pulsate in a strictly defined rhythm, demonstrating something like a stellar heartbeat. Cepheids are extremely rare, but at least one of them is well known to most of us - the North Star is a Cepheid.
We now know that Cepheids pulsate in a similar way, because they are old stars that have passed, in the language of astronomers, the "main sequence stage" and become red giants. The chemistry of red giants is somewhat complicated for our presentation (it requires, for example, an understanding of the properties of singly ionized helium atoms and many other things), but, to put it simply, we can say this: they burn the remnants of fuel in such a way that the result is strictly rhythmic changes shine. Levitt's ingenious guess was that by comparing the relative brightness of the Cepheids at different points in the sky, one can determine how the distances to them relate. They could be used as reference candles, a term coined by Levitt that everyone began to use. This method makes it possible to determine only relative rather than absolute distances, but it was still the first way to measure large-scale distances in the universe. (To put the meaning of these insights in true light, it is perhaps worth noting that at the time when Levitt and Cannons drew their conclusions about the fundamental properties of space, having only vague images of distant stars on photographic plates, Harvard astronomer William G. Piquet-ring124, who, of course, could, whenever he wanted, look through a first-class telescope, developed his own, not otherwise as a pioneering theory that the dark spots on the Moon are caused by hordes of seasonally migrating insects.)(To put the meaning of these insights in their true light, it is perhaps worth noting that at a time when Levitt and Cannon were drawing their conclusions about the fundamental properties of the cosmos, for this purpose they had only vague images of distant stars on photographic plates, Harvard astronomer William G. Piquet-ring124, who of course could look through a first-class telescope whenever he wanted, developed his own groundbreaking theory that the dark spots on the moon were caused by hordes of seasonally migrating insects.)(To put the meaning of these insights in their true light, it is perhaps worth noting that at a time when Levitt and Cannon were drawing their conclusions about the fundamental properties of the cosmos, for this purpose they had only vague images of distant stars on photographic plates, Harvard astronomer William G. Piquet-ring124, who of course could look through a first-class telescope whenever he wanted, developed his own groundbreaking theory that the dark spots on the moon were caused by hordes of seasonally migrating insects.)whenever he wanted to look through a first-class telescope, he developed his own, nothing less than an innovative theory that dark spots on the moon are caused by hordes of seasonally migrating insects.)whenever he wanted to look through a first-class telescope, he developed his own, nothing less than an innovative theory that dark spots on the moon are caused by hordes of seasonally migrating insects.)
By combining Levitt's space ruler with Vesto Slipher's redshifts at hand, Hubble took a fresh look at estimating distances to individual objects in outer space. In 1923, he showed that the distant ghostly nebula in the constellation of Andromeda, denoted by M31, is not a gas cloud at all, but a scattering of stars, a real galaxy, one hundred thousand light years wide at a distance of at least nine hundred thousand light years from us. The universe turned out to be more extensive - much more extensive than anyone could have imagined. In 1924, Hubble published his key article "Cepheids in Spiral Nebulae", where he showed that the Universe consists not of one Milky Way, but of a large number of separate galaxies - "island universes", many of which are larger than the Milky Way and much more distant.
This discovery alone would have been enough to make him famous as a scientist, but Hubble now decided to determine how big the universe is and made an even more startling discovery. He began to measure the spectra of distant galaxies, continuing the work begun in Arizona by Slipher. Using Hooker's new 100-inch telescope at Mount Wilson Observatory, he used ingenious reasoning by the early 1930s that all galaxies in the sky (with the exception of our local cluster) were moving away from us. Moreover, their speeds are almost exactly proportional to their distances: the farther away the galaxy, the faster it moves, which was truly amazing. The universe expanded rapidly and evenly in all directions. You don't need to have a rich imagination to count backwards and understandthat it all started from some central point. It turned out that the Universe was far from being constant, motionless, endless emptiness, as everyone imagined it, it turned out to be a world with a beginning. This means that it may have an end.
It is surprising, as Stephen Hawking noted, that the idea of an expanding universe had never occurred to anyone before. The static Universe, as it should have been obvious to Newton and any thinking astronomer after him, would simply collapse inward under the action of the mutual attraction of all objects. In addition, there was another problem: if the stars burned endlessly in a static universe, then it would become unbearably hot in it - too hot for creatures like us. The idea of an expanding universe solved most of these problems in one fell swoop. Hubble was a far better observer than a thinker, and did not immediately fully appreciate the significance of his discoveries. Partly because he was completely unaware of Einstein's general theory of relativity. This is rather surprising, because by that time Einstein and his theory were worldwide famous. In addition, in 1929, Michelson - then in his advanced years, but still had a lively mind and was respected as a scientist - took up a position at Mount Wilson to take up the measurement of the speed of light with his reliable interferometer, and he certainly had to at least mention to Hubble about the applicability of Einstein's theory to his discoveries. In any case, Hubble missed the chance to draw theoretical conclusions from his discovery. Hubble missed the chance to draw theoretical conclusions from his discovery. Hubble missed the chance to draw theoretical conclusions from his discovery.
This chance (along with a doctorate from the Massachusetts Institute of Technology) fell to the Belgian scientist and priest Georges Lemaitre. Lemaitre combined the two parts of his own "theory of fireworks", which assumed that the universe began from a geometric point, a "primordial atom" that was torn apart and has continued to scatter ever since. This idea very closely anticipated the modern idea of the Big Bang, but was so ahead of its time that Lemaître rarely gets more than the couple of phrases we have dedicated to him here. It will take decades for the world, coupled with the accidental discovery of cosmic background radiation by Penzias and Wilson and their hissing antenna in New Jersey, before the Big Bang turns from an interesting idea into a solidified theory. Neither Hubble nor Einstein took part in this big story. But,although no one would have guessed it at the time, they both played as significant a role in it as could have hoped for. In 1936, Hubble wrote the popular book Kingdom of the Nebulae, in which he praised his own remarkable achievements. Here he finally showed that he had become familiar with Einstein's theory - at least to a certain extent: he devoted four pages out of two hundred to it.
Hubble died of a heart attack in 1953. One last, somewhat strange circumstance awaited him. For some mysterious reason, his wife refused the funeral and never said what she did to the body. Half a century later, the location of the remains of the greatest astronomer of the twentieth century remains unknown. As for the monument, you need to look at the sky, where the space telescope is located, launched in 1990 and named after him.
- Part one -