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The speed of light is one of the most important constants in physics. Olaf Römer, the Danish astronomer, first estimated the speed of light in 1676. However, scientists who established that it was the light that sets the upper limit of the achievable velocity in our universe, which is almost 300,000 kilometers per second, was exactly Albert Einstein. And yet, according to the same Einstein theory, everything in this universe is relative, including motion. This, in turn, makes us ask a completely logical question: what is the speed of the complete opposite of light - darkness?
We are far from the first to ask this question, but Gizmodo portal decided to go deeper into it and on this occasion turned to one of the most respected and famous scientists, researchers, theorists, experts on black holes and quantum physics. Interestingly, they all do not have a common opinion on this matter. Some believe that darkness can have the same speed as light. Others believe that it can be infinitely slower. Still others are sure that everything will depend on the point of view with which you will look at this question.
George Masser
The editor of Scientific American and Nautilus journals, the author of the books "Eerie long-range action: a phenomenon reinterpreting the concepts of space and time. The significance of the phenomenon in the theory of black holes, the theory of the Big Bang and the Theory of Everything ", as well as" The Complete Guide to String Theory for Idiots "
"The speed of darkness? The simplest answer is that the speed of darkness is equal to the speed of light. "Turn off" the Sun, and our sky will turn dark eight minutes after this point. But this is a boring answer! No, well, the truth! First, what we are accustomed to calling the "speed of light" is the speed of propagation, and this is not always a decisive factor. The shadow falling on the landscape is discarded by objects. And the feature of these objects, as well as the distance from them, will determine how fast it will fall.
For example, a rotating beacon light illuminates the environment at a regular interval. However, the relative speed of darkening of the environment increases with increasing distance to the lighthouse itself. If you move away from the lighthouse far enough, then the shadow will overtake you faster than the speed of light. The same, for example, occurs with neutron stars in space. In other words, in this case the speed of light will only mean a delay. Even if the beacon is directed directly at you, you will see the light not immediately, but with some delay. However, this will not affect the course of events that you will see when you are in your place.
But is there such a thing as darkness at all? More precisely, the concept is, but is there a phenomenon? Even if you "turn off" the Sun, the Earth will not plunge into total darkness. The light from stars, nebulae and even the Big Bang itself will illuminate your sky in this case. The planet itself and everything that is on it, including our bodies, also emit light. And it will be visible in the infrared range. Even if you somehow found a way to "turn off" the sun, then even in this case it will radiate a certain level of glow almost forever. For your century and for many centuries ahead is enough for sure. That is, as long as we have the opportunity to see, we will see. No optical sensor is able to determine the total darkness, because even if there are no light sources nearby, the available quantum fluctuations will also produce very light flashes of light. Or take at least black holes - the darkest of the supposed objects. Even they are capable of emitting a certain percentage of the light, according to some theories. In physics, unlike the sphere of interpersonal relations, light always "conquers" darkness.
Darkness is not a physical category, it is rather a relative state. Not even so. This is a subjective perception of the state. Photons may or may not be reflected, retinal cells can trigger memory processes, but can not explain the subjective sense of darkness, just as waves can not be represented by anything larger than our experience of observing color or sound. Our subjective experience changes from time to time, however, separate parts of this experience lie outside of time. And in this sense, we can say that darkness itself does not possess speed.
What is speed in the general sense? And is there anyway? It presupposes a certain space in which it can be measured. However, many scientists who work with quantum physics - the world where the usual notions of conventional physics often become useless - believe that space itself is one of the derivatives of a more fundamental level of reality, where there are no concepts such as position, distance or the same speed".
Avi Loeb
Professor of Astrophysics at Harvard University, founder of Black Hole Initiative (BHI)
"The matter attracted to the center of the black hole reaches a velocity close to the speed of light. Everything that falls within the so-called horizon of events of black holes, can not escape. Even the light is forever sealed inside the event horizon. In view of this, black holes can be considered as some prisons of eternal darkness. But this is not so.
A star similar to the Sun can be "spagetted" into a gas stream, it will pass next to a massive black hole, such as the one in the center of our Milky Way galaxy and whose mass is equal to 6 billion solar masses.
However, when falling into a black hole, matter can create friction between itself and heat up. The end result of this friction is radiation. If the rate of accretion (the mass increment process) is sufficiently large, the pressure of the outgoing radiation will potentially be able to save the additional surrounding matter from the fall. Many of the most massive black holes in the universe, with a mass of billions of suns, have the highest possible accretion rate. "
Neil Degrass Tyson
Astrophysicist, Ph.D. in physics, writer, popularizer of science, director of the planetarium Hayden at the American Museum of Natural History in Manhattan. Leading the popular science series "Space: Space and Time"
"The speed of darkness, then ... Given that the darkness itself is the result of the cessation of the light? If the speed of light is represented by a constant, then the speed of darkness will be directly opposite to the speed constant of light. If light is a vector, it has a magnitude and direction, then ... speaking of its negative meaning, we will talk about its opposite direction. Darkness in this case is the opposite direction, and not direct. I would say that darkness has exactly the opposite negative value of the speed of light. "
Sarah Codill
Doctor of Science from the Leonard E. Parker Center for the Study of Gravitation, Cosmology and Astrophysics, University of Wisconsin-Milwaukee
"The force of gravity of black holes is so great that even light can not avoid it, after it falls into the radius of its event horizon - invisible borders creating a point of no return. Since black holes have such a strong gravity, the effect of slowing down time will influence the observations made outside this strong gravitational field.
Suppose that far from the black hole is an outside observer who sees how a certain luminous object falls into a black hole. From the viewpoint of the observer, this luminous object will first slow down its speed, and then "go out", becoming so dim that it will be impossible to see. The observer will not even be able to see how the object crosses the boundary of the event horizon.
If we consider the situation from the point of view of matter falling into this black hole. Let us now imagine a black hole surrounded by a cloud of glowing gas. This cloud is formed by a torn star, passing too close to this black hole. This gas cloud will be represented in the form of an oblate disc, also called an accretion disk. So, the gas of this disk will eventually be completely absorbed by the black hole, but it will not happen immediately.
The fact is that there is a speed limit that depends on the radiation pressure of the heated gas, which will resist the action of the internal gravitational force of the black hole itself. In the end, as soon as all the gas is absorbed by the black hole, its size will increase. For example, if we take a black hole whose initial mass is 10 times the mass of our Sun, and the rate of its accretion of mass will reach a maximum limit (the so-called Eddington limit), then after about a billion years, the mass of this black hole will reach a mass of 100 million times greater than the mass of our Sun. "
David Reize
The scientific leader of the Laser Interferometric Gravitational-Wave Observatory (LIGO)
"Basically, everything will depend on whether you are that matter that is absorbed in the endless abyss of a black hole, or whether you are far enough from the scene of the event and are a dispassionate observer of the event of the fall of someone or something else into this very abyss. If you are unlucky and you are in the first place, the speed will be very high. Most likely, it will be about indicators close to the speed of light.
If you are in the place of the second and are far enough from the black hole, then the speed at which matter will be absorbed by the black hole will seem to you significantly reduced due to the effect of gravitational time dilation. According to him, the "clock" under the influence of the gravitational field is slower, and under the influence of a very strong gravitational field - even slower, which will be just as the horizon approaches the events of the black hole.
By the phrase "far enough" I mean that in your local coordinate system you will remain stationary relative to the black hole (that is, you will not be attracted to it) and your local time system will not be affected by the gravitational field of this black hole. In this case, for a person outside the black hole, it will seem that the object or matter will move to the horizon of the events of the black hole for an infinitely long time. "
Nyaesh Afshordi
The astrophysicist of the Department of Physics and Astronomy of the University of Waterloo, as well as the head of the Department of Cosmology and Gravitation at the Institute of Theoretical Physics "Perimeter" in Canada
"I believe that the speed of" darkness "is infinite! In classical physics, under the general concept of the darkness of the cosmos, an empty vacuum can be considered. However, thanks to quantum mechanics, we know that in reality there is no darkness and empty space. Even if it seems to you that there are no light sources that we could see, this source can be fluctuations of electromagnetic fields. More recently, even within the gravitational waves that cut space-time and discovered by the LIGO laboratory, these quantum fluctuations must be present.
The problem is that the level of gravity in this quantum ripple is infinite. In other words, at the moment there is no fairly convincing theory of quantum gravity, which most scientists would agree with. The necessary answer to the question may be hidden in the very possibility of the speed of "darkness," that is, the quantum ripple to reach an infinite value (or to become arbitrarily large), especially on a small scale and for a short time. Of course, this is only an assumption, but it seems to me that this is the effective way to understand the principle and essence of the Big Bang, black holes, dark energy and quantum gravity. "
The article is based on materials .
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