In order to truly understand all the possibilities presented by "Interstellar", we must understand (do not expect to understand, understanding requires a huge mathematical theoretical foundation as the backing; so this article hides all the expected properties and mathematical details related to space physics, otherwise it will be like :
R_rtr^t=-R_rrt^t=(1-b⁄r )^(-1) e^(-2φ)
Once a formula like R_ttr^t appears in the article, it goes against the original intention of this film review) The following Four knowledge points:
1. Black holes and white holes;
2. Wormholes;
3. The relationship between time and gravity;
4. Gravity and the fifth dimension.
"Interstellar" hired Kip S. Thorne, a Tarzan-level figure in theoretical astrophysics, to provide scientific support for the film's hard science fiction. First of all, Kip Thorne proposed the idea that black holes cannot be used for interstellar travel as early as 1986, so how did he formulate this idea?
1. Black holes and white holes
"Black holes not usable for interstellar travel" "Black holes are not usable for interstellar travel
"
1. The
black hole horizon is located on the surface of space to separate those trapped within the black hole and cannot communicate with the outer universe. and the outer cosmic airspace in which we live. The mass M of an object is at the boundary of the black hole, the tidal force of the celestial body generated by the huge mass of the black hole acts on the object, and produces a huge relative acceleration at its two ends, then the value of the length L between the two ends of the object will tend to be positive. gigantic.
To explain in earthly words, we can imagine a person who lives on the earth. Because he is closer to the earth, his gravitational force is larger than that of an astronaut who is farther away from the earth, so the calcium deficiency of earth people needs to be Decades of insufficient calcium intake to achieve this, and astronauts only a few months in low-Earth orbit have various discomforts, such as osteoporosis and can not walk and so on.
Consider further, if we expand the mass of the earth to four million times the mass of the sun, it is sufficient to form a black hole. Let us first assume that an astronaut has a mass of M and a height of L, and his feet are facing the black hole and his head is facing the black hole. The outer cosmic airspace, and is located in a three-dimensional space point between the black hole boundary (we can simply understand the black hole boundary as the horizon of the black hole) and the outer cosmic airspace, then the foot of our sad astronaut is affected. The tidal gravitational force of the celestial bodies attracted by the black hole is much greater than the tidal gravitational force of the celestial bodies that his head is subjected to. The tidal gravitational difference formed by the force difference between the two forces will act on the astronaut's feet and head to form different accelerations. The acceleration is greater than that of the head. Then there will be the following terrifying and magical phenomenon: Astronauts start from their feet to their heads, and are torn apart by tidal gravity into atomic forms, even quarks, and finally become countless energy rings, which are mentioned in string theory. Strings, which in turn contribute to the mass of the black hole (doesn't the mass come from the fluctuations of the strings?).
Therefore, Kip Thorne pointed out that before the astronauts have not reached the limit of the black hole, they have already died heroically due to the effect of the gravitational force of the celestial body. Therefore, it is wrong to think that any object will be torn apart after falling into a black hole. The actual situation should be that it has been smashed to ashes and gorgeously changed before it has time to feel what the horizon of the black hole looks like. The body becomes billions of pulsating energy rings, blue, purple, yellow, any color, but because the black hole's tidal gravitational force is too great, even light cannot escape, so it can be assumed that this cruel process, We humans can't see the truth.
2
“A black hole horizon is a one-way membrane
”
Things can fall in, but nothing can come out. Therefore, the round-trip journey to the black hole is forbidden; and even if it is a one-way entry into the black hole, the matter is at the exit at the other end of the black hole, and if the astronaut can still get out in any form, the exit is absolutely impossible. black hole. It must be another, or even more bizarre, object - say, a white hole.
Can't Kip Thorne speak well? The brief and concise second explanation about black holes made Xiaoqing'er feel foggy, and had to check Google Du Niang to understand a little bit. What he meant was that once any matter entered the horizon of the black hole, it would be like being trapped by a layer. The diaphragm is there, and as long as the black hole is still there, don't think about going back the same way, unless the black hole is dying, and the matter that enters the black hole must be transformed into other matter - such as those sparkling and shaking rings, and then when the black hole dies and disappears, it is destroyed. Spit out, the exit that was spit out is no longer a black hole (because the black hole is dead), but a white hole.
2. Wormholes
To understand wormholes, we must first understand two concepts: space-time and space. Space is three-dimensional and time is static; while space-time is four-dimensional, the space at a certain point in time forms a time axis one by one along the advancement of time, and the time direction is always forward and never backward, just like shooting. General arrows out. So, when we describe the motion of something in four-dimensional spacetime, we call it an event. Simply put, the moment an apple hits Newton's head, it is a four-dimensional space-time event: space has three dimensions - length, width, and height, while it is one-dimensional, and it keeps moving forward.
Combined with the time-related phenomena involved in the movie "Interstellar", it is realized through black holes and the fifth dimension, not through wormholes, which will be explained in detail below. The function of wormholes in the film is to connect two outer universes that are very far apart. We can imagine these two co-existing outer cosmic spaces as two 2D planes. The columnar channel between these two planes is a wormhole, a hyperspace pipe that exists in the universe; it is like an apple being The bug bites right through from one end to the other, rather than making a half-circle along the outer arc of the apple. So, when a spacecraft travels from the outer space near Earth, such as from the Kuiper Belt, which is located at the outer edge of the solar system, enters a wormhole (travel time in the wormhole is negligible), and then travels from outer space on the far Earth, such as Drilling from the vicinity of λ Ursa Minor star 888 light-years away from the earth, the spacecraft itself does not perform superluminal motion or time travel, but the act of passing through the wormhole itself indirectly achieves the effect that superluminal speed can achieve, that is, The spacecraft traveled a distance of 888 years at the speed of light in a negligible amount of time, as if two distant universes at the same point in time were instantly folded. The spacecraft in "Interstellar" traveled through a wormhole to Miller-Miller, a planet beyond the boundaries of a black hole called the Gargantua black hole. About the knowledge points of Miller's star, Xiaoqing'er will discuss with the time in Chapter 3. The gravitational relationship is explained in detail.
There are many questions on the Internet about the shape of the wormhole in the film - why is the wormhole a spheroid?
Kip Thorne first assumed that the metric that can pass through a wormhole is statically spherically symmetric. This is of course not necessary, but it is the preferred simplified condition in the study of general relativity. For example, the first strict solution of general relativity - the Schwarzschild solution, is obtained under this simplified condition. Hole research is also logical. And from the perspective of astrophysics, if a wormhole is a large-scale material structure, its natural form is indeed most likely to be close to static spherical symmetry like other large celestial bodies.
Also, as explained in the film, wormholes are two points that connect two outer cosmic spaces that are far apart, starting and ending. The above has simplified the two outer cosmic spaces into two planes, and after the planes are folded in half, the starting point and the ending point are coincident. This coincidence point is realized under the 2D plane, and now imagine entering 3D space, the coincidence point will expand in all directions to form a sphere.
Therefore, the shape of the wormhole in the film is not a columnar channel between two outer cosmic spaces, but a transparent sphere like a gas bubble.
Kip Thorne believes that the construction of a passable wormhole needs to meet the following nine conditions:
1.
The metric (metric standard) of a passable wormhole should be both spherically symmetric and time-invariant, that is, the so-called static spherical symmetry . The original intention of this specification is to simplify the calculation, and we must also realize that the wormhole may become unstable due to spherical or non-spherical perturbations. Wormholes in Interstellar are of course stable, as humans have begun to utilize the phantom matter that keeps wormholes open.
2
Any calculation result must satisfy the field equations of general relativity, provided that we assume that Einstein's general theory of relativity is correct, that is, matter tells space-time how to bend, and space-time tells matter how to move.
3
In order to form a wormhole, the throat of the wormhole (the center of the columnar channel) must connect the two progressively flat space-times of the entrance and exit respectively - the framework of the basic structure of the wormhole.
4
Wormholes do not have a wormhole boundary (event horizon) - as with black holes, the existence of an event horizon prevents the possibility of two-way travel.
5
The gravitational force of the celestial body on the object passing through the wormhole must be within an acceptable range - it will be no use if it is shredded.
6
An object traveling through a wormhole must pass through the wormhole in a finite and reasonably short period of time, say less than a year, not only in terms of the time of the object itself, but also in terms of the time of the individuals outside the wormhole waiting for the object to appear. Look - I'm afraid of dreaming more at night.
7
The energy, momentum and tensors of matter are physically reasonable - that is, they can be found in space, some can be reasonably sourced locally; others can be exploited, such as the acceleration used by spacecraft to escape Gargantua's massive tidal gravity and deceleration.
8
The solution of the wormhole must be in a perturbed stable structure that is stable enough for a spacecraft to pass through. Kip Thorne did not specify how to achieve such stability, Xiaoqing'er guessed that it must be achieved by mining dark matter and using phantom matter.
9
Wormhole construction should be theoretically possible. For example, the mass of the material required for the construction process must be much smaller than the mass of the universe, and the construction time must also be much smaller than the age of the universe. In other words, the raw materials in the universe must be used within a limited time without wasting resources. Build wormholes quickly and cheaply.
Wormholes have been theoretically demonstrated in the microscopic world to demonstrate the possibility of their existence. To sum up, if human’s technology can reach the level that meets the above nine conditions, then in theory, human beings can use the resources of the universe to achieve the great feat of artificially constructing a passable wormhole.
The future human in "Interstellar" did it, so the part involving wormholes in the film does not deviate from the astrophysical theory that represents the highest level in the world today, and shows ignorant human beings from a grand perspective. A picture of freedom from extinction Doomsday scenery.
Perhaps, wormholes are really the first stepping stone to the ultimate salvation of mankind. The reason is very simple. If there is no curvature of time and space, even if human beings can develop the technology of flying at the speed of light, from the beginning of interstellar travel, they are destined to be lost in space. In this way, Mr. Hawking signed up for the interstellar travel, how much cosmic heroism tragic and solemn!
3. The relationship between time and gravity In the
film, Cooper (Matthew McConaughey) and Brand (Anne Hathaway) came to a Miller planet next to the Gargantua black hole, which is entirely composed of water, through a wormhole.
Many netizens at home and abroad have complained about this setting. Using VPN to rummage through IMDb and similar blogs, the complaints can be roughly classified into three categories. One: Why is Miller Planet not sucked into a huge black hole? Second: How did Cooper and Brand escape the tidal gravitational pull of the giant black hole in and out of Miller's star? Third: Why is one hour on Miller's star equal to seven years on Earth?
Xiaoqing'er is here to answer them one by one.
First, Kip Thorne wisely set the Gargantua black hole as a rapidly rotating black hole in "Interstellar", which is different from Schwarzschild's static black hole, involving the astrophysics and related aspects of rotating black holes. The physical theories of static black holes are quite different. Rotating black holes theoretically allow the existence of Miller-like stars at relatively close distances, while the surroundings of static black hole event horizons (boundaries) do not, in principle, allow the formation of Miller-like stars. This is a solution. Returning to the above description of the black hole boundary (event horizon), we must be able to understand that the location of Miller's star must be outside the black hole event horizon of the Gargantua black hole, far enough away from the event horizon to not be decomposed by the action of tidal gravity; At the same time, it is also close enough to the black hole event horizon (boundary) of the Gargantua black hole so as not to deviate from the orbit of the black hole. This is solution two. Therefore, the huge wave that appears on Miller's star in the film is as shocking as the towering mountains has its astrophysical basis - only the huge gravitational force of the celestial body generated by the black hole of Gargantua can cause such a large-scale wave / Tsunami.
Second, according to the formula in Chapter 61 and Article 117 of Chandrasekhar's "Mathematical Theory of Black Holes", the specific energy value given by an object's orbit around the black hole is calculated by the time dilation effect (which will be given in the following paragraphs). Explanation) As a starting point, a rough estimate of the orbital radius of the black hole is:
r ≈ 2.000025339 M
If the above estimates are within the acceptable range, for a strongly rotating black hole rotating at maximum speed, Chandrasekhar's formula gives The specific energy value is then:
E ≈ 0.777
That is to say, the energy involved in entering and leaving the orbit is the order energy equivalent to 22.3% of the rest mass of the object (the change in free energy caused by the ordering of a solid solution), that is, a point of mass, such as a spacecraft, to The energy transferred by orderly movement can be regarded as work, such as electrical energy, chemical energy and mechanical energy. The mass of the spacecraft is within the controllable range, and 22.3% of its mass is not as infinite as other netizens imagined. Therefore, this specific energy value is rationally supported by its technology. In short, the spacecraft has the ability to enter and leave Miller's planet and successfully escape the tidal gravity of the black hole, and the energy required is only the order energy equivalent to 22.3% of the spacecraft's mass. It is not difficult to calculate the magnitude of this order energy. According to the following steps, let the mass of the spacecraft in the film be M, and E is the order energy required for the spacecraft to enter and leave the orbit. Now :
E = M • 22.3% •(299,792,458 m/s)2
In fact, this specific energy value is also very huge. According to the current level of technology, it seems that human beings cannot reach it. That's 89.9 trillion joules, or the energy released by the explosion of 21.5 kilotons of TNT, or the energy released by the complete combustion of 568,000 gallons of gasoline. It is conceivable that if the spacecraft in the film wants to fly away from the terrifying trap of the tidal force of the black hole celestial body, it must be completely opened by the N power of the unbelievable equivalent!
Third, one hour on Miller's star is equivalent to seven years on Earth, that is to say, Cooper and Brand have traveled to twenty-three years later in more than three hours relative to Earthlings. Arabian Nights? Not also. It's neither bullshit nor imagination, but real hard science. Unlike wormholes, the physics community has not yet confirmed the existence of wormholes, and black holes do exist - there is a huge and strongly rotating black hole in the center of our galaxy, otherwise, why would our galaxy show a weak What about the spiral disc shape?
In fact, the phenomenon of time travel occurs every day between the earth and low-Earth orbit. If you don't believe it, please go to Baidu GPS calibration. To explain the problem of GPS calibration, we have to mention gravitational time dilation.
Einstein described gravitational time dilation as a phenomenon in which time passes at different rates in regions of the universe with different potential energies. The greater the rate at which space-time is warped by gravity, the slower time passes. The phenomenon of GPS calibration is ironclad.
The gravitational force on the earth's surface is greater because the earth's surface is closer to the earth than GPS in low earth orbit is farther away from the earth's surface. This is similar to the difference in the tidal gravitational force on the head and feet of the sad astronaut with a length of L mentioned above. Earth people are in a high potential energy region because they are close to the earth, and the space-time distortion rate caused by gravity is relatively large on the surface of the earth, and time passes slower than the atomic clock of GPS in low-Earth orbit; and GPS is in low-potential energy space, The gravitational force is naturally smaller, so the space-time distortion rate is not as obvious as that on the surface of the earth, so the time constraints are less than those of the earth, so the time runs a little faster, a few nanoseconds a day- But cumulatively, one week can also yaw GPS navigation on the Earth's surface by as much as 6 miles. So the atomic clock of GPS is automatically calibrated every day.
In the same way, this phenomenon is copied to Miller's star near the black hole of Gargantua. Now the earth and Miller's star are two mutual reference objects. The potential energy of the area where the people of the earth are located remains unchanged, and the potential energy of Cooper and Brand in Miller's star is unchanged. It's completely different. The tidal force of the celestial body of Gargantua's black hole is not comparable to that of the earth's gravity. Cooper and Brand are in a region of extremely high potential energy caused by tidal gravity, and the surrounding space-time distortion rate is also amazing, which leads to The time on Miller Planet passed super slowly, and Murph, who was on Earth, grew from a 10-year-old loli to a middle-aged woman in just over three hours that her father spent. .
We can understand it this way, if through the wormhole, human beings find an incomparably huge cosmic super-large black hole, which is hundreds of millions of times more than Gargantua. If you can stay alive for a second near it without being torn apart, maybe thousands of years have passed on the earth. , ten thousand years. It was no longer magic, but extreme panic. Given this, perhaps the eventual discovery/construction of wormholes is not a good thing for humans. On the other hand, if there is no folding of the outer space of the universe, how can human beings find another planet that continues human civilization before the sun becomes a red giant star and bakes the entire solar system into nothingness?
Writing this, I suddenly understood the point that Nolan preached in the film that only love can travel through time and space. Many netizens at home and abroad complained that the so-called pale and promiscuous love was incompatible with the hard sci-fi, saying that a happy ending would reduce the force of hard sci-fi. Xiaoqing'er wanted to say that they were all wrong, so inhumane, because Nolan had raised the story to the philosophical level of whether human beings should be saved. In fact, human beings and human civilization will eventually disappear. Throughout history, human beings do not seem to be worth saving, so Plan B was implemented, and the human migration of Plan A was set as impossible at the beginning of the film. This is the most chilling hard horror. To borrow a stalk from the movie "2001: A Space Odyssey": If the audience of the film really understands what the film is about, then Nolan and Thorne must be wrong. .
4. Gravity and the Fifth Dimension
Gravity exists in the fifth dimension, which bends and deforms space-time according to the field equations of Einstein's general theory of relativity.
According to the holographic principle, all fifth-dimensional events can be transformed into other fourth-dimensional space-time events.
The phenomenon of gravity acting on the fifth dimension is the most brain-burning part of Interstellar. The film demonstrates this bizarre concept by stringing together Cooper, a human being in high-dimensional space, a cabin in four-dimensional space and time, and a middle-aged Murph.
Why is it amazing? The description of black holes in the whole article above is nothing more than to say that you should not fall into a black hole. And the key to opening the fifth dimension in the film actually started with Cooper falling into the black hole, or more precisely, being brought into the black hole by future humans in higher dimensional space-time - so what about the black hole event horizon? Where did the role of the unidirectional diaphragm go? What about the tidal force of the huge celestial body of the black hole?
These are actually ignored in the film. Theoretically, we have clearly recognized that once inside a black hole, nothing can come out - unless it is ejected from a white hole in shreds, and the premise must be after the black hole dies. So it can be understood that Cooper must have decided to reduce the load on the main ship with the determination to die, and also chose to fall into the black hole. Thinking further, Cooper also wants to try to see if he can safely pass the black hole event horizon and get closer to the singularity as the theory sets. The film sets the singularity (center) of the black hole as a mild singularity, which is derived from the nature of the Gargantua black hole, which is a strongly rotating black hole. near the point. And a necessary condition for mankind to build the fifth dimension is super-giant gravity, and such gravity only exists at the singularity of super-large cosmic objects (such as massive black holes). It may be theoretically feasible to pass through the black hole event horizon at high speed, but after passing through, Cooper is absolutely impossible to live close to the singularity. However, Cooper escaped the fate of being turned into powder because of the existence of the fifth dimension.
Cooper was pulled into the fifth dimension by them, that is, us. At first, everyone didn't know much about this; Cooper, who entered the fifth dimension, suddenly realized that they were actually us. Xiaoqing'er understands that this we do not specifically refer to us composed of Cooper and robots in the future, but refers to the future human beings with higher intelligence and wandering in high-dimensional space and time. why would you say so? From the basic logic point of view, Cooper's lifespan is limited after all. In his limited time, the level of technology will not develop so quickly to be able to build a five-dimensional space. And when Cooper was pulled into the black hole, the whole event formed an infinite loop with time as the carrier.
Having said that, there is still a concept that needs to be clarified, that is, the fifth dimension that constitutes the five-dimensional space-time is not gravity, but a three-dimensional space composed of time. Any object in the four-dimensional space-time has its own timeline, the timeline of the individual forward, the timeline of the car you drive, and even the timeline of the keyboard used to write this review, etc. Now imagine that these infinite time axes are spread out on both sides to form a time plane; and then expand upward and downward respectively, and the countless time axes further form a three-dimensional space composed of time axes. The existing four-dimensional space-time travels through a corresponding time axis. In fact, these time axes are the same time axis, moving in the only direction of history, and time will never go backwards. And each four-dimensional space-time event is presented in the form of a three-dimensional space in the five-dimensional space-time, that is, the cube-corner cylinders called Tesseract in the film - a five-dimensional space-time constructed in a three-dimensional representation.
Strong gravity exists in the fifth dimension, bending and deforming spacetime, and all fifth-dimensional events can be transformed into other four-dimensional spacetime events. The time axis in the five-dimensional space-time is clearly separated, and each three-dimensional space constructed by the time axis represents a certain four-dimensional space-time event on the time axis, and this series of four-dimensional space-time events together seems to be the haunted episode at the beginning of the film.
Because four-dimensional space-time is distorted by gravity in the fifth dimension, Cooper can only use gravity, the only tool that can travel through time and space, and objects that use gravitational energy to act, such as books, fine sand, and the beating of watch hands, to transmit two to Murph. Dimension code and Morse code. As for Cooper himself, he didn't go back in time.
Maybe you can't describe "Interstellar" with good-looking, because the word good-looking is too small in front of such a frightening movie - good-looking, it is a blasphemy for this film.
At the end of the film, many happy 2B youths took the lead in applauding.
Xiaoqing'er is also one of them.
- The End -
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