General theory of relativity and special theory of relativity
The theory of relativity" is
General relativity was originallypublished by Albert Einstein in 1915. Before general relativity, gravity was thought to be a “force” that acted between objects that had mass.
However, Einstein's general theory of relativity changed this view of gravity. According to the general theory of relativity, our Universe consists of 3 spatial dimensions + 1 time dimension.
Together, these dimensions form a four-dimensionala continuum known as the fabric of space-time. Objects that have mass produce a curvature in the fabric of spacetime. This curvature of spacetime is responsible for gravity.
General theory of relativity (GR)
General relativity describes gravityas the curvature of space-time. General relativity predicted the existence of black holes and their properties even before they were discovered.
General relativity is based on fieldEinstein's equations, which are nonlinear and very difficult to solve. According to general relativity, objects with mass bend the fabric of space-time. The greater the mass, the greater the bend. General relativity has a number of consequences, which are discussed below.
The most famous early test of general relativity waspossible due to the total solar eclipse of 1919. Arthur Eddington showed that the apparent positions of stars change near the Sun in exact accordance with the predictions of general relativity
Basic principles of general relativity:
- The need to modify the Newtonian theory of gravity
Newton's classical theory of gravitation is based onthe concept of gravity, which is a long-range force: it acts instantly at any distance. This instantaneous nature of the action is incompatible with the concept of a field in modern physics. In the theory of relativity, no interaction can travel faster than the speed of light in a vacuum.
- The principle of equality of gravitational and inertial masses
In non-relativistic mechanics, there are two concepts of mass: the first refers to Newton's second law, and the second to the law of universal gravitation.
First mass- inert (or inertial) - there is a relationnon-gravitationalforce acting on a body to accelerate it.Second mass- gravitational - determines the force of attraction of a body by other bodies and its own force of attraction.
These two masses are measured, as can be seen from the description,in various experiments, therefore, they do not have to be connected at all, and even more so - proportional to each other. However, their experimentally established strict proportionality makes it possible to speak of a single body mass in both non-gravitational and gravitational interactions. By a suitable choice of units it is possible to make these masses equal to each other.
- The principle of movement along geodetic lines
If the gravitational mass is exactlyinertial, then in the expression for the acceleration of the body, which is acted upon only by gravitational forces, both masses are reduced. Therefore, the acceleration of the body, and hence its trajectory, does not depend on the mass and internal structure of the body. If all bodies at the same point in space receive the same acceleration, then this acceleration can be associated not with the properties of the bodies, but with the properties of the space itself at this point.
- Space-time curvature
If you launch two bodies from two close pointsparallel to each other, then in the gravitational field they will gradually begin to either approach or move away from each other. This effect is called geodetic line deviation.
A similar effect can be observeddirectly, if you run two balls parallel to each other on a rubber membrane, on which a massive object is placed in the center. The balls will disperse: the one that was closer to the object pressing through the membrane will tend to the center more strongly than the more distant ball. This discrepancy (deviation) is due to the curvature of the membrane.
- Space-time general relativity and the strong principle of equivalence
The main difference between the space-time of general relativity andspace-time SRT is its curvature, which is expressed by a tensor quantity - the curvature tensor. In SRT space-time this tensor is identically equal to zero and space-time is flat.
For this reason, it is not entirely correctname "general theory of relativity". This theory is only one of a number of theories of gravity currently being considered by physicists, while the special theory of relativity (more precisely, its principle of the metricity of space-time) is generally accepted by the scientific community and forms the cornerstone of the basis of modern physics.
None of the other developed theories of gravity, except for general relativity, has not stood the test of time and experiment, that is, all of them, with the exception of general relativity, have remained only hypotheses.
Special theory of relativity (SRT)
Before we go any further, we must first understand thatmovement is relative.For example, imagine that you are standing on a footpath and see a bus passing along the road at some constant speed "v".
Now for the people on the bus every one of themresting in relation to each other. But for you they all move with the bus at a certain speed "v". A person who seems to an observer to be motionless in one frame of reference may not necessarily appear to be motionless to another observer in another frame of reference - therefore, the motion is not absolute, but relative.
- Time synchronization
The SRT postulates the possibility of determininguniform time within the framework of this inertial reference system by the synchronization procedure of two clocks located at arbitrary points of the ISO (inertial reporting system).
- Unit alignment
To ensure that measurements made in different ISOscould be compared with each other, it is necessary to coordinate the units of measurement between the reference systems. Thus, units of length can be consistent by comparing length standards in a direction perpendicular to the relative motion of inertial reference frames.
For example, it could be the shortest distancebetween the trajectories of two particles moving parallel to the x and x axes’ and having different but constant coordinates (y, z) and (y’,z’). To coordinate time units, you can use identically constructed clocks, for example, atomic ones.
- Space and time are homogeneous
The laws of nature are the same in all coordinate systems moving rectilinearly and uniformly relative to each other. It means thatthe formdependence of physical laws onspace-time coordinates must be the same in all ISOs, that is, the laws are invariant with respect to transitions between ISOs. The principle of relativity establishes the equality of all ISOs.
Given Newton's second law, it can be arguedthat if the speed of some body in a given IFR is constant (acceleration is zero), then it must be constant in all other IFRs. Sometimes this is taken for the definition of inertial reference frames.
- The principle of constancy of the speed of light
The principle of the constant speed of light contradictsclassical mechanics, and specifically the law of addition of velocities. When deriving the latter, only Galileo's principle of relativity and the implicit assumption of the same time in all ISOs are used.
Thus, from the validity of the second postulate it follows that time must berelative- not the same in different ISOs.It necessarily follows from this that “distances” must also be relative. In fact, if light travels the distance between two points in some time, and in another system - in a different time and, moreover, at the same speed, then it follows that the distance in this system must be different.
What is the essence of the new “theory of everything”?
Two professors formulated a new theoryEngineering from NC State University: Larry M. Silverberg and Jeffrey W. Eischen. They published the results of their work and the mathematical apparatus they created in the journal Physics Essays.
To describe the interaction of matter, spaceand time, American scientists introduced the concept of “energy fragment”. According to them, this is the basic and indivisible structure from which the entire Universe known to us consists - from subatomic particles to stars and galaxies.
Silverberg and Aishen propose to do the followinga step in humanity's understanding of the world. According to them, at the current level in physics there is a dichotomy of wave and particle. The latter - the element of matter - exists at a specific point in space. Whereas a wave exists everywhere except the point from which it was emitted.
"Fragments of Energy" unite these two entities.According to the authors of the article, energy always "flows" through the regions of space and time. These flows do not begin or end anywhere, nor do they ever intersect.
The idea behind streams that have been named"Fragments of energy", arose when trying to mathematically describe the infinitely flowing energy. The theory is based on the most effective model. The flows in it are determined by the simple equation A = -⍺ / r, where ⍺ is the intensity and r is a function of distance.
As proof, Jeffrey and Larry applied their findings to two of the most famous confirmations of Einstein's theory. It's about calculationanomalous precession of the perihelion of MercuryAndgravitational deflection of light.
Abnormal displacement of the perihelion of Mercury- a feature of movement discovered in 1859planet Mercury, which played an exceptional role in the history of physics. This displacement turned out to be the first movement of a celestial body that did not obey Newton’s law of universal gravitation. Physicists were faced with the need to look for ways to modify or generalize the theory of gravity.
The search was crowned with success in 1915, whenAlbert Einstein developed the general theory of relativity (GR); from the equations of general relativity followed exactly the same value of the displacement, which was actually observed. Later, similar displacements of the orbits of several other celestial bodies were measured, the values of which also coincided with those predicted by general relativity.
Gravitational deflection of light - changing the direction of propagation of light ingravitational field. It is a consequence of the principle of equivalence. It was first calculated by A. Einstein in 1916. An important consequence of the gravitational deflection of light is the effect of gravitational lensing in astronomy.
Is the new theory easier and more convenient?
The results obtained taking into account the "fragments of energy" coincided with those within the framework of the theory of relativity. Whether they were simpler is not specified.
Assessment of the world scientific community
Since only a short version is publicly availablepresentation of the theory, it is difficult to judge how much the theory of Silverberg and Aishen stands up to criticism. Larry's essay is posted on The Conversation and provides just two pieces of evidence.
If the work of American scientists attractssufficient attention of the scientific community, perhaps a discussion will arise. In the course of it, it will become clear how useful the new theory is for science, whether it is redundant or whether it contains fundamental flaws.
Read more:
Abortion and science: what will happen to the children who will give birth
NASA published a photo of the Earth from the moon, which was taken in 1968
Check out the most beautiful pictures of Hubble. What has the telescope seen in 30 years?