Gravity (English: Gravity, Gravity), that is, any twoobjectOr twoparticleThe attraction related to the product of distance and its mass, the most common force in nature, is called gravity for short.
Assuming that there are countless small particles in space impacting each other, gravity is generated from the high-speed impact of invisible small particles. When the two objects are close, due to the shielding of the two objects themselves, the frequency of particle impact on the near surface is less than that on the back of the two objects. This is a guess generated by gravity. In fact, it isquantum fluctuation , resultingCasimir effect。It's not gravity.
The attraction between any two objects or two particles related to the product of their mass is also the most common force in nature, called gravity for short.stayParticle physicsMiddle termGravitational interactionandStrong、weak forceandElectromagnetic force4 kindsBasic interaction。Gravity is one of the weakest, between two protonsUniversal gravitationOnly between themElectromagnetic force1/(1.235 * 10 to the 36th power), the proton's gravitational force by the earth is only 1/(9.761 * 10 to the 9th power) of its electromagnetic force in a weak electric field of 1000V/m.So study the interaction between particleselectron microscopeWhen moving in the accelerator, the effect of gravity is not considered.Generally, the gravity between objects is also very small. For example, when two iron balls with a diameter of 1 meter are close together, the gravity is only 1.11 × 10-3Newton, equal to 0.113 grams of the weight of a small drop of water.But the mass of the earth is very large, and these two iron balls are respectively affected by 4 × 10fourNewtonianGravity of the earth。So the research object is on the earthgravitational fieldThe gravity of other objects around is usually not taken into account when moving in.
Celestial bodies, such as the sun and the earth, have a large mass, and the product is even greater. The huge gravity can make the monster rotate around the sun.Gravity has become a force that controls the movement of celestial bodies, but the reason for this kind of gravity is not the pull between celestial bodies, but the distortion of the surrounding space-time by celestial bodies.The formation of stars does not disperse under high temperature, but gradually shrinks, and finally collapses intoWhite dwarf、neutron starAnd black holes due to their massiveSpace-time distortion, resulting inSpatiotemporal extrusionCaused by the action ofCelestial evolutionImportant factors.The greater the mass, the greater the distortion of space-time, and the greater the gravity.
The attraction of gravity on the earth gives weight to objects and makes them fall to the ground.In addition,Universal gravitationIt is the reason why the sun and earth and other celestial bodies exist;Without gravity, celestial bodies cannot attract each otherformationsphere systems , and as we all knowLife formsIt will not appear.Gravity also makes the earth and other celestial bodies revolve around the sun according to their own orbits,MoonAccording to its own orbit, it revolves around the earth, forming tides, and other kinds ofnatural phenomena。
Gravity is the force generated by the movement of all objects. The whole universe is a big vortex, in which there are countless small vortices, one constellation after anotherGalaxyIt is a small vortex. There is a small vortex in the small vortex, and then it drives the space it rotates according to its mass. Just like the size of the fan that drives the air to rotate, the running track of the universe is in the form of a vortex. This is the so-called universe expansion theory, because the matter outside the vortex will be rotated farther and farther, and the faster the rotation speed of the matter, the greater the gravity it will generate,The gravitational range that matter can generate is proportional to the space rotation speed driven by its mass. When the size of the same mass matter is the same, the faster its rotation speed will generate gravity on another matter, so a black hole can not escape even light. Because the speed of the black hole is far faster than the speed of light, photons are attracted when passing through the black hole,If there is a kind of material whose speed is greater than the rotation speed of the black hole, it can pass through the black hole, and the black hole is actually a wind eye. Suppose you do an experiment, a kind of material that rotates faster than the speed of light, then light touches the high-speed rotating material, and photons will rotate with it, which is like a piece of paper, moving slowly,But a gas with very high speed can pierce the paper in an instant as long as it is extremely fast. On the contrary, the rotation speed of the paper is far faster than that of the gas. Then the gas hit the paper will be dissolved by the rotation speed and then rotate with the paper. People can't feel the rotation on the earth, just like a bee flying with the plane in an airplane,When people leave the rotation range of the earth, the gravity of the earth on people will disappear. Newton said that the apple fell to the ground because of gravity. What he wanted to say was that a basin size fan blowing upward was placed above the apple. As long as the fan was fast enough, the apple would fall upward.
Universal gravitation
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1. A law of interaction between objects, 1687NewtonFound.Any object has mutual attraction, and the magnitude of this force is related to theMass of objectProportionalAnd inversely proportional to the square of the distance between them.If m1. m2 represents the mass of two objects and r represents the distance between them, then the mutual attraction between objects is
, G is calledUniversal gravitational constant。 The law of universal gravitation was published by Newton in 1687Mathematical Principles of Natural PhilosophyFirst proposed in the book.Newton used the law of universal gravitation to explain not onlyPlanetary motionIt also points out thatJupiterSaturn's moons have the same motion law around the planet.He believes that the moon is not only attracted by the earth, but also by the sun, thus explaining what has long been discovered in the movement of the moonMean square error, business trip, etc.In addition, he explainedcometThe motion orbit ofTidal phenomenon。according toLaw of universal gravitationSuccessfully predicted and discoveredNeptune。After the emergence of the law of universal gravitation, the research on the motion of celestial bodies was formally established on the basis of mechanical theory, thus establishingCelestial mechanics。In short, the greater the mass, the greater the gravity generated. The gravity generated by the mass of the earth is enough to hold everything on the earth firmly.
2. Any two particles pass throughCentripetal lineThe forces in the direction attract each other.The gravity is proportional to the product of their masses, inversely proportional to the square of their distances, and proportional to theChemical essenceOr physical state and intermediary matter.
Different interpretations
GravityClassical physicsIs considered to be the largest in the universeFundamental forceOne is proportional to the mass and inversely proportional to the square of the distance.But inEinsteinIn his theory, gravity is no longer a basic force, but only a manifestation of the curvature of space-time structure.The reason for the curvature of the space-time structure is the huge mass.
Take an example:solar systemThe planets in the inner circle the sun. The explanation in classical physics is that the planets are attracted by the sun and circle the sun.
According to the theory of general relativity, the space-time around the sun is affected by the huge mass of the sun, forming a space-time curveGeodesic lineExercise.
Newton's law of gravity is still the general understanding of gravity in modern times. In 1687 (Ding Mao year), Newton《Mathematical Principles of Natural Philosophy》The law of universal gravitation is published in the book.Newton's law of universal gravitation is stated as follows:
Newton and Gravity
"Each particle in the universe attracts other particles with a force that is proportional to the product of the mass of each particle and inversely proportional to the square of the distance between them“
（Every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.）
Specific to the cosmic objects under extreme conditions such as black holes.It has a strong attraction. When scientists explain this attraction, they attribute it toSpace bending。Resulting inSpace bendingThe reason is the huge mass of the black hole itself.
Gravitational lensing of galaxy clusters
When it comes to gravity, in the final analysis, it is related to mass. Gravity is regarded asA basic force caused by massEinsteinrelativityThe gravity is regarded asQuality inducedSpace-time curvaturePerformance of。
quantum mechanicsIt is believed that,Gravity is due to the exchange of two particlesGravitoncauseOf.
significance
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In the early 17th century, people were able to distinguish many forces, such asfriction, gravityair resistance, electricity and gravity, etc.Newton accurately attributed these seemingly different phenomena to the concept of universal gravitation for the first time: apples fall, people have weight, and the moon revolves around the earth. All these phenomena are caused by the same reason.NewtonianLaw of universal gravitationSimple and easy to understand, covering a wide range.Newton's concept of universal gravitation is one of the most practical concepts in all sciences.Newton believed that gravitation is the basic feature of all matter, which has become the theoretical cornerstone of most physical sciences.
black hole
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The reason why light is sucked into the black hole is that gravity causes space distortion. Light enters the black hole with the distorted space. Everyone knows that light only goes straight. Light is not sucked in by gravity, but light still goes straight, but space distortion enters the black hole.For example, if you draw a line on the paper and twist the paper, it is still a line.
Light is alongRectilinear propagationAccording to general relativity, space willgravitational fieldBending under action.At this time, although the light still travels along the shortest distance between any two points, it is no longer a straight line, but a curve.Figuratively speaking, it seems that light is supposed to walk in a straight line, but the strong gravityStretch bendingHas.
