The earth is so big and so heavy, why doesn t it fall?

There are many friends who do not believe in the gravitational force generated by the huge mass, for the earth, the North Pole is not up, the South Pole is not down, the real bottom is pointing to the center of the earth, but this point seems to be very difficult to understand for the gravitational force of friends who have repulsion, so the following will explain from two angles, why the earth will not fall!

1. From the perspective of "centrifugal force", explain why the earth does not fall

From this point of view, the explanation is simple and intuitive, and it is very common in daily life

This is easy to understand, as long as the speed is high enough, then the resultant force of the "centrifugal force" and gravity will be more and more deviated from the center of rotation, and tend to be horizontal, which is the direction of the flight chair when the "centrifugal force" is much higher than gravity!

Of course, this premise is that you should believe that the earth revolves around the sun, and if you think that the sun revolves around the earth, or even in its own orbit, then this simple explanation may not be valid!

Do you agree that because the Earth is orbiting the Sun at a speed of up to 30 km/s, its "centrifugal force" is sufficient to maintain equilibrium?

Second, from the perspective of the balance between gravity and "centrifugal force", understand why the earth does not fall

The gravitational force between two particles is equal in magnitude and opposite in direction, directly proportional to their mass and inversely proportional to the square of the distance! In the Oort cloud, we can think that the gravitational pull of the sun is absolutely dominant, so we don't need to think too much, just consider the gravitational battle between the sun and the earth, if there is no "centrifugal force" mentioned above, then the sun will make the distance between the sun and the earth shrink day by day, and eventually fall into the sun! Therefore, in space, if there is no "centrifugal force" generated by the additional revolution, then I am sorry that the earth will really fall!

The solar system is also orbiting the galactic center at a speed of 240 km per second, generating enough "centrifugal force" to oppose the combined forces of the central black hole and the stars of the nuclear sphere, so the sun will continue to revolve in its current orbit!

Motion is a way to maintain balance between celestial bodies, and even we can't find an absolutely stationary object in the entire universe, reaching galactic celestial bodies, as small as proton quarks, are in constant motion, even if you don't accept it, it's a fact that can't be changed!

The Earth and the stars around it have a strong effect, so even if the Earth is very large and heavy, it will not easily fall or change its position.

This is due to the effect of gravity, and if gravity exists, the earth will not fall.

Because of gravity, didn't you learn physics in junior high school? The reason why the earth doesn't fall down is because of gravity.

This is because although the earth is heavy, it has a certain buoyancy and can levitate in the universe.

Because the gravitational pull of the earth is very strong, the earth will not fall.

Because for the earth, the surface of the sun's digging shirt is actually like the "ground", the sun exerts a strong gravitational pull on the earth, and always closes the side to drag the earth to the surface of the sun.

However, the Earth moves in an approximate circular motion around the Sun at a certain speed, and the centrifugal effect created in the process can counter the Sun's gravitational pull and thus avoid falling on the Sun's surface. In this way, the earth seems to be "suspended" in the universe. In the same way, satellites and the moon move around the earth at a certain speed, and they can avoid being dragged to the ground by the earth's gravity.

In addition, the solar system also moves around the center of the Milky Way to avoid falling into the galactic center, and the earth is not "floating in the universe, it is just an illusion that is invisible and intangible due to the effect of gravity." When we are in the sun, we are looking at all the planets with the sun (or the earth) as a moving point, and we will have a sense of why these planets revolve around the sun instead of falling into the sun.

Like the illusion of floating in the sky, in fact, for the planets, the gravitational pull of the sun (almost) completely provides the centripetal force, so the planets can continue to revolve around the sun spontaneously and spontaneously, just like someone holding a rope and throwing a small ball, as long as the force of the sedan rubber traction is still there, then the planet can always rotate around the center, and when we exchange the traction provided by this rope for the gravitational pull of the sun, the planet looks like it is suspended in the universe.

Summary. The Earth is weightless because there is gravitational attraction in the galaxy in which the Earth is located. The mass of the earth is large enough to produce a gravitational force sufficient to counteract the centrifugal force of the object moving around the earth, thus keeping it a certain weight.

Even in space, objects on Earth still have the same mass and weight.

Why won't the Earth.

Small-time meeting 2nd grade questions.

The Earth is weightless because there is gravitational attraction in the galaxy in which the Earth is located. The mass of the Earth is large enough that the gravitational force of the resulting type is sufficient to counteract the centrifugal force of the moving object around the Earth, so that it retains a certain weight. Even in space, objects on Earth still have the same mass and weight as the barricades.

Isn't this a bit esoteric for the second grade of elementary school?

Because the earth is very heavy, the sedan chair will not be weightless. It's like when you take a heavy bag, you will feel tired and quietly, but if you put the bag down, you will feel relaxed. The earth is the same, it is too heavy, so it will not be weightless.

Children may be like this, ignoring the <> drama

Because the earth is big and heavy, just like when we eat a lot, it becomes very heavy. So the earth is not weightless.

I don't think the earth is weightless because it's big and heavy, and there's a lot of stuff on it, so there's gravity that makes us feel weight.

The weight of the Earth reaches 60 trillion tons.

The weight of an ordinary person is generally less than 100 kilograms, and people who can exceed 100 kilograms can be said to be very fat, and now the global population has reached 7 billion, if everyone counts according to 100 kilograms, then the global population is 700 billion kilograms, which is 700 billion tons. However, the weight of the earth is 60 trillion tons.

Gravitational attraction through Einstein's eyes:

Newton's theory of mechanics and the law of gravitation are what we call classical physics. Physics has changed dramatically in modern times, and the mainstream view of gravity today comes from Einstein's general theory of relativity.

In his special theory of relativity, Albert Einstein unified time and space, and he believed that time and space should be merged into space-time, and human beings live in a four-dimensional space-time. In the general theory of relativity, Einstein further extended this special theory of relativity, arguing that gravity does not exist, and the essence of gravitational phenomena is the curvature of space-time.

The Moon revolves around the Earth because the Earth bends the surrounding space-time, and the Earth moves along the "geodesic" of space-time. The term "geodesic" here refers to the shortest distance between two points.

In the same way, the Earth revolves around the Sun, in fact, because the Sun bends the surrounding space-time, and the Earth moves along the geodesic. In other words, the earth is to some extent walking in a "straight line" in four-dimensional space-time, which is in line with Newton's first law: the earth is not subjected to force, but only moves in a straight line at a uniform speed.

From our point of view, its trajectory is just an ellipse. Therefore, from the perspective of relativity, the curvature of space does not cause the earth to move downward, and at the same time, there is no force to cause the earth to move downward, and the earth will not fall.

What is the "down"? There is no upper or lower in the space.

Who is holding up the planet? Our daily experience is that the Earth must be made of something of this mass"Hold it up", otherwise it will definitely fall, but over the years, images of the Earth taken from space show that it"Like"Suspended in space. In addition, Hubble's images of other objects in our solar system, as well as galaxies containing hundreds of billions of stars, are visually so"Suspension"in space.

Therefore, the reality of the universe is taken for granted by human beings"Common sense"There was a collision. Earth floating in space?

Anyone who has studied basic physics knows that an object always remains at rest or moves in a uniform straight line until it is subjected to an external force. At the moment, the Earth under our feet is orbiting the Sun at a speed of 30 kilometers per second, which can be described as:"Sitting on the ground drives 80,000 miles a day"。From the point of view of physics, an object on the earth is attached to the ground, and because the center of mass of the earth is located at the center of the earth, the object is"Attract"to the center of the earth.

<> Einstein's general theory of relativity, from the end of the 19th century to the beginning of the 20th century, with the deepening of physics to the microscopic world and the expansion of the macrocosm, Newton's law of universal gravitation, which is only applicable to low-speed macroscopic motion, began to show errors, and the guide chain Bixin caused a series of problems that physicists could not solve at that time, including the perturbation of Mercury's perihelion. Common sense tells us that no object, no matter how heavy or small it is, can be suspended in the air for no reason. The heavier an object is, the faster it will fall from the air and the harder it will be to float in the air.

Nothing on Earth can violate this law, but interestingly, the Earth itself seems to contradict it. The Earth we live on is a rocky planet weighing 6 trillion tons, but it can remain suspended in space and never fall. Why is Huizhao like this?

This seemingly mysterious problem can only be explained by the application of classical mechanics. When it comes to falling objects, one of the first issues that needs to be addressed is how to define the direction. On Earth, the direction of up and down is very clear, whether we are in the Southern Hemisphere or the Northern Hemisphere, the direction of our feet is downwards and the direction of our heads is upwards.

There is no dispute at this point.

Because space is a vacuum environment, there is no gravity in this place, and there is a certain gravitational force between the earth and the sun, so it will be in space.

Because it is a vacuum environment in space, and there is a gravitational pull between the earth and other planets, it will not fall.

It's because there is a gravitational pull in the universe that puts many planets in a state of equilibrium.