The earth is always in motion. Although it seems that we are standing motionless on the surface of the planet, it is constantly rotating around its axis and the Sun. This movement is not felt by us, as it resembles flying in an airplane. We are moving at the same speed as the plane, so we don't feel like we are moving at all.
At what speed does the earth rotate on its axis?
The earth rotates once on its axis every 24 hours. (to be precise, in 23 hours 56 minutes 4.09 seconds or 23.93 hours). Since the circumference of the Earth is 40075 km, any object at the equator rotates at a speed of approximately 1674 km per hour or approximately 465 meters (0.465 km) per second (40075 km divided by 23.93 hours and we get 1674 km per hour).
At (90 degrees north latitude) and (90 degrees south latitude), the speed is effectively zero because the pole points rotate at a very slow speed.
To determine speed at any other latitude, simply multiply the cosine of latitude by the planet's rotational speed at the equator (1674 km per hour). The cosine of 45 degrees is 0.7071, so multiply 0.7071 by 1674 km per hour and get 1183.7 km per hour.
The cosine of the required latitude is easy to determine using a calculator or look in the cosine table.
Earth rotation speed for other latitudes:
- 10 degrees: 0.9848×1674=1648.6 km per hour;
- 20 degrees: 0.9397×1674=1573.1 km per hour;
- 30 degrees: 0.866×1674=1449.7 km/h;
- 40 degrees: 0.766×1674=1282.3 km per hour;
- 50 degrees: 0.6428×1674=1076.0 km per hour;
- 60 degrees: 0.5×1674=837.0 km/h;
- 70 degrees: 0.342×1674=572.5 km per hour;
- 80 degrees: 0.1736×1674=290.6 km per hour.
Cyclic braking
Everything is cyclical, even the speed of rotation of our planet, which geophysicists can measure to within milliseconds. The Earth's rotation typically has five-year cycles of deceleration and acceleration, and the final year of the deceleration cycle is often correlated with a surge in earthquakes around the world.
Since 2018 is the last year in a slowdown cycle, scientists expect an increase in seismic activity this year. Correlation is not causation, but geologists are always looking for tools to try and predict when the next big earthquake is going to happen.
Oscillation of the earth's axis
The earth wobbles slightly as it rotates as its axis drifts at the poles. It has been observed that the drift of the earth's axis has accelerated since 2000, moving at a rate of 17 cm per year to the east. Scientists have found that the axis is still moving east instead of moving back and forth due to the combined effect of the melting of Greenland and, as well as the loss of water in Eurasia.
Axis drift is expected to be particularly sensitive to changes occurring at 45 degrees north and south latitude. This discovery led to the fact that scientists were finally able to answer the long-standing question of why the axis drifts at all. The wobble to the East or West was caused by dry or wet years in Eurasia.
How fast is the earth moving around the sun?
In addition to the speed of the Earth's rotation on its axis, our planet also revolves around the Sun at a speed of about 108,000 km per hour (or about 30 km per second), and completes its orbit around the Sun in 365,256 days.
It wasn't until the 16th century that people realized that the sun is the center of our solar system, and that the earth moves around it rather than being the stationary center of the universe.
The movement of the planet in orbit is determined by two reasons:
- linear inertia of motion (it tends to rectilinear - tangent)
and the gravitational force of the sun.
It is the force of gravity that will change the direction of movement from rectilinear to circular. And gravitational forces applied to a smaller radius will act
stronger on the planet.
If we consider gravity as a force applied to the center, then this gives a change in the direction of movement to a circular one.
If we consider gravity as the sum of forces applied to the entire mass of the planet,
then this gives both a change in the motion vector to a circular one and a rotation around the axis.
Look at the picture.
The planet has points closer to the Sun and points more distant.
Point A will be closer to the Sun than point B.
And the attraction of point A will be greater than point B. Recall that the force of gravity depends on the squared radius.
When the planet moves clockwise, the gravitational force through point A will pull the planet more than through point B. This difference in forces, gravity applied to diametrically opposite points of the planet, while moving, creates rotation.
Thus, the period of revolution of the planet around its axis directly depends on the equatorial radius of the planet.
With large planets such as Jupiter and Saturn, the difference in the attraction of opposite points is greater and the planet rotates faster.
Table of solar days for planets and equatorial radius:
r
Mercury..... - 175.9421 .... - 0.3825
Venus ..... - 116.7490 .....-0.9488
Earth ...... - 1.0 .... .. - 1.0
M a r s .... - 1.0275 ... ... - 0.5326
Jupiter..... - 0.41358 ... - 11.209
Saturn..... - 0.44403 .... - 9.4491
U r a n ..... - 0.71835 ... - 4.0073
Neptune..... - 0.67126 ... - 3.8826
Pluto..... - 6.38766 .... - 0.1807
The first number is the period of rotation of the planet around its axis in Earth days, the second number is similar - the equatorial radius of the planet. And it can be seen that the largest planet, Jupiter, rotates the fastest, and the smallest, Mercury, the slowest.
In general, the reason for the rotation of the Earth can be explained simply.
When the planet moves in orbit, there is a constant change in the direction of its movement from direct to circular. And at the same time, the planet simultaneously rotates, due to the fact that the points of attraction of the planets located closer to the Sun will pull the planet more strongly than the distant ones.
For example, on Jupiter, where the planet is not a monolith, rotation occurs in layers. The equatorial motion of the layers stands out in particular. And, interestingly, there is a reverse movement of some, apparently lighter layers, which are displaced by layers that are harder and more massive.
Reviews
Dear Nikolay!
There is no gravity. Newton's and Einstein's laws do not work.
It is impossible to justify the causes of rotation by such methods.
But the topic is interesting.
I hope that by joint efforts, and not on this site, we will solve it.
No. Gravity is everything! But the reasons for its appearance have not yet been established by us.
"Gravity force" - the term conditionally accepted hereinafter, means an external influence on the body. Conditionally in physics it is called "force" the force of gravity.
And the rotation comes from the action of two forces: the inertia of the rectilinear motion and its change to a circular one under the action of the gravitational force, which is perpendicular to the vector of inertia in terms of the vector.
Dear Nikolay!
Dear Nikolay!
In your works there are already calculations, I will not say, justifying the absence of gravity. These works aroused my interest in you, because. it is clear that there is a large statistical material and on it, together and quickly build a science for ourselves, where many things will fall into place. And whether they accept it or not, it should not concern us. Let Volosatov prove it, and we will do it.
I can formulate my position on gravity as follows.
Gravity, as a force of attraction that occurs between two bodies, does not exist.
Exists - an external influence on bodies, the consequence of which is the appearance of a force that causes them to move towards each other. Force leads not to the appearance of another force, but to movement. In this case, the vector of this force is directed along the line connecting these two bodies.
Not attraction, but movement towards.
And not the force arising in the bodies themselves, but the force of external influence.
As the wind blows on the sail.
In general, I understand force as a factor of external influence.
Dear Nikolay!
You, having refuted the forces and their reactions, return to them again.
Yes, these are the "weights" of our teachings. It is difficult to break away from them. I still break away from the remnants of the "institute" teachings. But the physics of the world is completely different. You intuitively felt it. The rest is in personal correspondence.
The fact that the Earth revolves both around its axis and around the Sun, our natural luminary, today there is no doubt among any of the people. This is an absolute and confirmed fact, but why does the Earth spin the way it does? We will look into this issue today.
Why does the earth spin on its axis
Let's start with the very first question, which is the nature of the independent rotation of our planet.
And the answer to this question, as to many other questions about the mysteries of our universe, is the Sun. It is the impact of the Sun's rays on our planet that sets it in motion. If we go a little deeper into this issue, it is worth noting that the sun's rays warm the atmosphere and hydrosphere of the planet, which are set in motion during the heating process. This movement is what makes the earth move.
As for the answer to the question why the Earth rotates counterclockwise, and not along it, there is no actual confirmation of this fact as such. However, it is worth noting that most of the bodies in our solar system rotate exactly in the counterclockwise direction. That is why this condition also affected our planet.
In addition, it is important to understand that the Earth rotates counterclockwise only on the condition that its movement will be observed from the north pole. In the case of observations from the south pole, rotations will occur differently - clockwise.
Why does the earth revolve around the sun
As for the more global issue related to the rotation of our planet around its natural star, we considered it in as much detail as possible in the framework of the corresponding article on our website. However, in short, the reason for such a rotation is the law of universal gravitation, which operates in the Cosmos as it does on Earth. And it lies in the fact that bodies with a larger mass attract less "weighty" bodies to themselves. Thus, the Earth is attracted to the Sun and rotates around the star due to its mass, as well as acceleration, moving strictly along the existing orbit.
Why does the moon revolve around the earth
We have also already considered the nature of the rotations of the natural satellite of our planet, and the reason for such a movement is of a similar nature - the law of universal gravitation. The Earth, of course, has a more serious mass than the Moon. Accordingly, the Moon is attracted to the Earth and moves along its orbit.
For billions of years, day after day, the Earth rotates around its axis. This makes sunrises and sunsets commonplace for life on our planet. The Earth has been doing this since it formed 4.6 billion years ago. And it will continue to do so until it ceases to exist. This will probably happen when the Sun turns into a red giant and swallows our planet. But why Earth?
Why does the earth rotate?
The Earth was formed from a disk of gas and dust that revolved around the newborn Sun. Thanks to this spatial disk, particles of dust and rock were folded together to form the Earth. As the Earth grew, space rocks continued to collide with the planet. And they had an impact on it that made our planet rotate. And because all the debris in the early solar system revolved around the sun in roughly the same direction, the collisions that made the earth (and most of the rest of the solar system's bodies) spin round the sun in that same direction.
Gas and dust disk
A reasonable question arises - why did the gas and dust disk itself rotate? The sun and the solar system were formed at the moment when a cloud of dust and gas began to condense under the influence of its own weight. Most of the gas came together to become the Sun, and the remaining material created the planetary disk surrounding it. Before it took shape, gas molecules and dust particles moved within its boundaries evenly in all directions. But at some point, randomly, some gas and dust molecules folded their energy in the same direction. This set the direction of rotation of the disc. As the gas cloud began to contract, its rotation accelerated. The same process occurs when skaters start to spin faster if they press their hands to the body.
In space, there are not many factors capable of planetary rotation. Therefore, as soon as they begin to rotate, this process does not stop. The rotating young solar system has a large angular momentum. This characteristic describes the tendency of an object to continue rotating. It can be assumed that all exoplanets probably also begin to rotate in the same direction around their stars when their planetary system is formed.
And we're doing the opposite!
Interestingly, in the solar system, some planets have a direction of rotation opposite to the movement around the sun. Venus rotates in the opposite direction relative to the Earth. And the axis of rotation of Uranus is tilted 90 degrees. Scientists do not fully understand the processes that caused these planets to get such directions of rotation. But they have some guesses. Venus may have received such a rotation as a result of a collision with another cosmic body at an early stage of its formation. Or perhaps Venus began to rotate in the same way as other planets. But over time, the Sun's gravity began to slow down its rotation due to its dense clouds. Which, combined with the friction between the planet's core and its mantle, caused the planet to rotate in the opposite direction.
In the case of Uranus, scientists have suggested that there was a collision of the planet with a huge rocky fragment. Or perhaps with several different objects that changed the axis of his rotation.
Despite such anomalies, it is clear that all objects in space rotate in one direction or another.
Everything is spinning
Asteroids are spinning. The stars are turning. According to NASA, galaxies also rotate. It takes the solar system 230 million years to complete one revolution around the center of the Milky Way. Some of the fastest rotating objects in the universe are dense, round objects called pulsars. They are the remnants of massive stars. Some city-sized pulsars can rotate around their axis hundreds of times per second. The fastest and most famous of them, discovered in 2006 and called Terzan 5ad, rotates 716 times per second.
Black holes can do this even faster. It is assumed that one of them, named GRS 1915 + 105, can rotate at a speed of 920 to 1150 times per second.
However, the laws of physics are inexorable. All rotations eventually slow down. When , it rotated around its axis at a rate of one revolution every four days. Today, our star takes about 25 days to complete one revolution. Scientists believe that the reason for this is that the Sun's magnetic field interacts with the solar wind. This is what slows it down.
The Earth's rotation is also slowing down. The moon's gravity acts on the earth in such a way that it slowly slows down its rotation. Scientists have calculated that the Earth's rotation has slowed by a total of about 6 hours over the past 2,740 years. This is only 1.78 milliseconds over a century.
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It took man many millennia to understand that the Earth is not the center of the universe and is in constant motion.
The phrase of Galileo Galilei "And yet it spins!" forever went down in history and became a kind of symbol of that era when scientists from different countries tried to refute the theory of the geocentric system of the world.
Although the rotation of the Earth was proven about five centuries ago, the exact reasons that prompt it to move are still unknown.
Why does the earth spin on its axis?
In the Middle Ages, people believed that the Earth was stationary, and the Sun and other planets revolved around it. Only in the 16th century did astronomers manage to prove the opposite. Despite the fact that many associate this discovery with Galileo, in fact it belongs to another scientist - Nicolaus Copernicus.
It was he who in 1543 wrote the treatise "On the Revolution of the Celestial Spheres", where he put forward a theory about the motion of the Earth. For a long time this idea did not receive support either from his colleagues or from the church, but in the end it had a huge impact on the scientific revolution in Europe and became fundamental in the further development of astronomy.
After the theory of the rotation of the Earth was proven, scientists began to look for the causes of this phenomenon. Over the past centuries, many hypotheses have been put forward, but even today no astronomer can accurately answer this question.
Currently, there are three main versions that have the right to life - theories about inertial rotation, magnetic fields and the impact of solar radiation on the planet.
Theory of inertial rotation
Some scientists are inclined to believe that once (during the time of its appearance and formation) the Earth spun, and now it rotates by inertia. Formed from cosmic dust, it began to attract other bodies to itself, which gave it an additional impulse. This assumption also applies to other planets in the solar system.
The theory has many opponents, since it cannot explain why at different times the speed of the Earth's movement either increases or decreases. It is also unclear why some planets in the solar system rotate in the opposite direction, such as Venus.
Theory about magnetic fields
If you try to connect two magnets with the same charged pole together, they will start to repel each other. The theory of magnetic fields suggests that the poles of the Earth are also charged in the same way and, as it were, repel each other, which causes the planet to rotate.
Interestingly, scientists recently made a discovery that the Earth's magnetic field pushes its inner core from west to east and causes it to rotate faster than the rest of the planet.
Sun exposure hypothesis
The most probable is considered to be the theory of solar radiation. It is well known that it warms up the surface shells of the Earth (air, seas, oceans), but heating occurs unevenly, resulting in the formation of sea and air currents.
It is they who, when interacting with the solid shell of the planet, make it rotate. A kind of turbines that determine the speed and direction of movement are the continents. If they are not monolithic enough, they begin to drift, which affects the increase or decrease in speed.
Why does the earth move around the sun?
The reason for the revolution of the Earth around the Sun is called inertia. According to the theory about the formation of our star, about 4.57 billion years ago, a huge amount of dust arose in space, which gradually turned into a disk, and then into the Sun.
The outer particles of this dust began to combine with each other, forming planets. Even then, by inertia, they began to rotate around the star and continue to move along the same trajectory today.
According to Newton's law, all cosmic bodies move in a straight line, that is, in fact, the planets of the solar system, including the Earth, should have long flown into outer space. But that doesn't happen.
The reason is that the Sun has a large mass and, accordingly, a huge force of attraction. The Earth, during its movement, is constantly trying to rush away from it in a straight line, but gravitational forces pull it back, so the planet is kept in orbit and revolves around the Sun.