For the same reason that speed cannot be understood without looking out the window from a fast-moving train or airplane, it is difficult to perceive its speed even standing in a fast-moving world.
Just like a small child looking out the window of a moving bus or train and asking 'why are the trees moving backwards', just like standing on the earth, people have thought that the earth is still for a long time. People thought that all the planets and stars in the sky, including the sun, revolved around the earth. This is how people have interpreted sunrise and sunset.
But the theory that the earth is fixed, everything revolves around the earth has a strong religious basis but has not got a scientific basis. It was not possible to explain the question of why the stars in the night sky are often seen moving backward and then moving forward again through the concept of an earth-centered world.
[Both Earth and Mars revolve around the Sun. Mars is seen retrograde once in the sky when Earth transits Mars. It is then seen moving forward again.]
Parallax is another evidence of a heliocentric world
After keeping the finger in front of the eye and closing the left eye and looking at the finger with the right eye, closing the right eye and looking at the finger with the left eye, the position of the finger seems to have changed.
Similarly, the positions of relatively nearby stars in the night sky also change at different times of the year. Earth orbits the sun once in 365 days. As a result, we see the sky from different positions at different times of the year. That is why the position of relatively close stars in the night sky changes at different times of the year. The distance of stars can also be calculated using this parallax.
How fast is the earth spinning?
Earth takes about 24 hours to rotate on its axis. As a result, a linear motion is created on the Earth's surface. This velocity is lowest at the North and South Poles and the highest at the equator. Here the Earth's circumference is the largest, 24,898 miles or 40,070 kilometers. That is, the earth is crossing this entire circumference in 24 hours.
Velocity can easily be deduced from here (circumference/24 hours). So the Earth's speed at the equator is 1,037 miles per hour or 1,670 kilometers per hour.
This velocity gradually decreases as you move from equatorial region to polar region. At 45 degree north latitude or south latitude, this velocity can be extracted from the trigonometric cosine. The value of cosine 45 is 0.707. So the speed of the earth at 45 degree latitude is 0.707×1037 = 733 miles per hour (1,180 kilometers per hour).
Reasons for launching rockets from areas near the equator
It is seen that as one moves from the north or south pole towards the equator, the value of the linear velocity of the earth's rotation increases. For this reason, space agencies try to launch rockets into space from locations as close as possible to the equator. So that the energy consumption can be reduced with the help of this speed of the earth. The United States chose Florida and the Soviet Union chose Baikonur, Kazakhstan. Today's Russia also launches rockets from the Baikonur launch site in Kazakhstan.
How fast is the Earth orbiting the Sun?
So far we have discussed about the rotation of the earth on its axis in 24 hours. But the earth also revolves around the sun in a certain orbit. This speed is about 67,000 miles per hour or 107,000 kilometers per hour.
Although the Earth revolves around the Sun in an elliptical orbit, the orbit can be assumed to be circular for the sake of reducing the mathematical complexity. The distance from the Earth to the Sun, or the radius of this circular orbit (r), is 9,29,55,807 miles or 14,95,97,870 kilometers. So the circumference of a circular orbit can be calculated from the formula 2 x π x r. It is 584 million miles or 940 million kilometers that the Earth travels in about 356 days and 6 hours. From here the velocity of the earth can be taken out. Earth orbits the Sun at 66,627 miles per hour or 1,07,226 kilometers per hour.
In the galaxy, our sun also rotates in a certain orbit along with the other planets along with the earth
The Sun is about 25,000 light-years away from the center of the Milky Way galaxy. The diameter of the Milky Way is at least 100,000 light years. That is, we are approximately at a medium distance from the center of the Milky Way. The Sun and our solar system rotate through the galaxy at 448,000 miles per hour or 720,000 kilometers per hour (200 kilometers per second). Despite orbiting at this high speed, the Sun takes about 230 million or 2,300,000,000 years to make one revolution of the sky. Along with the mighty Sun, our Earth, Moon and other satellites also orbit the Milky Way.
Meanwhile, the Milky Way galaxy is not stationary with respect to other galaxies or galaxies. Andromeda is the closest galaxy to the Milky Way. These two galaxies are rushing towards each other at a speed of 70 miles per second or 112 kilometers. As a result, they will collide after about 4 billion years. In short, everything in the universe is in motion. Our world is also moving at a speed that we do not understand.
