Can a planet rotate around two axes


Why is the earth rotating?


The rotation of the earth around its axis within 24 hours is like a precise clockwork. The rhythm of this clockwork determines the perpetual change between day and night and thus leads to that mild climate in large parts of the world that made life possible in the first place. To understand why the earth rotates, it is necessary to visualize the birth of our solar system.

Almost 5 billion years ago, our solar system was nothing more than a gigantic cloud of dust and gas. Its components were attracted by gravity, so that the cloud condensed and finally formed a huge flat disk that began to rotate faster and faster the smaller it became due to gravity. The speed of the rotation increased according to the same principle that accelerates the rotation of a figure skater who puts his arms on during a pirouette. The sun eventually emerged in the center of the disk. The remaining gas and dust floating around clumped together and formed into planets like Earth, moons, asteroids and comets. The birth of the solar system from a rotating disk of dust explains the rotation of all planets around the sun.

However, the rotation of the earth around its own axis has a different cause. As the planets formed, they very often collided with other celestial bodies, large and small. These collisions changed the speed of rotation of the planets. Scientists today believe that a very large object, about the size of Mars, struck the young Earth and released large chunks from it, which came together and formed our moon. This collision made our earth rotate so fast on its own axis that a day lasted only about six hours! The moon was much closer to earth at that time than it is today and filled almost the entire sky.

But why is today's day 24 hours long? As the earth rotates, the moon's gravity makes the oceans' waters rise and fall. This is how ebb and flow arise. The movement of water creates friction that slows the rotation of the earth by a tiny fraction with each revolution. The moon moves a little bit away from the earth every time. However, these small changes become noticeable over billions of years. They increased the length of a day to 24 hours and multiplied the distance between the moon and the earth.

Like every clockwork, the cosmic timepiece adjusts itself to the rotation of the earth and continues to slow down. However, that is not a cause for concern. In a hundred years, a day will only be about two thousandths of a second longer than it is now. Now, however, a conflict arises between the time measurement of astronomical time (UT1), which is based on the rotation of the earth, and the physical atomic time, which is determined by cesium atomic clocks on earth.

For this reason, the Earth's rotation is now measured with an accuracy of 3 millimeters using a global network of radio telescopes. All the data are then evaluated at the Max Planck Institute for Radio Astronomy and combined to form world standard time (UTC). So the time difference does not end in time chaos.