EducationThe science

Space velocity

Any object, being thrown up, sooner or later is on the earth's surface, whether it's a stone, a piece of paper or a simple feather. At the same time, a satellite launched into space half a century ago, the space station or the Moon continues to rotate in its orbits, as if the force of gravity of our planet does not work at all. Why is this happening? Why does not the Moon threaten to fall to Earth, and the Earth does not move toward the Sun? Do they really not have universal gravitation?

From the school course of physics, we know that universal gravitation affects any material body. Then it would be logical to assume that there is a certain force that neutralizes the effect of gravity. This force is usually called centrifugal. Its action is easy to feel by tied a small load to one end of the thread and untwisted it around the circumference. At the same time, the higher the speed of rotation, the stronger the thread tension, and the slower the load, the more likely it will fall.

Thus, we have come very close to the notion of "cosmic speed". In a nutshell, it can be described as a speed that allows any object to overcome the gravitation of the celestial body. As a celestial body , a planet, its satellite, solar or other system can act. The space velocity is at each object, which moves in an orbit. By the way, the size and shape of the orbit of a space object depend on the magnitude and direction of the speed that the given object received at the moment of turning off the engines, and the altitude at which the event occurred.

Space velocity is of four kinds. The smallest of them is the first one. This is the smallest speed that a spacecraft should have to get into a circular orbit. Its value can be determined by the following formula:

V1 = √μ / r, where

Μ is the geocentric gravitational constant (μ = 398603 * 10 (9) m3 / s2);

R is the distance from the launch point to the center of the Earth.

Due to the fact that the shape of our planet is not an ideal ball (at the poles it is slightly flattened), the distance from the center to the surface is the most at the equator - 6378.1 • 10 (3) m, and least at the poles - 6356.8 • 10 (3) m. If we take the average value - 6371 • 10 (3) m, we get V1 equal to 7.91 km / s.

The more cosmic speed will exceed this value, the more elongated shape will be acquired by the orbit, moving away from the Earth for an ever greater distance. At some point, this orbit will burst, take the form of a parabola, and the spacecraft will go to plow space expanses. In order to leave the planet, the ship should have a second space velocity. It can be calculated by the formula V2 = √2μ / r. For our planet, this value is 11.2 km / s.

Astronomers have long ago determined what is the cosmic speed, both the first and the second, for each planet of our native system. It is not difficult to calculate them by the above formulas if we replace the constant μ by the product fM, where M is the mass of the interesting celestial body, and f is the gravitational constant (f = 6.673 x 10 (-11) m3 / (kgx2).

The third cosmic speed will allow any spacecraft to overcome the gravitation of the Sun and leave the native Solar system. If we calculate it relative to the Sun, then we get 42.1 km / s. And in order to get from the Earth to the near-solar orbit, you need to accelerate to 16.6 km / s.

Well, finally, the fourth space velocity. With its help, you can overcome the attraction directly to the galaxy itself. Its magnitude varies depending on the coordinates of the galaxy. For our Milky Way, this value is approximately 550 km / s (if calculated relative to the Sun).

Similar articles

 

 

 

 

Trending Now

 

 

 

 

Newest

Copyright © 2018 en.birmiss.com. Theme powered by WordPress.