Determination of the masses of space objects

Determination of the masses of space objects – At the beginning of solving this problem, the first step was taken, this is the determination of the mass of the Earth. The most difficult part of the work was calculating the radius of the Earth. To do this, it was necessary to carry out accurate geodetic measurements of the length of one degree of the arc of its meridian. Using the law of universal gravitation and knowing the measured value of the acceleration of free fall, it was possible to calculate the mass of the Earth. This fact allowed, in turn, using Kepler’s third law, to first determine the mass of the Moon, and then use this value to determine the mass of the Sun. Due to the application of the same law that is already used to determine the mass of the Sun, it became possible to determine the mass of all the planets and their satellites in the Solar system.
It is generally believed that the mass composition of stars can be determined only by accurate and painstaking measurements of the relative position of the components of binary stars. They were determined using Kepler’s third law, and after determining the mass of about 200 stars that were combined into stellar pairs, an unambiguous relationship between their mass and luminosity was found. This fact was confirmed, among other things, for stars whose mass was calculated by measuring the gravitational redshift of spectral lines in their electromagnetic waves, as described in the general theory of relativity. Now it is possible to determine the mass of almost any single star, except for white dwarfs and pulsar stars, by measuring its luminosity.
Types of estimation of the mass of star clusters. In the case of large-sized scattered star clusters, it is necessary to calculate the mass of their stars. When determining the masses of globular star clusters, which have narrow viewing zones in their central part and are often not available for observation, one should be guided by knowledge of their sizes, measurements of the velocity of the stars entering them and statistical methods.
There are different methods for determining the mass of galaxies, but they are all based on already known principles. In order to estimate the mass of galaxies, Kepler’s third law is applied for interacting and mutually influencing galaxies; empirical relationships between the mass and luminosity of galaxies, as well as the speed of rotation of stars around the center of the galaxy and methods used to determine the masses of globular clusters are also used.