In the school textbook on astronomy, we read that the Earth rotates around the sun. However, modern science is much more accurate: all bodies in the solar system - including the sun itself - rotate around a common center of mass, called a barcenter. This discovery, confirmed by new astrophysical studies, changes our understanding of the dynamics of space.
The barcenter is a point determined by the joint gravity of all massive bodies of the system. In our solar system, it is constantly shifting depending on the position and weight of the planets. For example, Jupiter and Saturn have such a large mass that they can "pull" a barcenter beyond the surface of the sun. So, technically, the sun describes a small "circle" around this point.
Similar processes are observed in double star systems, where both stars rotate around the common center of masses. Moreover, even the month does not rotate just around the center of the Earth. It moves around the barcenter of the land system - moon, which is located about 5000 km from the center of our planet, that is, inside the earth, but not in its nucleus.
These details rarely get into textbooks, but they are critical in the precise planning of space missions, the calculation of satellite orbits and understanding of the interaction of bodies in complex gravitational systems.
Knowledge of the barcenter is not just a scientific curiosity. This is the key to a deeper awareness of how our space house really is.
