The sun is the center of the Solar system, around which revolve eight planets, dwarf planets, asteroids, a few meteorites and a couple of distant comets. This is what we know from school. We can say that it’s kind of undeniable truth, as scientists have proved that earth is not the center of the Universe and that the Earth, like other planets, revolves around the Sun.
By the way, it’s true, but with some reservations. In fact, everything in the Solar system revolves around the so-called “center of mass of the Solar system”, including the Sun itself. Recently, scientists told in a series of videos. What are the secrets they revealed?
Rotation around center of mass
The center of mass or barycenter, around which revolve the various planets and heavenly bodies in our Solar system, is the point at which the object is perfectly balanced, and all his weight is evenly distributed on all sides. By the way, sometimes the center of mass is directly in the middle of the object.
For example, you can easily find the center of mass of the ruler. Try putting a ruler on a finger and align it so that it was resting on the finger and not fall. Thus you will find the place on the ruler, allowing it to keep it just on one finger. This is the center of mass or, as it is called, the centre of gravity.
In our Solar system the centre of mass rarely coincides with the center of the Sun. This means that all bodies in the Solar system do not rotate around the center of the Sun. Of course, the planets revolve around the Sun, but here we will tell about the exact position and the true center around which revolve all the objects in the Solar system.
To prove this fact, a planetary scientist of the Japanese space Agency JAXA James O’donoghue have created an animation that shows how the Sun, Saturn and Jupiter are playing “tug of war” around the barycenter, causing the Sun begins to move in a loop the mini-orbits.
In his spare time, planetary scientist creates animations that demonstrate how the planets, stars and the speed of light from the point of view of physics. According to him, it is natural to think that we revolve around the center of the Sun, but it very rarely happens, because the center of mass of the Solar system rarely coincides with the center of the Sun, and the Sun itself rotates on millions of miles around the barycenter, sometimes passing over them, sometimes deviating from it.
The center of mass of the Solar system does not coincide with the center of the Sun
Question: why the center of mass of the Solar system does not coincide with the center of the Sun, although the vast majority of the Solar system’s mass belongs to the Sun? Logically, the center of the Sun must coincide with the barycenter of the Solar system, because the vast majority of the mass of the Solar system have on it — 99,8%.
Actually all the fault of Jupiter and its gravity. As we have previously said, the Sun is 99.8% of the mass of the Solar system, but Jupiter contains most of the remaining 0.2%. This mass causes a gravitational pull, gently pulls the Sun from the barycenter of the Solar system, which should coincide with the center of the Sun.
We can say that a little Sun revolves around Jupiter. In other words, the assertion that the planets revolve around stars is not an absolute truth, as planets and stars revolve around their barycenter.
What is the center of mass?
Astronomy center of mass or barycenter is the center of mass of two or more bodies orbiting each other, i.e., the point around which to rotate the objects. It is an important concept in such fields as astronomy and astrophysics.
If one orbital body more than the other, and their bodies are located relatively close to each other, the barycenter will usually be within a larger facility.
In this case, instead of two bodies rotating around a point between them, the less massive object will orbit a more massive. At the same time you notice that a heavier body will slightly jiggle. This is also the case with the system Earth-Moon, because the center of mass is at the distance of 4691 km from the centre of the Earth, which is only 75% of the Earth’s radius (6378 km).
The earth and Moon perform more than a simple dance, with the barycenter remains inside the Earth. By the way, it does not correspond to the real center of the Earth because of the gravity of the moon, which slightly pulls the Earth.
When two bodies have the same mass, the barycenter, as a rule, will be between them, and both bodies rotate around it. So is the case with Pluto and its satellite Chiron, as well as many double asteroids and stars. Within the Solar system a similar phenomenon can be observed among the many planets and their satellites.
By the way, Pluto performs a special dance with his companion of Chiron, but there is one difference, which is that always the barycenter is outside of Pluto.
When a less massive object is located at a great distance, the barycenter may be located outside of a larger facility. This is the case with Jupiter and the Sun. Despite the fact that the Sun is a thousand times more than Jupiter, the barycenter is outside the Sun because of the relatively large distance between them.
Eventually, each planetary system revolves around an invisible point which is in the center.
The importance of the mass center for scholars
The barycenter sometimes it helps astronomers to find hidden planets revolving around other stars, because it is very difficult to immediately determine the location of exoplanets. As a rule, they are hidden the brilliant light of the stars rotating around the center of mass.
By the way, thanks to the vibration of the stars, scientists can determine the existence of the planet. And studying the barycentre and using many different methods, astronomers have been able to find many planets orbiting other stars.
In astronomy there are so-called “barycentrische coordinates”, that is, the coordinates of the point relative to the coordinate system which origin is at the center of gravity of the system. The international celestial coordinate system (ICRS) is barycentrically system of coordinates, which focuses on the center of the Solar system, identifying the location of its objects.