Earth Does Not Orbit Around the Sun But Around a 'Center of Mass,' Claim Researchers

'How planets revolve' is possibly one of the first extraterrestrial phenomena that educators taught students at school. They are told that in this phenomenon, the planets move around the sun in fixed orbits, according to IFL Science. However, the image is a bit different in space. The concept of revolution has been simplified in popular imagination. Technically, the planets are not orbiting the sun, but a barycenter. The barycenter of the solar system is typically near the sun and not at its center, as normally promoted. It is claimed that planets orbit stars; in reality, though, both bodies orbit around a common center of mass, according to NASA Science.

This common center of mass is called the barycenter. The center of mass, as it sounds, is the exact epicenter of all the material an object is composed of or a point where the object "can be balanced." For a ruler, it is the point at which it is divided into two equal parts. In a rotating object, typically, the spin is facilitated by focusing on the center. However, in objects like a hammer, the mass is balanced at one end instead of at the middle, compared to a ruler. In a planet's rotation, it is the "system" of two astronomical bodies taken into consideration during the process.

Between the sun and other planets, the center of mass is the point around which the planet orbits. In the duo, the center of mass, which is the barycenter, is close to the object with more mass, as evident in a hammer. Here, the heavier object is the sun, so the barycenter is near the sun or sometimes inside it. However, most of the time, the planets are usually not orbiting around the sun but around a point near the central star. James O'Donoghue, a planetary scientist at the Japanese space agency, JAXA, claims that even the sun orbits around the solar system's barycenter, according to Science Alert.

In terms of the solar system, this point is where all the mass is distributed evenly. O'Donoghue created an animation showing how three astronomical bodies function around the 'center of mass' in the solar system. The bodies in focus are the Sun, Saturn, and Jupiter. The scientist further added that this center of mass does not typically occur inside the sun. "The natural thinking is that we orbit the Sun's center, but that very rarely happens," he said. "It's very rare for the Solar System's center of mass to align with the Sun's center."

Astronomers calculate this barycenter by tracking the movement of planets and other astronomical bodies in the solar system, according to Space. These observations have indicated that the solar system's barycenter is not static. The point keeps on moving. Sometimes, it can be near the center of the sun, and sometimes it can be beyond the scorching star. However, these readings are not completely accurate because the motions of several planets, especially Jupiter, are not entirely understood by experts. 

Scientists are trying to find new ways to detect the solar system's barycenter with more accuracy. The most recent on the list is figuring out the deviation between the time taken by different signals from the same pulsar to reach Earth. The difference could indicate how far off experts are in their estimates of the barycenter's positioning and could correct it accordingly. Findings regarding this analysis have been published in The Astrophysical Journal.