Researchers have discovered that the solar system is influenced not only by gravity but also by other forces.

It has long been believed that gravity is the dominant force in the Solar System. It governs the orbits of planets and their moons, but there are other forces that have shaped our environment. In a new study, the authors describe how bouncing ice from comets can push them and how solar radiation pressure expels material outward. There are also relativistic effects that can cause particles to spiral inward toward the Sun, as noted by Universe Today.

Gravity is the force that governs the structure and motion of the Solar System. The Sun, which has an enormous mass, creates a strong gravitational pull, keeping planets, asteroids, comets, and other objects in orbit around it. The orbit of each planet results from a balance between its velocity and the Sun's gravitational force, creating trajectories described by Kepler's laws.

Moons remain in orbit around planets due to the latter's gravitational pull. Gravity not only maintains the stability of these orbits but also influences phenomena such as tides on Earth, caused by the Moon's gravitational attraction.

Scientists have studied other forces that shape the Solar System. Gravity certainly describes the motion of planetary bodies, but there are other forces that affect smaller bodies, which are susceptible to their influence. These forces include recoil (according to Newton's third law, every action has an equal and opposite reaction), torque from mass loss, solar radiation pressure, and more.

The researchers provide an informative overview of various non-gravitational forces acting in the Solar System. The authors of the study suggest that all orbits in the Solar System are circular, although in reality, planetary bodies are not perfect spheres and do not have perfectly circular orbits.

Among the non-gravitational forces described by the researchers, the most significant is the recoil generated by the sublimation of ice on comets and asteroids. Heat from the Sun causes ice to turn directly into gas, rather than first becoming liquid and then gas. According to Newton's law, when ice sublimates, the escaping volatile gases carry momentum and exert a recoil force on the body. The sublimation process largely depends on the temperature of the body under the influence of solar radiation.

Another non-gravitational force is radiation pressure, which shapes the distinctive tails of comets. This force is created by light as photons transfer momentum to an object, such as comet dust and gas, pushing them away. Radiation pressure depends on its intensity and the reflectivity of the object, with more reflective objects experiencing a greater force. Although radiation pressure is relatively small, scientists believe it can shape comet tails and gradually alter the orbits of small bodies in the Solar System.