A heliocentric orbit is an orbit circulating the barycenter of the solar system. This center of mass is usually very near the sun’s surface or within it. Such an orbit is under the centric classifications of gravitationally curved trajectories. In the solar system, all the planets, comets, and asteroids follow a heliocentric orbit, meaning they move around the sun. However, the moons of planets within the solar system do not follow heliocentric orbits because they orbit their planets. The helio-prefix comes from a Greek word meaning “sun” and also from a personification of the sun found in Greek mythology, called Helios. Over the course of history, some countries have placed artificial objects in heliocentric orbits in space.
The heliocentric system is a model that shows the Earth and other planets revolving around the sun. Aristarchus of Samos proposed this notion around the 3rd century BCE but received less attention since there were no explanations on why the position of the stars did not change although the Earth moved around the sun. In the 16th century, Nicolaus Copernicus presented a geometric mathematical model showing the heliocentric system, a move that led to the Copernican Revolution. Copernicus’s publication began the re-establishment of the heliocentric system. Galileo Galilei supported the model with observations from a telescope. Other astronomers including William Herschel and Friedrich Bessel made observations that the sun was not at the center of the universe, but close to the Solar System’s barycenter.
Orbits under centric classifications include heliocentric, galactocentric, lunar, and geocentric orbits. Galactocentric orbit is one that revolves around the center of a galaxy, such as the sun in the Milky Way. Geocentric orbit is a revolution around the earth that the moon and artificial satellites follow. The moons and artificial satellites of the planet Mars follow the areocentric orbit, while objects revolving around the Earth’s moon follow the lunar orbit. Other orbits under this classification are the jovicentric, aphrodiocentric, and kronocentric, which are orbits around the planets Jupiter, Venus, and Saturn respectively.
Artificial Objects in Heliocentric Orbit
Some first world countries have satellites in heliocentric orbits for various purposes such as exploration of the moon, sun, and other planets. These countries are the United States, the Russian Federation, Japan, and China. The European Space Agency, which includes 22 nations, also has objects in heliocentric orbit. Some of the spacecrafts that the United States have placed in space include Pioneer 4 on a lunar mission in 1959 and Mariner 2 in 1962 to Venus. Most of the space missions sent by the Russian Federation failed due to loss of communication en route. Some of these missions include Venera 1 intended for Venus in 1961 and Mars 1 planned for Mars in 1962.
Heliocentric and Geocentric Orbits
When the heliocentric system failed to get more support, the geocentric system proposed by Claudius Ptolemy of Alexandria in the 2nd century CE dominated. The geocentric system suggested that the sun and other planets revolved around the Earth. The method assumed that the Earth was at the center of the universe. This theory commanded the scientific world for about 1,400 years until its disapproval by Nicolaus Copernicus’s publication of the De Revolutionibus Orbium Coelestium Libri VI in 1543.