# Difference between Sidereal and Synodic

When astronomers use the word “year,” they may be referring to either a sidereal year or a synodic year. While these two years are both measures of time, they refer to different phenomena. This article will explore the difference between a sidereal year and a synodic year.

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## What is Sidereal?

The sidereal period is the length of time it takes for an object in space, such as a planet or satellite, to make one complete orbit around another object. The sidereal period is used to calculate the orbital periods of planets and other astronomical objects. The Sidereal period of Earth is 365.24 days, which is the length of a year. The Sidereal period of Mars is 687 days, which is the length of a Martian year. The Sidereal period of Jupiter is 4,332 days, which is the length of a Jovian year. Sidereal periods can be used to calculate the orbital periods of any astronomical object.

## What is Synodic?

Synodic period is the time it takes for a planet or satellite to return to the same position relative to the sun or star. It’s also the time it takes for the moon to complete one full orbit around Earth. The word “synodic” comes from the Greek word “synodos,” which means “meeting.” Synodic period can be used to describe any repeating event, but it’s most often used in astronomy. For example, Mercury has a synodic period of 116 days, meaning it takes 116 days to return to the same position relative to the sun.

The synodic period is important because it can be used to predict eclipses and other astronomical events. Synodic period is also a key concept in astrology. Synodic cycles are thought to influence our moods, emotions, and behavior. Synodic periods can last for years or even decades. For example, Jupiter has a synodic period of 398 days, meaning it takes almost four years to return to the same position relative to the sun. Synodic periods are affected by a number of factors, including gravity and orbital inclination.

## Difference between Sidereal and Synodic

Sidereal and synodic are two terms that are often used to describe the relationship between celestial objects. Sidereal refers to the position of an object relative to the stars, while synodic refers to the position of an object relative to the Sun. As a result, sidereal and synodic motion can be used to describe the orbital motion of planets and other celestial bodies. For example, a planet’s sidereal day is the time it takes for the planet to complete one revolution relative to the stars. In contrast, a planet’s synodic day is the time it takes for the planet to complete one revolution relative to the Sun. Sidereal and synodic motion plays an important role in astronomy and helps us understand the relationships between celestial bodies.

## Conclusion

Sidereal months are based on the movement of the stars in the sky while synodic months are based on the relative positions of Earth and the Sun. This means that a sidereal month is about 20 minutes shorter than a synodic month. While this may not seem like much, it can add up over time and create discrepancies in our calendar year.