The planets in our Solar System move around the Sun at different speeds. Some take a long time to complete their journey, while others travel much faster. Their speed depends on how far they are from the Sun and the pull of its gravity. Learning about these differences helps us understand how planets orbit and how the Solar System works.
Which is the Fastest Planet?
Mercury is the fastest planet in the solar system. It travels around the Sun very quickly, thanks to the strong pull of the Sun’s gravity. Its orbit is shorter and closer to the Sun, which helps it cover its path much faster than other planets.
Why Mercury Move So Fast?
Mercury is the closest planet to the Sun. The Sun’s gravity pulls it strongly, forcing Mercury to move at high speed to stay in orbit. Its small size and light mass also allow it to travel quickly without much resistance.
How Fast Does Mercury Orbit the Sun?
Mercury moves at around 47 kilometers per second (about 170,000 km/h). This is nearly one and a half times faster than Earth. Because of this speed, Mercury has the shortest year in the solar system, completing a full orbit in just 88 Earth days.
Mercury’s Short Year
A year on Mercury lasts only 88 days. That means while Earth completes one orbit in 365 days, Mercury can circle the Sun more than four times in the same period. Its short year makes it the fastest planet in terms of orbital motion.
Mercury’s Orbit Path
Mercury’s orbit is not a perfect circle—it is oval-shaped. This elliptical path means Mercury speeds up when it is closer to the Sun and slows down a little when farther away. These changes make its motion unique and interesting for scientists.
Interesting Facts About Mercury
- Smallest Planet: Mercury is smaller than Earth’s Moon but still has a strong gravity for its size.
- Extreme Temperatures: Daytime can reach over 400°C, while nights can be freezing.
- No Thick Atmosphere: It has a thin exosphere, so heat escapes quickly, causing huge temperature swings.
- Day Longer Than Year: Mercury rotates once in 58 Earth days but orbits the Sun in 88 days, making a single day last almost 176 Earth days.
- Molten Core: Mercury has a liquid metal core that generates a magnetic field, which is unusual for such a small planet.


Top-5 Fastest Cats in the World, Know th...
November 2025 Month Current Affairs PDF
The Forgotten Story of Tamils in Moreh: ...

