The Fastest Planet Orbiting the Sun
The planet Mercury holds the title of being the fastest planet in its orbit around the Sun, completing a full revolution in just 88 Earth days. Additionally, it is the closest planet to the Sun, situated at approximately one-fifth the distance between the Earth and the Sun. This proximity results in extreme temperature fluctuations on Mercury; during the day, temperatures can soar to 450 degrees Celsius, which is hot enough to melt lead, while at night, they can plummet to -180 degrees Celsius. Mercury is also the smallest planet in our solar system, slightly larger than Earth’s Moon. It can be observed from Earth as a bright star visible in the evening sky near sunset or in the morning sky near sunrise. The ancient Greeks mistakenly identified it as two separate celestial bodies, naming the morning star “Apollo” and the evening star “Hermes.”
A day on Mercury lasts 58.6 Earth days. Its orbit around the Sun is elliptical, with the closest distance to the Sun being about 47 million kilometers and the farthest distance reaching up to 70 million kilometers. When viewed from Mercury at its closest point, the Sun appears three times larger than it does from Earth.
For more information about Mercury and the other planets in our solar system, you can read the article: What are the Planets of the Solar System.
How Planets Orbit the Sun
All planets share similar, nearly circular orbits around the Sun. Their movements are influenced by the gravitational pull of the Sun, which governs their stable motion based on Newton’s first law: an object in motion will remain in motion unless acted upon by an external force.
To further explore how planets orbit the Sun, refer to the article: Planetary Motion Around the Sun.
Orbital Speeds of the Planets
The time taken by each planet to complete one orbit around the Sun varies, indicating differences in their orbital speeds. Orbital speed is defined as the velocity required for an object to maintain a stable orbit around a celestial body, such as a planet or a star. The table below illustrates the orbital speeds of each planet along with the time taken for each to complete its revolution around the Sun:
| Planet | Orbital Speed (km/s) | Time Taken to Orbit the Sun (Days) |
|---|---|---|
| Mercury | 47.4 | 88 |
| Venus | 35 | 224.7 |
| Earth | 29.8 | 365.2 |
| Mars | 24.1 | 687 |
| Jupiter | 13.1 | 4331 |
| Saturn | 9.7 | 10,747 |
| Uranus | 6.8 | 30,589 |
| Neptune | 5.4 | 59,800 |
For more insights into the planets of our solar system, consider reading the article: Characteristics of the Planets in the Solar System.
To learn more about the solar system, please refer to the article: What is the Solar System.