Mercury

Length of Year on Mercury

[/caption]
The length of year on Mercury is 87.969 days. In other words, it takes almost 88 Earth days for Mercury to complete one orbit around the Sun. Mercury completes just over 4 orbits for each year on Earth.

Mercury has the most eccentric of all the orbits of the planets. Its distance from the Sun varies between 46 million and 70 million kilometers. This means that the speed of its orbit varies dramatically depending on the point of its orbit. If you could stand on the surface of Mercury and watch the Sun, you would see the Sun rise in the morning go part way up in to the sky and then go backwards in the sky, and set again. And then it would rise again and this time it would go across the sky and set. Four days before the fastest point of its orbit around the Sun, Mercury’s orbital speed matches its rotational velocity so that the Sun appears to stop in the sky. Then it’s orbiting faster than it’s rotating for about 8 days and so the Sun appears to move backwards.

We’ve written several articles about the length of years for Universe Today. Here’s an article about the years of all the planets, and here’s an article about how long a year is on Mars.

If you’d like more info on Mercury, check out NASA’s Solar System Exploration Guide, and here’s a link to NASA’s MESSENGER Misson Page.

We’ve also recorded several episodes of Astronomy Cast about Mercury. Listen here, Episode 49: Mercury.

Fraser Cain

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay. Here's a link to my Mastodon account.

Recent Posts

Curiosity Rover is Climbing Through Dramatic Striped Terrain on Mars

Just about every day we here on Earth get a breathtaking picture of Mars's terrain…

5 hours ago

A Giant Gamma-Ray Bubble is a Source of Extreme Cosmic Rays

Gamma-ray bursts (GRBs) are one of the most powerful phenomena in the Universe and something…

6 hours ago

New Study Addresses how Lunar Missions will Kick up Moondust.

Before the end of this decade, NASA plans to return astronauts to the Moon for…

2 days ago

How Warm Are the Oceans on the Icy Moons? The Ice Thickness Provides a Clue.

Scientists are discovering that more and more Solar System objects have warm oceans under icy…

2 days ago

NASA Tests the New Starship Docking System

The Apollo Program delivered 12 American astronauts to the surface of the Moon. But that…

2 days ago

China Has Built a Huge Space Simulation Chamber

Well it certainly caught my attention when I saw the headlines  “China’s first Space Environment…

3 days ago