We all know that Mercury is the closest planet to the Sun. With its hot and cold temperatures and small size, it’s one of the most difficult planets to spot when looking up into the night sky. However, Mercury is actually not that far away from Earth.
However, just how long does it take Mercury to make one full trip around the Sun? Well, it’s actually still a pretty lengthy time, even if it doesn’t take quite as long as Earth.
How long does it take Mercury to revolve around the Sun?
Mercury has the shortest year of any planet; it takes Mercury 88 days for it to compete one full orbit around the Sun. That means that for every one year on Earth, a little over 4 years go by on the planet Mercury.
But why does this happen? Well, one of the main reasons is that Mercury has a far shorter distance to travel than the planets that are farther out. This is also much less than Venus, which takes around 224 days to make it all the way round. Mercury is only 0.4 AU (astronomical units) away from the Sun, or approximately 36 million miles. That means that when it does go around the Sun, it really doesn’t have to go as far as the other planets.
However, there is another factor at play here which has a big impact on the amount of days there are in a year on Mercury, and yes, it’s because of its close proximity to the Sun. Because it’s up close and personal, the gravitational pull of the Sun is much greater, meaning that Mercury whizzes around its perimeter much faster than any other planet.
How fast does it go? Well, it averages at a speed of around 106,000 miles per hour. In comparison to Earth, which travels at a sluggish(!) 67,000 miles per hour, it’s clear to see why Mercury zooms round the Sun at such a fast pace. These are just a few simple facts about the planet; you can read many more here.
Mercury orbital pattern & rotation
It is well known that out of all of the planets, Mercury has the most eccentric orbital path around the Sun. What this means is that not only is it oval as opposed to circular, but it’s shaped more like an eye than it is a circle. This isn’t that abnormal as none of the planets truly travel in a circle around the Sun, but there’s a reason why Mercury moves this way.
And yes, again it’s down to its close proximity to the Sun. At its closest, which we call its perihelion, Mercury is only 28 million miles away from the Sun. And at its farthest, which we refer to as its aphelion, it can reach as far as 44 million miles away from the Sun. So as you can see – far from circular in its orbit.
One thing that often does surprise people about Mercury is that it has a long day length. Because it’s so close to the Sun, many assume that it rotates on its axis very quickly, but actually, the opposite is true. It travels so fast around the Sun that it rotates so very slowly that a full day on Mercury is equal to approximately 59 days on our planet. That means that when the Sun goes down, you may not see it again for another month!
In conclusion, Mercury has the shortest travel time of any planet, which is largely dictated by how close it is to the Sun. But because Mercury is travelling at such a great speed away from the Sun whilst being pulled in by the Sun’s gravity, it continues to orbit the center of the solar system and will do for billions of years to come. And actually, even though Mercury’s path is a little odd, it’s still stable enough for it to stay in orbit.