A year is often considered to last 365 days, but because a year is based on the length of time that it takes the Earth to orbit around the Sun, this definition of a year only applies to the Earth. The duration of each planet’s year is completely unique, because each planet orbits at a unique distance from the Sun. I should also mention that the duration of a day is unique on each planet too, but that is a topic for another post.
The existence of different types of years would suggest that we could technically use other planets’ years to measure events on Earth, however, this would become extremely confusing because it would not be based on our planet’s orbit.
To demonstrate the difference in the length of a year on other planets, let me share this table which states the length of each planet’s year and an event that occurred approximately 1 year ago from today (September 12, 2024) for each of the different planets’ years. I will be including Pluto, which was always called a planet when I was growing up, and Sedna, one of the most distant dwarf planets that is orbiting the Sun near the edge of the solar system.
| Planet | Year Length | Significant Event 1 Year Ago |
|---|---|---|
| Mercury | 0.24 Earth years | Flag Day, 2024 |
| Venus | 0.62 Earth years | Groundhog Day, 2024 |
| Earth | 1 Earth year | September 12, 2023 |
| Mars | 1.9 Earth years | October, 2022 |
| Jupiter | 12 Earth years | NASA’s Curiosity rover lands on Mars (August, 2012) |
| Saturn | 29 Earth years | Windstorms with wind speeds exceeding 100 MPH damaged millions of trees in Itasca State Park, Minnesota (July, 1995) |
| Uranus | 84 Earth years | The Battle of Dunkirk, WWII (May, 1940) |
| Neptune | 165 Earth years | Oregon became the 33rd state (February, 1859) |
| Pluto | 248 Earth years | The United States of America became the nation’s official name (September, 1776) |
| Sedna | 11,400 Earth years | Before recorded history (hypothetically 9,376 BC) |
Here is a table of the number of years that have elapsed for each of the previously listed planets since the establishment of the United States.
| Planet | Years Elapsed Since July 4, 1776 |
|---|---|
| Mercury | 1,034 Mercurian years |
| Venus | 400 Venusian years |
| Earth | 248 Earth years |
| Mars | 131 Martian years |
| Jupiter | 21 Jovian years |
| Saturn | 8.6 Saturnian years |
| Uranus | 3.0 Uranian years |
| Neptune | 1.5 Neptunian years |
| Pluto | 1.0 Plutonian years |
| Sedna | 0.02 Sednian years |
Sedna has one of the most extreme orbits; it is not only very distant from the Sun, but its orbit is also quite eccentric, which means that it is shaped like an ellipse and not a circle. Sedna’s perihelion (the point at which it is closest to the Sun) is an impressive 7 billion miles (76 AU) and its aphelion (the point at which it is furthest from the Sun) is an astounding 90 billion miles (937 AU). Sedna has only completed about 2% of a year since the Declaration of Independence was adopted; to put this into perspective, 2% of an Earth year is about 1 week.
Which planet’s year is your favorite?
Onward American 