Mars and Earth have similar elliptical orbits and axial tilts, but Mars has a more eccentric orbit with a perihelion of 1.38 AU and aphelion of 1.66 AU. Mars’ year is 1.88 times longer than Earth’s, and its seasons are more extreme. The orbit of Mars was less eccentric in the past.
Most people are familiar with the orbital model of the Earth, so it’s easier to discuss the orbit of Mars in relation to that of the Earth. Mars and Earth share many similarities in their orbits. They are both elliptical designs and are held on a similar axial tilt. Mars’ orbit has a more eccentric pattern than Earth’s, which introduces some differences in the weather patterns between the two planets.
When viewed from above, both Earth and Mars appear to orbit the sun counterclockwise and are nearly in the same plane. An astronomical unit is a measurement of about 150 million km, or the distance from the Earth to the Sun. Earth’s orbit is therefore 1 astronomical unit (AU), while Mars averages 143 million miles (230 million km) or 1.5 AU. The Earth takes one year to orbit the sun, while an orbit of Mars takes about 687 Earth days or 1.88 times longer than an Earth year. A day on Mars is slightly longer than a day on Earth, averaging about 24 hours, 39 minutes and 35 seconds.
Eccentricity is used to define the shape of any planetary orbit. A perfect circle has zero eccentricity. Ellipses have an eccentricity between 0 and 1, while parabolas have an exact measurement of 1. The orbit of Mars has an eccentricity of 0.09, making it the second most eccentric orbit of all the planets. Only Mercury has a bigger one.
This eccentricity means that there is a large difference in the distances from when it is closest to the Sun, or at its perihelion, and when it is further away, at aphelion. Perihelion on the orbit of Mars is approximately 1.38 AU or 129 million miles (207 million km.) Aphelion is approximately 1.66 AU or 155 million miles (249 million km.)
The axial tilt of Mars is 25.19 degrees. Since this is very similar to the Earth’s tilt of 23.45 degrees, the seasons on Mars are very similar to those on Earth in that there are four of them. Each season is nearly twice as long as an Earth season since Mars’ year is longer. They also tend to be much more extreme since aphelion and perihelion are so drastically different. Summers are hotter as Mars orbits closer to the sun, while winters are colder further out.
It is assumed that many years ago the orbit of Mars was much less eccentric. It is estimated to have been closer to 0.002 about 1.35 million Earth years ago. The gravitational forces created by the other planets have slowly pulled Mars into a larger elliptical pattern.
Protect your devices with Threat Protection by NordVPN
