Did you know that the distance between the Sun and its planets is not constant? This is because the paths of planets around the Sun, called orbits, are not exactly circular! They are elliptical, which are nothing but slightly flattened circles with two foci instead of one. Our Sun is located in one of these two foci.
This means that the distance between the Sun and Mars can be anywhere between 206.6 million and 249.2 million kilometres. Quite a huge range, isn’t it? For the sake of convenience, we say that the mean distance between the two is 228 million kilometres. This is approximately 1.5 times the distance between the Earth and the Sun. It takes Mars nearly twice as much time as the Earth to complete one full orbit, 686.97 Earth days to be exact.
We have to specify ‘Earth’ days here because a ‘Mars’ day or sol is slightly longer than an Earth day. It is approximately 24 hours, 39 minutes, 35 seconds long. A Martian year is approximately 668 sols, equivalent to approximately 687 Earth days or 1.88 Earth years.
In this manner, as Mars moves around the Sun, there comes a period when the two come on either side of the Earth. This “opposition” phase is the best time to view Mars from the Earth as its full face gets illuminated by the Sun’s rays.
Picture Credit : Google
