What planet is closest to Earth? Common sense suggests it is Venus or Mars, and common sense will be right. But technically speaking, this is not entirely true. At different points in their respective orbits, the Earth, Venus, and Mars are at different distances from each other. Out of curiosity, if these variations in space were counted on which planet will be closest? The answer is weird: it’s Mercury. Point circle method is a technique that averages the distance between each point to the orbit of a planet and each point on the second planet’s orbit.
Using this, 3 researchers found that Venus is on average is 1.14 astronomical units away from Earth and Mercury is 1.04 AU away. The researchers figured that for any two bodies in the same plane and moving in concentric orbits, the normal distance between the two bodies is directly proportional to the radius of the internal orbit. To validate this corollary, they steered the planets in their real elliptical orbits in 3D and ran a simulation for 10, 000 decades. The simulation captured the distances between every pair of planets each 24 simulation hours. The average measured distances deviated from the results in PCM by less than 1% – so their calculation was right.