The order of the planets is something most of us learn in school: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and (until 2006) Pluto.
So, as Earthlings, you might think that our closest planetary neighbor is Venus or Mars. Also, at certain times of the year, your opinion is true. When Venus is at its closest point, it comes closer to Earth than any other planet in the Solar System. Likewise, its orbit is closer to our orbit than the others. However, that thought may not always be true, at least according to an article published in Physics Today.
Engineers at NASA, Los Alamos National Observatory, and the U.S. Army Engineers Research and Development Center used the average of Earth’s three closest planets (Mars, Venus, and Mercury) over a 10,000-year period to determine our nearest neighbor. created a computer simulation to calculate its proximity. Because of the way the planets align during their orbits, the model showed that Earth spends more time near Mercury than Venus or Mars.
“In other words, Mercury is, on average, closer to Earth than Venus because it orbits closer to the Sun,” the authors explain.
In fact, this situation is not only valid for the Earth. Further calculations show that most of the orbits of the seven planets in the Solar System (excluding Mercury) are closer to Mercury than any other planet.
The results are based on a technique called the dot-circle method (PCM). Basically, this technique can be defined as a mathematical equation that takes the orbits of two planets as circular, concentric and coplanar and calculates the average distance between the two planets as they orbit the sun.
“Thanks to the PCM, we noticed that the distance between the two orbiting objects was at a minimum when the inner orbit was at a minimum,” the authors explain. “It is clear from this result and the table that Venus (average orbital radius 0.72 AU) ), but Mercury (mean orbital radius 0.39 AU) is the closest planet to Earth on average.”
And a little note: The AU is an astronomical unit and defines the distance between the Earth and the Sun.