A team of scientists has just demonstrated something that might shock you: Mercury, not Venus, is the closest planet on Earth.
The researchers presented their results this week in an article in the journal Physics Today. They explain that our methods of calculating which planet "comes closest" simplifies the matter. But that is not everything.
"Furthermore, Mercury is on average the closest neighbor to each of the other seven planets in the solar system," they write. Wait what?
Our misconceptions about how close the planets are come from the way we usually estimate the distances to other planets. Normally we calculate the average distance from the planet to the sun. The average distance from the Earth is 1 astronomical unit (AU), while Venus is approximately 0.72 AU. If you subtract one from the other, you calculate the average distance from the Earth to Venus as 0.28 AU, the smallest distance for a few planets.
But three researchers realized that this is not an accurate way to calculate the distances to planets. After all, the Earth spends just as much time on the other side of its orbit as Venus, and places it 1.72 AU away. Instead, one must calculate the distance between each point along the orbit of one planet and each point along the orbit of the other planet. The researchers performed a simulation based on two assumptions: that the orbits of the planets were approximately circular and that their orbits were not at an angle to each other.
It seems a bit logical: if you were to get seats in a football match, you would want to have one at the 45.72m line instead of one of the end zones, to see the most action, even if you occasionally are closer to the players from the end zone. That's kind of what's happening here.
In fact, they discovered that on average, Mercury was closest to Earth for most of the time – and for every other planet in the solar system. Pluto's sloping and eccentric orbit does not work with their assumptions, but it is not a planet as defined by the International Astronomical Union. Please do not send me an e-mail about this.
You can read about the mathematical details of Physics Today or view an explanation of mathematics on YouTube.
But assuming there are no blatant errors in the analysis, I think it's time to say "goodbye" to Venus and to welcome our new neighbor, the best planet, Mercury.