In case you ask an astronomer which planet is closest to Earth, you’d in all probability count on to get a single, easy reply in response. And in case you had been paying consideration in school, you’d in all probability be moderately assured you would guess which one of many seven different planets in our photo voltaic system it’s.Â
So what’s the closest planet to us? Turns on the market is not only one proper reply — there are technically three, relying on how you’ve got phrased the query and while you’ve requested it.Â
One of the best ways to clarify why that is so contentious is to undergo the totally different potential questions and reply them, separately.Â
Which planet will get closest to Earth?
The reply to this specific query is simple — Venus. At its closest proximity to Earth, the hellish planet is just round 24 million miles (38 million kilometers) away from our planet, and no different planet will get nearer to us.Â
Utilizing this logic, our subsequent nearest neighbor is Mars, which may get to inside 34 million miles (54.7 million km) of our planet, adopted by Mercury, which is round 48 million miles (77.2 million km) from Earth at its closest level to us.Â
Associated: What number of occasions has Earth orbited the solar?
Nevertheless, we’re very hardly ever close to our closest level to any of those planets, and all three of them (in addition to Earth) are continuously orbiting the solar at totally different speeds, that means the distances between our blue marble and every of them are continuously altering over time. In consequence, most astronomers don’t discover this reply very satisfying.Â
Which planet is closest to Earth proper now?
For this query, the reply will be both Mercury, Venus or Mars, relying on the place every planet is on its orbital path in comparison with Earth.
For instance, if Venus and Mercury are positioned close to their farthest factors from Earth on the opposite facet of the solar and Mars is close to its closest level to Earth, then Mars can be the closest planet to us at that time. But when Mars is at its farthest level from Earth, and Mercury and Venus are close to their closest factors, then Venus can be the closest planet to us.Â
However the reply to this query modifications on a regular basis, which additionally would not make it an excellent method of figuring out our closest neighbor.Â
For instance, when this text was written (January 2024), the closest planet to Earth was Mercury. However in round eight months, Venus would be the closest planet to us, and in one other two months or so, Mars may have surpassed Venus as our closest neighbor. Nevertheless, lower than a month later Venus may have wrestled again the title.Â
You’ll be able to hold observe of this your self utilizing this simulator from TheSkyLive.com.Â
Which planet is closest to Earth on common?
That is the place issues get actually attention-grabbing.Â
In case you look on-line for a listing of planets’ common distances from Earth, you’ll get outcomes saying that Venus is way nearer to Earth on common than Mercury or Mars. For instance, ThePlanets.org lists Venus’ common distance to Earth as round 25.7 million miles (41.4 million km), in contrast with 57 million miles (91.7 million km) for Mercury and 48.6 million miles (78.3 million km) for Mars.Â
Associated: Why do the planets within the photo voltaic system orbit on the identical aircraft?
However these lists are incorrect as a result of they’re primarily based on flawed assumptions, Tom Stockman, a analysis and improvement engineer at Los Alamos Nationwide Laboratory in New Mexico, informed Dwell Science. To get these numbers, individuals have merely calculated the typical distance between the radius of every planet’s orbital distance from the solar, he mentioned. However this doesn’t bear in mind the planets’ relative positions to at least one one other throughout their orbits — it solely tells you the way far aside they orbit the solar on common, Stockman mentioned.
As a substitute, the right approach to work out the typical distances between planets is by utilizing a point-circle methodology (PCM), which calculates a median of all of the distances between every level on each orbits, Stockman mentioned.Â
In 2019, Stockman co-wrote an article in Physics Right now that identified this primary error and shared the true common distances between every of the planets primarily based on a PCM mannequin — which the authors  named the whirly-dirly corollary after an episode of the cartoon “Rick and Morty.” This revealed that Venus really has a median distance of 105.6 million miles (169.9 million km) from Earth, whereas Mars is round 158.1 million miles (254.4 million km) away on common. Nevertheless, Mercury is just round 96.6 million miles (155.5 million km) from Earth on common.
Nevertheless, these averages nonetheless do not paint the entire image as a result of they solely signify distance and never time. Subsequently, Stockman and his colleagues ran their simulations for 10,000 years to see how lengthy, on common, every planet was closest to Earth. This revealed that Mars spent roughly 17% of the time as Earth’s closest neighbor and Venus spent roughly 36% of the time holding the title. However the winner was Mercury, which was closest to Earth for roughly 47% of the time, making it our true closest neighbor on common.
Mercury is our closest companion as a result of it’s the closest to the solar and has the smallest orbit, which implies it’s extra usually on the identical facet of the solar as Earth, and even when it isn’t, it is by no means that distant. In the meantime, Venus and Mars spend lengthy durations of time a lot farther away from Earth.
For a similar purpose, it seems that not solely is Mercury our closest neighbor on common, however it is usually the closest common neighbor of all six different planets in our photo voltaic system, the whirly-dirly corollary revealed.
Earlier than the whirly-dirly corollary, different astronomers had in all probability already figured all this out, that means it wasn’t “totally unknown,” Stockman mentioned. “I feel most individuals that knew, like me at first, simply handled this as a enjoyable little truth to speak about at events,” he added.Â