As of: January 23, 2024, 5:42 a.m
By: Sandra Sporer
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On a graph like this, the answer to the question of which planet is closest to Earth seems obvious.
However, it's not quite that easy.
© IAU Martin Kornmesser DLR/dpa
The smallest average distance is usually used to answer the question.
However, researchers showed that this method has a weakness.
Munich – “My father explains our night sky to me every Saturday.” Almost everyone knows this motto or its earlier version, which included the dwarf planet Pluto.
And perhaps that's why the question of which planet is closest to us seems perfectly clear at first glance.
If you follow the list, only Venus and Mars come into consideration.
If you google the question, you get a clear answer: Venus.
However, it's not quite that simple.
The information comes from the European Space Agency (ESA) website, but comes with the caveat that this information refers to the point closest to Earth in the planet's orbit.
And that's exactly the crux of the matter - the planets are constantly in motion and so there is no universal answer to the question of which planet is closest to Earth.
The answer actually depends on what standard you use.
Which planet is closest to Earth is constantly changing
As already mentioned, which planet is currently closest to Earth changes again and again.
Therefore, this answer is not necessarily the most practical, as in order to answer it you first have to check what the current position of the planets is.
This is possible, for example, on the website The Sky Live.
Currently (as of January 17th) Mercury is closest to Earth.
On October 17, 2024, Mars will be the closest planet in our solar system.
However, very few people have this knowledge in their heads.
Venus is the closest planet to Earth at the average distance - but there is a catch in the calculation
Alternatively, you can answer the question by asking which planet is closest to Earth on average.
This data is also listed on several websites.
For example, theplanets.org provides the following information about the average distances from Mars, Mercury and Venus to our home planet:
planet |
Distance to Earth (in km) |
Mercury |
91,691,000 km |
Venus |
41,400,000 km |
Mars |
78,340,000 km |
The answer seems clear here too.
However, these numbers are actually based on a simplification.
“Through a phenomenon of negligence, ambiguity, or groupthink, science journalists have disseminated information based on a faulty assumption about the average distance between planets,” says an article on the subject by Tom Stockman, Gabriel Monroe, and Samuel Cordner written and
published by
Physics Today .
The following briefly explains the incorrect procedure: "To calculate the average distance between two planets, subtract the average inner orbit radius, r1, from the average outer orbit radius, r2."
Researchers develop alternative calculation methods and come to astonishing results
However, this calculation method does not take into account the relative positions of the planets during their orbit, explains Tom Stockman, research and development engineer at Los Alamos National Laboratory in New Mexico, to
Live Science
.
In the article published in
Physics Today
, he and his two co-authors present a more precise alternative method, the Point-Circle Method (PCM).
This calculates an average of all the distances between the individual points on both paths, explains Stockman.
The three scientists created a simulation based on this method.
They let this run for 10,000 years in order to take the time component into account and to determine even more precisely how long each planet was closest to Earth on average.
The astonishing result: Mercury was, on average, closest to Earth most often over time.
The three planets that are closest to Earth are always the focus of research.
For example, a study showed that life is possible on Mercury - but only to a very limited extent.
Meanwhile, researchers discovered oxygen on Venus.
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