Apparently even NASA is wrong about which planet is closest to Earth

Three scientists publish a paper proving that Mercury, not Venus, is the closest planet to Earth.

  • Earth is the third planet from the Sun, so our closest neighbor must be planet two or four, right?
  • Wrong! Neither Venus nor Mars is the right answer.
  • Three scientists ran the numbers. In this YouTube video, one of them explains why our nearest neighbor is... Mercury!

Did Musk pick the wrong planet to die on?

Image: upload.wikimedia.org

Elon Musk has said he wants to die on Mars.

By 2024, Elon Musk wants to land humans on Mars – the billionaire entrepreneur has said that he himself wants to go to the Red Planet, and even wants to die there (just not on impact, he quips). But has SpaceX chosen the wrong planet to colonize? If the plan was to pick the closest planet: yes indeed.

While Mars looms large in human culture and imagination, most scientific sources refer to Venus as the planet that's the shortest distance away from Earth. NASA mentions Venus as our closest neighbor. But while it's true that no other planet comes closer – the shortest approach is 0.28 AU (1) or 25 million miles (41 million km) – it's not true that Venus is the closest planet (2) on average (even though that too is often erroneously asserted).

A faulty line-up of the solar system 

Image: Wikipedia

A line-up of the usual suspects. Only the sizes are to scale, not the distances. And they usually don't line up as nicely as this.

"As it turns out, by some phenomenon of carelessness, ambiguity or groupthink, science popularizers have disseminated information based on a flawed assumption about the average distance between planets," write Tom Stockman, Gabriel Monroe and Samuel Cordner in an article published by Physics Today.

They go on to explain the mathematical method they devised to prove that, when averaged over time, it is in fact Mercury – the first rock from the Sun – that is Earth's nearest neighbor.

Long story short: Mercury is closest to Earth on average because it orbits the Sun more closely. That also means – mind-blowingly – that Mercury is the closest neighbor of all planets in our solar system, including gas giants Jupiter and Saturn and snowball planets Neptune and Uranus on the freezing outer edges of the system.

Unbelievably cool or unbelievably obvious?

Image: Tomment Section

Simulation of Mercury (grey), Venus (orange), Earth (blue) and Mars (red) circling the Sun, and the calculation of average distances to Earth.

In Physics Today, the three scientists describe their method in great detail. For laypeople like (probably) you and (certainly) me, the YouTube video at the top of this post, narrated by Mr Stockman, is more illuminating. In 6 minutes 40 seconds, he had me convinced.

While some commenters agree ("a neat new way to think about it!"), one or two are irritated that the hoi polloi are only now clocking on to this ("Any idiot should have been able to point this out").

Either way, one has to feel for the one commenter who seems to have figured this out a long time ago, but didn't have this video to prove their point: "I told my school teacher many years ago that Mercury is nearest to Earth but they laughed at me."

Video found here on YouTube. If you like your math like Saturn likes its gravity (spoiler: heavy), here's the article in Physics Today.

Strange Maps #966

Got a strange map? Let me know at strangemaps@gmail.com.


(1) 1 Astronomical Unit (AU) is the average distance between the Earth and the Sun: 93 million miles (150 million km).

(2) Their name aptly derived from the Greek 'planetai' for "wanderers", planets orbit around the Sun, hence the immense variation in the distances between them.

3D printing might save your life one day. It's transforming medicine and health care.

What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.

Northwell Health
Sponsored by Northwell Health
  • Medical professionals are currently using 3D printers to create prosthetics and patient-specific organ models that doctors can use to prepare for surgery.
  • Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
  • Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
Keep reading Show less

Where do atoms come from? Billions of years of cosmic fireworks.

The periodic table was a lot simpler at the beginning of the universe.

10 excerpts from Marcus Aurelius' 'Meditations' to unlock your inner Stoic

Great ideas in philosophy often come in dense packages. Then there is where the work of Marcus Aurelius.

(Getty Images)
Personal Growth
  • Meditations is a collection of the philosophical ideas of the Roman Emperor Marcus Aurelius.
  • Written as a series of notes to himself, the book is much more readable than the dry philosophy most people are used to.
  • The advice he gave to himself 2,000 years ago is increasingly applicable in our hectic, stressed-out lives.
Keep reading Show less

An organism found in dirt may lead to an anxiety vaccine, say scientists

Can dirt help us fight off stress? Groundbreaking new research shows how.

University of Colorado Boulder
Surprising Science
  • New research identifies a bacterium that helps block anxiety.
  • Scientists say this can lead to drugs for first responders and soldiers, preventing PTSD and other mental issues.
  • The finding builds on the hygiene hypothesis, first proposed in 1989.

Are modern societies trying too hard to be clean, at the detriment to public health? Scientists discovered that a microorganism living in dirt can actually be good for us, potentially helping the body to fight off stress. Harnessing its powers can lead to a "stress vaccine".

Researchers at the University of Colorado Boulder found that the fatty 10(Z)-hexadecenoic acid from the soil-residing bacterium Mycobacterium vaccae aids immune cells in blocking pathways that increase inflammation and the ability to combat stress.

The study's senior author and Integrative Physiology Professor Christopher Lowry described this fat as "one of the main ingredients" in the "special sauce" that causes the beneficial effects of the bacterium.

The finding goes hand in hand with the "hygiene hypothesis," initially proposed in 1989 by the British scientist David Strachan. He maintained that our generally sterile modern world prevents children from being exposed to certain microorganisms, resulting in compromised immune systems and greater incidences of asthma and allergies.

Contemporary research fine-tuned the hypothesis, finding that not interacting with so-called "old friends" or helpful microbes in the soil and the environment, rather than the ones that cause illnesses, is what's detrimental. In particular, our mental health could be at stake.

"The idea is that as humans have moved away from farms and an agricultural or hunter-gatherer existence into cities, we have lost contact with organisms that served to regulate our immune system and suppress inappropriate inflammation," explained Lowry. "That has put us at higher risk for inflammatory disease and stress-related psychiatric disorders."

University of Colorado Boulder

Christopher Lowry

This is not the first study on the subject from Lowry, who published previous work showing the connection between being exposed to healthy bacteria and mental health. He found that being raised with animals and dust in a rural environment helps children develop more stress-proof immune systems. Such kids were also likely to be less at risk for mental illnesses than people living in the city without pets.

Lowry's other work also pointed out that the soil-based bacterium Mycobacterium vaccae acts like an antidepressant when injected into rodents. It alters their behavior and has lasting anti-inflammatory effects on the brain, according to the press release from the University of Colorado Boulder. Prolonged inflammation can lead to such stress-related disorders as PTSD.

The new study from Lowry and his team identified why that worked by pinpointing the specific fatty acid responsible. They showed that when the 10(Z)-hexadecenoic acid gets into cells, it works like a lock, attaching itself to the peroxisome proliferator-activated receptor (PPAR). This allows it to block a number of key pathways responsible for inflammation. Pre-treating the cells with the acid (or lipid) made them withstand inflammation better.

Lowry thinks this understanding can lead to creating a "stress vaccine" that can be given to people in high-stress jobs, like first responders or soldiers. The vaccine can prevent the psychological effects of stress.

What's more, this friendly bacterium is not the only potentially helpful organism we can find in soil.

"This is just one strain of one species of one type of bacterium that is found in the soil but there are millions of other strains in soils," said Lowry. "We are just beginning to see the tip of the iceberg in terms of identifying the mechanisms through which they have evolved to keep us healthy. It should inspire awe in all of us."

Check out the study published in the journal Psychopharmacology.