“We know more about it the moon than the deep sea.”
This idea has been repeated by for decades scientists and science communicatorsincluding mr David Attenborough in the 2001 documentary series The Blue Planet.
Recently in Blue Planet II (2017) and other sources, the moon is replaced by Mars.
As deep-sea scientists, we have examined this supposed “fact” and found it to have no scientific basis. it is not true in any quantifiable way.
Where did this strange idea come from?
depth mapping
The earliest written mention is available a 1954 article in which Journal of Navigationin which oceanographer and chemist George Deacon refers to a claim made by geophysicist Edward Bullard.
A 1957 paper published in the Journal of the Royal Society of Arts: “The deep oceans cover more than two-thirds of the earth’s surface, and yet more is known about the shape of the lunar surface than that of the ocean floor”.
This relates in particular to the sparse amount of data available on seafloor topography, and goes back to both the first manned descent into the deepest part of the ocean, the Mariana Trench (1960), and the first moon landing (1969) return.
This citation also predates the practice of using ship-mounted sonars to map the seafloor from acoustic data known as swath bathymetry.
Almost a quarter of the world’s seabed (23.4 percent, to be precise) was mapped to high resolution. That equates to about 120 million square kilometers, or about three times the total surface area of the moon. Maybe that’s why the comparison has shifted to Mars, which has an area of 145 million square kilometers.
Surprisingly many visitors
Another related and incorrect comparison is that more people have walked on the moon than have visited the lowest place on earth.
This statement is difficult to prove. “The deepest place on earth” could refer to the Mariana Trench, or just the deepest part of it (Challenger Deep, named after the British survey ship HMS Challenger).
Despite this, at least 27 and up to 40 or more people have visited the Challenger Deep by early 2023. On the other hand only 12 people have “entered” the moon and 24 people have visited it.
Out of sight out of mind
So why do people keep saying we know more about the moon or Mars than we do about the deep sea?
It feels natural to compare the deep sea to outer space. Both are dark, scary and far away.
But we can see the moon very easily just by looking up. By being able to see it, we accept what appears to be a luminous rock hanging in the sky, rather than parts of the ocean being very deep. We can see the moon waxing and waning and we can experience the pushing and pulling of the tides.
It feels like we know more about the moon than the deep sea because we’re forced to accept its presence. It invades our lives in a tangible way that the deep sea does not have.
We don’t think much about the deep sea, unless we’re watching a documentary or horror movie, or maybe reading about a “terrible alien monster” that was dredged by a deep-sea trawler.
A useful analogy
Because the deep sea is so physically inaccessible, a comparison to outer space can provide a useful analogy for an otherwise difficult-to-imagine ecosystem. but some deep sea scientists argue that the ongoing alienation of the deep sea minimizes the tremendous body of research about it that has emerged in recent decades.
Deep-sea biology has been harshly labeled as a discipline that knows less about its own subject than it does about a relatively small, barren rock devoid of atmosphere, water, and life. And yet this self-deprecating line is echoed by scientists themselves, who may find that highlighting the lack of knowledge about the deep sea helps promote the need for marine exploration.
After all, the idea that we know more about the moon than the deep sea is about 70 years old at best. We know a lot more about the deep sea – but there is still more to know.
Prema Arasupostdoc, The University of Western Australia; Alan JamiesonLecturer in Marine Ecology, Newcastle Universityand Thomas LinleyResearch Associate, Marine Ecology, Newcastle University
This article is republished by The conversation under a Creative Commons license. read this original article.
