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Comment by olivermarks | Hacker News Reader

Amazing to realize that 75% of the oceans - which are 70% of the earth's surface - are unmapped and unknown

99% of what's 10 meters below the surface on land is probably also unknown.

Soil scientists and some conservationists will tell you that 95% of what's a centimeter underground is unknown as well.

I read somewhere E. O. Wilson stating that were he to start over again he would go into research of life in the soil. He also said there is so little we understand about the things just beneath our feet.

We don't even know how to document it all when we extract DNA from soil. You might be able to put things into general families of species but too much is uncharacterized. Some research is opting to just consider things in terms of ecological niches occupied instead of absolute species found.

Even on, and in our feet.

There's an aquatic cave in Death Valley called Devil's Hole; divers have gone to ~600 ft, but the cave is likely over twice as deep.

A magnitude 7.6 earthquake 1,500 miles away caused 4 ft high waves at Devil's Hole: https://www.cbsnews.com/news/mexico-earthquake-triggers-4-fo...

It may be that the aquifer in Devil's Hole is somehow connected to a network of underwater aquifers thousands of miles away in Mexico… but we just don't know, and have no way of knowing right now.

Can’t we just use some form of ultrasonic wave from one end and detect at other end ?

I’d imagine the amount of energy you’d have to push into the water would be insane to hear it 1500 miles away, wouldn’t it?

Whale noises travel thousands of kilometers underwater. https://en.wikipedia.org/wiki/Whale_vocalization

There's an inverse relationship between wavelength and range, and the higher the frequency the better the resolution.

https://acousticstoday.org/wavelength

What other end?

Pour in some traceable mix of chemicals, and see if it turns up somewhere.

There're these fish called the Devil's Hole Pupfish. Can't do that.

There is a near infinite number of non toxic chemicals to choose from.

Ah, but can you show that they're not toxic to Devil's Hole Pupfish? And the population is tiny and fragile--you're not allowed any test subjects.

There might well be 5 separate regulations forbidding it. That's a different question.

The safest class of substances I can think of are unusual isotopes.

They're chemically identical to the regular elements, which is what matters for life forms, but can be detected by scientific instruments.

You'd deafen the poor troglobites.

As your link says, it's a seiche. https://en.wikipedia.org/wiki/Seiche .

> Earthquake-generated seiches can be observed thousands of miles away from the epicentre of a quake.

https://weather.com/news/video/how-mexicos-earthquake-caused... says the waves started about 20 minutes after the earthquake, which was 1,500 miles away. That's about 2 km/sec, which makes it (I think) due to the S-wave.

It's certainly not underground water being compressed for hundreds of miles before arriving at Devils Hole, if only because underground water flow doesn't work that way.

Seiches happen even in swimming pools, as at https://www.youtube.com/watch?v=-2JwUSD3x2s where the pool starts sloshing around from an earthquake about 200 miles away. They don't need to be connected to a larger water system.

I see from https://en.wikipedia.org/wiki/Devils_Hole :

> The pool has frequently experienced activity due to far away earthquakes in Japan, Indonesia, Mexico, and Chile, which have been likened to extremely small scale tsunamis

and https://home.nps.gov/deva/learn/news/alaska-quake-shakes-wat... notes the Alaska earthquake was 2,000 miles away in the other direction.

Who named it?

These sorts of things really give me pause when thinking about colonizing Mars and all of the hand-waiving that gets tossed around.

We still do not know a lot about our own planet. What makes us so confident we won't just screw up another planet with our lack of understanding...

With our current understanding and technical abilities - no need to worry, they’d all die shortly or bankrupt the host country.

Miracle Max: Look, I'm retired. And besides, why would you want someone the King's stinking son fired? I might kill whoever you wanted me to miracle.

Inigo: He's already dead.

Miracle Max: He is, huh? I'll take a look. Bring him in.

We screw up everything. The question is, can we leave places alone and screw up others instead? Screwing up the moon is probably better than screwing up Yosemite, or the Great Barrier Reef.

Screwing it up today prevents us from doing something useful tomorrow with a more complete understanding.

Patience is a virtue, as they say. I fear the current raft of would-be planet colonizers are not very patient...

There isn't much to screw up on a dead planet.

I'll bite. You know it's dead how? Mind you I grew up reading Heinlein juveniles like Red Planet.

You're right, there may well be some sub surface microbial life on Mars, and we should figure that out before doing anything too drastic.

Mars is already screwed up. It would be hard to screw it up even more.

I've read that for some parts of the world, ocean floor maps are still based on data from 18th century surveys.

Nautical charts incorporate the latest (usually) data from each area, but it's eye opening to realize that in many areas the most recent data is actually centuries old.

https://nauticalcharts.noaa.gov/updates/how-accurate-are-nau...

How does that compare to the surface of the moon, or mars

The resolution could be better, but it's still better than what we have of the ocean floor.

https://www.google.com/moon/

We know way more about the moon than we do the ocean. Most if not all of the moon not on the dark side is fully mapped.

There is no permanently dark side of the moon. It's all lit eventually.

The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the near side, because of synchronous rotation in the moon's orbit. ... The hemisphere is sometimes called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight"

https://en.wikipedia.org/wiki/Far_side_of_the_Moon

While you're not wrong, the grandparent comment said that most of the "dark side" is not fully mapped, implying—at least to in reading of it—that the reason it's not mapped is due to it being the "dark side".

In reality though, our maps of the far side of the moon are as good as those on the near side.

If you re-read the quoted bit it addresses this "dark side" vs "far side":

> The hemisphere is sometimes called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight"

[ed note: compare "dark ages"]

So the "unknown" (relatively anyway) side of the moon is less mapped, but not because it's unlit, but because it's dark. The lit side of the moon is well mapped, not because it's always lit - sometimes it's unlit, but it's certainly the known bit as we've been looking at it since before we were human.

> The hemisphere is sometimes called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight"

Tbqh I think "dark side of the moon" is more often a genuine misconception than a poetic way of saying unknown. Fundamental misconceptions of the Moon abound, such as the mistaken belief that the Moon is opposite of the sun and rises when the Sun sets. You'd think that people would notice the Moon in the sky during the day for much of the month, but some people just don't pay attention to the sky, don't think about it much, and pick up the meme of the antisolar synchronous moon from cartoons, video games and grandfather clocks.

And sometimes people simply mispeak, perhaps due to Pink Floyd.

That sort of makes sense. Not only are we naturally positioned above the moon, looking down on it, but it’s also not covered in a 5000m thick layer of dilute whale effluent.

That was 95% when I first heard this years back

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