Seabed

Three quarters of the solid surface of this planet has never been surveyed properly.

We have better topographic maps of Mars, Venus, and the Moon than of our own seabed, because mapping a planet from orbit is straightforward, and mapping a sea floor requires driving a ship slowly over every square kilometer of it while pinging downward.

The satellite-derived maps most people have seen, the ones that show the whole ocean floor with ridges and trenches, are inferred rather than measured.

Seafloor mass creates tiny variations in the sea surface height above it, and those variations can be measured from orbit and used to estimate what's underneath.

It works, and the resolution is coarse.

Features smaller than a kilometer or two simply don't appear.

There is a coordinated international project, Seabed 2030, working to map the entire ocean floor by the end of this decade.

Progress has been substantial and the target is ambitious.

And all the cities and all the farmland combined, it is by a wide margin the most common surface on Earth, and most of it has never been mapped.

The numbers shift slightly every year, because mapping is ongoing, but as of the most recent data from the Nippon Foundation GEBCO project, Approximately 26% of the ocean floor has been mapped to what scientists consider modern resolution.

Modern resolution in this context means multi-beam sonar, a technology in which a ship-mounted or submersible-mounted sonar system sends out a fan-shaped array of acoustic beams that bounce off the seafloor and return, creating a detailed topographic picture of the bottom.

Multi-beam sonar can resolve features as small as 100 metres across, depending on the depth and the system used.

It is the gold standard for ocean floor mapping, and it has been applied to roughly one quarter of the ocean floor.

The remaining 74%, roughly 267 million square kilometres, is known only from satellite-derived gravity measurements.

Satellite gravity mapping works like this.

A bulge of perhaps a metre or two, spread across many kilometres, completely invisible to anyone on a ship but detectable by extremely precise satellite altimeters.

If you look at Google Maps, you might think that we know the precise topography of all of this, but that's a lie.

We know less about the ocean floor than we do about the surface of Mars, by a lot.

How is that possible? We have mapped Mars to a resolution of five meters per pixel.

For comparison, we've mapped the land on Earth to about 30 centimeters, but most of our oceans, 1.5 kilometers, meaning 300 times less detail, and that's a big problem because we're using the ocean all the time.

But hang on, we're smart.

Why is that? Well, cartographically speaking, water sucks.

For Mars or Earth's surface, we can take pictures, but light doesn't get to the ocean floor, so we need other ways to see it, and the good news is that we're developing that tech right now.

There is a terrifying, incredible alien world right there on our own planet, and finally, we're using technology to see it more clearly.

And the telegraph cable, as you'll know, was a very important piece of telecommunications at the time.

It's pretty much the nervous system of the empire, but it's very technically challenging because you've got all kinds of gubbins on the ocean floor, and we don't really know what's going on there.

So at one end, there was...

The Americans.

What is the machine? I mean, it's just a bucket that you're dropping over the side.

What's the problem? So the problem is when you have like miles and miles of thick rope and then you hit the sea floor and then all that weight apparently makes the rope liable to snap.

What, as you try and pull it back up? And so even when it just hits, even when it hits the ocean floor, I think.

No, surely it'll be just as you try and pull it up.

There was a theory for a while, but it, it didn't last very long.

So what you've got to do is find out where the ocean floor's going because we've not got an ever-expanding ocean floor, so we must be destroying it elsewhere.

So they knew it was, it was d- uh, the, the seas, [laughs] that it was spreading but-

Yes

The oceans

...

the ocean floor-

Yes

We hardly moved upon our seats, and it is as well that we did not, for we had perched upon some sort of a projecting hummock clothed thickly with the viscous gelatinous mud and there we were balanced rocking gently with nearly half our base projecting and unsupported there was a danger that we would tip over on our side but finally we steadied down and remained motionless as we did so dr maricot staring out through his porthole gave a cry of surprise and hurriedly turned out her electric light to our amazement we could still see clearly there was a dim misty light outside which streamed through our port-hole like the cold radiance of a winter morning we looked out at the strange scene and with no help from our own lights we could see clearly for some hundred yards in each direction It was impossible, inconceivable, but nonetheless the evidence of our senses told us that it was a fact.

The great ocean floor is luminous.

Why not? cried Mariko, when we had stood for a minute or two in silent wonder.

Should I not have foreseen it? What is this pteropod or globigerina ooze? Is it not the product of decay, the mouldering bodies of a billion, billion organic creatures? and is decay not associated with phosphorescent luminosity where in all creation would it be seen if it were not here ah it is indeed hard that we should have such a demonstration and be unable to send our knowledge back to the world and yet i remarked we have scooped half a ton of radiolarian jelly at a time and detected no such radiance it would lose it doubtless in its long journey to the surface but what is half a ton compared to these far-stretching plains of slow putrescence and see see he cried in uncontrollable excitement the deep-sea creatures graze upon this organic carpet even as our herds on land graze upon the meadows As he spoke, a flock of big black fish, heavy and squat, came slowly over the ocean bed towards us, nuzzling among the spongy growths and nibbling away as they advanced.

Thus the matter stands, and we trust our weak wireless will carry our message as far as the Cape de Verde station.

The fuller details of this wonderful adventure will come later, as is fitting, from the adventurers themselves.

END OF SECTION FIVE SECTION SIX There are very many people who have written both to me, Cyrus Headley, Rhodes Scholar of Oxford, and to Professor Maricot, and even to Bill Scanlon, since our very remarkable experience at the bottom of the Atlantic, where we were able, at a point 200 miles southwest of the Canaries, to make a submarine descent, which has not only led to a revision of our views concerning deep-sea life and pressures, but has also established the survival of an old civilization, under incredibly difficult conditions in these letters we have been continually asked to give further details about our experiences it will be understood that my original document was a very superficial one and yet it covered most of the facts there were some however which were withheld and above all the tremendous episode of the lord of the dark face this involved some facts and some conclusions of so utterly extraordinary a nature that we all thought it was best to suppress it entirely for the present now however that science has accepted our conclusions and i may add since society has accepted my bride our general veracity is established and we may perhaps venture upon a narrative which might have repulsed public sympathy in the first instance Before I get to the one tremendous happening, I would lead up to it by some reminiscences of those wonderful months in the buried home of the Atlanteans, who by means of their vitrine oxygen bells are able to walk the ocean floor with the same ease as those Londoners, whom I see now from my windows in the Hyde Park Hotel, are strolling among the flower beds.

When first we were taken in by these people, after our dreadful fall from the surface, we were in the position of prisoners rather than of guests.

Later, Marie used the same kind of attention in a very different place.

That place was the ocean floor.

The ocean floor is the ground beneath the sea.

Most people never see it directly.

They see waves.

Heinrich Berann was an Austrian painter and map artist.

He was known for clear and beautiful landscape maps.

Together, they helped create a large map of the ocean floor.

It was impossible, inconceivable, but nonetheless the evidence of our senses told us that it was a fact.

The great ocean floor is luminous.

Why not? cried Marico when we had stood for a minute or two in silent wonder.

Should I not have foreseen it? What is this terrapod or globigerina ooze? Is it not the product of decay, the mouldering bodies of a billion billion organic creatures? And is decay not associated with phosphorescent luminosity? Where in all creation would it be seen if it were not here? Ah, it is indeed hard that we should have such a demonstration and be unable to send our knowledge back to the world.

This involved some facts and some conclusions of so utterly extraordinary a nature that we all thought it was best to suppress it entirely for the present.

Now, however, that science has accepted our conclusions, and I may add, since society has accepted my bride, our general veracity is established, and we may perhaps venture upon a narrative which might have repulsed public sympathy in the first instance.

Before I get to the one tremendous happening, I would lead up to it by some reminiscences of those wonderful months in the buried home of the Atlanteans, who by means of their vitrine oxygen bells are able to walk the ocean floor with the same ease as those Londoners whom I see now from my windows in the Hyde Park Hotel are strolling among the flower beds.

When first we were taken in by these people after our dreadful fall from the surface, we were in the position of prisoners rather than of guests.

But I don't think there's any- anything beyond what you put-

Whoever ends up being the Seabed guy, and we don't know who that is yet.

I've heard lots of speculation about lots of players.

You know, I, until there's actual meaningful games being played, I don't think we're gonna fully know who these Seabed guys are and then, and then we will know.

I mean, I, I mentioned Diop and that's the only one that's on my radar from a, a bench perspective.

And it's not, yeah, just 'cause-

Sure

... well, why not? So-