From ropes to sound to satellites - how we map the sea floor
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- Опубликовано: 1 июл 2024
- Our current understanding of the structure of the seafloor is a recent achievement. Less than 200 years ago, the ocean bottom was thought to be a featureless expanse of mud and sediment.
Even now, over 100 years since the invention of sonar, only about 15% of the seafloor has been directly mapped. Most maps showing seafloor structure uses mean sea surface measurements taken by satellites to infer the shape of the ocean bottom.
Underrated video and underrated channel
Excellent video; why is it, though that the water follows the shape of the surface beneath it? At first, I was under the wrong impression that ridges had increased gravitational forces therefore, water directly above them was pulled downwards more and there was a dip.
You're almost right.
Gravity *does* pull it down extra hard, but it also pulls water sideways towards the region with more density.
It may be easier to understand when you think about gravitational potential instead of gravitational forces.
The water surface is (roughly) a surface of equal gravitation potential.
If you get to be closer to something heavy, then you have a lower gravitational potential (like further down).
If you are far away from heavy things, then you are at higher gravitational potential, like being higher up.
Nice video sir
Thanks
LOL water is level it doesn't "follow" the ridges on the bottom of the ocean
Consider this extreme example:
If there was a tiny black hole on the ocean floor - and let's say for the sake of arguments the ocean isn't draining into it - then water will get attracted to that spot.
Subsequently it will form a bump on the ocean surface.
Now, while we don't have any black holes on the surface of the oceans - if you've got a deep trench, then there will be water in a placr where there "should" be rock. The place is lighter. There is less gravity.
And so, water is pulled slightly away from that spot and towards places with more mass.
Complete utter lies. Unreal someone could even suggest this
I agree it is unreal that someone would suggest that there is anything untrue in the video. It is all based on extremely well established science.
@@SciencePrimer wake up and be your own teacher. Children are taught things for a specific purpose. No way can you prove that the undisturbed surface of water is affected by what is below. Actually go ahead and think what will. Doesn't effect my reality
The reality is this is extremely well-established science. If you've seen an online map of the Earth with ocean bathymetry shown, you've looked at this data. Only about 20% of the seafloor has been mapped by sonar. All the rest is the best estimates based on satellite altimetry data.
We have decades of satellite data. There are scores of peer-reviewed papers demonstrating the correlation between variation on the mean sea surface (with tides and waves subtracted) and independently measured sonar maps of the seafloor. This work dates back to the 1980s and continues to this day.
This paper by Tozer et al. from 2019 (agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019EA000658) provides a good summary of the state of the science. I encourage you to check out the many references cited in the second paragraph of the introduction to learn more.
@@SciencePrimer do you know what the abyssal plain is?
what would the abyssal plain have to do with mapping the rest of the ocean?