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Asked by Maya Cove to Aaron, Abbey, Keith, Natalie, Pete on 14 Nov 2015.
Question: whats at the botttom of the ocean?
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Peter Burgess answered on 14 Nov 2015:
Evidence of the Earth’s magnetic history!
I mean, there are all kinds of things at the bottom of the ocean, but I like this one.In the middle of the Atlantic Ocean there is a ridge where the Earth’s crust is split between where the Americas sit, from those where Europe and Africa site. As these plates draw apart, lava flows up to make new rock at the ridge. As they set, the crystals in the rock line up with the Earth’s magnetic field. Very occasionally, the Earth’s magnetic field flips so that what we now call the North Pole would (magnetically speaking) become the South Pole. We know how often this happens based on the stripey pattern of magnetism in the rocks on the bottom of the Atlantic with bands of rock with crystals pointing north, then south, then north again and so on.
There is some evidence to suggest we might be entering into one of these ‘flips’, as the strength of the Earth’s magnetic field has been getting weaker, and the exact location of the magnetic North Pole has been wandering. I don’t know that anybody is completely sure how the flipping process works, or what it means for those who will live through it, but the Earth’s magnetic field is really important for keeping radiation from space away from the Earth.
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Aaron Boardley answered on 17 Nov 2015:
It depends on which part of the ocean. Usually it’s quite rocky – things look a bit different than the sandy water at the beach because at the bottom of the ocean the floor is under A LOT of pressure – just think of all the water on top of it, the weight of that is all pushing down.
As Pete has said, in some parts of the ocean you get the edges between the earth’s tectonic plates, where lava comes up (like a slowly flowing sea volcano) and cools down to become rock.
The other thing to say is that at the bottom of the ocean it tends to be dark! Light from the sun doesn’t just pass through the water above you like it would through a small glass of water – over that distance a lot of it is lost and scattered, so you’re left with a very dark ocean floor.
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Natalie Garrett answered on 20 Nov 2015:
We know more about the dark side of the moon than we do about what’s at the bottom of our deepest oceans. The reason for this is that the pressure is so enormous (over 1000 times as much as that you’d feel standing at the beach) that it’s very hard to send anything down there to take a look. Even if you do send something down there, it’s so very dark that you need a lot of lights to be able to take pictures.
What we do know is that there are extremely strange looking creatures in the deepest oceans, like these:
We also know there are fossils, bodies of dead animals, sand, rocks, volcanoes and if you go deeper, you will go into the earth’s crust.
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