
Earth may have been a 'water world' 3B years ago, scientists find - Hooke
https://www.theguardian.com/science/2020/mar/02/earth-may-have-been-a-water-world-3bn-years-ago-scientists-find
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stewbrew
Erm, is this actually news? I remember a small book from my childhood where
the early earth was described as covered with water. My memories are vague
though because I was more interested in the dinosaurs and sable tigers.

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rjkennedy98
I remember a big book from my childhood where the early earth was described as
covered with water. I remember being more interested in the animals on the ark
going in 2 by 2.

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gwd
But even before that:

> _In the beginning God created the heavens and the earth. Now the earth was
> formless and empty, darkness was over the surface of the deep, and the
> Spirit of God was hovering over the waters. ...And God said, “Let there be a
> vault between the waters to separate water from water.” So God made the
> vault and separated the water under the vault from the water above it. And
> it was so. ... And God said, “Let the water under the sky be gathered to one
> place, and let dry ground appear.” And it was so._

So:

First, Earth covered with water, clouds right up against the water, no sun

Then, Earth covered with water, a clear visible area between the clouds and
the water.

Then Continents appear.

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TheFiend7
I'm as atheist as they come, but I guess it's a little weird how many
religions describe the earth as being completely covered in water initially.
Maybe it's a coincidence and a natural progression in thought when thinking up
a random story of earth's creation, but interesting nonetheless.

Pfft everyone knows this is all just a simulation and "gods"/creation was just
the init-script. Gotta do a bulk load into memory of all that water first
before computing textures and other compute intensive shit....

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elwell
Another 'coincidence' is that the order that plants, water animals, land
animals, flying animals, and humans are created seems to match what you might
derive from evolution theory. And, that man is created from dust of the earth.
Kind of weird to even think that different animals came about within an
orderly process. Kind of weird to think that the universe had a beginning;
seems to make more sense to assume it just always was and will be, but current
science agrees: universe had a beginning and will have an end.

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scotty79
And yet God made Sun, 'day' after he made fruit-bearing trees. Wonderful lack
of coincidence.

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mcv
In Genesis 1, light and dark, day and night, were created well before plants
and trees. It's just the sun and stars that came later somehow.

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scotty79
Yea... but we know that light comes from fusion happening inside the sun, so
the light on day 1 must be some other kind of light. Some spiritual light? Not
sure how plants can photosynthesize that.

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mcv
_We_ know that, but the author of the poem didn't. During the day, light seems
to come from everywhere, and not just the sun. Raleigh refraction was not a
familiar concept at the time.

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scotty79
Author didn't know what he was talking about and any relation of his writings
to actual reality is purely accidental.

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corentin88
I learned only a few months ago that you can find in Australia some rocks that
are 3bn years ago. It’s a unique situation I’ve learned and very "useful" to
scientists!

I went to Australia a few years ago and didn’t knew about that. Just want to
go back there to see that! The site is very difficult to access though.

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samatman
A note to anyone who wants to follow up on this lead: these are called
stromatolites.

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amelius
So, were they completely immersed in water?

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samatman
They formed in shallow water, so to begin with, yes.

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ngneer
Costner would be pleased...

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RickJWagner
But the viewers (and movie financiers) would not.

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vixen99
For the viewers, 'mixed reception' is more appropriate. Some of us will agree
with reviewer Roger Ebert "The cost controversy aside, Waterworld is a decent
futuristic action picture with some great sets, some intriguing ideas, and a
few images that will stay with me".

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Tade0
I wonder how our planet would be characterised in the context of the whole
galaxy.

We have no reference point(as in, other civilisations), so the fact that we're
e.g. tilted somewhat, rotate at a decent speed or are in 70% covered by water
might well be the weirdest thing in the universe.

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jon_richards
The weirdest thing about us is most likely the fact that our moon is almost
exactly the same size as our sun (relative to distance).

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Ididntdothis
I hope that in a billion years we will have time lapse videos of how Earth
changes :-).

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soperj
You could get it now. You just need a very powerful telescope that you send to
somewhere a billion light years away faster than the speed of light, and take
pictures along the way.

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jcims
There is a thin slice of space in which photons are bent 180 degrees around a
black hole.

Given sufficient resolving capability, you could theoretically zoom into that
slice and see earth as it was 2x the distance in light years ago.
Realistically it would be a dusty noisy mess, but there are photons coming
back to earth after bouncing off in the direction of the center of our galaxy
50,000 years ago.

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titzer
Actually, even more than that! There is a very narrow region where photons can
actually orbit a black hole multiple times before escaping. In fact there is a
region where photons may orbit indefinitely!

[https://www.universetoday.com/110682/can-light-orbit-a-
black...](https://www.universetoday.com/110682/can-light-orbit-a-black-hole/)

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ToadBoatFording
The article mentions the photon sphere, but is there any source on "orbit
multiple times before escaping"? My experience is just in Kerbal Space
Program, which is a 2-body approximation, but afaik once you are in orbit, you
can't escape without changing your velocity. Also, 180 degrees is the
exclusive limit of a gravity bend; less than 180 is not an orbit, but as soon
as you reach 180 degree bend, it becomes an orbit.

Of course, with 3-body things get much more complicated. For a third body to
pull photons out of a photo sphere, fascinating and I can imagine it
happening, but I haven't seen any sources along these lines.

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jcims
With all of the mass inflow there is likely a very turbulent gravitational
environment just outside of the event horizon. This could be sufficent to
provide a little transient local lensing to kick a photon back out (or in).

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justlexi93
Was all the land flat or where did the water go? Melt all the ice and empty
all the clouds, rivers and lakes - you still won't have enough water to cover
the continents.

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bpodgursky
If the earth's landmass was flat, you don't need as much water to cover the
continents.

If the earth had just "recently" cooled from being a ball of magma, it makes
sense that there weren't major upheavals yet. It was only after significant
tectonic motion, subduction, etc, that you got the variety of geographic
terrain and continents we have now.

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fyrefoxboy12
that's very likely. I mean, Water World is pretty much a future-set-in-the-
past story isn't it?

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ThefinalResult
And it will be again! ;)

