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The Silurian Hypothesis (2020)

theparisreview.org

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Re: The Silurian Hypothesis (2020)

#111

Post by throw310822 »

T-A wrote: post #108
throw310822 wrote: post #105

Earlier quoted context omitted.

> A quick search on "rock weathering depth per century" That's a great illustration of what I meant. Of course an exposed rock consumes away in the space of a few millennia- this is exactly where the "Silurian theory" comes from. Yet it's also obvious that we have plenty of perfectly conserved rocks that are intact after hundreds of millions of years- i.e. fossils. Any small sculpture buried in clay can survive for a…

> Any small sculpture buried in clay can survive for an eternity. If it's made of granite, maybe. But how many granite sculptures have you seen? Sculptors tend to prefer prettier and more easily shaped materials, like marble and limestone. Those happen to be mostly calcium carbonate, just like bones and teeth, so section 1.2 in [1] (chemical dissolution in acidic environments) applies, along with section 1.3 and [2]…

> how many granite sculptures have you seen?

We use enormous amounts of it in construction, cut to precise shapes.

> just like bones and teeth

Of which we have ample amounts of fossils. Even included in marble, which is itself hundreds of millions of years old.

> it would not have stayed that way over tens of millions of years.

So we don't have fossils from hundreds of millions of years ago?

> Would bears endowed with human-level intelligence want to wear clothes and boots?

Absolutely if they had a civilisation capable of producing climate change. We're talking about at least a billion individuals living in all environments on Earth, from the tropics to the arctic, and doing all things an advanced civilization does: farming, mining, building, transporting, exploring etc. At least elements of technical clothing are needed in many of these activities.

> See section 1.3 in [1]

You keep repeating an argument that disproves the possibility of all fossils. Really you can't understand that it's contradicted by facts?

Re: The Silurian Hypothesis (2020)

#112

Post by gorgolo »

Surprised so few are pushing back against some of the claims in this article.

Eg that the entire surface of the earth gets replaced in a million years by tectonics.

Many of the large plates are more than 1000km across, they’d need to be moving meters per year for that to happen. In reality it’s cm per year. Also typically it’s oceanic plates that get subducted and take material under the crust, not continental plates. If it were true, then how do we see dinosaur fossils, and creatures even older than that; how do we find rocks that are over a billion years old.

This doesnt reject the possibility that there was a civilization tens of millions of years ago, but it makes the article hard to take seriously. If you’re gonna spend time writing an article on this you might as well try to research it a bit more. Someone is gonna read this and repeat this nonsense like it’s some fun trivia.

Re: The Silurian Hypothesis (2020)

#113

Post by inhumantsar »

tonymillion wrote: post #54

The fact there is still coal(and oil) in the ground pretty much rules out any "advanced" industrialized civilization that came before us. I also use the Carboniferous Period as a metric as to why "Advanced alien life" isn't more abundant (and I believe it should be factored into the Fermi equation)... All those trees growing, soaking up sun, dying and just laying there to be compressed and buried without anything to…

one thing I enjoyed about The Children of Time by Adrian Tchaikovsky: the spiders learned to build "computers" out of ant colonies by hijacking the ants ability to generate and respond to chemical stimuli.

not that it makes me believe in the silurian hypothesis, but i'm always reminded of that whenever i start to think "well it couldn't possibly be done any other way".

Re: The Silurian Hypothesis (2020)

#114

Post by JPLeRouzic »

gorgolo wrote: post #112

Surprised so few are pushing back against some of the claims in this article. Eg that the entire surface of the earth gets replaced in a million years by tectonics. Many of the large plates are more than 1000km across, they’d need to be moving meters per year for that to happen. In reality it’s cm per year. Also typically it’s oceanic plates that get subducted and take material under the crust, not continental plates…

> Many of the large plates are more than 1000km across, they’d need to be moving meters per year for that to happen. In reality it’s cm per year.

A plate moving one centimeter per year would move over 10,000 km (6000 miles) over a million year, isn't?

It's two times the distance from New-York to San Francisco, one fourth of the Earth circumference!

And the Cretaceous–Paleogene extinction event was approximately 66 mya.

Re: The Silurian Hypothesis (2020)

#115

Post by T-A »

throw310822 wrote: post #111
T-A wrote: post #108

Earlier quoted context omitted.

> Any small sculpture buried in clay can survive for an eternity. If it's made of granite, maybe. But how many granite sculptures have you seen? Sculptors tend to prefer prettier and more easily shaped materials, like marble and limestone. Those happen to be mostly calcium carbonate, just like bones and teeth, so section 1.2 in [1] (chemical dissolution in acidic environments) applies, along with section 1.3 and [2]…

> how many granite sculptures have you seen? We use enormous amounts of it in construction, cut to precise shapes. > just like bones and teeth Of which we have ample amounts of fossils. Even included in marble, which is itself hundreds of millions of years old. > it would not have stayed that way over tens of millions of years. So we don't have fossils from hundreds of millions of years ago? > Would bears endowed wit…

> We use enormous amounts of it in construction, cut to precise shapes.

The question, which you did not answer, was about granite sculptures.

We use enormous amounts of granite in construction, crushed and mixed with cement, sand, and water to make concrete. Larger irregular pieces are also used for roads (under the asphalt and mixed with it) and railways. Some regularly shaped objects made of granite are used in construction, which is not generally undertaken on the kind of waterlogged terrain needed for clay to sink in, and will be subject to weathering at the previously discussed rates, to the extent that they are not broken or recycled when buildings are torn down.

>> just like bones and teeth

> Of which we have ample amounts of fossils.

A few million, counting all fossils of all species which have existed over the past three billion years or so.

Humans are one out of the billion or so species which have lived on Earth [1], the ~200k years we've been around are less than a millionth of that time span, the vast majority of humans never make sculptures, and the vast majority of sculptures are destroyed within a few centuries. But here you are, complaining that we have no sculptures from tens of millions of years ago.

>> Would bears endowed with human-level intelligence want to wear clothes and boots?

> Absolutely if they had a civilisation capable of producing climate change.

Ah yes, I can totally see a bear going "OMG it's getting so hot, I totally need to wear some artificial fur over my own!"

> You keep repeating an argument that disproves the possibility of all fossils.

No. You keep ignoring the time scale, the dynamics and the odds.

[1] https://www.livescience.com/animals/how-many-animals-have-ev...

Re: The Silurian Hypothesis (2020)

#116

Post by xg15 »

masklinn wrote: post #87
xg15 wrote: post #81

Earlier quoted context omitted.

> There's a seam of volcanic mountains that runs down the center of the Atlantic Yeah, that's the pacific rim, which in some sense is the opposite of a volcano.

No the seam at the center of the Atlantic is a mid-oceanic ridge, and it’s very much like a volcano since magma comes out. Icelandic volcanology comes from it being on the ridge. There are ridges off of the US coast (Explorer, Juan de Fuca, Gorda) but the ring of fire which surrounds the pacific is mostly subduction areas.

Sorry, you're right of course (and yeah, the Pacific rim can obviously not be in the Atlantic, typed too fast there...)

With "opposite" I meant the role in plate tectonics, in that classical volcanoes seem to mostly appear near subduction zones or hotspot but not on the ridges from what I know. (Iceland being the exception, but even there it's because of a hotspot that happens to be located right on the ridge)

But I think the ridge system usually does not have volcanoes in the sense that there are magma chambers that fill up or cause eruptions. So the usual scenario of the "asleep supervolcano" does not apply.

> The supervolcano complex under the Pacific is one of the largest known in the solar system, however.

That sounds interesting. Do you have some links about that?

Re: The Silurian Hypothesis (2020)

#117

Post by graemep »

senshan wrote: post #49
graemep wrote: post #32

Earlier quoted context omitted.

I think there is no evidence for it, but I think the point of the Silurain hypothesis (which the article does not convey well) is that if there were such civilisations we would not know as its unlikely we would find any evidence.

So it not a falsifiable statement from the onset? https://en.wikipedia.org/wiki/Falsifiability

Its not, which is why it should not be treated as a theory. It is a speculation.

On the other hand, a claim that we are the first species on the planet to reach a particular point of development of civilisation (agriculture, cities, various levels of technology) is a falsifiable statement.

Re: The Silurian Hypothesis (2020)

#118

Post by nkrisc »

krapp wrote: post #93
amazingamazing wrote: post #22

Earlier quoted context omitted.

right, so how can one easily say this hypothesis is false? "advanced civilization" seems to be strangely characterized. would something a few steps above beavers be advanced enough?

When people speculate about "advanced" ancient civilizations they usually mean said civilizations had technology at least as advanced as our own if not more so like nuclear weapons, antigravity, modern manufacturing and engineering, etc. A hypothesis that millions of years ago humans or some progenitor could build rough shelters out of sticks isn't particularly interesting.

You don’t have to even hypothesize about other species that can create shelters out of sticks, they exist today.

Re: The Silurian Hypothesis (2020)

#119

Post by MrDrMcCoy »

xg15 wrote: post #116
masklinn wrote: post #87

Earlier quoted context omitted.

No the seam at the center of the Atlantic is a mid-oceanic ridge, and it’s very much like a volcano since magma comes out. Icelandic volcanology comes from it being on the ridge. There are ridges off of the US coast (Explorer, Juan de Fuca, Gorda) but the ring of fire which surrounds the pacific is mostly subduction areas.

Sorry, you're right of course (and yeah, the Pacific rim can obviously not be in the Atlantic, typed too fast there...) With "opposite" I meant the role in plate tectonics, in that classical volcanoes seem to mostly appear near subduction zones or hotspot but not on the ridges from what I know. (Iceland being the exception, but even there it's because of a hotspot that happens to be located right on the ridge) But I…

My recollection seems to have been from a very early story on the subject and got some terminology wrong. Apparently, supervolcanoes have to have had an eruption in the past of a certain magnitude in order to earn that title, and that hasn't happened yet. Pretty sure it was this: https://en.wikipedia.org/wiki/Tamu_Massif

Re: The Silurian Hypothesis (2020)

#120

Post by ben_w »

JPLeRouzic wrote: post #114
gorgolo wrote: post #112

Surprised so few are pushing back against some of the claims in this article. Eg that the entire surface of the earth gets replaced in a million years by tectonics. Many of the large plates are more than 1000km across, they’d need to be moving meters per year for that to happen. In reality it’s cm per year. Also typically it’s oceanic plates that get subducted and take material under the crust, not continental plates…

> Many of the large plates are more than 1000km across, they’d need to be moving meters per year for that to happen. In reality it’s cm per year. A plate moving one centimeter per year would move over 10,000 km (6000 miles) over a million year, isn't? It's two times the distance from New-York to San Francisco, one fourth of the Earth circumference! And the Cretaceous–Paleogene extinction event was approximately 66 my…

> A plate moving one centimeter per year would move over 10,000 km (6000 miles) over a million year, isn't?

No, 10,000 km is 10e6 meters, or 1e9 cm, so at 1cm/year it would take a billion years, not a million.

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