A current xkcd forum thread is discussing the possibility that a spacefaring civilization could have arisen many millions of years ago on Earth but it was so long ago that we can’t see any fossil evidence for them. One counter-argument is that we’d know about them, no matter how carefully they cleaned up after themselves, because they would have depleted Earth’s mineral reserves. What do you reckon?

Kingy said:

Possible, I guess.

I did read an article about our civilisation, and if it went tits up and we went back to the stone age, it would never rise again because there would be no easily available metals.

furious said:

• it would never rise again because there would be no easily available metals.

Why, where did they go?

dv said:

A sufficiently advanced civilisation would not need to do any mining at all so that’s not a very good point in itself, but there would certainly be evidence of cities, unless they really did a superb job of deliberately cleaning up after themselves.

The raptors had a massive world war 65 million years ago and then fled in a handful of ships that down,t really dip into the worlds resources too much.

dv said:

There are easily available metals in rubbish tips all over the world…

There would be something in the fossil record. There are 100 million year fossils showing fine details and soft tissues, so any randomly lost spanners made of unobtanium would be in the geological record.

I think a sufficiently advanced civilisation could cover their tracks if suitably motivated, but a close eye would still note extinctions in the fossil record, gas exchange markers etc. Perhaps they could make these look like a natural catastrophe.

Is a bone more, or less, likely to be preserved in the fossil record than a bolt?

morrie said:

If they arose on earth, then they would have had to go through a mining phase.

Visitors might be a different story.

That’s what I thought.

But I guess there are places with lots of minerals that we haven’t yet touched, like nodules on the ocean floor. And if it was a very long time ago, they could’ve mined mountain ranges that no longer exist.

• Perhaps they could make these look like a natural catastrophe.

Like a comet (or whatever it was} impact?

Is a bone more, or less, likely to be preserved in the fossil record than a bolt?
—

Phosphatic bones are actually pretty hard to preserve but we still have some fossils because there have been so many billions of living things.

A steel bolt will of course rust away eventually but one can imagine circumstances where it would leave a cast.

Why did they limit it to millions of years ago? What about a billion? Large meteor wipes out all organisms larger then a microbe. Wipes the fossil slate clean.

Kingy said:

There would be something in the fossil record. There are 100 million year fossils showing fine details and soft tissues, so any randomly lost spanners made of unobtanium would be in the geological record.

we have a fossil record that stretches back 3.4 billion years and a mineralogical record that dates back 4.0 billion years. It would be très hard to hide all evidence of an advanced civilization.

PM 2Ring said:

morrie said:

If they arose on earth, then they would have had to go through a mining phase.

Visitors might be a different story.

That’s what I thought.

But I guess there are places with lots of minerals that we haven’t yet touched, like nodules on the ocean floor. And if it was a very long time ago, they could’ve mined mountain ranges that no longer exist.

They would not have had the advantage of coal and oil as fuels perhaps.

dv said:

I think a sufficiently advanced civilisation could cover their tracks if suitably motivated, but a close eye would still note extinctions in the fossil record, gas exchange markers etc. Perhaps they could make these look like a natural catastrophe.

Maybe the Chicxulub impact event happened when an asteroid mining venture went horribly wrong.

(semi-TIC)

And if it was a very long time ago, they could’ve mined mountain ranges that no longer exist.
—-

Unless we are really, really mistaken about life on earth, it could not possibly have been older than the Cambrian.

But (shrugs) the fact that they were an advanced civilisation doesn’t mean they would have completely removed all minerals. (Obviously, new ore bodies, coal and hydrocarbons have formed since the Cambrian, but let us assume that the question is about whether the appearance of an advanced civilisation in a given epoch would cause suspicious depletions in the geological record before that epoch.)

“ It would be très hard to hide all evidence of an advanced civilization.”

Well, how advanced? If they were sufficiently advanced they could do anything. They could completely remake the crust. They could be godlike.

>But (shrugs) the fact that they were an advanced civilisation doesn’t mean they would have completely removed all minerals.

We’re a fairly advanced civilisation and I doubt we’ve remove all the minerals. If we we wiped out on the morrow could a new species spring up and prosper on what we have left over?

sibeen said:

Why did they limit it to millions of years ago?

They didn’t.

sibeen said:

What about a billion? Large meteor wipes out all organisms larger then a microbe. Wipes the fossil slate clean.

Sure.

But if we go back too far we don’t seem to have enough time to allow a highly complex biosphere to evolve. Also, lack of fossil fuels may slow down development of an industrial civilization, but I guess that’s not really an insurmountable problem.

We’re a fairly advanced civilisation and I doubt we’ve remove all the minerals.
—

I doubt that too.

dv said:

And if it was a very long time ago, they could’ve mined mountain ranges that no longer exist.
—-

Unless we are really, really mistaken about life on earth, it could not possibly have been older than the Cambrian.

But (shrugs) the fact that they were an advanced civilisation doesn’t mean they would have completely removed all minerals. (Obviously, new ore bodies, coal and hydrocarbons have formed since the Cambrian, but let us assume that the question is about whether the appearance of an advanced civilisation in a given epoch would cause suspicious depletions in the geological record before that epoch.)

Yeah, the suspicious depletions thing is my favourite angle of attack. But I am not a geologist-type person, so I really don’t know how obvious that sort of thing is.

In my post you quoted above, I also meant to include mountain ranges that are currently underneath the ocean, as well as ones that have been eroded or subducted.

Basically…

I think a fairly advanced civilisation would leave evidence, but an amazingly advanced civilisation with powers far beyond ours if suitably motivated could cover its tracks.

dv said:

Basically…

I think a fairly advanced civilisation would leave evidence, but an amazingly advanced civilisation with powers far beyond ours if suitably motivated could cover its tracks.

David Brin’s fallow worlds, for those that know the series.

Why on Earth would they want to cover their tracks? Makes no sense.

Why on Earth would they want to cover their tracks? Makes no sense.

—

If humans are anything to go by, advanced civilisations sometimes do things that, when viewed from outside or in hindsight, seem baffling.

dv said:

Basically…

I think a fairly advanced civilisation would leave evidence, but an amazingly advanced civilisation with powers far beyond ours if suitably motivated could cover its tracks.

Ok. But then we have the question of why they left without a trace and never drop by to visit. Although I guess they could’ve left us a monolith or two somewhere in the solar system.

Bubblecar said:

Why on Earth would they want to cover their tracks? Makes no sense.

Why on Earth indeed.. perhaps earth itself covered their tracks?

sibeen said:

dv said:

Basically…

I think a fairly advanced civilisation would leave evidence, but an amazingly advanced civilisation with powers far beyond ours if suitably motivated could cover its tracks.

David Brin’s fallow worlds, for those that know the series.

I had in my mind’s eye some beings that resemble us. But we evolved from apes. There are no older ape records, so they would have had to have evolved from something else. And then covered up all the fossil record of that evolution.

Ok. But then we have the question of why they left without a trace and never drop by to visit
—

(shrugs) Religious reasons?

if they depleted a certain substance, wouldn’t they be no trace?

sibeen said:

dv said:

Basically…

I think a fairly advanced civilisation would leave evidence, but an amazingly advanced civilisation with powers far beyond ours if suitably motivated could cover its tracks.

David Brin’s fallow worlds, for those that know the series.

I’ll pay that. But in the Uplift Wars even badly damaged planets are only left fallow for 50,000 years, IIRC. I don’t think there’d be a lot of benefit in leaving them fallow for hundreds of millions of years, although I guess it does give them time to accumulate new fossil fuel reserves.

>If humans are anything to go by, advanced civilisations sometimes do things that, when viewed from outside or in hindsight, seem baffling.

Nah, we make no effort to cover our tracks. Indeed we do the opposite, hoping that our best achievements will last for as long as possible.

Ancient superintelligent critters being anxious to hide any evidence of themselves for future species makes even less sense than the idea that there are flying saucers out there right now deftly evading any positive proof of their existence. It’s just nonsense.

Bubblecar said:

Why on Earth would they want to cover their tracks? Makes no sense.

As others have said, who can fathom the minds of god-like beings?

Maybe they wanted any subsequent intelligent lifeforms to have a fresh start, and not feel like they were merely following in the footsteps of greater beings.

>As others have said, who can fathom the minds of god-like beings?

Bah.

Are there any SF books on this subject?

CrazyNeutrino said:

Are there any SF books on this subject?

Sort of.

>If humans are anything to go by, advanced civilisations sometimes do things that, when viewed from outside or in hindsight, seem baffling.

Nah, we make no effort to cover our tracks.

——
I did not say that we make efforts to cover our tracks, so your “Nah” seems inappropriate.

It is obvious that we’ve done baffling things. Humans spent 15 trillion dollars building a nuclear armaments system that could eliminate the species but that they had no intention of using. We’ve dedicated vast resources to ends that are pointless, ultimately.

These psychological or motivational objections that you raise don’t make any sense. They could only be relevant, in discussion of a putative prior advanced civilisation, if it could be shown it would be impossible for such a race to be motivated to eliminate evidence of itself. I think “religion” or “politics” could explain most otherwise inexplicable behaviours.

Metallic aluminium and titanium.

Neither metal is found chemically uncombined in nature. Both metals are chemically protected by their hard, inert, high melting point, instantaneously formed, thin oxide coating.

Basically, I would expect to see coke cans or similar in the fossil record.

Michael V said:

Metallic aluminium and titanium.

Neither metal is found chemically uncombined in nature. Both metals are chemically protected by their hard, inert, high melting point, instantaneously formed, thin oxide coating.

Basically, I would expect to see coke cans or similar in the fossil record.

So that fossil of T Rex holding a ciggie and can of coke is true?

It might be easier to find to evidence of their activities on the moon.

One of the most lasting effects of human civilisation might the globalisation of certain animal and plant species.

there would have been a clean up then the earth watched for excavations/ strange stuff being dug up

if you could get to the humans before the message was spread you might be able to contain the truth, the brain might be given some temporary amnesia, de ja vu and the like are echoes of the brain being tampered with to keep the continuum going.

assuming that the level of surveillance was beyond even our basic NSA type it would be easy to keep the lid on discoveries that could change our history.

of course you’d need to control the minds of geologists

geologists that stumble on other evidence or suspect that something is amiss get disappeared to Singapore, coal fields or the like where they can be reprogrammed in vast alien bases that turn out to be very lucrative enterprises.

The only (remote) possibility would be if the species lived in a subduction zone, where all traces of them have since been recycled.

http://en.wikipedia.org/wiki/Subduction

wookiemeister said:

of course you’d need to control the minds of geologists

geologists that stumble on other evidence or suspect that something is amiss get disappeared to Singapore, coal fields or the like where they can be reprogrammed in vast alien bases that turn out to be very lucrative enterprises.

.

Hahahahaha!
Nice work… :)

the rest could be held captive on internet forums effectively in stasis until woken to the terrible truth by the beautiful wookiemeister

you might know wookiemeister from such as

white paint – the short term answer to global warming

the meaning of life not 42 but the unemployment level of 5.5 % (also see government theory)

management theory 1 and 2

government theory

why democracy in Australia doesn’t exist

how military programmes and societies are sabotaged (see sun Tzu – the art of war)

how solar power can already power the world and why solid state renewables are the logical power supply

the theory of the law

The Internet Ecosystem
http://imgur.com/gallery/5sxCM

honey badger doesn’t care, just re images the computer

honey badger would like to re image the internet, but the upload speed is too slow

Is honey badger like honey boo boo?

Honey badger doesn’t give a shit.

Divine Angel said:

Honey badger doesn’t give a shit.

exactly

:)

How does it pass solid waste ?

The honey badger (Mellivora capensis), also known as the ratel (/ˈreɪtəl/ or /ˈrɑːtəl/), is a species of mustelid native to Africa, Southwest Asia, and the Indian Subcontinent. Despite its name, the honey badger does not closely resemble other badger species; instead, it bears more anatomical similarities to weasels. It is classed as Least Concern by the IUCN owing to its extensive range and general environmental adaptations. It is primarily a carnivorous species and has few natural predators because of its thick skin and ferocious defensive abilities. It is famed for not giving a fuck, hence the expression “I couldn’t give a mad badgery fuck”.

Honey Badger
http://www.youtube.com/watch?v=4r7wHMg5Yjg

Divine Angel said:

Honey Badger
http://www.youtube.com/watch?v=4r7wHMg5Yjg

Could you link that for me please

Dropbear said:

Divine Angel said:

Honey Badger

Could you link that for me please

no one tells honey badger what to do

That’s a bit mean. Is honey badger meant to work out everything by herself?

PM 2Ring said:

dv said:

I think a sufficiently advanced civilisation could cover their tracks if suitably motivated, but a close eye would still note extinctions in the fossil record, gas exchange markers etc. Perhaps they could make these look like a natural catastrophe.

Maybe the Chicxulub impact event happened when an asteroid mining venture went horribly wrong.

(semi-TIC)

i’m sorry but I would have to disagree, the body in charge had done everything by law to make sure that the risk assessment had been put together in the appropriate way, from a risk assessment perspective it all went to plan.

We have developed metals that don’t degrade easily