How Long Does Mass Extinction Take?
smithsonianmag.com
smithsonianmag.com
At least with geoscience, science journalists usually manage to get things horribly wrong. Judging from previous articles, Helen Thompson (the writer) looks like she might be a biologist instead of a geologist, but she nailed the subject matter, regardless.
With the decline in our birthrate, it will be interesting to see (from a historical perspective, I'll be long dead) if we die out, or if we get out of this funk we're in now.
Actually its a fun thought problem. How would we convey to a follow up intelligent species what we did wrong if things go bad?
Lets assume squid take over the planet (hey why not they're smart), what would we have to do to allow them to understand?
We have to control for a lot of situations: * Assume they don't consider past relics a heresy to their religion (assuming again that they even have a corrolary). If they're destroyed in that regard its pretty much wasted effort. * Try and assume how long it would take for intelligent life to re-appear. The timeline for this is somewhat critical to any decision we make on how we build a marker/library of "don't eff this up and get off this rock pronto". Or whatever we choose.
I'm sure there are more but I"m at work so not much time to devote to this thought experiment.
I don't remember any other game where I literally thought for like 10 minutes before making a choice.
And I've never heard a compelling response to that, so why do people still think leaving the planet is important for our survival?
The only scenario I can think of where a radiation-soaked pocket in the Canadian mountains is less habitable than "off planet" is when the Sun starts dying. But that's not really a pressing concern.
It was probably all heavily fictionalized, but I keep wondering what happens if some sort of mischievous version of Elon Musk really wanted to just start firing green stuff at that planet to see if any of it would stick.
* Temperatures nearly always below the freezing point of water, often several hundred degrees lower.
* Very small amount of air pressure, 0.6% that of earth, and no oxygen at all.
* Because of the two factors above, no liquid water at the surface.
* High levels of radiation directly from space (primarily the solar wind) to the surface, for lack of a global magnetic field. Astronauts visiting Mars will also need to protect themselves from this threat.
Poor defenseless moss. :)
http://en.wikipedia.org/wiki/Extremophile
Some organisms can already handle the radiation: http://en.wikipedia.org/wiki/Tardigrade
We could live in stations such as that and hop down to planets to mine new materials (or from asteroid mining) when we had to. The entire world's population could fit in about 30,000 of those stations (assuming it's designed for 140,000 people). Having the human race distributed across 30,000 stations scattered around the solar system / galaxy would certainly make the race more robust to mass extinction events.
The day we have ships that can get us to new planets will be the day there's no reason to go there.
Think of it like exploiting a very large asteroid for resources and shelter. ;)
I value the same things you mention, but don't know how much that tells me about deep future humans. I worry our ancestors of long antiquity might think, were they inclined, "Well, surely our far future descendants will still live in trees. I mean, there's fruit, protection from predators, sweet brachiation, what's not to like?"
On the other hand, we still get fruit from trees, and they make kickass forts, so I really don't have any idea. "Gravity wells" might indeed be the kickass forts of 22,014. :)
Even though Mars is clearly less habitable than Earth in general, the point is that the humans living there would be ready for it. If there were a disaster here that killed off most of our crops or something, society would collapse and have trouble recovering.
I think we should colonize Mars, not because things on Earth might become impossible, but just because it's another planet, suitable for some adventurous, hardy souls to colonize.
Having a self-sufficient population on (say) Mars would make it likely that some portion of human civilization would survive such a disaster. I guess you might argue that we could achieve much of the same effect by using the same technologies to establish self-sufficient populations in safe(r) locations right here on Earth: underground or deep underwater, for example. But those would still be more affected by local disasters than a colony off-planet would be, and I feel like it would be harder to recruit people to live there (and harder to guarantee that they were truly self-sufficient). As you say, Mars would attract the adventurous. The Underground Civilization Vault would just attract the astoundingly paranoid.
Just for perspective, 70,000 years ago a supervolcano eruption in Indonesia with global effects nearly wiped out the human race (http://en.wikipedia.org/wiki/Toba_catastrophe_theory). On the basis of genetic diversity studies, it's estimated that all but somewhere between 3,000 to 10,000 people were killed.
We may think ourselves immune from the consequences of a similar super-eruption today, but for most people in the world, people who aren't rich and who can't create a well-stocked underground shelter, the risk is very high.
Short list of extinction events: global nuclear war, major asteroid hit, deadly disease that can't be contained, skynet like scenarios if AI turns out to be possible, global warming making us go Venus like etc etc.
The chance of each of these events is very small (except probably the last one which many would say is almost certain), but why would you not hedge your bets? When colonization would be so cool - the final frontier after all.
Because there are actual, high probability problems that we could use the resources to solve. The events you describe having a severity enough to destroy every continent on earth are so unlikely as to be effectively impossible.
I'm not 100% certain on this, but all porcelain/ceramic pieces should be dateable through Potassium-Argon and Argon-Argon methods.
You'll never see it used in archeology as it's only useful for fairly old (greater than a few hundred thousand years) samples, but Potassium-Argon (and the complimentary Argon-Argon) is a _very_ common dating method for geologic samples.
Porcelain is mostly made from kaolinite, but usually includes quite a bit of various feldspars as well. I think (?) the process of making ceramics should get the feldspars involved up above the Curie temperature, if not entirely melting and re-crystallizing them.
If so, you should be able to date porcelain/ceramics in the far, far distant future.
That being said, it seemed to be posted with perfect timing; I was thinking about this walking to work today. What if all of these mass extinctions (hypothetically or other wise) were caused by some species on the planet similar to us. Granted there is NO EVIDENCE for this, but what if... It seems that all mass extinction events happen in similar ways, each time some parts of an ecosystem are disturbed and it collapses.
Then, the most highly adaptable (fungi, bacterium, viruses are the most due to their short lifespan) survive. It's interesting to note that it took 30,000 - 50,000 years for the humans to develop this extremely complex society and ecosystem. Perhaps so short that when if we were destroyed this very day nothing would remain, say from nuclear war. All of our buildings would decay and there would be very little remnant in the fossil record.
I am not claiming any of this to be true, nor do I even believe any of it to be true. It was just an interesting thought I had that horrified me, and I felt I would share it.
The other problem is location. Humans like to build on coastlines, and coastlines shift. We have very little evidence of ice-age era settlements today, but the few sites we do know of show that there were some pretty sophisticated societies around at the time. It's very likely that there are/were more sites, but today they're under a few hundred feet of water off our coasts.
As far as natural resources: apparently there are extensive empty holes in the ground around the great lakes that used to be full of copper ore, based on what's left in the walls. So much copper ore that the mining must have gone on for centuries, or involved tens of thousands of people. No one knows who did that, but a likely possibility is the Phoenicians during the Bronze Age. So that's one example of the type of evidence you're talking about, albeit for a more recent period. To go back much further, we'd have to know what kind of resources they were after and where, and hope that the landscape hasn't changed so much that we can't recognize the evidence of resource mining.
That said, it's super unlikely that all, or even most traces of humanity will be gone. As you point out, the redistribution of resources - most specifically our landfills will probably be clear signals on the time scales of at least 10s or maybe 100s of thousands of years.
Still a fascinating question, mind you! (But honestly, I'm dubious that anything humanity could do today would lead to a Permian-scale mass extinction. That one was remarkable.)
That reminds me of something:
> The [Science of Discworld] also features a fictional crab civilization and the dinosaurs (both of which are wiped out by comets/asteroids colliding with the earth), before jumping ahead to when an advanced civilization (presumably humans) has evacuated the earth due to an impending natural disaster.
http://en.wikipedia.org/wiki/The_Science_of_Discworld
Anyway, I wouldn't be surprised if (for example) the field of astrobiology is thinking about what could be used as indirect proof of intelligent lifeforms tampering with an ecosystem. Also, while you are obviously are aware of this, I think it's worth emphasizing that all mass extinctions showing a similar pattern is not a proof agency.
So I guess we'll be finding out shortly (i.e., the next 100-1000 years)