Spurred on by a comedy bit I saw on stumbleupon, I started wondering.
How does humanity meet its end? Obviously, there’s no way of knowing, but what do you think would be at the top of the Vegas odds, if there were any? (Maybe there are…)
For instance, it’s pretty much a sure bet everyone on Earth would die when the Sun goes out. However, it seems pretty likely to me that we’ll all be killed off long before then, too. Or, if not, that we’ll be colonizing other star systems or something by then. That’s what, tens of millions of years away? Color me optimistic.
On the other hand, it’s got to be pretty much a given that we get annihilated by a huge rogue asteroid or comet long before then, right? Does that get higher odds, given both the near certainty of the event, and the likelihood it happens while our species remains Earthbound?
How does that stack up against an un-survivable virus? Or thermonuclear armageddon? Or the return of Quetzalcoatl?
I put a lot of stock in the Peak Oil scenario, but more as a civilization crusher than an E.L.E.
What say you?
For reference, the article that generated this morning’s coffee house argument can be found at http://afreakshow.com/articles/how-will-the-world-end-in-2012/. Although, you might want to give it a pass, since it takes a much more cavalier look at this Very Serious Business.
As you’re new here, I’ll just point out that there is no factual answer to your question, and so I expect a mod to move this thread either to GD or IMHO. This forum is only for questions with factual answers.
I don’t think sensible odds can be given on most civilisation-ending disasters. The one we probably have the best handle on is the chance of getting hit by a large asteroid or comet, by surveying the solar system and extrapolating from the rate of past cratering events. I don’t know how to begin estimating the odds of us being wiped out by a nuclear war, virus or supervolcano.
It’s not a smart bet to make, due to the difficulty of collecting if you are right.
The Earth is quite infested with humans. They live and thrive in almost every available place, from the cold and barren to the hot as hell. They are harder to get rid of than bed bugs. They are cunning and adaptable. You’ll find it easier to just move to a planet without them.
To eliminate them all from every island, forest, tundra, desert, antarctic outpost, etc is going to take an event that will also kill almost every other form of life on Earth.
An asteroid the size of the one that supposedly ended the reign of the dinosaurs isn’t even going to come close. You need something much bigger, big enough to reform the surface of the entire planet, or there will be some, somewhere that will survive.
And the nuclear war scenario is laughably weak. If every weapon in all the current stockpiles were fired in one last whoop-ti-doo there will survive several hundred millions of the things around the globe. Probably in the 1 to 2 billion range. And those humans are horny little fuckers and the population will bounce back as food supply and infrastructure is rebuilt.
I think we are going to have to learn to live with them until the Sun sterilizes the planet. By then some of the little bastards may have hitched a ride somewhere else and we’ll never be rid of them.
Even odds on a potentially hazardous object (PHO) impact are highly speculative. Most of the interplanetary objects that would result in an extinction-level scale of damage are visible and calculable. Smaller PHOs (~1 km or smaller) could do a massive amount of damage that might result in unprecedented fiscal loss, regional destruction, and potentially set back industrial civilization by a few decades, but would probably not cause the literal end of the world (or complete destruction of humanity). Of course, there is always the rogue extra-solar planetoid that enters the system at an oblique angle to the ecliptic and intercepts the Earth which we’d never see until it was too late, but the odds of that are enormous and probably less likely than other extra-solar threats like gamma ray bursts (GRB) or traveling through unseen high density gas clouds.
Please tell me that astronomers are on the look out for this. :eek:
I mean, I’d be great to get a warning if this is about to happen, rather than suddenly experiencing mass die-offs without a clue as to what’s happening.
A supervolcano, you can estimate, or at least you can estimate your chance of dying from it. It’s harder to figure out if it would end civilization or not (or what “the end of civilization” means, exactly).
Yellowstone erupts about once every 600,000 years. To make the math easier, let’s pretend it has the same chance of erupting in each of those years, for a 1 in 600,000 chance of erupting this year. I’ve seen estimates that an eruption could kill about a billion people (including deaths from volcanic winter). We’ll call that 1/10 of the world population, just to make the math easier. Assume that everybody in the world has about the same chance of being killed by Yellowstone (again, just to simplify things). You get a 1 in 6 million chance of being killed by a Yellowstone supereruption in any given year. It’s far from an exact calculation, but it’s probably at least somewhere in the ballpark.
Well, if the gas clouds really can’t be seen, keeping a look out for them wouldn’t do much good. I’m not the kind of astronomer who studies the interstellar medium and gas clouds, so I don’t know how hard they actually are to find.
Also, what good does it do to say that doom is coming from something like this, if there’s nothing we can do about it? There’s absolutely no way to deflect an interstellar cloud. They’re diffuse and several thousand times more massive than the Sun.
Another possible scenario of impending astronomical doom is a long-period comet coming right at us. Comet Hale-Bopp was a long-period comet, with a nucleus about 40 km in diameter. That’s larger than the asteroid that wiped out the dinosaurs. We discovered it about two years before it got to perihelion. It could have been headed right for Earth, and there would have been nothing we could do about it if it had been. We’d have known that something worse than the extinction of the dinosaurs was coming in about two years.
People aren’t at their best when they think they’re going to die soon. I could see civilization collapsing just from knowing about inevitable impending doom. You wouldn’t be terribly motivated to get up and go to work tomorrow if you knew everybody on Earth was going to die in two years, would you? If enough people stop doing the work that civilization needs to continue, it collapses.
I don’t actually think astronomers could hide something like this, though. They certainly couldn’t cover up a comet. Anybody with a telescope can look for one, and many people who are not professional astronomers do. Presumably an interstellar cloud would cover up stars as it got closer, and people could see that.
There’s no central organization of astronomy that could enforce secrecy on something like this. Astronomers are employed by universities or in some cases governments, not by some central world organization of astronomers. The IAU or one of the astronomical societies could tell people not to leak the secret, but there’s not much they could do to someone who didn’t listen to them.
I wouldn’t say speculative, as it’s possible to carry out a statistical analysis and come up with a sensible figure for, say, the average time between chicxulub level impacts. The error margin would be considerable, but we aren’t talking orders of magnitudes here. Of course, we don’t really know what level of impact is survivable, but again a sensible estimate can be made.
By comparison, trying to work out the odds that humanity will be wiped out by a nuclear war in the next million years would be pure speculation.
As you say, the odds are very low, as we have yet to detect a comet with a likely extra-solar origin. We can say with confidence that the odds of being hit by an extra-solar object are very small compared to those of being hit by something in a solar orbit.
Yes, it’s possible to roughly estimate the time between supervolcano eruptions, but I don’t think one has ever been connected with a major extinction event. While they have the potential to devastate the planet, it’s not clear if one could actually wipe us out.
It wouldn’t have to be of extrasolar origin. There’s no indication that Comet Hale-Bopp was, and we didn’t discover it until two years before perihelion. We’re working on getting a good comprehensive list of Earth-crossing asteroids. We’re a lot farther from getting such a list of Kuiper belt objects that could hit Earth.
Yes, but I doubt a similar eruption today would threaten us with extinction, given how widespread we now are and given our level of technology. 70,000 years ago we were confined to Africa, and agriculture had not been developed.
True, but I thought we had enough information to make an order of magnitude estimate of how often comets strike the Earth. Is this not the case?
I’m not so sure. Having humans in more parts of the world is going to be an advantage to us, yes. But supervolcano ash screws up transportation, and a lot of us rely on food and other stuff transported from somewhere else.
If Yellowstone goes off, it’s going to wipe out the US and Canadian wheat crop, probably for several years. The volcanic winter could affect the whole northern hemisphere, which includes Russia, China, the EU, and India (the other major wheat producing countries).
Extinction, ok, probably not. The end of civilization as we know it, maybe.
We can. Phil Plait did, in his book Death from the Skies. I’m going to look it up when I get home.
The speculative nature comes in a very incomplete data set. Even our catalog of Near Earth Objects (NEOs) continues to evolve, and our catalog of long period comets and other objects is very limited due to the relatively short period of time that we’ve been making systemic observations.
Posterior probability calculated by Bayesian inference is almost just as variable, insofar as our knowledge of impacts is also limited. The Chicxulub crater was only discovered in 1978 and only by accident; impacts in other areas, and especially in mid-ocean, may not be identified, and the fact that known, recordable events occur as extreme outliers of all potential impacts (so-called “black swan events”) limits the ability to develop a statistical distribution with useful confidence levels. Such events may only occur at a mean interval of, say, fifty million years, but the probability of one occurring may be much higher than suggested by a Gaussian distribution of the existing data set. Any statistical estimate we make about the probability of impact based upon current data has error intervals that are large enough to easily be off by a couple of orders of magnitude.
As for molecular gas clouds, we would anticipate seeing something the size of a planetary nebula, both by obscuration of the background and by internal luminescence. We might not see a smaller, cloud that is nonetheless large enough to damage the upper atmosphere and obscure the Sun, and there is no way we could deflect or otherwise disrupt such a threat. The only recourse would be to escape the Earth.
It’s obvious the world will end when the sun finally engulfs it and not before.
What you probably meant to ask about was the odds on how humanity will end.
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My guess on how humanity will end is - evolution. We will simply not be human (as we recognize it today) any more.
It seems obvious to me that sometime in the next 100ish years our current civilization will crash and burn. We’ll run out of oil, the yellowstone volcano will erupt, the zombies will rise, etc.
When this happens the population will crash. Humanity will limp along for a bit and rebuild.
Lather, rinse, repeat.
As mentioned above; life will hang on given even the smallest chance and humanity is nothing if not adaptable.
