So I’m reading this thread about a potential eastern-seabord destroying tidal wave and I get to thinking.
Should a large asteroid impact earth say, in five years time…
Could we, as a species survive the event and following problems using technology? What would be required to do so?
Could we survive a dinosaur killer? Well, most of us would. I wouldn’t however, since (in my kids’ eyes) I’m a dinosaur. 
Seriously, however, there are just too many factors to take into account - size of the rock, location of the impact, angle of impact, etc. In any event, according to the NEO monitoring people, there are no significant threats looming until March 16, 2880, when there is a 1 in 300 chance that 1950DA could hit us.
Zev Steinhardt
No known significant threats, zev, and that’s a significant caveat.
The short answer to the OP is “yes,” IMHO. But for a great many years afterward, life would seriously suck.
Consider an asteroid the size of a small mountain - a kilometre across, say. There may be millions of such asteroids in the solar system, utterly unkown to us. Should one head directly towards Earth it would noly become visible a few days before impact, and even then only if someone had a telescope trained directly on it, which is highly unlikely given that the number of such dedicated asteroid scouts worldwide is not much more than the staff of a single McDonalds outlet.
It would become visible to the naked eye one second before impact. It would compress the air to a temperature similar to the sun’s surface, and blow out 1000 cubic kilometres of rock upon impact. A wall of death travelling at 1000 mph would spread out and kill everything within 1000 miles.
Volcanoes, tsnuami, earthquakes and burning rock storms would kill around 1 billion people on the first day. The winter caused by the soot would last ten thousand years. Could we survive this? I’m not sure - it would certainly involve much hardship.
An asteroid this size crashes into Earth roughly once every million years.
The Chicxulub asteroid which killed the dinosaurs was TEN kilometres across.
No chance!
True enough, and I should have been clearer.
Of course, in any event, we’re not likely to have much notice anyway if it happens. Most of the rocks flying around out there are pretty dark and are usually not noticed until they are pretty darn close.
Zev Steinhardt
Actually, further consideration yields some possibilities. Some places such as New Zealand appear to have been sheltered from the worst of the devastation, even to the extent that plant growth might have been possible. Also, the sulphuric acid rain capable of burning through skin might only have lasted a few months, and geothermal and nuclear power plants could perhaps function in the dark millennia and grow food hydroponically.
I seems that humans might just be part of the 10% of land-dwelling species which survived, although the bottleneck might comprise no more than a few thousand individuals worldwide. (Such a bottleneck already happened just seventy thousand years ago, incidentally.)
To put it another way, why should we fare any better than the dinosaurs? Just because we have some level of technology? Fiddlesticks. Our technology is pitiful comparied to the kind of global destruction we’re talking about. As Sentient Meat points out just up there ^, there may be some survival level but only from good luck.
pan
Wow! That link is really interesting. There were only 2000 individuals left! One wrong move and we’d have been doomed. That’s a thought for all those that argue that species that become extinct are just evolutionary dead-ends anyway.
pan
I find that story very hard to believe.
Why? Do you disgree with the methodology or the conclusions, or both?
Do you have a good, informed reason why?
Quite. Everything becomes such an ‘evolutionary dead end’ eventually: 99.99% of species that have ever lived are no longer with us. Complex species have an average lifespan of around four million years.
The human species has been around for roughly four million years. Let us make hay while the sun is not obscured by a three mile thick mass of toxic dust.
Look, in the event of a large Meteor crashing towards Earth, all one has to do is cast Holy and the problem is solved.
Well, maybe. It never was really made very clear, was it?
Seriously, I think there are too many variables. Technological progress at time of impact, how long the impact has been known about, what can be done to the rock before it gets to Earth, and so on.
There was a good article in Scientific American describing what it was like on Earth during and just after the Chicxulub impact.
Yow.
If you were anywhere near the point of impact, forget it, you’re plasma. It was about a 500 gigaton expolsion.
After that, the great majority of the Earth’s surface that could burn was on fire, due to enormous amount energy transmitted to the upper atomosphere, and the millions of tons of super-heated rock and dust that the meteor sent into partial orbit, later to come raining down anywhere from near the crater to clear around the globe. In other words, over most of the world, the atomosphere was temporarily heated to the point that green vegetation would simply burst into flame. Soon after, the debris, smoke, and soot lofted by the impact and the ensuing global conflagration covered the skies, reflected most of the Sun’s energy, and plunged most of the planet into a deep freeze that lasted for decades.
It’s a wonder anything survived at all. I suppose a lucky few housed in deep shelters underground with provisions for, oh, a couple centuries, might be able to survive, procreate, and re-establish the human species. It’s a fair bet that almost everyone above ground would perish, either very soon after the impact, or due to starvation in the ensuing global winter.
Loopydude, I’m not sure I buy that description of events. After all, not all species died- not even all large species. Crocodilians, for example, survived. How could they have made it through the conditions you describe?
How could any land-based mammals have survived such conditions? (E.g. a global atmosphere hot enough to cause green vegetation to burst into flame?)
How could birds have survived?
Just not sure I buy that scenario.
I think at least a few humans would survive. Our brain-enabled adaptability is our great feature, and one which certainly separates us from the dinosaurs. i see no reason at least a small number of humans couldn’t build some sort of life for themselves, even if primarily underground.
I think humans as a species could handle a large scale disaster, and not just because of our intelligence (though that is our single best advantage over every species that has come before us), but also we have several other factors in our corner. We are omnivorous, and can eat a wide variety of foods. Humans are also very disbursed geographically, with significant populations on every landmass except those in the Artic & Antartic climes. Even if just one small area like New Zealand, or Hawaii remains habitable, then humanity can continue on; we have surived bottlenecks before.
I guess some places on the planet escaped the direst conditions. BTW, I misquoted the size of the blast: It was a 100 teraton explosion. The 500 gigaton figure was from another article that I read on the web, from much earlier, so it looks like they underestimated the blast by a few orders of magnitude.
I can’t link to the whole article, because you need a subsription, but you can read the first couple paragraphs and download it if you’re willing to pay:
http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=0006BD07-8711-1FA2-85B083414B7F0103
SciAm is generally a very reliable source of info; at least, it’s as reliable as any other outlet for current views in science. It takes a considerable level of authority in a subject to author an article in that mag, and I think the estimates of the impact energy, coupled with what that would lead to in terms of heating the atomosphere, is supported by the geology. It’s been known for a couple decades that a layer of soot covered the entire planet around the time of the Chicxulub impact (the so-called K-T boundary), and as that layer contains enriched amounts of iridium, it was hypothesized that a meteor impact was the culprit. I think until the crater was discovered and fully mapped out, it perhaps wasn’t known just how great a catastrophe that impact was, but it was known that something big and bad happened, and that it had devastating consequences, given the mass extinctions that followed.
Just imagine: An explosion about ten million times bigger than that produced by a hydrogen bomb. The first hydrogen bomb detonated (ten megaton) literally vaporized the island of Elugelab, and left behind a crater about 3km wide and 1km deep. So multiply that by ten million times.
I can’t even comprehend what it would be like to witness one hydrogen bomb explosion. The Chicxulub impact was a holocaust event beyond our worst nightmares.
In North America (specifically, one site in North America, the Hell Creek Formation in South Dakota), which was obviously fairly close to the impact site (considering its size), huge wildfires, as just one proximate killer resulting from an ultimate extraterrestrial cause (and also implicated in supervolcanism), should have wiped out most everything. Yet amphibians, mammals, bony fish, turtles, champsosaurs and crocodilians all survived, while sharks and other elasmobranchs, marsupials, lizards and dinosaurs died out or suffered very heavy losses. This pattern doesn’t fit the “global wildfire” scenario. Nor does it fit the “acid rain” or “nuclear winter” scenarios. Indeed, the ultimate cause which most neatly fits the survival pattern in this region is neither supervolcanism nor asteroid impact; rather, it is seaway regression.
While the Chicxulub impact was certainly no picnic, we simply lack sufficient evidence to claim with any certainty that it was responsible for the whole, or even the majority, of the numerous extinctions at the end of the Cretaceous. Everyone likes to focus on dinosaurs, but there were several groups that died out completely, and others that suffered significant losses, while yet others breezed through.
The impact may have combined with, or possibly even initiated, the massive volcanic plumes which were also occurring at around the same time. But we lack sufficient resolution in the fossil record to be able to identify a timetable of extinctions, in order to determine if they happened quickly (on the order of a few hundred years, perhaps, if impact were the primary cause), or were more prolonged (over a few millenia, perhaps, if volcanism was primarily responsible for most of the deaths, or likely even longer for seaway regression).
So, a Chicxulub-sized impact would be tremendously devastating, but would also obviously be survivable. The problem is, we don’t know what the “trick” to survival really is at this time. So we also can’t really say whether humans would be among those lucky enough to survive the next such impact.
I’m under the impression that the global wildfire scenerio is informed at least in part by the physics of the impact. Simply put, the Chicxulub impact released vast amounts of energy, and knowing what we know (which admittedly may not be enough, given the complexity of atomospheric physics) about how that energy would have been dissipated, it appears that a global conflagration is a likely result.
So which school of thought is wrong: The one that says global wildfires cannot account for the survival of certain species, or that special circumstances spared some animals from the holocaust, and some fraction of those were obviously resilient enough to survive the subsequent changes in global climate?