So…when the giant meteor strikes, how will you die? There’s actually a study of potential deaths in an asteroid impact. I guess it shouldn’t surprise anyone, but the odds of being instantly disintegrated because you are replaced by a crater are very low; the most likely cause of death is from violent winds and the shock wave. Your house, for instance, will be shattered and you’ll just be one more piece of debris flung outwards amidst a tumbling mass of jagged shards of wood and metal and stone.
This study only analyzed short-term consequences, though. I suspect that even more deaths would follow from exposure and starvation and disease and roving feral gangs of Trumplicans.
And stampeding dinosaurs don’t even get a mention!!!
Earth’s “half-life” for large extinction-level impacts is about 5×10^7 years. It’s a virtual certainty to happen (more than once) before we get swallowed by the red giant formerly known as the Sun.
Don’t worry. I have a plan to get Putin to launch all his nukes* at the rock beforehand, so it’s slightly warmer when it hits us.
* Even his North American ones.
I’m disappointed in the way the researchers chose only 3 meteor sizes, and even there, scaled them not linearly by mass, but (seemingly) arbitrarily by diameter.
With more data points plotted against a linear scale, it would be very interesting to see if death tolls rose linearly as well; or if, at some point, they jump from “wow – that’s a lot of dead people” (say, 200 million) directly up to human-extinction level, 7 billion. It’s hard to conceive of a middle-ground impact – something capable of killing 2 billion people that 5 billion others somehow survive.
And, echoing PZ, I’m disappointed they didn’t account for longer term deaths, specifically “loss-of-infrastructure”, climate impact, etc. I’d imagine mortality rates for the 10 years after the 400m impact would be many times higher than present day.
Call me stupid, but what’s the difference between “shock wave” and “wind”? Maybe it’s the language barrier, but to me, any “wind” strong enough to knock me off my feet would be part of a “shock wave”… Or I may have my concepts completely wrong.
I presume the shock wave is a pressure wave.
A shock wave is short, isolated event cause by a supersonic disturbance. The wind is just.. the wind.
I can’t resist a hat tip to Lars von Trier’s Melancholia:
Shock waves are cause by supersonic velocity. Wind is subsonic. When a rock or an airplane or a rocket travels faster than sound the air can’t get out of the way fast enough and piles up in front of the moving object and propagates at the speed of sound.
It’s the difference between a hurricane and a sonic boom.
A big rock will cause the mother of all sonic booms.
Explosions also create shock waves and Atomic and Hydrogen bombs create ones that do most of the immediate damage from them. The shock waves from a big rock will dwarf the ones from Hydrogen bombs.
A hurricane force wind clocks in at 75 miles per hour or more. Tornadoes reach 300 m.p h. in their centers.
Shock waves propagate at the speed of sound.
Bill Buckner @ 2. Hah! Looks like the joke will be on the sun.
@5 A wind will knock you down, a shock wave of the size this would create would cause massive internal bleeding in your lungs (and other tissue), because it compresses you as it moves through you. This is what kills people in large explosions, not debris. See https://en.wikipedia.org/wiki/Pulmonary_contusion
Thanks all for the explanations. :)
My old atomic bomb calculator had the ability to calculate how fast glass was likely to be moving when it went through you, depending on blast size and distance from center (along with thermal radiation) – it was pretty scary stuff: if you were far away enough that the flash wouldn’t set you on fire, you’d still get pelted with glass going 50mph. I assume the shockwave from an asteroid would throw cars and trees at much higher speeds, much farther out.
I have an article somewhere in my “gee wow” queue (been meaning to post a blog entry on it) that the rebounding rock and material from the Chixculub event would have made a temporary ring a bit taller than the Himalayas, but it would have fairly quickly collapsed in on itself because it wasn’t solid rock anymore. That is one hell of a “splat mark” by any measure.
I’m reminded of the bad joke: “what’s the last thing that goes through a bug’s mind when he hits your car’s windshield?”
Marcus @14. The way I heard it was this:
Q: What’s the last thing that goes through a bug’s mind when he hits your car?
A: The windshield.
The mildly deranged penguin claims it depends on the direction the bug was flying. If towards the windscreen, or downwards, the last thing that goes though the bug;s mind is indeed the windscreen. If the bug was flying left or right, or sufficiently fast away from the oncoming car, it’s “Whew! That was close!” Anything else is usually “Wee! WEE!! That was fun, let’s do it again!!!”
Besides the toll of fatal casualties, the study neglects to mention what proximal survivors might have to endure. One is that over a considerably larger area anything that has ears (or equivalent) would be rendered completely deaf or severely hearing-impaired for life. Things with eyes that happened to be gazing in the direction of a bolide of sufficient energy and within a certain range (i.e., above the horizon) in a clear unobstructed sky is also at risk of blindness. Even the Chelyabinsk bolide, estimated to have been several times brighter than the Sun from a vantage directly beneath its peak burst along its track, caused some pretty severe ‘sunburn’ on the exposed faces of a number of people.
#6 yes – consider normal sea-level pressure is about 14.7 pounds/square inch; people have been documented to have survived without injury when exposed to shock overpressures of from 20 to 144 pounds (from aircraft flying past them at a range of less than 100 feet). Damage to eardrums is estimated to occur when the overpressure reaches about 720 pounds. Internal organ damage (lungs, say) occurs at 2160 pounds. https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-016-DFRC.html
microraptor @15
Actually the answer to that riddle that I’ve heard was ‘its bum’ (the windshield being the first thing).
The really cool use of shock waves is that we routinely use them in physics to detect particles traveling faster than light.
Bill Buckner, your use of the word “routinely” needs to be examined.
@21: Experimental physicists DO ‘routinely’ detect particles by their Cherenkov radiation. It really is a cool use of shock waves.
FTL particles?
Ed Seedhouse @9:
Shock waves are necessarily supersonic relative to the medium they move into. For air at sea level, the shock wave speed is about
c{1 + (0.86)[(p₂/p₁) – 1]}^(1/2)
where c is the speed of sound in stationary air, p₁ is the pressure of stationary air, and p₂ is the pressure behind the shock wave. See equation (15) here, with γ=1.4 and u₁=0.
Of course, they rapidly lose energy and eventually become regular sound waves (aka “Bang!”).
davidnangle @23: Faster than the phase velocity of light in the medium they are travelling through. E.g. speed of light in water is about 0.75c
Oh, cool. I didn’t realize that was being shown in those Cherenkov tanks.
davidnangle,
We use Cerenkov detectors to help (no one type of detector does it all–and it is a harder job than you might imagine) identify particles after interactions. For example electrons, having low mass, are much more likely to be traveling faster than light (in the medium) than pions.
having grown up during the “cold war” and have “enjoyed” much post apocalyptic fiction these thoughts of utter devastation are very familiar. I also think that this study’s results apply to T plus 10 to 24 hrs only with worse to come in the days and weeks to follow. I doubt that any new equilibrium would settle in for some considerable time and would depend on where exactly the impact occurred.
I would expect that the details would be different for an impact in central Eurasia compared to say the area where we de-orbit satellites in the pacific.
bleak in any case.
uncle frogy