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Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

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Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#101

Post by codeulike »

downrightmike wrote: post #22
geuis wrote: post #12

Just to put the numbers in slightly easier to imagine numbers: imagine ocean waves about 13000 feet or 4 kilometers high. No, I can't really imagine it either. In San Francisco, the tallest building is the Salesforce Tower at 1070ft. The biggest wave would be about 13 times taller than that. I totally have trouble visualizing it, other than just looking up and up and up.

The best hope would be that the mountains and ground whittle it down and that it drains quickly. May explain why rodents survived, in that dry to moderately dry ground doesn't soak up water quickly, so if it drained away before the burrows were soaked/drowned, there is a chance at survival.

There was a lot more to worry about than the wave. Anything within about 1500 km of the impact site was instantly vaporised. Then afterwards the whole atmosphere was oven-hot for several minutes. Then there was very little sunlight for decades. https://www.youtube.com/watch?v=dFCbJmgeHmA

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#102

Post by throwaway4aday »

frankfrankfrank wrote: post #72

That seems like a bad model if it does not include the effects of the waves penetrating inland and instead acts as if the coasts are inviolable.

Most of these asteroid impact models are also missing the secondary impact events from ejecta. For very small asteroids it's not much of a concern but anything large enough to be dangerous would kick out enough material to create a storm of falling superheated boulders. Big enough asteroids can blast stuff into orbit which then falls all over the Earth.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#103

Post by qikInNdOutReply »

echelon wrote: post #46
jacquesm wrote: post #40

Earlier quoted context omitted.

It would save quite a few ocean going ships if this was more appreciated. Those once-in-a-thousand-year-rogue-waves are much more frequent than once in a thousand years. https://www.theguardian.com/science/2006/jul/26/uknews But we're still designing ships as though they only happen once every thousand years because the cargo and the ship are insured and the crews are considered expendable.

> Research at Imperial College, London, shows that far from being rare events, rogue waves can emerge frequently, and may be responsible for some of the 200 supertankers and container ships longer than 200m that have sunk in poor weather conditions in the past two decades. The loss of ten ships a year seems incredible to me. Surely "weather", if it were to blame, could be avoided. This amount of loss is steep. Is it…

There are also source of loss, nothing can be done against. One can not even predict them.

Ocean floor methanhydrate and a volcanic shift, results in tremendous bubble columns, which just open up a shaft that can carry nothing. Water begins to boil, ship falls in, breaks apart... End of story.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#105

Post by Buttons840 »

fritzo wrote: post #26

> 30,000 times more initial energy than any recorded events As a statistician: this is why heavy-tailed modeling matters. Schools teach the finite-variance version of the Central Limit Theorem and students believe they live in a normal world. The real Central Limit Theorem [1] predicts large rare events following Lévy α-stable distributions. [1] https://en.wikipedia.org/wiki/Stable_distribution#A_generali...

I'm no expert on stats, this discussion is a bit over my head, but it reminds me that not all distributions have a mean. A Cauchy distribution has no mean; as you average successive samples, it never settles down to a consistent average. I was surprised when I first encountered Cauchy distributions and up until then had considered that all distributions would have a mean. I suppose it is one of those "heavy-tailed" distributions you're talking about?

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#106

Post by throwaway4aday »

yodon wrote: post #53
12907835202 wrote: post #30

If this were to happen today now much evidence would be find of our current civilisations? Would archeologists be able to figure out our cities?

Asking how you could tell if Dinosaurs had a civilization like ours used to be a standard Geology Dept. PhD orals question. Their cities would of course be long long, so that's not a productive search area. The answer is you'd look at the distribution of minerals. If they built cities with skyscrapers they would have had to mine the materials required to make them. There is no evidence the Dinosaurs exploited their a…

Of course this also means that pre-industrial civilizations are completely undetectable after several million years.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#107

Post by Gibbon1 »

las_balas_tres wrote: post #34
bash-j wrote: post #23

I wonder how they simulate the displacement of water since it's not from how tsunamis usually occur. A lot of water you think would be vaporised into the air and moved with the shockwaves. Plus there is only so much water at the impact site, not an unlimited amount. Given the speed of the impact, would it move as much water? They say when you jump off a bridge, the impact is like hitting cement.

As far as i know, the earth's crust below and around the impact gets displaced by a fair amount. I think the crust acts like a rubber sheet bouncing backwards and forwards. This most likely contributes toward the displacement of water above.

That reminds me, I remember reading some NASA stuff my dad would bring home talking about simulations of impacts. While there are very few on earth there are vast numbers on the moon and other planets.

I think the forces and energies are so large that the fluid dynamics dominate.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#108

Post by dsfyu404ed »

perihelions wrote: post #78
m_mueller wrote: post #60

Earlier quoted context omitted.

LEO may not even be safe, would it? Afaik a large part of the damage was the heating of the atmosphere from enormous amounts of secondary impacts due to the debris - many of these small rocks probably flung up into LEO, though it would be interesting to know how risky a stay in LEO would be during such an impact. If you want a SciFi story touching many such topics I highly recommend "Seveneves" by Neal Stephenson.

Parameters for 300 km range (200 km STS altitude + downrange) https://impact.ese.ic.ac.uk/ImpactEarth/cgi-bin/crater.cgi?d... Thermal Radiation: Time for maximum radiation: 11.5 seconds after impact Visible fireball radius: 223 km ( = 138 miles ) The fireball appears 169 times larger than the sun Thermal Exposure: 7.72 x 10^9 Joules/m^2 Duration of Irradiation: 49.7 minutes Radiant flux (relative to the sun): 2590 (T…

>(The physics aren't the same, but just for the sake of comparison: Chicxulub's 4e8 megatons-TNT of energy, at 300 km, is 1/r^2 equivalent to a 4 megaton nuke, at 30 meters).

Altitude 300mi is not the same as linear distance to blast 300mi

At 300mi up you could be over a different continent and get a good view and you would probably want to be so that you get a better view from the side.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#109

Post by marmetio »

random314 wrote: post #81
Idiot_in_Vain wrote: post #73

Earlier quoted context omitted.

Because a few ships a year are expendable for the global economy. Not worth it to try to make every ship less sinkable - e.g. it may decrease the number of annual losses by 50% at the cost of making an average ship 10% more expensive - obviously a bad trade. Some ships will still sink, because of stuff like human errors.

You know that ships have crew in it?

Occupational safety doesn't happen just because you think it should. Recognizing when financial incentives are insufficient is important to designing a realistic solution.

Re: Simulation of tsunami from dinosaur-killing asteroid that brought 2.5 mile waves

#110

Post by jvm___ »

charlieyu1 wrote: post #28
alister wrote: post #21

Earlier quoted context omitted.

> Or how 536 was the worst year on record Although I didn't listen to the 11 minute podcast, I was curious to know basically what it was about. This is what Wikipedia says about year 536: "In 2018, medieval scholar Michael McCormick nominated 536 as 'the worst year to be alive' because of the extreme weather events probably caused by a volcanic eruption early in the year, causing average temperatures in Europe and Ch…

A single source of quote, and I really doubt we can find anything related in recorded history. The history books of China definitely didn't mention anything significant about year 536.

They should, a global darkening of the skies due to an unknown volcano or volcanoes (or something else that spewed massive amounts of dust into the atmosphere).
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