What if Mars and Venus were habitable?

[Dilandu]

Apophis is big enough that an impact is likely to be civilization-ending, if not extinction level;

Are you kidding? It's just 370 meters. Local destruction would be enormous, of course, but no long-lasting planetary effects.

 

[Orionblamblam]

Apophis is big enough that an impact is likely to be civilization-ending, if not extinction level;

Are you kidding? It's just 370 meters. Local destruction would be enormous, of course, but no long-lasting planetary effects.

Secondary effects. If nothing else, the resulting "nuclear winter" would likely lead to India, Pakistan and China nuking the bejesus out of each other. Chances are good that that silliness would spread, and the results of *that* would likely entail unprecedented mass deaths due to crop failures and civilizational collapse from multiple EMP bursts.

 

[Orionblamblam]

And so when the automated fuel processor starts up, it'll either work or it won't. If it fails, there are no astronauts relying on it.

And so your program would be doomed to rather unavoidable failure. Thank you, I prefer the methodical approach better.

You and I have very different definitions of "methodical approach." I have laid out a strategy of buuilding up capability through increasingly complex unmanned missions. Your approach seems to be to land a TEL, a fully loaded solid propellant ICBM, the Trabant-equivalent of a space capsule and a couple of saps on the surface of Venus on Day one and just kinda hope it all works out.

If such *basic* technology as a fuel processor - a machine that could have been made in the 1800's - is impossible on Venus due to insanely insidious algae, then there is no point in going there *at* *all.* Even if the Space Trabant manages to lurch into Venus orbit, the best option for the mothership would be to blow the capsule straight to hell before it got within a hundred kilometers in order to prevent contamination.

 

[Dilandu]

Secondary effects. If nothing else, the resulting "nuclear winter" would likely lead to India, Pakistan and China nuking the bejesus out of each other. Chances are good that that silliness would spread, and the results of *that* would likely entail unprecedented mass deaths due to crop failures and civilizational collapse from multiple EMP bursts.

The calculations and modeling did not confirm that atmospheric effects of Apophis impact would have noticeable long lasting effects. Of course, localized destruction would be significant; if it hit North America Atlantic coast, it would probably wreck the whole coastal agglomeration. But since the impact belt would be predictable for quite a long time (months, maybe years, a large-scale evacuation would be possible)

P.S. To be exact, large-scale evacuation would be possible, for, say, China. Americans would probably be arguing till the impact that "there is nothing in Constitution about asteroids!", "the asteroid is inflatable, it's all government plot to put all True Patriots in camps" and "asteroid impact effects are greatly exaggerated" (sorry, but I could not resist the pun

 

[Dilandu]

Your approach seems to be to land a TEL, a fully loaded solid propellant ICBM, the Trabant-equivalent of a space capsule and a couple of saps on the surface of Venus on Day one and just kinda hope it all works out.

Well, it worked perfectly well in 1960s

If such *basic* technology as a fuel processor - a machine that could have been made in the 1800's - is impossible on Venus

Sigh. You are confusing "impossible" with "impractical without serious research". Serious research required boots on the ground.

due to insanely insidious algae,

Sigh. Where I said anything about "insanely insidious algae"? All I mention is that overcomplicated RIS mission without proper research could fail due to such unforeseen effect as local aglae clogging the filters.

 

[Orionblamblam]

Your approach seems to be to land a TEL, a fully loaded solid propellant ICBM, the Trabant-equivalent of a space capsule and a couple of saps on the surface of Venus on Day one and just kinda hope it all works out.

Well, it worked perfectly well in 1960s

What ICBMs were launched full of solid propellant to other planets in the 1960's?

Sigh. You are confusing "impossible" with "impractical without serious research". Serious research required boots on the ground.

You mean like Surveyor? Viking? Sojourner? Pathfinder? Venera? Lunokod? Curiosity? Spirit?

All I mention is that overcomplicated RIS mission without proper research could fail due to such unforeseen effect as local aglae clogging the filters.

And as I've pointed out to you several times now, a rational, methodical program would include several unmanned landers of increasing cost, complexity and capability well in advance of a manned mission. This would be true no matter what technology was proposed for the manned launch system. And if the program managers used a sane system like in situ propellant production, the landers would test out that technology in increasing scale, so that by the time a manned system was planned, it would already be known that it was feasible. If the program managers *didn't* care about an affordable and sustainable program and were only interested in using Venus as a dumping ground for political undesirables, then, sure. Tell 'em it's a solid propellant ICBM.

 

[Orionblamblam]

The calculations and modeling did not confirm that atmospheric effects of Apophis impact would have noticeable long lasting effects.

Doesn't need to be long-lasting to be civilization-ending. Does it spark a global thermonuclear war? Does it spark a series of EMPs that shut down industrialized civilization?

Civilization is fragile. Cut it off from, say, petrochemicals for a few weeks, and that's the end of it. A *real* pandemic that took out half of the planetary population in a year would be *nothing* as far as the planet is concerned, but it could easily bring modern civilization to an end.

Of course, localized destruction would be significant; if it hit North America Atlantic coast, it would probably wreck the whole coastal agglomeration.

It would also trash the American economy and end the US as a world power. Since the US is currently the sole power, expect everybody to take the opportunity to act the jackass. The middle east will explode. The far east will explode. Who knows how far Putin would go.

Also: no reason why an asteroid couldn't hit close enough to one of Earth's several supervolcanoes to set the damn thing off. The last time Toba went off it almost did humanity in; set it off again and throw in some genocidal nuclear wars like India/Pakistan and China/Russia and things could get dicey again.

 

[Kat Tsun]

Apophis is big enough that an impact is likely to be civilization-ending, if not extinction level;

Are you kidding? It's just 370 meters. Local destruction would be enormous, of course, but no long-lasting planetary effects.

Secondary effects. If nothing else, the resulting "nuclear winter" would likely lead to India, Pakistan and China nuking the bejesus out of each other. Chances are good that that silliness would spread, and the results of *that* would likely entail unprecedented mass deaths due to crop failures and civilizational collapse from multiple EMP bursts.

Just like when Krakatoa caused a world war.

Not sure how a famine, even assuming one could occur in the modern world on a large scale at all, would cause a major war. Wars tend to exacerbate food shortages, not improve them, for obvious reasons.

Giant volcanoes and pint-sized asteroids are probably similar in local and global effects: lots of heat, blast damage, and large holes in the ground. Except giant volcanoes probably are better for the environment because they produce more sulfate aerosols, which are a prospective AGW mitigator, so they have that going for them. They're really the Earth's natural sunscreen. Anyway, for people who aren't in the immediate blast area or part of the polity that takes the hit would probably not care beyond "that's sad" and go about their day.

They will wonder next year why it's so much cooler during the height of summer I suppose.

The United States losing either coast would not spell the end of "modern civilization", whatever that means, since plenty of places in both major oceans can do the things the United States does there and has been the case for so long that the United States stopped doing the things that are tangible and real and left that to the other people. It might spell the end of a lot of banks and maybe a major famine if America's breadbasket is seriously affected, but famines rarely cause the collapse of polities or wars by themselves.

Even the rickety political engine known as the Qing was barely affected by Mount Tambora in terms of violent uprising and modern countries are much better at squashing rebellion than they were 200 years ago. There would still be plenty of places to store your tax haven cash besides Delaware, like Malta, Panama, or Singapore.

 

[Justo Miranda]

Humanity has been very lucky so far, if the Tunguska event had occurred over Kapustin Yar during the Cuban missile crisis... or just a Chelyabinsk over Moscow...

 

[Justo Miranda]

In my opinion the terraformation of Venus and Mars would be technically feasible within a century, assuming that humanity had some powerful reason to do so, but these worlds would never be comfortably habitable for humans.

Mars has no magnetic field and life on its surface will always be subjected to excess radiation and low gravity is an insurmountable inconvenience to the health of humans in the medium term.

Venus can cool itself by surrounding it with a cloud of dust from an asteroid located in polar orbit and it would also be feasible to divert numerous comets so that they disintegrate in the upper atmosphere forming water vapor, rain and over time, oceans.

But the surface of Venus does not have the same geological mechanism as that of the earth, there the tectonic plates have been replaced by a convection phenomenon similar to that of boiling water. When cooled irregularly, the surface would be subject to earthquakes and apocalyptic tsunamis.

Perhaps the best thing we can do with those worlds is to sow life into them, a life specially designed to thrive in those harsh environments, and let evolution run its natural course.

 

[Orionblamblam]

Secondary effects. If nothing else, the resulting "nuclear winter" would likely lead to India, Pakistan and China nuking the bejesus out of each other. Chances are good that that silliness would spread, and the results of *that* would likely entail unprecedented mass deaths due to crop failures and civilizational collapse from multiple EMP bursts.

Just like when Krakatoa caused a world war.

Krakatoa occurred in a world without nuclear weapons and world powers with the ability to act, and overreact, on a global scale and a minutes notice. It was also, compared to an asteroid impact like this or a supervolcano, a *small* event. Even Tambora 1815 would be tiny comparatively.

Not sure how a famine, even assuming one could occur in the modern world on a large scale at all, would cause a major war. Wars tend to exacerbate food shortages, not improve them, for obvious reasons.

Wars happen over resources. The Gulf War, after all, was over oil... Iraq wanted Kuwaits oil, and tried to get it. End result? Oil fields on fire, a whole lot of oil simply lost. If an asteroid led to nuclear winter or a supervolcano winter that blocked out the sun for a growing season in the norther hemisphere, food production would crash. For a year, maybe two, the industrialized world would probably get along on food stores and reduced rations; the less indutrialized world would be in a world of hurt. A few centuries ago, that would mean they would starve. Today? That means they get in cars and trucks and boat andon their own two feet and get themselves into Europe. What would happen if fifteen million starving, alien refugees showed up on Hungary's border tomorrow, while the Hungarians are barely hanging on with the resources they've got? A hundred million refugees crossing the Med into Greece and Spain and Italy?

If you think people wouldn't get stabby in that situation, you've a different understanding of human nature than I do.

Also:

How Famines and Epidemics Trigger Wars​

 

[Orionblamblam]

Mars has no magnetic field and life on its surface will always be subjected to excess radiation and low gravity is an insurmountable inconvenience to the health of humans in the medium term.

A magnetic field can be added artificially, and the health effects of reduced gravity are wholly unknown. We only have datapoints for 0 G and 1G, with some suggestions regarding 1+ G from centrifuge testing. 0.5 G? 3/8 G? 0.75 G? Absolutely no data. No way to know if things *promptly* go downhill the moment you hit 0.95 G, or if everything is perfectly cromulent all the way down to 0.05G, or if it's a linear curve or... whatever. That's why artificial gravity space stations should have been built fifty years ago, to test the long term effects of exactly that.

 

[Justo Miranda]

Mars has no magnetic field and life on its surface will always be subjected to excess radiation and low gravity is an insurmountable inconvenience to the health of humans in the medium term.

A magnetic field can be added artificially, and the health effects of reduced gravity are wholly unknown. We only have datapoints for 0 G and 1G, with some suggestions regarding 1+ G from centrifuge testing. 0.5 G? 3/8 G? 0.75 G? Absolutely no data. No way to know if things *promptly* go downhill the moment you hit 0.95 G, or if everything is perfectly cromulent all the way down to 0.05G, or if it's a linear curve or... whatever. That's why artificial gravity space stations should have been built fifty years ago, to test the long term effects of exactly that.

I agree with that, I've always wondered why something has never been built to test artificial gravity by rotation in space. Life at zero-G is a pretty miserable experience from the astronaut accounts I've read.

 

[Orionblamblam]

I agree with that, I've always wondered why something has never been built to test artificial gravity by rotation in space. Life at zero-G is a pretty miserable experience from the astronaut accounts I've read.

That would require effort, expense and determination, something that has been in short supply in Congress and NASA since 1968. Well, except for expense...

 

[Dilandu]

I agree with that, I've always wondered why something has never been built to test artificial gravity by rotation in space. Life at zero-G is a pretty miserable experience from the astronaut accounts I've read.

Mostly because the main purpose of current space stations is, after all, to perform research in zero-g. Including human biological research. So it would be generally counter-productive to create permanent gravity modules.

 

[ngatimozart]

So if you land an Apollo capsule on the surface of Venus, you'll need something akin to a Saturn I - with all the launch infrastructure that implies - to get back to Venus orbit.

Actually no, you could get out with much smaller, solid-fuel (or storable-fuel) rocket, dropped in launch container. Just make the return capsule REALLY light. After all, its strictly Venus-to-Orbit craft; all it does need is to launch from Venus and dock with orbiting Earth return ship. V-t-O capsule does not need to have thermal protection (it would not need to re-entry atmosphere), does not need to have prolonged life support (we could safely get away with crew being in spacesuits all the return flight).

Basically, look at something like Space Cruiser/STAR:

View attachment 670715

View attachment 670716

Threw away all thermal titles, lifting surfaces, most of the fuel. Leave only the basic: structure, life support, ACS and minimal propulsion. You could fit it in the one ton of payload, or even less. My IMHO, a 500-kg return capsule is perfectly possible. And 500 kg to low Venusian orbit is within the Minotaur-I rocket capabilities.

It's going to require a fair amount of protection. At the planet's surface the atmospheric pressure as about 90A; that is 90 times the atmospheric pressure at sea level on Earth, so that's the equivalent depth of 2970 ft in the ocean. The atmosphere mostly comprises CO2 with some clouds comprised of sulphuric acid. The temperature at the surface is hotter than on the surface of the side of planet Mercury that faces the sun. This is because of the runaway green house effect. Source:https://www.space.com/18527-venus-atmosphere.html

Because of the atmospheric density you will require a significant amount of energy to drive the space vehicle through the atmosphere due to high resistance. Your explorers will have to wear protective suits that can stand more than 90A of pressure and they have to be solid because the human body cannot handle such pressures. At 10A the oxygen in normal air becomes toxic. IIRC the Soviet lander that made it to the surface lasted I think eight minutes before it was crushed completely.

Hence a rethink is advised. Time for Plan B.

 

[Orionblamblam]

It's going to require a fair amount of protection. At the planet's surface the atmospheric pressure as about 90A; that is 90 times the atmospheric pressure at sea level on Earth, so that's the equivalent depth of 2970 ft in the ocean. The atmosphere mostly comprises CO2 with some clouds comprised of sulphuric acid. The temperature at the surface is hotter than on the surface of the side of planet Mercury that faces the sun.

You've rather missed the point of the topic.

 

[Orionblamblam]

Mostly because the main purpose of current space stations is, after all, to perform research in zero-g.

Incorrect. The main purpose of the ISS, at least, is to spread the bread around. Science of *any* kind is at best a secondary concern.

 

[ngatimozart]

It's going to require a fair amount of protection. At the planet's surface the atmospheric pressure as about 90A; that is 90 times the atmospheric pressure at sea level on Earth, so that's the equivalent depth of 2970 ft in the ocean. The atmosphere mostly comprises CO2 with some clouds comprised of sulphuric acid. The temperature at the surface is hotter than on the surface of the side of planet Mercury that faces the sun.

You've rather missed the point of the topic.

Fair enough I stand corrected. As long as the ship has an operational flux capacitor and is powered by dilithium crystals it should work.

 

[ngatimozart]

Apophis is big enough that an impact is likely to be civilization-ending, if not extinction level;

Are you kidding? It's just 370 meters. Local destruction would be enormous, of course, but no long-lasting planetary effects.

In the real world the impacts oud be planetary because of it's size and mass. Depending upon where it hit it would throw up enough material to block out sunlight for one or more years. That would be long enough to kill most crops. Since I am fond of bacon I would not be happy.

In an alternate world such effects would of course be mitigated by technologies that are unknown to humanity today. In fact the bolide would be either diverted or destroyed longer before it reached Earth. Some enterprising antipodean miner will probably liberate it from the authorities and mine it selling the products on the black market.

 

[Justo Miranda]

Apophis is big enough that an impact is likely to be civilization-ending, if not extinction level;

Are you kidding? It's just 370 meters. Local destruction would be enormous, of course, but no long-lasting planetary effects.

Secondary effects. If nothing else, the resulting "nuclear winter" would likely lead to India, Pakistan and China nuking the bejesus out of each other. Chances are good that that silliness would spread, and the results of *that* would likely entail unprecedented mass deaths due to crop failures and civilizational collapse from multiple EMP bursts.

There are other types of side effects that are never talked about: when the asteroid hit Chicxulub, the concentric shock waves spread across the surface of the planet losing more and more energy, until they reached the maximum diameter, but then they regained a large part of their destructive power as they closed the circle at the other end of the planet.

At that time India was an island located northwest of Madagascar, in the antipodes of Chicxulub, the shock wave generated a column of magma that lifted the island from the bottom of the sea moving it north to collide with Asia and form Everest, it is still growing.

He also generated the Deccan Traps (https://en.wikipedia.org/wiki/Deccan_Traps) that polluted the atmosphere for less than 30,000 years doing much more damage than Sagan's famous nuclear winter.

 

[Justo Miranda]

I agree with that, I've always wondered why something has never been built to test artificial gravity by rotation in space. Life at zero-G is a pretty miserable experience from the astronaut accounts I've read.

Mostly because the main purpose of current space stations is, after all, to perform research in zero-g. Including human biological research. So it would be generally counter-productive to create permanent gravity modules.

Now that the subject has been sufficiently studied, we can affirm that long-duration space travel requires artificial gravity devices to preserve the health of astronauts. The time has come to work on it, but the guys on the space station still have the same problems as ever as Zero-G and nobody does anything to remedy it.

 

[Dilandu]

Now that the subject has been sufficiently studied, we can affirm that long-duration space travel requires artificial gravity devices to preserve the health of astronauts. The time has come to work on it, but the guys on the space station still have the same problems as ever as Zero-G and nobody does anything to remedy it.

Well, the rotating part on the station, not designed to be rotating, would actually be... problematic. How to spin it without the whole station rotating the opposite direction? Also, rotating part would work as giant gyroscope, making attitude control work... problematic, since they would be forced to counteract the gyro effect of the module.

 

[Justo Miranda]

Now that the subject has been sufficiently studied, we can affirm that long-duration space travel requires artificial gravity devices to preserve the health of astronauts. The time has come to work on it, but the guys on the space station still have the same problems as ever as Zero-G and nobody does anything to remedy it.

Well, the rotating part on the station, not designed to be rotating, would actually be... problematic. How to spin it without the whole station rotating the opposite direction? Also, rotating part would work as giant gyroscope, making attitude control work... problematic, since they would be forced to counteract the gyro effect of the module.

The classic solution is for the entire station to rotate, except for the cargo hangar located in the central part of the wheel. Friction problems at the rotation-no rotation interface have long since been solved using electromagnetic levitation techniques and liquid metals. The larger the diameter of the station, the fewer the problems of the Coriolis effect, the lower the rotational speed and the lower the structural load.

 

[Justo Miranda]

Mostly because the main purpose of current space stations is, after all, to perform research in zero-g.

Incorrect. The main purpose of the ISS, at least, is to spread the bread around. Science of *any* kind is at best a secondary concern.

Sometimes I think that the ISS has been designed by a committee of sociologists from the United Nations.

 

[Dilandu]

The classic solution is for the entire station to rotate, except for the cargo hangar located in the central part of the wheel. Friction problems at the rotation-no rotation interface have long since been solved using electromagnetic levitation techniques and liquid metals. The larger the diameter of the station, the fewer the problems of the Coriolis effect, the lower the rotational speed and the lower the structural load.

Yes - for the specifically constructed rotating station. ISS wasn't designed to rotate, that's the problem.

Sometimes I think that the ISS has been designed by a committee of sociologists from the United Nations.

It was essentially the compromise between USA, that have money, but zero experience in building and maintaining large, multi-module space stations, and Russia, which have great experience, but no money to replace aging "Mir".

 

[Kat Tsun]

Mostly because the main purpose of current space stations is, after all, to perform research in zero-g.

Incorrect. The main purpose of the ISS, at least, is to spread the bread around. Science of *any* kind is at best a secondary concern.

Sometimes I think that the ISS has been designed by a committee of sociologists from the United Nations.

It's an amalgam of Freedom, the successor to the pintsized Almaz equivalent Skylab, and Mir 2. So yes, that's partly correct. They're technically sociologists and space scientists from the P5.

Literally no space agency in 1980, when Mir 2 and Freedom had started, had the design experience, understanding of zero gravity construction, or the economic-industrial output to construct something like the Von Braun magic space ring stations anymore than they could build torch drive powered O'Neill cylinder starships.

They still don't these days, but they're significantly closer now than they were in 1980. Gateway is a good stepping stone to a manned Mars mission though I suppose if NASA had abandoned putting flags on dead useless rocks and focused entirely on LEO exploration and spacecraft it could build a small rotating space station, like an artificial gravity Skylab or something. Not sure what this would accomplish since there's nowhere to go that's interesting and we can get to Mars without rotating gravities probably, provided we throw peoples' skeletons in the dumpster.

It wouldn't be as impressive as a Mars landing either so I guess that and "return to the Moon" ultimately beat the centrifuge module.

The classic solution is for the entire station to rotate, except for the cargo hangar located in the central part of the wheel. Friction problems at the rotation-no rotation interface have long since been solved using electromagnetic levitation techniques and liquid metals. The larger the diameter of the station, the fewer the problems of the Coriolis effect, the lower the rotational speed and the lower the structural load.

Yes - for the specifically constructed rotating station. ISS wasn't designed to rotate, that's the problem.

Sometimes I think that the ISS has been designed by a committee of sociologists from the United Nations.

It was essentially the compromise between USA, that have money, but zero experience in building and maintaining large, multi-module space stations, and Russia, which have great experience, but no money to replace aging "Mir".

There was a centrifuge module that was going to be used for testing this exact issue that the ISS would've got. It was built by JAXA.

It was unfunded along with the permanent habitation module and crew escape vehicle, but they would have used mice models as proxies for humans under artificial gravity. I'm going to blame Space Shuttle launch bottlenecks and the "faster, better, cheaper" privatization push of the '90's that took funding from public agencies like NASA and threw them at fiscally obese "market" solutions like X-33, when they probably could have been better used building a expendable launch system like NLS.

Of course that's a bit hindsighty and irrelevant I guess. No one knew ISS was going to be real in 1994 or whatever.

Maybe if Challenger or Columbia hadn't exploded then there would have been enough launch slots available for the centrifuge and habitat (I don't think the CEV would be important enough in any hypothetical situation to get full funding, the ISS is infinitely safer than the literal death traps that built it) and we'd be able to run a few more nice experiments aboard like "how to make a sandwich in zero-g" and "emergency appendectomy" alongside the spinny bits.

OTOH I suppose but that would just circle back to the cost issue since NASA kinda didn't do enough safety checks to begin with because it was concerned with escalating costs and delays so...

 

[Nik]

Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...

My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...

I'm glad it missed.

FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...

 

[Nik]

Just a thought about rotating space stations:

IIRC, that's why '2001' did that lonnng 'Blue Danube' sequence, elegantly aligning shuttle to rotating axial dock using the 'nav display' and its rotating reference frame.

AC Clarke unsubtly raising two fingers to many critics who reckoned such docking was 'impossible'...

 

[Archibald]

Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...

My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...

I'm glad it missed.

FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...

Don't forget the fall of 1983 as a very ugly, very scary moment, from late August to early December.
KAL-007, Petrov, Able Archer, and just to lighten the mood: The day after and Threads.
Reagan was granted a screening of The day after one month before it hit the screen; and ended pretty depressed by it. Now imagine if he had been screened Threads or On the beach. Or Fail safe.

(I remember watching the remake of Fail safe twenty years ago, the one with the E.R actors: Noah Wyle and Clooney, from memory. What really scared the shit out of me was the US president being on the phone with the ambassador in Moscow when the unstoppable rogue squadron came nuking the place.

Ambassador "Mr President, they are coming. When our conversation ends with a howl / whistling sound, its me and the phone melting in a thermonuclear in-" weeeeeeeep hooooowl there goes the ambassador and the phone.
And now the president has to trade New York 10 million souls against the planet, to cool the very pissed-off Soviets...

 

[Kat Tsun]

There is a story about this that H. Beam Piper wrote. Except it was an antimatter rock blowing up a town in New York or something.

 

[PMN1]

Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...

My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...

I'm glad it missed.

FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...

Don't forget the fall of 1983 as a very ugly, very scary moment, from late August to early December.
KAL-007, Petrov, Able Archer, and just to lighten the mood: The day after and Threads.
Reagan was granted a screening of The day after one month before it hit the screen; and ended pretty depressed by it. Now imagine if he had been screened Threads or On the beach. Or Fail safe.

(I remember watching the remake of Fail safe twenty years ago, the one with the E.R actors: Noah Wyle and Clooney, from memory. What really scared the shit out of me was the US president being on the phone with the ambassador in Moscow when the unstoppable rogue squadron came nuking the place.

Ambassador "Mr President, they are coming. When our conversation ends with a howl / whistling sound, its me and the phone melting in a thermonuclear in-" weeeeeeeep hooooowl there goes the ambassador and the phone.
And now the president has to trade New York 10 million souls against the planet, to cool the very pissed-off Soviets...

Thought the remake was crap......the original however was superb.

 

[bobtdwarf]

Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...

My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...

I'm glad it missed.

FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...

Don't forget the fall of 1983 as a very ugly, very scary moment, from late August to early December.
KAL-007, Petrov, Able Archer, and just to lighten the mood: The day after and Threads.
Reagan was granted a screening of The day after one month before it hit the screen; and ended pretty depressed by it. Now imagine if he had been screened Threads or On the beach. Or Fail safe.

(I remember watching the remake of Fail safe twenty years ago, the one with the E.R actors: Noah Wyle and Clooney, from memory. What really scared the shit out of me was the US president being on the phone with the ambassador in Moscow when the unstoppable rogue squadron came nuking the place.

Ambassador "Mr President, they are coming. When our conversation ends with a howl / whistling sound, its me and the phone melting in a thermonuclear in-" weeeeeeeep hooooowl there goes the ambassador and the phone.
And now the president has to trade New York 10 million souls against the planet, to cool the very pissed-off Soviets...

It is pretty likely that he had seen Failsafe and On the Beach given the era, at the very least heard about them.

But Threads would have scared the ever loving peewadens out of him!

 

[Orionblamblam]

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

An additional fun ponderable: assume an Apophis-level impactor is incoming. Assume further that instead of a rock, it's a comet. Assume further further that it is found to be on an impact tractory on it's way *out* rather than on it's way *in.* What difference does all that make? After rounding the sun, it will have been warmed substantially. It will be outgassing, it will have jets and vents and geysers. In short, it's path will be slightly erratic. So NASA and ESA and what all can confidently predict that on April 13, 2027, the thing will hit Earth.

But they can't say *where* it will hit, except for the hemisphere, until just a few days before. And just a few days before, this impactor which will kill every human within 600 nautical miles is found, two days before impact, to be on a trajectory to hit... (spins wheel) India. A billion people will die in two days unless they all evacuate. but to where? Pakistan? China? Where can a billion people go that fast... where they won't meet with armies at the border saying "nope?" Will the Indian military bust out with the nukes in order to colonize Pakistan? Will the Chinese nuke the Indians to prevent an Indian invasion?

Or it's going to hit Pakistan, and the only hope they have is to invade India. How well will take go?

Or it's going to hit Israel. Where are they going to go? It's going to plow into North Korea. Or South. Or Japan.

Some of these would of course be nightmares even if the targeting was known to high precision a year in advance. But shorten the clock and a nightmare becomes apocalyptic.

 

[Kat Tsun]

If it hits Israel then the Arab-Israeli wars would be over. Forever. Maybe Judaism and Christianity would stop existing since their most holy sites were just incinerated by a celestial detritus. If it hit North Korea then the Korean War would likewise be over in an instant. There wouldn't be any questions because all the people directly involved would be dead or dying. Possibly Beijing would be losing its mind because a giant space rock broke all the windows in the business district with a massive aftershock. If it hit Pakistan then America and India would both golf clap and the PRC would burst an anger vein and start wooing Uzbekistan even harder.

You might as well be asking what if Tunguska hit London or something. It would be bad. For those people. Everyone would either quietly rejoice or scurry around like chickens with their heads cut off trying to get food and medicine to the survivors depending on how they view the British Empire.

An asteroid like Apophis hitting a populated area versus "literally the middle of nowhere" or "the ocean" is pretty fantastic to begin with. Even if it hit Bos-Wash, the worst it can do, is wipe out like two (NYC and Toronto) of half a dozen major financial centers, but nothing of notable tangible productive capability. The USA would still have railroads and food, it would probably just revert to a barter system for a bit. London or Tokyo and Shanghai can pull up the slack from the NYSE. Maybe the UK will be relevant again, and the USA will be steamed, and probably have to move the capital to Philadelphia or something.

That wouldn't cause China to nuke India though lol.

"Civilization" in the modern sense would continue without much upset beyond a period of rationing for the afflicted area.

There are more breadbaskets and people aren't reliant on food grown in a 50 mile radius anymore because we can chill food and grow wheat in tons of places, which makes you naturally less vulnerable to the effects of famine and local weather events. Historic droughts were the cause of famine because people couldn't just import phosphorus in a week and cover the difference by ordering soybeans from Brazil or wheat from Kazakhstan. When the United States can just accept food gifts from China or something (even then, America has several breadbaskets, not all of which would be covered by any Apophis impact in the middle of Montana or Idaho or whatever due to their sheer size and dispersion) it's not really fair to say there would be a famine.

Unironically a major railroad like Union Pacific or BNSF going bankrupt would do far more damage to the US logistical services and ability to deliver food than a giant space rock nuking Bos-Wash could ever hope to do. There are multiple offsite backups of NYSE data to other stock exchanges and in other cities, and even other continents, so it's not like BNSF or UP would lose money. The important big heads might be losing their minds until Tokyo or London start booting up the backups that are made and stored in a offsite data center in San Francisco or Chicago or something. Even ICE, the people who operate the XSE clearinghouses, isn't fully headquarted in New York since it has offices in Chicago and Singapore and a ton of other places that could takeover in the event of a Bos-Wash wipeout.

Either way it wouldn't affect the railroads' day to day operations, probably not their future operations, and it might even invigorate people to work harder because they're helping people get food who need it because they're sick/starving/dying of glass and thermal flash related injury, which is a real and genuine goal, rather than making money for shareholders and dividends which is a bit too abstract for the average Joe Six Pack to fully cogitate. I'm also pretty sure Warren Buffett lives in Montana or Nebraska which is where BH lives, so the biggest railroad in America that delivers all your food ain't gonna be killed.

Not unless Apophis goes sicko mode and wipes out Omaha because it's directly targeting SAC headquarters at Offutt. Rocks can't think that fast.

That's the worst case scenario. The actual scenario is something more like "New York subway flooded again lol" and people try to swim in the subway to get to work because they gotta make that bread because the Earth is 75% water and a big space rock is gonna land "in the middle of nowhere" or "in the water" more likely than hitting the biggest financial center of the world.

Suffice to say the modern global economy and civilization these days has no single point of failure that Apophis could exploit. Anything less than Bos-Wash being hit is an easily solved problem, akin to Bos-Wash, and there isn't anything worse than Bos-Wash being hit.

It would be like the UK and the rationing period: a few decades of fats and cereals being rationed by cards, but nothing too serious, because the number of connections between the USA inside itself wouldn't be severed totally by a big explosion like Apophis. If people can't ship food through the northeast corridor they will just use barges. Or highways. Or people will come to where food is. Or there wouldn't be people to feed because they were vaporized by a space rock.

Modern famines since the advent of containerization and refrigeration are always induced by leadership for social capital gains, not by any tangible want of food, because the world has enough food to feed itself many times over. Even if the silly chart of bread prices to revolutions are true, no modern revolutions caused by bread prices have been successful, which is rather important: revolutions are harder to pull off because states are better at resisting them. Even weak and crummy states that can't fight funny RC planes can squash marauding bandit gangs with main battle tanks and barrel bombs. Syria's revolution, the most successful bread price/famine/drought-related revolution, was squashed by the government after a decade of combat and is basically non-existent now. There's a tiny village controlled by the CIA's puppet group (the FSA) and both Syrian Kurdistan/Rojava and the Syrian Arab Army are resisting Turkish incursions into a tiny sliver of land, but there's no real combats occurring so the war is frozen.

Ultimately the world produces more than enough food even if a breadbasket or two goes kaput. This has been true since the Green Revolution and cheap fertilizers showed up, none of which are coupled directly with breadbaskets in geography (you don't put a fertilizer plant in a farm field in other words, you ship fertilizer to fields by trucks or trains), and very few of which are produced in the most economically important regions (i.e. California's south coast and New England) of America. There are some on the Mississippi and Gulf Coast but they're also inside cities, so farming doesn't occur there.

It would just be rationing for a bit and people would be less likely to waste food afterwards.

A few dozens of millions of people might be incinerated by a gigaton surface burst, but that's relatively minor as far as civilization and the global economy is concerned. Far more pressing is the issue of helium, how the DOE is going to handle student debt, or the SSA/healthcare industry its declining tax incomes and rising insurance premiums. Compared to a rock the size of the Empire State Building I think those problems rank at least as, if not far more, pressing issues.

On a forum that constantly wanks to strategic nuclear weapons exchanges, Kahnian megadeaths, and meanders about potential nuclear combats between the USA and USSR, an Apophis impact in a economically vital zone of a country should be considered a good dry run for learning how to handle a major atomic combat on a regional strategic scale anyway because the effects would be similar: big thermal shock, large blast wave, destruction of a city and a chunk of logistics infrastructure, and millions of dead people.

I'm not sure why it's being considered some giant problem that will end the world, though. The USAF and Edward Teller once considered bigger bombs to wipe out the USSR. Even SIOP would be five or ten times more destructive in raw yield and vastly more devastating across a bigger area, and it would probably just turn both Russia and USA into poverty stricken places not unlike modern North Korea at its worst. Even Japan and Germany, when they were completely leveled with nuclear quantities of firepower, built back better with outside money from former enemies.

Whoever gets hit will need a lot of foreign aid but that's about it. There's plenty of money in the world though, and even if a few stock exchanges break, there's plenty of tangible production capacity and goodwill (or cynical exploitation, depends on how you look at it) to work without pay because some people far away got hit by a space rock. Maybe the PRC would build an OBOR line in the post-Apophis United States to finally fully connect Vancouver and Ontario or Montreal. Maybe Aztlan would become real like in War Day.

But it definitely wouldn't cause China or India to nuke each other if the Atlantic Ocean eats an asteroid. It also would be pretty obvious that a big space rock hit someone because you'd see the big rock on a radar and with your actual eyes, and no atom bomb has a 1,000 megaton yield.

Sheesh.

 

[Orionblamblam]

You might as well be asking what if Tunguska hit London or something.

Yes, and?

On a forum that constantly wanks to strategic nuclear weapons exchanges, an Apophis impact in a economically vital zone of a country should be considered a good dry run for learning how to handle a major atomic combat on a regional strategic scale anyway, so I'm not sure why it's being considered some giant problem. The USAF and Edward Teller once considered bigger bombs to wipe out the USSR. Even SIOP would be five or ten times more destructive in raw yield and vastly more devastating across a bigger area, and it would probably just turn both Russia and USA into poverty stricken places not unlike modern North Korea at its worst.

You have a wonderfully sunny view of how awesome it would be to incinerate a few dozen million people.

 

[Kat Tsun]

I have a realistic view of what it would mean if Apophis hit the world. The answer is "not much".

You just have a weirdly narrow view of what constitutes "the world" and "civilization". It's not "one big city", "America", or "huge finance markets". It's a lot of moving parts that are hard to break and difficult to understand because they often move in sync but without knowledge of each other. Whatever will kill the world economy will be about as knowable as a Great Old One and strike about as fast as a pit viper. Space rocks are too slow, dumb, and easily anticipated for it to do much, but it would be a great test of the broken window fallacy.

Apophis might devastate a tiny country like France or Britain and leave it permanently uninhabitable at worst (or at least really shitty) for a long time near the impact site. Big fires raging across dozens or hundreds of kilometers from the impact zone and eating away at trees, choking smoke, etc. The whole nuclear firestorm thing would happen. Then it would stop because modern cities are bad at sustaining firestorms, tend to ring rivers, and for the most part Apophis wouldn't literally flatten anything outside of about 150-250 kilometers (but it would break windows out to 1,000 I suppose).

That's about the worst it gets in terms of local conditions: it hits a tiny place like that and utterly wallops it. That's bad...if you're British or French. Good thing there's like 6.99 billion people (with a b) in the world who aren't British or French. Those other 6.99 billion people also make more things than Britain or France put together, so the guys who got hit would be back up and running in a few years given some decent crisis management and willingness to make hard choices.

So that's not a big deal for the global scale and might even benefit a lot of major actors. The USA or PRC could instigate Marshall Plans to rebuild either country and fight over the heaps of construction contracts that would surely be outpouring from the New London Redevelopment Fund. But that assumes it would hit any of those countries specifically. If it hit most countries it would just utterly kill everyone because it's a gigaton nuclear bomb that literally flattens a country the size of Israel and has a fireball radius approaching a couple miles.

Of course it's a big rock, so it's gonna be throwing its energy into the ground, not necessarily into the surrounding atmosphere, so it would be less efficient at widespread local destruction than a nuclear bomb. It might cause major earthquakes or something for a time. We don't know. It's not a very big rock though, and as far as asteroids go, Apophis is the one you want to be hit by. It certainly isn't a dinosaur killer, it's more like a Strategic Air Command bomber wing or a Strategic Rocket Forces missile battalion.

That's a pretty reasonable and containable level of potential damage because it's easily understood by emergency managers. It's "big" or "catastrophic" but not "world ending" unless you live right there.

Since it isn't going to hit the Earth it's impossible to say to what would happen, you can only throw out a hypothetical. I just gave you the worst possible outcome: the most important country today loses its most powerful financial asset. ...too bad I s'pose? It has other powerful financial exchanges and there are other stock exchanges equipped to take up the slack to an extent, and stock exchanges aren't important for daily operations. People would still get their paychecks if they care about that sort of stuff, and the most important thing in the world since WW2 just happened so they would be motivated by common goodwill towards man.

It certainly wouldn't cause some apocalyptic cascade. The world is both too intertwined and the individual countries too irrelevant for that to happen. I'm not sure what would cause a "nuclear war" between China and India but it's probably something more important, less knowable, and less predictable than a space rock.

It would be a boon for Chinese fiber optics manufacturers I suppose because they'd have to build tons of terminals and linkages to get the global finance system back to the point where it recovers from losing the NYSE and NASDAQ data centers. They're backed up but I don't think Chicago has the bandwidth to support major trades at the same volume. It would probably kill penny stocks and a lot of hedge funds would die, figuratively and literally, but things of tangible worth would still be intact, and all trade volume would go towards tangible goods industries like food producers, railroads, i.e. the real shakers and movers of the global economy.

You can run a factory without stock markets though, but you can't run a factory without electricity, feedstock, or workers though. Apophis still can't kill every factory in the world, it just seriously wound (not kill) the stock markets. As it turns out that's not hugely important, both because the stock market is highly robust, decentralized, and resilient (it has to be, fiber optics and cable lines/switchboards were notoriously finicky back in the day), and because the stock market isn't actually very important.

 

[Orionblamblam]

I have a realistic view of what it would mean if Apophis hit the world. The answer is "not much".

You have a limited vision of secondary effects and human stupidity.

Chances are fair that it would hit the Pacific. So... where is *everybody* who lives along the Pacific Rim going to go? You're going to have to evacuate *all* of Japan and Hawii and Indonesia and New Zealand and all the rest to save them from the mile-high tsunami that *may* result. A large fraction of the Chinese population will have to uproot from the coast, presumably move into all those inland cities the Chinese seem to have built for no reason. You're talking about moving billions of people on potentially short notice... and possibly moving them somewhere they're not wanted.

Europe may end up in some form of conflict over the ongoing colonization of a few dozen million from Africa and the Middle East. Imagine if they were told that the entire Indian subcontinent was going to show up on their doorstep at the same time that Fimbulwinter was going to make an appearance. People tend to get short tempered about such things. Individually, humans get stabby in such circumstances; geopolitically, they break out the tanks.

 

[Kat Tsun]

"Mile high tsunami" lol. Apophis's tsunami would have been smaller than the one that hit Japan in 2011.

An impact by a 2km diameter stony asteroid is thought to be at the threshold of a global
catastrophe. It has been estimated that one quarter of the world's population could die from
starvation and other indirect effects due to such an impact (Morrison and Chapman 1995).

(...)

Crawford & Mader (1998) explain that, for an impact to produce a coherently propagating
wave (one that does not dissipate substantial energy when it travels over great distances) the
"cavity" must be 3 to 5 times broader than the depth of the ocean. Using a rule-of-thumb (derived
from simulations) that the cavity diameter is 20 times the asteroid diameter then, for a typical
ocean depth of 4km, the impactor must be at least 1 km in diameter to produce a coherent wave.
On this basis, for asteroids smaller than about 1km, the wave will dissipate considerably as it
travels over thousands of kilometres of ocean.

(...)

Ward & Asphaug (1999) predict a s imilar tsunami height to that of Hills & Goda for a
250m diameter asteroid. There have been no detected asteroid impacts into an ocean on Earth so
it is difficult to verify the models. However, the CTH computer code used by Crawford and
Mader successfully predicted the consequences of the impact of Comet Shoemaker-Levy 9 with
Jupiter. In the (fortunate) absence of experimental evidence on the Earth, the conservative results
produced by Crawford & Mader have been used in the following analysis. In other words, it is
assumed that asteroid impacts will generally produce non-coherent waves which dissipate quickly

The given number is between 5-11 meters, since there's no actual modeling of a 370 km asteroid. Probably close to 8-9 meters. Which is, frankly, nothing to even bother with beyond typical tsunami warnings. It's very ordinary as far as "dangerous tsunami" go, but nothing that Japan hasn't faced before. The average height of the Tohoku tsunami was probably 10-15 meters, reaching 40 meters in the worst affected areas. Existing sea walls would deal with it for vital infrastructures (reactors) and no one would notice except fishermen whose boats would end up on the beach or down main street, and the occasional izakaya that gets their kitchen and bar absolutely mudded.

I guess they would need to pay to have their boats towed or interiors renovated or something? Real big issue that, but that literally fits the "unknowable" and "rapidly striking" descriptor I gave. Now we just need to do macroeconomic modeling to determine how we go from "Japanese fishermen stranded for a weekend on the street" to "China and India nuclear war" to "global economic meltdown". If we can't do that you might be right.

But we already had 10 meter tsunamis in Japan in 2011 and no one seemed to bat much of an eye. OTOH New York hasn't been nuked flat so that would probably raise eyebrows, not the least because it would be the one thing New Yorkers haven't seen.

In all seriousness, only Chicxulub is strong enough to break the modern economy and there are very few Chicxulubs out there. One less, actually. I literally described the absolute worst that could happen (biggest stock exchanges btfo'd and millions dead), because Apophis hitting the ocean (or somewhere uninhabited) is both most likely and least dangerous for anyone, not the least because it's something that has been done before very recently, but you do you I suppose.

 

[Archibald]

Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...

My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...

Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.

I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...

I'm glad it missed.

FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...

Don't forget the fall of 1983 as a very ugly, very scary moment, from late August to early December.
KAL-007, Petrov, Able Archer, and just to lighten the mood: The day after and Threads.
Reagan was granted a screening of The day after one month before it hit the screen; and ended pretty depressed by it. Now imagine if he had been screened Threads or On the beach. Or Fail safe.

(I remember watching the remake of Fail safe twenty years ago, the one with the E.R actors: Noah Wyle and Clooney, from memory. What really scared the shit out of me was the US president being on the phone with the ambassador in Moscow when the unstoppable rogue squadron came nuking the place.

Ambassador "Mr President, they are coming. When our conversation ends with a howl / whistling sound, its me and the phone melting in a thermonuclear in-" weeeeeeeep hooooowl there goes the ambassador and the phone.
And now the president has to trade New York 10 million souls against the planet, to cool the very pissed-off Soviets...

It is pretty likely that he had seen Failsafe and On the Beach given the era, at the very least heard about them.

But Threads would have scared the ever loving peewadens out of him!

Imagine if Maggie Thatcher did it: private screening of Threads for Reagan. Sweet Jesus.
Then Mitterrand calls and says "Hey, you should read Malevil, by Robert Merle".
Then Helmut Kohl "Heard of Nena 99 led balloons song ?"

Or better, this happens at a G7 summit...