The Destruction from an Asteroid Strike

The Day the Dinosaurs Died is an amazing tale of scientific discovery. You should read the whole thing. One sub-point, however, is a vivid description of the asteroid that wiped out the dinosaurs.

The asteroid was vaporized on impact. Its substance, mingling with vaporized Earth rock, formed a fiery plume, which reached halfway to the moon before collapsing in a pillar of incandescent dust. Computer models suggest that the atmosphere within fifteen hundred miles of ground zero became red hot from the debris storm, triggering gigantic forest fires. As the Earth rotated, the airborne material converged at the opposite side of the planet, where it fell and set fire to the entire Indian subcontinent. Measurements of the layer of ash and soot that eventually coated the Earth indicate that fires consumed about seventy per cent of the world’s forests. Meanwhile, giant tsunamis resulting from the impact churned across the Gulf of Mexico, tearing up coastlines, sometimes peeling up hundreds of feet of rock, pushing debris inland and then sucking it back out into deep water, leaving jumbled deposits that oilmen sometimes encounter in the course of deep-sea drilling.

…The dust and soot from the impact and the conflagrations prevented all sunlight from reaching the planet’s surface for months. Photosynthesis all but stopped, killing most of the plant life, extinguishing the phytoplankton in the oceans, and causing the amount of oxygen in the atmosphere to plummet. After the fires died down, Earth plunged into a period of cold, perhaps even a deep freeze. Earth’s two essential food chains, in the sea and on land, collapsed. About seventy-five per cent of all species went extinct. More than 99.9999 per cent of all living organisms on Earth died, and the carbon cycle came to a halt.

…One of the authors of the 1991 paper, David Kring, was so frightened by what he learned of the impact’s destructive nature that he became a leading voice in calling for a system to identify and neutralize threatening asteroids. “There’s no uncertainty to this statement: the Earth will be hit by a Chicxulub-size asteroid again, unless we deflect it,” he told me. “Even a three-hundred-metre rock would end world agriculture.”

When the asteroid hit it unleashed the energy of a billion Hiroshimas, that’s one reason I support foundations like the B612 Foundation who are working to map asteroids and develop systems to protect our world. As Tyler and I point out in textbook, protection from asteroids is a true public good which is one reason why we aren’t spending enough on this project.

Hat tip: Kevin Lewis.

Comments

An asteroid of the size that wiped out the dinosaurs

Will be attacked before it gets here

But

Not Global Warming

Because of our Dinosaurs.

You do understand that asteroids are real and AGW is a leftwing scam to seize more power and money.

I thought Jina was behind the scam.

Yes, it is a left wing scientist scam instigated by the guys in the Blue UN helmets who will descend in their helicopters at night to take away your guns because you will be helpless and unable to flee because your gas tank is empty. You did not hear about the nighttime UN helicopter attack because there was no electricity as you were relying upon the sunlight for your electricity and the wind turbines were not turning because there was no wind.

Only Donald Trump can save you. Repeat after me and look into my eyes and repeat so that the repetition of lies will make them true. You are getting sleepy.

Good thing we cut off aid to those 3 Mexican countries!

Repel the caravans! Attack! Attack!

"3 Mexican countries" sure was a little nugget of racism. Because there's simply no other way the headline writer's mind could have gone there. What are "Mexican countries?" The kinds of countries with "Mexicans" in them.

I allow a small possibility it was an honest mistake and "Mesoamerican" was meant. Maybe even an Autocorrect mistake- I had some doozies due to that. Still, are there no editors. No fact checkers?

Next thing you know, they'll claim radium causes cancer.

Or they’ll claim that capitalism causes AGW (those commie countries are carbon neutral I guess) or that implementing the GND in the US will save the world (when the US is about the only country whose emissions and coal usage is decreasing). Virtue signaling, it’s the new craze.

Capitalism doesn't cause AGW. China and Russia emit carbon too. And, when you fart, so do you.

If you have virtue, and do good, don't you want to signal to establish group norms that others then follow. It's cheaper to shame and its cheaper to develop group norms.

In fact, some people even recycle because others do. Whoda thought.

How’s that approach working out? US reduced coal consumption the last 2 years meanwhile the countries that signed the Paris Accord have increased usage so much that the net increase in CO2 exceeds all of the air transportation sector. I belong to the Sierra Club and you’ll never hear about this from them (or from the GND people). It’s all the US’ fault — makes you wonder if they are just US-haters after all. They’re certainly not serious people.

Your comment is misleading because it 1) is not on a per capita basis and 2) the US is one of the largest emitters.

On a per capita basis, US emits 15, German 8 and China 6.5

Here is the data from the Union of Concerned Scientists: https://www.ucsusa.org/global-warming/science-and-impacts/science/each-countrys-share-of-co2.html

I think you missed my point. As your article shows, the US is responsible for 15% of CO2 (and I agree that’s too much). But that 15% is decreasing while the other 85% from the Paris Accord countries is increasing, for a huge net global increase — at a time when we’re told that without a significant decrease over the next 12 years it’s all over now Baby Blue. The fact that GND and Sierra Club etc only talk about the US is just virtue signaling to their anti-American base. But I’m repeating myself.

GJ, If you look at the chart, and also the commentary, china is at 6.59 per capita; developing countries have relatively lower emissions per capita, and the risk is that with growth there will be an increase from that along. It is appropriate to talk about the US, AND, at the same time, talk about everyone else. It's not either or or nothing at all.

If everyone in the U.S. who believes in AGW were to reduce their CO2 emissions to zero it would go a long way to getting the U.S. down to 6.95 per capita. Go ahead, take the challenge...

Every read any articles about public goods and the prisoner's dilemma in the provision of public goods? That's why we have elected representatives who create laws.

And that's why our elected representatives are bought and paid for by those who would be our masters.

Per capital numbers are irrelevant, although pushed by China and India as a “restrictions don’t apply to us” ploy.

Physics doesn’t care about per capita, just global totals.

"Consumerism" might be a better claim, and only one step removed from mercantile capitalism.

That may be more accurate. Although if we look at pollution then it’s clear the pre-consumerist countries like the old Soviet Union, old commie China, current India, Indonesia, Philippines etc had/have way more pollution than the US. Look at the hysteria over plastics in the oceans — most of it comes from Asia. BTW I was just quoting AOC — did you see her definition of capitalism? Like her definition of socialism it doesn’t mean what everyone else means by these terms.

AOC lure .. rejected :-)

The pure-thermodynamics model of how much increasing carbon dioxide should increase the temperature of Earth: 1 degree Celsius per doubling of carbon dioxide.

The instrumentally-recorded rate of temperature increase against carbon dioxide concentration increases in the instrumental data era: 1.1 degrees Celsius per doubling of carbon dioxide.

At-current-rate-of-increases-in-emissions number of doublings of carbon dioxide in the atmosphere from the current level by 2100: 1, from c.400 ppm to c.800 ppm.

But if you insist, go and yell and scream in a panic about how if we don't do something, we'll miss the Paris goal of limiting warming to 2 degrees Celsius, because the computer models of climate scientists predict four times the warming that one would expect from either the physics or instrumental measurement.

Just yell and scream for something that would actually do some good -- building nuclear power plants. With hydroelectric almost fully exploited in North America and the trouble enhanced geothermal ran into with causing large earthquakes, nuclear is the only economically viable source of large quantities of low-emissions baseload power generation available.

Lunatic, Here is a link from NASA with climate data and all the scientific organizations which support the claim of climate change. https://climate.nasa.gov/scientific-consensus/

He's not disputing AGW, he's disputing the projections which show about double the warming that the pure physics would explain.

But hey if the argument went over your head, just call him a lunatic.

That's the problem with the true believers. If you don't attach a religious fervor to GW then you are a denier. Science supports that there is GW, and probably less than 50% is AGW. It won't be that bad, but we'll need to make some accomodation.

This too:

https://www.nbcnews.com/mach/science/key-greenland-glacier-growing-again-after-shrinking-years-nasa-study-ncna987116

You guys are basically engaged in autoerotica at this point.

Rats, Let's see if he can get his scientific "discovery" published. If this were a scientifically supported claim, someone else would have made the claim. Nothing is over your head if it makes no sense and if interested parties have not already discussed it.

There is no discovery, it's all already published in the literature. There are plenty of published-in-reputable-journals estimates of climate sensitivity in the 0.5-1.5 degrees per doubling of concentration range.

Please point to the article and I will read it.

You could start by reading any of the IPCC reports over the last 20 years.

For something on the low side, how about "On the Observational Determination of Climate Sensitivity and Its Implications" in the Asia-Pacific Journal of Atmospheric Sciences, August 2011, DOI:10.1007/s13143-011-0023-x .

For something closer to the IPCC consensus in a bigger journal, but with a range that includes under-1.5K sensitivity numbers, "The implications for climate sensitivity of AR5 forcing and heat uptake estimates", in Climate Dynamics, September 2014, DOI 10.1007/s00382-014-2342-y .

As far as the pure physics argument, I'll just aim you at Wikipedia on climate sensitivity; look for the words "which is easy to calculate and is undisputed"; there's a nearby link to how to actually do the calculation.

Everything separating "lukewarmists" form "alarmists" is arguments over the feedbacks and how to weigh the available evidence about the feedbacks, with a side argument over techniques for getting the numbers to calculate the feedbacks and how much bias is affecting everything. None of that involves ignoring anything strongly established empirically, or any big theoretical disputes . . . but the policy implications of 1.0K versus 4.5K are huge.

Thank you. That looks like a rational response.

Scanned the first article and also found this criticism of it the Skeptical Scientist along with evidence: https://skepticalscience.com/Richard_Lindzen_art3170.htm and for the second article here: https://skepticalscience.com/questions-on-climate-sensitivity-answered.html

The dispute appears to be about the degree, with the criticisms noted above.

So, if your doctor said: Lunatic, you will either die, or you will be miserable, unless you take this medicine. Would you choose to forgo the medicine because you could tolerate misery, even though there is a chance you would die. Sounds like neither is a good option, given that neither are good alternatives.

"Scanned the first article and also found this criticism of it... "

Translation: "I immediately sought anything that would dispute new information I didn't like"

Bill, this is the central argument for GW over the past 30 years and has been know for over 100. Most agree on the 1.2-2 range for CO2, but the warmest feel there are feedback loops that bring it higher. There could be, or feedback loops that make it lower. 1.5 seems to be the correct number, but if it is, then there is little reason to panic.

Little reason to "panic". Does that mean you do nothing?

I did write above "...but we'll need to make some accomodation" We are headed in the right direction, but even another doubling is still beneficial to life on earth, so no imminent threat.

TMC pretty much has it right here. There's nothing wrong with reasonable efforts to curb emissions and accommodate climate change. There's no reason to panic.

https://en.wikipedia.org/wiki/Ariadne#/media/File:Titian_Bacchus_and_Ariadne.jpg

Absolutely everything on that page is 100% consistent with my post. Climate change is real and measurable, otherwise you couldn't come up with estimates of it from the instrumental record -- which is, by the way, the very lines shown on that animated chart.

The question is not whether there is warming in response to carbon dioxide emissions, it is how strong it is.

One method is to assume that the likely amount of warming in response to carbon dioxide emissions is best determined by looking at how thermometer readings have changed as atmospheric carbon dioxide has increased by roughly 50%, remembering that due to the logarithmic response of the physics more heating happens tih the first 50% of any doubling than the second. There's also a fudge factor related to aerosol particulates lowering temperatures that's tricky to factor out. This gives an estimate of somewhere between the basic physics response and 1.5 degrees Celsius per doubling, and so an increase from the current 411 ppm to 822 ppm as +1 to +1.5 C, under the Paris temperature targets for 2100 with no effort.

A second method is that the likely amount of warming in response to carbon dioxide emissions is best determined by trying to estimate what temperatures were like thousands of years ago via proxies and then how they changed in response to things like estimated changes in how the Earth wobbled in its orbit. This has to be done with assuming other factors that we can't measure from a distance of thousands of years stayed constant. Then the estimate-to-estimate guess of how much temperature changed in response to the estimated changes is used to create the estimate of how much nonlinear response there will be to increased heat retention due to increased carbon dioxide, and then (despite the previous assumption that the response is nonlinear) apply that linearly from a different starting point than the one you derived the estimate from. This gives you something between +1.5 and +4.5 C per doubling of carbon dioxide, and a need to heavily rely on aerosols and heat hiding in the oceans and other methods to explain the discontinuity of the instrumental record.

If you are deliberately trying to create a worst-case scenario for warming, the second method has its points. But pretending that the measurements that are used in the first method and have to be explained away in order to not contradict the second somehow proves second method indicates either substantial ignorance or substantial disingenuity.

So you acknowledge nonlinear response, but defend linear estimates as successive approximation.

Ok, fine.

That means you can't give us your Nth estimate for 2050.

By that standard, neither can the IPCC.

The beginning/ends of the Ice Ages clearly had some sort of nonlinear response if the cause is Milankovitch cycles. The thing is, the most obvious nonlinearity is the albedo from icecaps. Because of the Earth's spherical nature, the closer the icecaps are to the Equator, the more effectively they reflect solar energy. Thus a retreat from mid-latitudes to inside the Arctic/Antarctic Circles will result in much more warming per square unit melted than they would today (and, incidentally, mean more square units, also because of the sphere shape). So there's an obvious reason to expect mean climate sensitivity to warming to drop off as the ice caps retreat. Melting ice inside the Arctic/Antarctic Circles just can't cause an effective increase in retained solar energy on the level that eliminating the Laurentide ice sheet did.

And the difference in where the ice is melting is another reason to prefer the instrumental record to historic estimates; the ice sheet conditions are more similar.

But, hey, you want to panic about the IPCC estimates, be my guest and demand a massive nuclearization of the electrical grid as the first and least-expensive step towards reducing carbon emissions. You have my full support in blasting away the dinosaurs opposed to that move. Replacing all of the New Deal TVA's coal plants with nuclear could even be called a Green New Deal if you like.

That's not the choice. Nuclear is more expensive than non-polluting alternatives:

"The first point is the very basic fact that new wind power and/or solar power plants are typically cheaper than new coal, natural gas, or nuclear power plants — even without any governmental support for solar or wind. Not only are they typically cheaper — they're much cheaper in many cases." From Google search on comparison of costs.

If new wind and/or solar plants truly are the cheapest new source of electrical generation - at scale and considering all costs - then the correct answer should be that little if any governmental action is required. Solar and wind should therefore grow over time to dominate electricity generation because they're the least expensive.

The real answer is that they aren't actually the cheapest options - especially once they account for more than a small percentage of electricity generation - for a variety of reasons, including the very important factor that an electricity grid getting something like 50% of generation from wind and solar would need huge amounts of backup capacity from other sources to account for the intermittency of wind and solar generation.

It is interesting, in a sad kind of way, that AT is writing about this as if most people don't already know. I have no reason to think he's wrong - other than the fact that if we're a species which is so stupid (in general) as to ignore clear existential risks, then we're probably a species which is too stupid to continue to exist. Alas, Babylon.

When I still considered myself an altruist, I wanted humanity to go extinct because this would prevent space colonization, which would prevent astronomical numbers of additional rape and torture victims.

Since I no longer consider myself an altruist, I don't care either way. Why would I, an individual person with a limited lifespan, care about the survival of a species, even if it's mine?

So the question really is, how big is the probability of an asteroid impact harming me, and what would it cost me to prevent it? Maybe it's cost-effective, maybe it isn't, but there's no reason to follow Parfit's or Bostrom's view that the issue should get a special bonus just because it's an extinction risk for Homo Sapiens.

Childless?

Yes, I'm childless. But even if you have children and care about them, the question of cost-effectiveness still matters. After all, you could use those resources to make your own children's lives better.

Even if a national government taxes people to run asteroid defense, it's a global coordination problem because there would be global free riders. If it's super cost-effective to prevent, it might still make sense, but otherwise you should probably tell the Effective Altruists to donate instead of taxing anyone. They're already obsessed with their assumed moral superiority, they'll probably cream themselves over the opportunity to pay those bills. :-)

Free lunch economics....

I bet you believe that if the 13th were repealed to Make America Great Again, except with the 14th, 80% of the population including white people would be slaves, the much lower labor costs would result in at least twice the consumer spending, easily doubling GDP.

Or by replacing 90% of workers with robots and AI, the slashed labor costs would double consumer spending, again doubbling GDP.

After all, economies are not zero sum.

Workers are never consumers.
Consumers are never workers.

Thus paying more workers must make consumers poorer, cutting GDP.

As if the reason Africa is poor is workers in Africa are paid a million dollars a month to work, making African consumers have too little money to spend.

Keynes was not the first to point out how cutting costs by not paying workers harms pretty much everyone, including those who cut costs to ensure they dont end up in poverty.

His point about treasury departments burying jars of money was not about giving away cash, but instead about getting workers paid to dig up the jars of money.

When FDR hiked the price government paid for gold used to balance international trade, he did what Keynes advocated as a thought experiment, without actually burying jars oof money. He simply caused twice as many workers to mine gold. US gold production doubled, until gold mining was banned to free up workers for the war.

Did paying workers to mine gold harm workers in general?

The gold added to the US gold reserves depleted by the recovery of Europe production reversing trade flows, enabling Europe to buy back its gold sent to secure US export profiteering on Europe's WWI destruction during the 20s.

Economies are in fact zero sum.

The only way to increase production is to pay consumers to work more. Workers are consumers, and woorker income is consumer spending.

Giving consumers money without requiring work is Venezuela. Ie, government buys imports, or pays local producers low prices, and sells below cost of producing in Venezuela to cut costs to consumers. Just as you want, lower costs of living by not paying workers.

>"Keynes was not the first to point out how cutting costs by not paying workers harms pretty much everyone, including those who cut costs"

Henry Clay said the same thing.

I saw a documentary which stated that bolides with the equivalent energy of the Hiroshima or Nagasaki blast collide with the Earth about every two weeks.
Given the short lead times experienced with Oumoumou or the green comet C/2018 Y1 Iwamoto, our money would be better spent developing better detection systems and civil defense preparation than on the current AGW craze whose predictions have not been accurate because of a bias against the historical causes of climate change.

I always thought it was an asteroid impact PLUS something else, but the description here makes it seems unnecessary for there to have been any secondary causes.

A secondary cause really was likely unnecessary, but it's probable the impact did cause a surge of vulcanism as seen in the Deccan Traps.

The truly amazing thing is that life recovered. It says, "the carbon cycle came to a halt," and yet life recovered. The asteroid said, "Take this, earth," and DNA just laughed. "I coded for every climate and environment. You're gone in a burst of flame, but I'll live on forever. I'll probably even use your rare elements to improve things."

"NEXT!"

The Cretaceous extinction was pretty bad at the time, I'm sure, but to Life, it was just another bump in the road.

https://en.wikipedia.org/wiki/List_of_extinction_events

I can only imagine the guilt and shame felt during the precambrian great oxygenation event, in which the endless greed of plant life for carbon dioxide led to spiraling levels of oxygen in the atmosphere and the mass extinction of most other forms of life.

Believe or no, but at least one alternative view does exist:

http://fictionaut.com/stories/strannikov/notes-from-an-extra-galactic-alchemist-on-an-observed-failure-of-proto-intelligence

(a matter of whether we are able to trust Nature to be natural)

I read that the animals would have seen the asteroid in the sky for a time, even during the daytime?

It is amazing how recent an achievement it was, figuring out the dinosaurs' end. My understanding is that Alvarez noticed the iridium layer, made the inference, and then years later (by chance?) a Texas reporter mentioned to somebody searching for the big crater that an oil company geophysicist had told him about a symmetry he noticed in the ocean off the Yucatan. A cool capper to the period during which all of us, but children especially, were captivated by dinosaurs.

The irony is that just at a moment in history when what happened 250 million years ago should be more broadly known, and taught, and heeded, Cretaceous-mania has completely overshadowed the End Permian Extinction.

Hey kids! Hypercanes?! The ocean farting great clouds of hydrogen sulfide? Coal deposits exploding? Lava 2 miles thick? CO2 pumped into the atmosphere at a rate that's never been ... oh wait ...

Even more amazing considering it was only in the 1930s people started to think craters on Earth could be caused by impact, not just volcanism.

The clip that Alex linked to starts with: "The world nearly ended on September 29th, 2004. That's when the asteroid Toutasis narrowly missed the planet."

[Al Gore sigh] No guys, no.

It continues that because an asteroid would kill everyone "the risk is greater than it appears." Risk is depends on the level of impact?

It’s pretty standard to assess “risk” as probability of occurance x magnitude of impact, i.e. 15% probability x $5 million cost = $750K risk.

If you run this for a 1% chance of large EMP event over the next 20 years, for example, it’s a huge risk, because the damage is (there is some dispute) truly catastrophic.

OK, but I've never heard risk used that way how Cowen used it: "the risk goes up".

The data suggests that an asteroid did indeed hit, left a mark and caused a big disturbance, but consider an alternative theory. Volcanic eruptions over hundreds of thousands of years may have been the cause of mass extinction vs. asteroid impact.

Not sure if this alters the risk equation - but certainly worth noting when discussing asteroids and dinosaurs.

https://www.theatlantic.com/magazine/archive/2018/09/dinosaur-extinction-debate/565769/

https://massextinction.princeton.edu/publications

http://science.sciencemag.org/content/363/6429/866

http://science.sciencemag.org/content/363/6429/862

However, I've seen some hypotheses that the Chicxulub bolide impact triggered the Decca volcanic outburst, which makes sense. Recall when ExxonMobil was HQ'd in northern VA, when they drilled those experimental fracking sites, it triggered a mild earthquake there. The earth is rather fluid and perturbations can cause magma to come to the surface. It happened in Indonesia a couple of years ago too (drilling an oil well caused magma to come to the surface). I've even seen papers that say extremely cold weather followed by hot weather can trigger an earthquake maybe, which to me has some anecdotal evidence.

BTW I've donated to the B612 Foundation several times.

Bonus trivia: there's an "alarmist" but not inaccurate book out now, reviewed by the Economist, on runaway global warming, another "public good" underrated event.

Given that B612 has raised something like $5M compared to its goal of $450M, I’d say the only reason to donate is so you can virtue signal to your fellow MR commenters. Well done Ray, my descendants will be so grateful!

What has it been such a failure? X-risk charities seem to be doing fairly well these days (rightfully so in my opinion)

That's the most important characteristic of public goods: neither private markets nor private donations will provide the optimum quantity of the good.

So B612 is doomed to be mere virtue signalling. The standard econ textbook solution is that government needs to step in to provide the public good. Are you agreeing or disagreeing with that solution? (For that matter it's not clear to me if Alex agrees or disagrees.)

I don't think impact protection is bad, but I'm not sure we'll have the tech in our lifetimes. Even if you can nuke a comet, you just turn a bullet into shotgun blast. And I think I've heard some recent studies say that fragments would recombine with mutual attraction anyway.

Worry about things you can change. Starting closest to home, that's still diet and exercise.

A little further afield, but not much, lead in the national water supply.

https://www.space.com/40943-nasa-asteroid-defense-plan.html

Pb in H2O is somewhat overrated as a threat. I know, I know, I've read the literature but consider that the Romans used lead in pipes, the 19th century Americans with great GDP growth rates used lots of lead, they used lead in gasoline as an additive for until the 1980s, and actually lead from legacy plumbing welds is still active in the Washington DC water supply (they use a chemical that combines with lead to leach it out of the holding tanks), and not to mention lead in paint, lead in fishing sinkers, lead in auto wheel alignment. Pb is dangerous long term, mimicking syphilis symptoms but it's not that bad, same with mercury (or syphilis). Life goes on, unlike a bolide impact.

Bonus trivia: after the Ordovician Period (485-444 Mya) there was a 'snowball earth' extinction event, where the earth froze almost solid, wiping out much sea life.

Just because lead's effects are insidious doesn't mean they are not potentially enormous and worth spending resources to avoid. If the people of Rome and the US 1800-1980 all lost on average one IQ point to lead, how would you know? Slight but widespread stupification is all that bad.

Exactly. Anyone who worries about national IQ should be all over this here-and-now problem.

As Todd says, we are in the planning on trying things stage of "planetary defense." That's fine, but .. sometimes I think "small government" types prefer remote "problems" because they are such a great slight of hand.

Got some here-and-now problem? Let's talk Mars missions!

Minor error. Burning all the surface carbon in the form of trees, etc. would not deplete the oxygen on the planet by a significant amount. However, it would increase the CO2 by a significant amount.

A significant amount is related to air-breathing land life like humans. We don't even notice at 4% decrease in O2 in the air, but a 4% increase in CO2 (a 100 times the present levels) will have very significant effects.

We can calculate the total CO2 added by the burning of surface carbon and I don't know what the number will be, but I know it will be proportional to the O2 removed. The basic chemistry and concentrations of atmospheric gases are reported at volume fractions which are equivalent to the molar fractions with one mole of carbon in trees producing one mole of CO2.

"Burning all the surface carbon in the form of trees, etc. would not deplete the oxygen on the planet by a significant amount. "

Sure, but all the plants burnt up would reduce the supply by a large amount. If there was an asymmetry in death rates between fauna and flora with the animals surviving longer, it would have reduced the O2 supply. Granted, that's just speculation, but it seems plausible.

We evolved for one job.

It looks to me as this entire issue is just an excuse to fund a big space exploration program. Now I am big enough of a nerd to support this nonetheless. However it is probably much cheaper and easier to figure out how to make humanity survive such a catastrophe. I'm thinking a crash program of dome building and hydroponic farming, etc. Obviously almost all of us die when the asteroid hits. But if we could save a million or so people that might do the trick. That is, we hunker down and wait for the planet to recover.

Yeah, that completely eliminates our incentive to actually fund this.

An alternate approach would direct funding to bio-engineering: in a scant few thousand years (maybe a few tens of thousands of years, but if the cosmos can work with cosmic timing, so can we), we could conjure a divergent aquatic human species to thrive serenely in comfortable ocean depths.

--although the newly-announced fossil deposits at the Tanis site in North Dakota seem to show at least as much dead marine life as the lone triceratops so far discovered.

Seems trivial that we would survive as a species? Plenty of people with bunkers, right? Why wouldn't a person in an underground bunker with at least a fe months' food supply survive this? Okay it's cold and hard to grow stuff for a little while, depending on where you are, but in the tropics you're probably good, growing season all year round. Many people have years worth of food, lost of spare resources probably lying around now. Not that it would be fun, of course.

Hilarity: you build a secret bunker, stock it well, and await the end of the world.

As impact day approaches you realise you've built it at ground zero.

The new find of fossilized animals that look to have died on that day:

https://news.berkeley.edu/2019/03/29/66-million-year-old-deathbed-linked-to-dinosaur-killing-meteor/

One of the things I liked about Alex's posts were they sounded different to Tyler's, I could always pick an Alex post. But it seems these days Alex is imitating Tyler's language which is a shame, I can't tell the difference any more except for the author tag line.

" the Earth will be hit by a Chicxulub-size asteroid again, unless we deflect it"
Yes but what are the chances that it will happen in the next fifty years? Maybe 0.000000000000001%? And with the technology that we will have in fifty years anything we do today will be laughable. Therefore, lets worry about it in fifty years when 1% of what we would spend today would be 1000 times more effective.

Deflection is probably beyond today's technology. Detection is not.

No, deflection probably isn't. A series of nuclear burst on the side of an asteroid could easily deflect it far enough to prevent a direct hit. Granted, we don't have the infrastructure in place to do so. But that's because we haven't chosen to build it, not because we can't do it.

Some asteroids are rubble piles. Detonation might not deflect them.

Physics says that force applies to rubble piles also. And in any case you wouldn't even need to deflect it, if it was a rubble pile. Just hit it in the center it will spread out and the atmosphere will burn up the diffused material.

Conservation of momentum: all that rubble will still be headed right toward earth, including chunks large enough to do enormous damage.

The nuke exploding on the side provides a lateral force. The asteroid being rubble will still move in the opposite direction. Newton's law applies to rubble. Though of course you'll have smaller pieces flying everywhere. But they'll burn up in the atmosphere.

The idea is a nuclear bomb is detonated near but not on a rubble pile will nudge it slightly. It is an inefficient use of energy though. Since we'll probably have plenty of time we could send solar sails close to the sun and then have them smack into the object. Or we could park a heap of solar PV next to it and "laser" it so the ablating material will act like rocket thrust and nudge it away.

Sure, it's inefficient. But....

We are pretty sure it will work. Marginal cost of the Nth nuke is small. And it's got great redundancy; a failed nuke or two won't matter.

By the time we realise the Solar PV isn't working we might have wasted months....I get the feeling this is an "engineers solution"; over-optimised.

As an engineer, I agree with the solution that has a failure contingency built in. Also, people fail to understand what even a little nudge can do in space.

If your nuke only nudges it laterally 10 m/s a week before impact it will completely miss the Earth. If you hit it 40 days before impact a nudge of 1 m/s would be enough.

The lead time we have on potential impacts can range from none to decades, so it's a matter of picking the right tool for the job.

By opening the door to opportunity for the commercial exploitation, the great nation of Luxembourg has taken the global lead in substantive versus rhetorical progress on this front.

https://spaceresources.public.lu/en.html

The technology to exploit an asteroid will have near, if not total, overlap with the technology needed to address a potential earth strike.

A tax-exempt paying rent for offices outside of Palo Alto is about as likely to accomplish anything as is the Southern Poverty Law Center about to admit that white supremacy is danger posed by a relatively few individuals that can be managed by law enforcement agencies.

The less NASA has to do with it, the better. If it has a fraction of the Aldrich Ames, James Hansens, and James Clappers that infest the intelligence agencies, the Chinese would have any technology we invent developed, weaponized, and used against us before we even got a funding bill passed.

Considering in any risk management framework, the costs of a large asteroid strike are near infinite (possible mega causality event of humanity and destruction of global economy) x very low probability = catastrophic results, I fail to understand why the US neocons aren't interested in serious investment in this field considering they think the US is the insurer of every rich sovereign nation.

"protection from asteroids is a true public good which is one reason why we aren’t spending enough on this project."
Clearly there are many public goods that are underprovided. What true public goods that are adequately are excessively provided? US national defense only?

The "good" news is the odds are really in favor of us getting city destroying asteroid hits long before a dinosaur killer comes along. If we don't have an asteroid defense before a city killer comes along one should focus our attention.

+1, that's probably the best thread response all things considered.

The thing is that a city killer already happened in 1908 with the Tunguska explosion that could have wiped out Moscow but happened in a remote area in Siberia. Large and small cities only cover 3% of the land so a little over 1% of the Earth.

Think of the historical differences if Moscow had been wiped out in 1908

It was similar longitude, wasn't it? A minute or three faster rotation on the earth.....

Would have made a super-cool conspiracy theory and talking point for the entire 20C..

The Russian seat of government was on St Petersburg in 1908, so while losing Moscow would have been horrific it would not have had the same impact that losing, say, London or Berlin would have had.

If dinosaur killers come on average once every 65 million years and roughly Tunguska sized impacts happen every century, then on average we'll have 65,000 Tunguskas for every dinosaur killer.

But the Tunguska hits don't happen anywhere nearly as often as once a century.

One estimate is Tunguska sized events happen roughly every thousand years, but it released energy roughly 1,000 times greater than the atomic bomb exploded over Hiroshima. An impact doesn't have to be that big to cause a lot of grief.

So a 1% chance of losing a city of 100,000 people once every thousand years and one just occurred a hundred years ago. A 1% chance in 2300 or 2800 is trivial and wouldn't serve as a wake up call because enough scientists are "woke" in 2019.

Asteroid hit - fantasy
Catastrophic climate change - science fiction
Nuclear war - a possible painful period for humanity
A.I. - heck if I know

What I think will happen is, because we are getting very good at cataloging earth orbit crossing objects and they are the most likely threat, at some point one will be found that is likely to hit the earth after many years. Because smaller objects are more common it strongly likely to be a smaller object and we will decide to do something about it. Because we will have advanced warning we will have plenty of time to prepare and so whatever we do is likely to work. With the knowledge gained and the -- barring disaster -- technology improvements that will have occurred in this time our ability to detect and deflect potential impactors will be much greater.

No human has been known to have been killed by an object from space over the last 1,000 years, although it may have happened in India in 2016.

"In fact, as best as we can tell, no large object is likely to strike the Earth any time in the next several hundred years."

At the end:
https://www2.jpl.nasa.gov/sl9/back2.html

Okay, and the Chelyabinsk meteor was 20m across and resulted in 1,491 injuries.

Wiki says that blast in 2013 was 30 times as powerful as the energy released over Hiroshima and the largest object (20 meters) known to have entered the atmosphere since 1908 and no deaths.

Yep, it sure does say that.

I figure the annual risk of a dinosaur killer asteroid at about 1 in 100 million. If you figure the statistical value of a life is maybe a million, then the cost of extinction would be on the order of $10^16. Hence it would be worth it to spend about $100 million per year on asteroid mitigation. Which is not much--a small fraction of the NASA budget.

"I figure the annual risk of a dinosaur killer asteroid at about 1 in 100 million."

We have a pretty good idea of the chances of a dinosaur killer hitting in the next several hundred years:

https://www.econlib.org/the-public-good-of-protection-from-asteroids/#comment-219571

Wouldn't a better idea be to spend money to verify that no impact is going to happen in the next couple hundred years rather than to spend money on how to defend against a hypothetical?

For example, suppose the NASA Sentry program to which I referred in that link shows that an asteroid 0.5 km in diameter (not extinction-class, but a very bad deal) will hit in 68 years. Wouldn't we be much wiser to spend much more than $100 million per year to defend against that particular threat, than to spend $100 million per year just thinking about a hypothetical much larger asteroid?

Put into malaria prevention the money might save lives at maybe $5,000 each. Of course, since malaria is gradually being beaten, you'd (hopefully?) soon run into diminishing returns on this. Fingers crossed the world soon runs out of opportunities to save lives at low cost -- in a nice way of course, not because an asteroid impact has rendered us extinct.

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