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Asteroid crater 520km in diameter buried in southeast Australia, scientists say (australiangeographic.com.au)
327 points by mafro on Aug 17, 2023 | hide | past | favorite | 192 comments


Looking at that map, it's wild how many "confirmed impact structures more than 100km wide" there are just in Australia. There must be dozens of mass extinction events that we don't know about because the fossil record is so unclear past 500Mya.

[0]: https://en.wikipedia.org/wiki/Extinction_event

[1]: https://en.wikipedia.org/wiki/Chicxulub_crater

[2]: https://en.wikipedia.org/wiki/Earth#Natural_history


I think this map can mislead you to think that but if you look at the graphs from the reference they quote, there's not much in the last billion years or so that's close to Chicxulub, a known extinction-causing impact. It's a real outlier and it's reasonable to assume much smaller impacts did not cause mass extinctions by themselves. I've fished graphs out here and marked Chicxulub in the first one:

https://i.imgur.com/Rwk6W3j.png

https://i.imgur.com/ATZIK2r.png


That's fun to think about, but Precambrian life was generally microscopic. Many impact craters across the world date from that era, so any extinctions they caused would not be visible to the naked eye.


Maybe they would though?

Individual bacteria aren’t usually visible to the naked eye, but they tend not to exists isolation.

So maybe the immediate post impact world had less pond scum?


During a cave tour one time the guide told us that the darker strata in the marble(?) in the cave walls was from microscopic life in an ancient seabed, and the lighter ones were from periods of...not sure if extinction is the right word, but "less of it".


Google "Chicxulub crater" for a fun animation



I wonder if more recent events will ever get this treatment?


Maybe in another 60 million years, by whatever the cockroaches evolve into.


Also imagine how many hit the oceans. A water hit can be even more catastrophic than a land hit, especially on shallow water like the continental shelf.


Every 26k years we pass through an asteroid belt with a high probability of impact


26,000 years sounds more like the period for Earth's axial precession. https://en.wikipedia.org/wiki/Axial_precession .

What you describe doesn't make sense. The Earth's orbit is effectively constant at that timescale, as are the asteroids in the main asteroid belt - otherwise interactions with Earth's would have changed the orbit.

There are conjectures of regular extinction events on 30-60M year intervals, but the data for that isn't strong. https://en.wikipedia.org/wiki/Extinction_event#Patterns_in_f...


Our star system has only a single asteroid belt, so if you are referring to it then the proper phrasing would be "the asteroid belt" (like "the moon" and "the sun"). And no, we (assuming that "we" is the Earth) do not pass through it at all.

If you are suggesting that we are passing through another asteroid belt, like the ones around Vega or Fomalhaut, then the damage done by passing so close to their star would far outpace the damage done by their asteroid belt!


Is there a source for this? I wasn't aware of that, and it sounds interesting.


So New Zealand might not be the best place to bug out to if Australia is a meteor magnet.


We’re a terrible choice for avoiding natural disasters. There is a 75% chance of the Alpine Fault between The Pacific Plate and the Indo-Australian Plate rupturing in the next 50 years and they tend to be earthquakes of magnitude 8+.

On average it ruptures every 291 years (+/- 23), and the last one was in 1717.

https://en.m.wikipedia.org/wiki/Alpine_Fault


The theory is that visitor centers attract meteors, but what is not understood is why the meteors never actually hit them directly, and why so many meteors land in craters.

https://www.reddit.com/r/funny/comments/fgztcd/look_how_clos...


New Zealand like Japan, Indonesia and other places around the pacific ring of fire is very geologically active.

I have only barely felt one earthquake living in Australia in half a century and it was almost imperceptible. I expect the low geological activity is one of the reasons evidence of meteor impacts is well preserved in Australia.


Not that meteor magnets exist, but https://en.wikipedia.org/wiki/List_of_impact_craters_on_Eart... says there are more known impact craters in Europe than Australia.


Wow that's a huge crater. It's bigger than the Vredefort impact structure in South Africa. The Vredefort dome is the second oldest at 2 billion years old that can be seen here:

https://upload.wikimedia.org/wikipedia/commons/b/b5/Vredefor...

And the full-sized version:

https://upload.wikimedia.org/wikipedia/commons/5/52/Vredefor...

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


> The impact structure was formed during the Paleoproterozoic Era, 2.023 billion (± 4 million) years ago.

> The asteroid that hit Vredefort is estimated to have been one of the largest ever to strike Earth since the Hadean Eon some four billion years ago...

Let that sink in (ugh) for a while. The Vredefort impact was so long ago, it's almost completely eroded away today. And yet, when it occurred the Hadean Eon was as ancient then as the Vredefort is to us today. The mind boggles.


There's another one straight north in the second picture. That one looks like someone dropped a rock in mud on a hot day.

I was confused about why the pictures seemed to have different craters, until I found the one you're talking about in the middle.


I know it's buried deep, but it's kind of weird for the reporting to not even show an image of the area? Perhaps a map with a little pin indicating where the Deniliquin structure is?

They say it's near the city of Deniliquin, which is here [0]. Oddly, that spot doesn't even show on the map of yellow dots of likely impact structures! Did they forget to mark their newly discovered largest-impact-crater-in-the-world on the map?

[0] https://goo.gl/maps/shvRY2CiEs3eR8iw5


> I know it's buried deep, but it's kind of weird for the reporting to not even show an image of the area?

It’s something I have seen becoming the norm nowadays. Articles about art or photographs without a single image. Political articles about borders without a single map. Articles about some thing some scientist has done, maybe with a picture of the scientist, but not of the actual thing. And it’s not a technical limitation of the medium; most articles will have numerous (but irrelevant) images.

I suspect that SEO measurement has told people that it doesn’t matter what images an article has, as long as it has some images, optimally interspersed with the text. Spending any money on getting relevant images thus becomes an unnecessary expense. Readers will still click on the article (because of the click-bait headline), and will still read (or at least scroll through) the article if the text is broken up by images by an optimal amount.


Perhaps putting a relevant image on the page quickly satisfies the users, so they click off the page quickly. But _not_ putting a relevant image on the page makes the user scroll more and stay longer, thus exposing all the advertisements and increasing engagement and retention metrics.


KPIs and A/B testing led to this. But those manager KPIs are directly against user-interest. Which managers measure user-happiness?


There is no Javascript API for to measure user-happiness.


Researchers often obscure the location of sites on purpose so that tourists and vandals don't show up and damage them. They'll share better photos and maps in person, but not anywhere that the public can see.

This probably applies more to something like the archaeological and geological digs at Lake Mungo than a 520km-wide buried crater, but there can be a "better safe than sorry" attitude in the field.


Could be as simple as the fact that images make the page take longer to load. Google penalizes that, as I understand it.


No, probably not, since many articles have images, but only irrelevant ones (i.e. stock images).


What specifically does Google measure? Entire load time, or just first contentful paint?


I think you're right. We know ChatGPT-4 can do image analysis, so all Google has to do is say that they're down ranking articles that don't have relevant images, and we'll be back to having useful images in artichokes again.


too late to edit, but -2? if there's feedback for me on why, I'm all ears!

(also, lol artichokes. ducking autocorrect.)


It's a huge area and it's very, very flat. Australia's geologically very inactive so any visible crater was gone many millions of years ago.

An image would just look like this: https://earth.google.com/web/search/Deniliquin+NSW/@-35.3522...

To give an idea of scale, the area they're talking about is equivalent to from Boston to Philadelphia. It's big.


1. I would love to still have that very photo! Captioned, “Buried under a swathe of never ending desert wasteland, the crater lies hidden under 8 kilometers of sand and rock”

2. You can still show me a map with a marker indicating where the hell the site is.


There's not a lot of interest around there. Deniliquin is a town of less than 8000.

This picture shows some surrounding towns https://images.theconversation.com/files/541855/original/fil...


The whole article seems AI generated to me.

The AI did not know to include THAT picture.


Maybe it's not yet considered likely?


I have always thought Lake Michigan/Huron look mighty round if you follow from the north end down through Green Bay and the Fox river to the west, and cut into Canada along the Niagara Escarpment [1] on the East. There seem to be signs of a round structure all the way down in Ohio. But while this does form a roundish structure, the history is quite different than an impact:

[1] https://en.wikipedia.org/wiki/Niagara_Escarpment

Still I wonder, what if this other stuff happened in this shape because of a giant impact crater billions of years ago before all that?


There's also the "Nastapoka arc"[0] of Hudson Bay that looks a bit cratery, but is apparently of a different origin.

[0] https://en.m.wikipedia.org/wiki/Nastapoka_arc


It's very distinctive on an elevation map.

https://mrgris.com/projects/oilslick/

I remember thinking there's no way that's not a crater.


Thought to be formed as a result of lithospheric flexure during the Trans-Hudson orogeny, apparently.


Craterish?


Apparently arcuate is the preferred term


I just read that word over here for the first time: https://en.m.wikipedia.org/wiki/Nastapoka_arc

As someone who reads a lot in general and on the topic of space in particular, I am surprised to only discover this word today. I suspect that it is not a common word, or maybe it is a new word.


(I found it in the same place :-) )


Crateroid?


crater-like


The Crater-ion Collection [cue logo, cue greyscale film of various impact events]


It's not related to the escarpment, that is a glacial feature. Their origin is not impact related, either, it is tectonic (the rift valley from a failed continental rift): https://en.wikipedia.org/wiki/Midcontinent_Rift_System


There is the Sudbury crater.

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

Just North-East of Lake Huron.


Article says the center of the impact crater is (was?) around 30km deep. Curious how big they think the asteroid that caused this was. The article doesn't mention anything, and a lazy search online came up with nothing.

Wondering just how big of an asteriod this was, and how capable we are of seeing candidate asteroids of this size.


http://simulator.down2earth.eu/planet.html?lang=en

According to this calculator you get a 446km diameter crater if you input:

- 15km asteroid diameter

- 90º Angle

- 80km/s

- Dense Rock asteroid

- Hitting on Water at level 10m


FYI these are the maximums you can input to get the largest possible crater using this simulator.


We’re going to need a bigger calculator.


... not great, not terrible.


Hehe. That's a great scene. Meanwhile, I think it was big enough to do the job.


Yeah I had to max inputs on that calculator. Pretty wild.


15kms at 80km/s

So, for a quarter of a second or less it was touching the ground and almost double the height of Everest (8.8kms).


It makes me wonder what an impactor like that would do if intercepted by the moon; that may be even enough mass to cause a temporary ring field just from the debris


If you wonder about things like that, you might want to read Seveneves by Neal Stephenson.


I wonder if just the atmosphere would've caused it to explode already. At those speeds it'd go through the atmosphere within a second though.


Got me thinking, What happens, when and where.

A column of air weighs ~1kg/cm^2 (handy!), and the example has a 15km span of "Dense Rock" which I've seen mean "Dense Rock Equivalent" in the Volcanic Explosivity Index, where it has a density of 2,500 kg/m^3. Assuming that, a column of the asteroid is

2500kg/cm^2/(100cm/m * 100cm/m) = .25kg/m * 15km = 3,750kg

The kinetic energy per column of the impactor is 1/2mv^2, or 0.5 * 3750 * 80000m/s^2, or

1875 * 6.4e9m^2/s^2 = 1.2e13 Joules

Which is about 20 gallons of gasoline equivalent. As you say, that's absorbed in ~1s (space is 100km up, so 80km/s is just about right). If so that warms up and starts melting the surface of the asteroid, but not much more I guess.


Whoops, I carried down the wrong number to the gasoline conversion.. I left off the 1875

The whole impact is like 40000 gallons of gasoline per cm^2 of surface, or I think like 2kt TNT.

So then, not sure what the kinetics/kinematics is there. How much is released by the atmosphere impact vs then the surface stopping the asteroid.


Ok! ChatG4 is amazing!

https://chat.openai.com/share/25e4cef6-321a-43f7-8d13-40d1fd...

Summary: my initial math checks out for the total KE of the asteroid, and then we used that to look at the surface heating by the compressed atmosphere and then the Fourier heat analysis of conduction into the asteroid surface

Answer: Tho the atmosphere would be heated to 100k degrees and that's 1000x more than needed for vaporization of e.g. granite, the duration of ~1s means that only a few millimeters of surface would be vaporized by the time of impact.


does it give the same answer repeatedly? every time i've tried to solve problems like that with chatgpt i've been given beautifully worded garbage that doesn't commpute by hand, and won't be repeated if I retry the prompt.


That's my experience with ChatGPT 3.5. But with 4.. well, as far as I'm concerned, this is AGI.

I just did a compacted single-shot request in a new session and got the same answer!

It basically elided the simplifying analysis, went directly for the heat diffusion equation and based its conclusion on that. Impressive.

https://chat.openai.com/share/0c857ebd-779a-4f40-93a9-c35cd2...


For such a size impactor, atmosphere does nothing. Might as well be vacuum.

Sure, milliseconds before impact the atmosphere might be super-compressed (and super-heated). Perhaps even exert considerable force. But compared with kinetic energy of that size impactor, at such speed: negligable.

Small objects 'feel' the atmosphere much stronger. Surface area vs. volume.


Whatever parts of the atmosphere were involved in the direct vicinity of the impactor would be heated to plasma. It is just too much energy, you're talking about the equivalent of a massive number of H-Bombs all going off at roughly the same time.


It would probably punch a 15km wide hole in the atmosphere, no? Which would then rapidly collapse from the sides and collide with whatever was ejected... would be fun to watch while parked somewhere safe in orbit.


15 km diameter is about the size of "thick" atmosphere. The mass of the air in this volume is something about 0.000..% . At speed of 80 km/sec, well, atmosphere didn't slow it down much. And if there was only microbial life at that time it adapted and bounced back quickly.


I was thinking of it's 80km/s wake through the atmosphere. Coming straight in it wouldn't be long horizontally but the clap of 15kms of atmosphere being pushed aside and then coming together behind it...


Most likely 'behind' was filled by evaporated water and rocks. But that was quite a shock wave both in atmosphere and in the ground.

It's strange that in managed to get only 2x of its diameter into the crust. I though it could just get though into magma. That would make the biggest volcano ever.


Better not be LEO... I wonder how high the ejecta would go and how far they would reach across the planet.


Much too large for that. Under 50 meters or so you can get airbursts, after that it is direct impact.


That's why "dense rock" setting was used. Imagine if they had selected "solid iron". I don't know what settings are available for the calculator used, but "loose bunch of rocks" would probably fall apart in the atmo, dense rock would hold together until impact, and solid iron would just keep burrowing further


A 15km chunk of solid iron, now that's the kind of bunker buster you throw around in an interplanetary war.

Would it do more damage to the surface than a rocky asteriod of comparable mass, though? If it burrows deeper, it means it transfers more of its energy to the mantle and core of the Earth, and less to the crust. It will be like a full metal jacket bullet that goes straight through the target and transfers most of its energy to the wall on the other side, versus a regular bullet that tumbles and expands as soon as it hits the target.


Throwing Meteors as interplanetary weapons was a storyline from The Expanse books/TV series if I recall.


Deorbiting a multi-million dollar satellite as a weapon was the plot of of a Tom Clancy book. The bad guy was going to launch a nuke from his ship and the only thing that could get there in time was the super special satellite.


Was this an OpCenter plot? It's definitely not a Jack Ryan series plot. I never really picked up the post-divorce stuff he wrote.


Yeah. Bad guy mounted thrusters on large asteroids from the belts. Not technically meteors, but close enough.

Neat sci-fi.


At that speed I’m pretty sure that it would be vaporised on impact, so it wouldn’t matter.


It would be exploding for the duration, but at that size you just can’t get through much of the asteroid before it touches the ground.


And it still only went down to about twice its diameter. Makes you really respect how tough the Earth's crust is.


The deepest borehole, about the size of a coffee can, is only 12km deep before the tooling started melting - can't drill with a liquid bit...

So 30km down it would be hitting liquid rock and a lot of heat.


Yes, the mantle is about that thick. And much thinner in some places even. Which makes me wonder how they detected this crater and what the crater is formed in. This is the relevant bit from the article:

"Between 1995 and 2000, Tony Yeates suggested magnetic patterns beneath the Murray Basin in New South Wales likely represented a massive, buried impact structure. An analysis of the region’s updated geophysical data between 2015 and 2020 confirmed the existence of a 520km diameter structure with a seismically defined dome at its centre.

The Deniliquin structure has all the features that would be expected from a large-scale impact structure. For instance, magnetic readings of the area reveal a symmetrical rippling pattern in the crust around the structure’s core. This was likely produced during the impact as extremely high temperatures created intense magnetic forces."

But they would not able to verify that at that depth without a lot of drilling and the end of the article suggests that they have yet to do so.


Would be wild if aliens had cameras on every planet and one day decides to show us what this looked like


Little grey dudes sitting us down in the slideshow room to show their holiday pictures from a few million years ago, lol. "And this is when ⌘⑩⌖⌦ nearly got eaten by a dinosaur!"


Well the article and the title here on HN both says "520km in diameter", which gives an idea (although there's more than the diameter to estimate the damaged caused by an asteroid, but 520km in diameter is quite something).


That's the crater diameter, which'll be much larger than the impactor.


Given that land mass is smaller than oceans, there was probably an even bigger asteroid which fell into the ocean.



Seems like maybe our ability to find and divert these asteroids might make all that burning of energy worth it, no?


Not really, since there are only a few known instances of asteroids hitting earth in hundreds of millions of years, but climate change is an immediate threat within the next 50. The odds we live to see an asteroid hit us are slim.


> The odds we live to see an asteroid hit us are slim.

Presumably this is based on a belief that humans are likely to go extinct. I don't agree; I think we're extremely unlikely to go extinct and, following from this, an impact is definitely something worth worrying about.

It doesn't even have to be a "planet-killer," a smallish impactor could wipe out a city.


The question is really how likely are we to be hit within the relevant time period. Had we taken a slower growth curve, we'd avoid climate change at the cost of an extra 50 or 100 years before being able to divert asteroids. That seems like a good bet. I am much more worried about climate change and irreversible destruction of ecosystems than getting hit with an asteroid in a very limited time period


Slim, but not zero; we can and probably should do both.


Well, maybe. It really comes down to the specific numbers. (At least for the objective part of the consideration.)


How realistic it to divert an asteroid of this size?


It doesn't necessarily need to be diverted entirely. Simply breaking it up into smaller components significantly reduces it's impact force.

Smaller pieces burn up more readily in the atmosphere and create smaller impacts (I believe exponentially smaller)


some of these asteroids we only have days warning. that's the scary part. To divert an asteroid you need to do it before it comes near so it has a long path to begin drifting in a new direction. ie it's only gonna nudge it slightly. Slightly adds up over many millions of miles, not so much when its a week out.


Now you're begging the question of how hard it is to break it up!


Significantly harder than diverting it slightly.


If you know find out years in advance then you barely have to change it's velocity to make it miss Earth. Probably a kinetic impactor would be sufficient, otherwise thermonuclear warheads exist.


Capable with current technology if intercepted early enough. I think most people visualize an asteroid hitting earth like a ball hitting the ground when dropped at arm's length. In reality, orbits of celestial objects are elliptical, and they're constantly moving. A small force, like that produced by an ion thruster, applied to an asteroid 15km in diameter for months or years would be enough to change it's orbit such that it wouldn't impact earth.


when did we learn it was heading our way, and how far away is it at detection? hours, days, months, years before impact? that's key things to know.


Lets say the same asteroid hit the same place in Australia today....

How many people would both directly from impact/shockwave and indirectly die (infrastructure collapse, tsunamis on beach towns, climate change, etc) from this, do we think?


This was bigger than the dinosaur-killer, which killed almost all land animals; only a tiny fraction survived. So almost everyone would die, all over the world. The shock wave would be extremely hot and kill pretty much anything that's outside, and the fires would be massive.


This is bigger than the KT impactor. Everyone would die. So would almost every other animal and plant on Earth. The lucky ones would die instantly, the unlucky ones in the following global firestorm. The really unlucky ones might live long enough to freeze to death.


No sunlight for years, no photosynthesis - same pronostic of 95% loss of life id guess


This kinda discovery is why I hold out hope there were super advanced ancient civilizations on earth. They just happened to figure out Stargates and peaced out entire cities to safer off-world locations.


Do you think a stargate is easier to figure out than redirecting an asteroid?


They obviously didn’t do the latter, so it must have been the former. ;)


Yes. One shot vs n.

Besides, Earth isn’t the only planet suitable for us :)


Should we as a species be more concerned about a mass extinction event like this? The longer we survive, the more likely it'll happen. Isn't it just a matter of time?


More important than the size, I think, is the angle of impact... Still huge numbers we could just fathom....


Composition matters a lot too (rubble pile vs monolith). Many things affect whether it will be a bolide, and at what altitude.

But size is the most important feature because it is unbounded. You can’t be more direct than a perpendicular impact, but asteroids can always be bigger. And a 10km rock at pretty much any angle is much more energetic than a 10m rock, no matter what you do.


yeah at that size it's going to be a huge-ass almost literally earth-shattering explosion no matter the composition...


Depends, but in general would say no.. energy is speed times mass, and mass is cubic in the size, while speed is linear.

Angle is complicated, I mean unless it is very shallow all will still go into earth? I wonder if and at which angle it could impact earth's rotation, but for that then direction is also relevant (:

*: Ah, interesting, the neal.fun/asteroid-launcher also gives same energy for different angles except very shallow ones.


Energy is (1/2)(mass)(speed)^2. That ^2 term is important.


I believe that all other factors kept the same, angle does matter b/c of the amount and time you spend going through the atmosphere.

e.g. a shallower angle means you pass through more atmosphere which leads to more heating time which in turn means to "icier" asteroids burning off more of the ice.

I can also imagine a scenario where the asteroid passes so close that it passes through the atmosphere but doesn't actually hit the earth.


Doesn't the ratio of mass of asteroid to atmosphere dominate? The larger the asteroid, the proportionally less momentum it loses to the atmosphere. Not sure how much a column of air the radius of a mountain weighs, but seems relatively very small?


I think the hypothesis is Uranus is tilted 90 degrees because of a collision. Crazy to think of a similar thing happening to the earth.


Uranus is the only planet whose equator is nearly at a right angle to its orbit, with a tilt of 97.77 degrees – possibly the result of a collision with an Earth-sized object long ago. This unique tilt causes the most extreme seasons in the solar system. For nearly a quarter of each Uranian year, the Sun shines directly over each pole, plunging the other half of the planet into a 21-year-long, dark winter.

Uranus is also one of just two planets that rotate in the opposite direction than most of the planets (Venus is the other one), from east to west.

https://solarsystem.nasa.gov/planets/uranus/in-depth/


> energy is speed times mass, and mass is cubic in the size, while speed is linear.

https://en.wikipedia.org/wiki/Kinetic_energy#Kinetic_energy_...


This sounds like the starting point for a cringey song about physics.


Somebody really didn't want to go to the Deniliquin Ute Muster.


Is there anything worth mining in these craters?


you can find large asteroid impacts by looking at Vulcanic traps and looking on the opposite side of the globe during that time.


I think it may have triggered what’s called the Hirnantian glaciation stage, which lasted between 445.2 and 443.8 million years ago...

This huge glaciation and mass extinction event eliminated about 85% of the planet’s species.

It was more than double the scale of the Chicxulub impact that killed off the dinosaurs.


Imagine an asteroid causing a glaciation event on Earth that lasts 1.4 million years.

That's mindblowing.


I think it goes to show just how short of a blink of the cosmic eye, that humanity has really existed for and the need to spread our bets by exploring the universe.


Only if you want the species to survive, if you're more nihilistic like me, it just doesn't seem to matter. Or if you're optimistic, WE don't matter because there's loads of other life and societies out there.

It does make you wonder whether life as we know it was a preceding civilization that launched life into the wider universe for the continued existence of life. But on tectonic timescales, any traces that e.g. a carrying vessel would have left behind are long gone.


That's a question in geology and archaeology called the Silurian Hypothesis: Could we even detect a millions-of-years old civilization in the geological record?

1. https://arxiv.org/abs/1804.03748


An Earth-originating civilization would have left our species bereft of the natural resources to industrialize with.

Coal was only made once. Maybe if abiotic theory of petroleum is true, you get that back over immense timescales, but you don't get a second shot at coal. Without coal, you can't even do metallurgy at scale. Is there some gotcha that I'm missing?


Coal was only made once because the earth basically ran out of carbon to turn into coal. There’s 1,100,000 million tons of economically viable coal and we’re running into environmental issues by burning ~1/1,000th of it.

Most projections suggest coal use is going to plummet over the next 50 years, both because we have better options and because we have little choice.

There’s enough coal in the ground to make earths atmosphere actively lethal to humanity. At ~70,000 ppm people are rendered unconscious in minutes and there’s enough coal go well over 100,000 ppm. There’s no way for humanity to use up the worlds coal as fuel, perhaps we could ship it into space as carbon source but that seems unlikely.


> Most projections suggest coal use is going to plummet over the next 50 years, both because we have better options and because we have little choice.

Sure. Already industrialized civilizations have better options. But if you're starting from scratch, you don't get to jump immediately to photovoltaics or whatever.

> and we’re running into environmental issues by burning ~1/1,000th of it.

But which 1/1000th? We didn't dig out the deepest coal first. "Economically viable coal" by 21st century standards isn't the same "economically viable coal" by the standards at the dawn of the industrial revolution.


> But which 1/1000th? We didn't dig out the deepest coal first. "Economically viable coal" by 21st century standards isn't the same "economically viable coal" by the standards at the dawn of the industrial revolution.

Across geologic timescales what’s accessible changes. It makes a huge difference if deposits are above or below sea level for example. The Industrial Revolution kicked off in a small geological area which would have looked very different even 100k years before.

Even beyond that we’re actually more selective not less when it comes to coal mines. Unlike say copper/silver/gold/etc there’s so much coal that what would have been a perfectly viable mine 150 years ago simply isn’t today. Larger equipment means fewer workers but it also requires thicker coal seams. Similarly we’re a lot more picky about sulfur content etc.

That’s also somewhat true of stuff copper, gold, etc. The minimum concentration required to make ore viable has decreased dramatically, but only when there’s huge quantities of ore. Plenty of potential mines could be worked by hand, but can’t complete with industrial scale mines or be used as one.

PS: It’s worth remembering even if things aren’t quite as efficient they can be viable. Building canals takes more effort than rail lines but they can still transport bulk goods on the cheap using minimal technology. Similarly solar smelting can reach extreme temperatures, just not 24/7. Wood plus just about any rock can get you to steel with enough effort and know how. It might take slightly longer but our history isn’t the only way to get to transistors and spacecraft etc.


Carbon sink? (instead of source...) Depends on your perspective I guess.


Maybe that is what happened, and we somehow managed to make due without energon deposits and vibranium.


On those timescales plenty of natural resources would be replenished, but not all. 500 million years is a long, long time.


Coal probably wouldn't and is pretty significant.

Edit: actually it seems like the coal resulting from lack of tree-consuming microbes theory isn't so widely supported these days.


But life hadn't evolved on land 500 million years ago.


Yes, that was sort of the point. So you get 100's of millions of years during which things can rearrange themselves. Whoever - or even whatever - inherits the Earth after the next big impact will find it changed dramatically compared to how it is today. By the time they evolve intelligence (optional) have toolmaking needs (optional) and are living on land (optional) they will have plenty of time to figure out where it is going to come from, the earths crust will be rearranged enough that you can expect all kinds of stuff to have risen to the surface that is now inaccessible.

Heck even the Himalayas have formed only 50 million years ago.


Related science fiction novel: The Ice People (La Nuit des Temps) by Barjavel

https://en.wikipedia.org/wiki/The_Ice_People_(Barjavel_novel...


If they wanted to be remembered they would encode a message in the DNA.

Or left it on the moon, I guess.


DNA sequences are undergoing frequent changes if there is no evolutionary pressure on them. The message would quickly be scrambled. They would have to encode it into highly conserved gene sequences, i.e., completely reinvent life as we know it.

The moon is a harsh environment and (like most places in the solar system) exposed to significant danger from meteorites over geological timescales.


Make use of the horseshoe crab genome then.


> Only if you want the species to survive

Paradoxically, "survival" assumes adapting to ever-changing circumstances, which means that homo sapiens, given enough time, is bound to evolve into one or multiple new species given enough time. Regardless of that happening elsewhere or on Earth.

Arguably, a species is just a mode of survival for a genome; a convenient vessel through time as the genome reproduces. The language we use is, ultimately, a social construct, but biological speaking by and large inconsequential in so far that language is a trait that fosters survival. Evolution isn't opinionated, it just 'is'.

The fate of the Neanderthal people feels apt here. While the species is extinct, our Sapiens genome still caries 1-4% of Neanderthal genes to date. Some of that influences traits in modern humans, some of that just doesn't. (Evolution is messy, in that regard) Now, maybe Neanderthals wondered - just like us today - what would become of them aeons in the future. Little did they know that we, Sapiens, are distant relatives to them.

In the same vain, our written record and collective memories spanning no longer then a few millennia, distant relatives in the far future may look back at our detritus in the soil and in their genes and maybe wonder the exact same thing.

Maybe the Great Filter isn't some civilization destroying event. Maybe it's just evolution. Maybe become a space-faring species might be the biggest mistake we could make. I think more then a few sci-fi authors coined the notion of the arrival of malevolent alien species in a distant future which turned out to be our distant relatives from space-faring humans who left Earth eons ago. Of course, that's just speculation. But there's some poetic food for thought there, it's a probability one can't readily exclude.


There's plenty that could have gone wrong in the last century that could have led to humanity's extinction. The next challenge is how to deal with exceeding the capacity of the planet to sustain our civilization. You're definitely on to something with your last paragraph.


circle symmetry like petals round a flower a galaxy's earths


Probably one of the best episodes of Trek imho - https://www.imdb.com/title/tt0708803/


Another related Trek episode - the one I expected you to link: VOY's "Distant Origin" - https://wikipedia.org/wiki/Distant_Origin


> It does make you wonder whether life as we know it was a preceding civilization that launched life into the wider universe for the continued existence of life.

There's data out there about the First Ancestral Race but AFAIK they've never released the unredacted version of the Secret Dead Sea Scrolls, so it's hard for the public to say.


Before social media I thought yes this was something we should do.

But now after being exposed to the true collective nature of mankind, it doesn’t matter. This species is a net negative for the universe. Just a bunch of monkeys squabbling over stupid things.


> This species is a net negative for the universe.

We're not important enough to be net negative, nor have we been around long enough. I am still hopeful that 10 million years from now, we'll have rampaged across the supercluster, spreading despair and wickedness in our wake.

Then, and only then, will we have achieved net negativity. Do your part, help us become that.


The universe doesn't care one way or another. There's no such thing as a net negative for the universe itself. It's amoral and has no values.


I agree with you and I'm saddened by the nihilist (and defeatist!) outlook that many people seem to have here. I'm fundamentally a humanist. I want humanity to survive and thrive.

I never understood the defeatism. It seems to arise from having the intellect to recognize that humans can (and do) have impact on their environment, and in the same breath resign on that impact being only negative and thus declaring that humans as a species should go extinct.

But there's so much good in this world that people do, isn't that worth saving? We know our capabilities are only limited by our own imagination, so why not strive for a grander human civilization that can span at least the solar system, if not the galaxy?

We can try, and we may still fail. Nothing is certain, except the way to ensure our demise by accepting that our fate is to go extinct and do nothing about it.


Eh, frankly it’s giving too much rational basis to emotional states IMO.

People posting on web forums, especially engineers, like to poke holes in things and aren’t big into expansion and exploration at the moment. Probably a bit depressed from sitting in front of their computers all day too.

Ask someone who just spent a month on the pacific coast trail, or who is about to go to Antarctica the question, and you’ll get a different set of answers.


I think it's more than the web but the way media is being curated. I'm one of those people who's really optimistic about society. However being a positive person is actually a lot of work.

I basically have to tune out all modern movies, television, news. Every new TV show is about some dystopia or the end of the world or a Zombie apocalypse or whatever. I watch mostly old TV shows from the 50s and 60s and read science fiction. In rare cases I'll watch a new show that's actually positive. You have to be careful though, even long-running franchises can quickly turn toxic when Hollywood gets a hold of it; Star Trek was headed that way until Strange New Worlds came out.


> I never understood the defeatism. It seems to arise from having the intellect to recognize that humans can

It actually correlates really well with the advent of teaching young children to be guilty about the civilization which gave birth to them. Maybe we shouldn't be slamming first graders with the ideas that everyone who came before them were supervillains and that they must shoulder the burden of correcting long dead injustices.

In any event, doesn't much matter. Every week there's a new article about how one nation or another has below-replacement fertility that doesn't seem to have any real prospect for reversing (tied to, more than anything else I think, what was described above). We are probably already a dying species, or at least heading into a post-civilization phase, and just don't know it yet.


I think you are over-reading it. The nihilistic mindset is not necessarily defeatism, it's just accepting that it does not matter in the universe-wide grand scheme of things.

I personally think that it's the most pragmatic view, if not the most rationale: with such an approach, only actions that are truly achievable retains attentions, if we try something, let's do the things that matters in the long run instead of trying literals shot in the stars.

Also, given the systematic and very damaging polarisation of all debates, I like being able to distance myself: it does not matter in the long run, so if the toxics annihilation has to happen, I won't be part of it, and it's probably the best I can actually do.


Nihilism is a nuanced concept that many great thinkers have grappled with but "web forum nihilism" isn't. Internet nihilism usually just reads like someone who is suffering from some sort of depressive or anxiety disorder and expressing their symptoms, like catastrophization, over the 'net.

What I submit is that we are living in a society with a record level of depression, anxiety and other mental illnesses (the US for example is prescribing record levels of antidepressants). This record level of mental illness is simply spilling over onto the Internet. Why so many people in our society are ill is left as an exercise for the reader.


> (the US for example is prescribing record levels of antidepressants)

I would argue that this is mostly very (too) efficient marketing and sales though, cynical as it sounds.


I would attribute depression and surge of mental illness to the fact that there is actually much less to be optimistic for in our times than not so long abo, instead of ideals or ideologies. Let's be pragmatic about it.


> and the need to spread our bets by exploring the universe.

I would like for us to get our house in order before we start this process.


I feel this is a why-not-both thing. We should fix our house and explore. We have enough people and capability to do both if we are politically and mentally willing.


Yeah. If anything, not having our house in order is even more motivation to create offsite backups.


We can and should do both. Our emphasis should indeed be on not shitting the bed. But we should also look for new beds. The big problem is that Mars at its best is worse than Earth at its worst. The Earth in "The Road", or almost any post-apocalyptic story, is still infinitely more livable than Mars!


Which problems do we need to solve before you would deem our species worthy of survival?


This is such a tired and simplistic take. The space program has been helpful in tidying our home. It’s not an either or choice.


That is a lie that is conveniently told to preserve the legacy of the Apollo program and the morale of the Nation, as well as the legacy of one of the most beloved figures in the history of the Nation: JFK , who by the way, when you start to dig deeper emerges to be just a younger Trump.


We literally have satellites in space that monitor the atmosphere and detect greenhouse gas emissions.


> > We literally have satellites in space that monitor the atmosphere and detect greenhouse gas emissions.

So monitor stuff that you can't do nothing about. Great

As far as weather goes you don't need satellites. Baloons, planes, radars, drones, buoys do exist and paint a picture which is 99% the same.

The Apollo program failed to repay itself, plain and simple. Unlike the Manhattan project and the rocket designs stolen from the Nazis and developed by Von Braun which kept us safe for 50 years now.


We're certainly setting a record at destroying this planet.


We're certainly setting a record at destroying ourselves.

It's seems like a pedantic distinction, but it's important. Earth doesn't care if we're here or not. The universe doesn't care if we're here or not. We are the only ones who should care, and we seem not to.

The planet will be fine, eventually, after we die out. Life will continue after we're long gone.

But we'll be long gone, and it's like we've all decided that's okay.


Destroying ourselves, as measured by population, which is the highest in the history of our species?

Or measured by longevity, or leisure time, or other living standards, all of which are drastically higher than they were only a few generations ago?


Those are all true! And they are important to remember. It is also important to remember that if you are driving a car to a brick wall, almost every metric will be perfect right until you hit it.


It's also important to remember that history is full of people claiming we're about to run into a brick wall (Malthus, Erlich and company), yet things just keep getting better.

Perhaps humans are better drivers than you think?


Malthus was essentially correct, but wrong about the when and how. Industrializing societies can play whack-a-mole with constraints that limit their population growth, successfully so far.

What saved us was the surprising phenomenon that those societies tend to have quite low birthrates. Multiple possible reasons for that:

* high cost of living and raising children,*

* availability of birth control,

* waning social pressure of getting many children,

* no immediate economic benefits of raising children (in agrarian societies, they are essentially free labor on the farm, and a huge young population makes it easier to bootstrap an industrial economy). Of course, eventually there will be a problem when a huge percentage of the population is too old to work.

We will be fine as long as we can sustain agriculture:

* oil must be a-plenty to run farming equipment. It will be a long time before electricity has taken over

* we need farmland with intact soil and water

* we need fertilizer (phosphorus is running low soon, and oil is required as well)

* we need pollinators for many crops. Hand-pollinating is expensive

* We must not run out of pesticides to maintain yields

And probably some more requirements. If any of them is not fulfilled, society collapses and things can get ugly quickly. These things partly contribute to recent wars in Africa, the Middle East, and other places.

Edit:

*: low child mortality makes it necessary to actually support most children all the way to adulthood


>What saved us was the surprising phenomenon...

It's only surprising if you (like Malthus and Erlich) had the intellectual arrogance to believe you could predict the future.

I cannot predict humanity's future, but I can look at our past, and our progress looks excellent so far. Betting against our continued success seems to require serious mental gymnastics.


I've always hated this smartass retort from Carlin (who was awesome otherwise). this is indeed a pedantic distinction. there may be billions of planets like earth around but what make it special is the life on it & we are destroying that for some imaginary 'capital' that wont matter in large scheme of things anyways.

The other significant problem with this punchline is that it is still heavily human centric. we are not gonna go away without a major fight in/against biosphere. and guess what since we dont ascribe any value to it other than how its useful to us its going to take the brunt of destruction. at this point if we hold our population & resource utilzation where we are and eventually settle down to a smaller size I'd be okay with it as long as we give the rest of biosphere a chance but we all know thats not going to happen. We need to keep growing, thats the system we are in. And sure there will be some targeted geoengineering & green energy hopium for us to hang our concerns on but at the end of day we'd end up in the same place.

there was a line I read somewhere that made me realize our current predicament, it goes -- if a distant civilization just looks at the rise in atmospheric greenhouse gas composition of the planet, they wont be able to tell if its a intelligent species consuming fossil fuels or a bacteria that just learnt metabolize fossils and just growing exponentially. its the same curve largely. So much for human discretion & intelligence.

/rant end.


> We're certainly setting a record at destroying ourselves.

I know things are bad but historically, I don't know how you can say that. In the 60's, 70s, and 80's we actually were, no-bullshit, on the brink of turning the world into a radioactive glass hellscape.

Despite all the turmoil in the world, I think things are looking up for humanity.


"In the 60's, 70s, and 80's we actually were, no-bullshit, on the brink of turning the world into a radioactive glass hellscape"

Have you watched the news lately?

I think there was something war related and people arguing about first strike and red lines.

Just because we are now used to the threat, does not mean it went away.


> We're certainly setting a record at destroying this planet.

In the grand scheme of things, I'm tempted to say: if that's the price to pay to expand beyond it, then so what? It's not like it's the only planet in the Universe.


"It's not like it's the only planet in the Universe. "

But so far it is the only known planet with conditions where we can live.

And I doubt we can make the jump to another planet we first have to find and then somehow survive getting there - when we cannot take care of our own planet.

(Btw. no matter how much we mess up earth, it will allways be way more hospital than mars)


Are we though? We're altering the planet's weather and ecosystem, but that's not the same as destroying. Plus there have been several large impacts in the past that acted quicker to alter the planet, and life found a way.


You can expect one of the really big (Chicxulub-size) impact every 100 million years or so (there is enough uncertainty here that experts all have their own ideas on the exact frequency but typically 25 to 500 million years seems to be the agreed upon range. We keep finding new craters though and then have to increase the estimate).

https://www.thespacereview.com/article/761/1

https://skyandtelescope.org/astronomy-news/how-often-do-chic...

And endless papers on the subject. TEOTWAKI is a fun rabbit hole to dive in to.


> You can expect one of the really big (Chicxulub-size) impact every 100 million years or so

Still, the Chicxulub asteroid is estimated to have caused a global cooling of the surface by around a decade, not 1,400,000 years.


Sure, ask the dinosaurs how that went. The point is: that was only a decade and only a relatively small asteroid and the effect was that the dominant species of the time was wiped out. Size is inversely correlated with frequency, so those smaller ones happen far more frequent. Anything larger than that and it is definitely game over.


What percent of species have humans killed so far? Are we going to eventually outcompete an asteroid causing over a million years of ice age?

https://www.un.org/sustainabledevelopment/blog/2019/05/natur...

https://amp.theguardian.com/environment/2018/oct/30/humanity...


> it may have triggered what’s called the Hirnantian glaciation stage

Maybe. but per the Brittanica article cited:

> No concentration of iridium has been identified near the extinction that would suggest a bolide (meteorite or comet) impact like the one identified at the end of the Cretaceous Period.




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