[HN Gopher] Asteroid crater 520km in diameter buried in southeas...
       ___________________________________________________________________
        
       Asteroid crater 520km in diameter buried in southeast Australia,
       scientists say
        
       Author : mafro
       Score  : 270 points
       Date   : 2023-08-17 10:39 UTC (12 hours ago)
        
 (HTM) web link (www.australiangeographic.com.au)
 (TXT) w3m dump (www.australiangeographic.com.au)
        
       | botanical wrote:
       | 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
        
         | vidanay wrote:
         | > 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.
        
       | lordfrito wrote:
       | 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.
        
         | hu3 wrote:
         | 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
        
           | m3kw9 wrote:
           | Would be wild if aliens had cameras on every planet and one
           | day decides to show us what this looked like
        
             | Cthulhu_ wrote:
             | 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!"
        
           | aintgonnatakeit wrote:
           | FYI these are the maximums you can input to get the largest
           | possible crater using this simulator.
        
             | irrational wrote:
             | We're going to need a bigger calculator.
        
             | FireBeyond wrote:
             | ... not great, not terrible.
        
               | jacquesm wrote:
               | Hehe. That's a great scene. Meanwhile, I think it was big
               | enough to do the job.
        
             | hu3 wrote:
             | Yeah I had to max inputs on that calculator. Pretty wild.
        
           | jvm___ wrote:
           | 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).
        
             | jacquesm wrote:
             | And it still only went down to about twice its diameter.
             | Makes you really respect how tough the Earth's crust is.
        
               | jvm___ wrote:
               | 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.
        
               | jacquesm wrote:
               | 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.
        
             | tomatotomato37 wrote:
             | 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
        
             | Cthulhu_ wrote:
             | 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.
        
               | pmayrgundter wrote:
               | 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.
        
               | pmayrgundter wrote:
               | 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.
        
               | pmayrgundter wrote:
               | Ok! ChatG4 is amazing!
               | 
               | https://chat.openai.com/share/25e4cef6-321a-43f7-8d13-40d
               | 1fd...
               | 
               | 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.
        
               | serf wrote:
               | 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.
        
               | pmayrgundter wrote:
               | 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-c35
               | cd2...
        
               | Filligree wrote:
               | 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.
        
               | dylan604 wrote:
               | 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
        
               | kijin wrote:
               | 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.
        
               | davidwritesbugs wrote:
               | Throwing Meteors as interplanetary weapons was a
               | storyline from The Expanse books/TV series if I recall.
        
               | mekkkkkk wrote:
               | Yeah. Bad guy mounted thrusters on large asteroids from
               | the belts. Not technically meteors, but close enough.
               | 
               | Neat sci-fi.
        
               | jvm___ wrote:
               | 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.
        
               | jacquesm wrote:
               | Much too large for that. Under 50 meters or so you can
               | get airbursts, after that it is direct impact.
        
               | RetroTechie wrote:
               | 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.
        
               | jacquesm wrote:
               | 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.
        
               | jvm___ wrote:
               | 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.
        
               | jacquesm wrote:
               | Better not be LEO... I wonder how high the ejecta would
               | go and how far they would reach across the planet.
        
         | TacticalCoder wrote:
         | 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).
        
           | ceejayoz wrote:
           | That's the crater diameter, which'll be much larger than the
           | impactor.
        
       | ChoHag wrote:
       | [dead]
        
       | moomoo11 wrote:
       | 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.
        
         | TearsInTheRain wrote:
         | Do you think a stargate is easier to figure out than
         | redirecting an asteroid?
        
           | moomoo11 wrote:
           | Yes. One shot vs n.
           | 
           | Besides, Earth isn't the only planet suitable for us :)
        
           | layer8 wrote:
           | They obviously didn't do the latter, so it must have been the
           | former. ;)
        
       | phkahler wrote:
       | 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?
        
         | jacquesm wrote:
         | There is the Sudbury crater.
         | 
         | https://en.wikipedia.org/wiki/Sudbury_Basin
         | 
         | Just North-East of Lake Huron.
        
         | throwaway5752 wrote:
         | 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
        
         | sdflhasjd wrote:
         | 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
        
           | dboreham wrote:
           | Craterish?
        
             | layer8 wrote:
             | crater-like
        
               | IIsi50MHz wrote:
               | The Crater-ion Collection [cue logo, cue greyscale film
               | of various impact events]
        
             | webnrrd2k wrote:
             | Crateroid?
        
             | foota wrote:
             | Apparently arcuate is the preferred term
        
           | evah wrote:
           | 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.
        
           | greggsy wrote:
           | Thought to be formed as a result of lithospheric flexure
           | during the Trans-Hudson orogeny, apparently.
        
       | zhengiszen wrote:
       | More important than the size, I think, is the angle of impact...
       | Still huge numbers we could just fathom....
        
         | spenczar5 wrote:
         | 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.
        
           | baq wrote:
           | yeah at that size it's going to be a huge-ass almost
           | literally earth-shattering explosion no matter the
           | composition...
        
         | throwbadubadu wrote:
         | 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.
        
           | alexpotato wrote:
           | 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.
        
             | pmayrgundter wrote:
             | 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?
        
           | irrational wrote:
           | 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.
        
             | adolph wrote:
             | _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/
        
           | ridgeguy wrote:
           | Energy is (1/2) _(mass)_ (speed)^2. That ^2 term is
           | important.
        
           | Jyaif wrote:
           | > 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_.
           | ..
        
             | CoastalCoder wrote:
             | This sounds like the starting point for a cringey song
             | about physics.
        
       | mastax wrote:
       | 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
        
         | greatpostman wrote:
         | Every 26k years we pass through an asteroid belt with a high
         | probability of impact
        
           | echelon wrote:
           | Is there a source for this? I wasn't aware of that, and it
           | sounds interesting.
        
           | eesmith wrote:
           | 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://e
           | n.wikipedia.org/wiki/Extinction_event#Patterns_in_f...
        
         | blahburn wrote:
         | Google "Chicxulub crater" for a fun animation
        
           | [deleted]
        
           | jader201 wrote:
           | For the lazy:
           | https://www.google.com/search?q=Chicxulub+crater
        
         | hindsightbias wrote:
         | So New Zealand might not be the best place to bug out to if
         | Australia is a meteor magnet.
        
           | eesmith wrote:
           | Not that meteor magnets exist, but https://en.wikipedia.org/w
           | iki/List_of_impact_craters_on_Eart... says there are more
           | known impact craters in Europe than Australia.
        
         | Tronno wrote:
         | 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.
        
         | jandrese wrote:
         | 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.
        
       | cubefox wrote:
       | Given that land mass is smaller than oceans, there was probably
       | an even bigger asteroid which fell into the ocean.
        
         | echelon wrote:
         | We might have found the biggest one, which could have led to
         | the formation of the moon:
         | 
         | https://www.express.co.uk/news/science/1606365/science-news-...
         | 
         | https://phys.org/news/2021-03-theory-large-blobs-material-ea...
         | 
         | https://www.science.org/content/article/remains-impact-creat...
        
       | autokad wrote:
       | you can find large asteroid impacts by looking at Vulcanic traps
       | and looking on the opposite side of the globe during that time.
        
       | coryfklein wrote:
       | 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
        
         | teddyh wrote:
         | > _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.
        
           | fragmede wrote:
           | 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.
        
           | CamperBob2 wrote:
           | Could be as simple as the fact that images make the page take
           | longer to load. Google penalizes that, as I understand it.
        
         | foota wrote:
         | Maybe it's not yet considered likely?
        
       | progrus wrote:
       | Seems like maybe our ability to find and divert these asteroids
       | might make all that burning of energy worth it, no?
        
         | CoastalCoder wrote:
         | Well, maybe. It really comes down to the specific numbers. (At
         | least for the objective part of the consideration.)
        
         | thelittleone wrote:
         | How realistic it to divert an asteroid of this size?
        
           | sebzim4500 wrote:
           | 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.
        
           | dylan604 wrote:
           | 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.
        
           | hoorayimhelping wrote:
           | 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.
        
           | SkyPuncher wrote:
           | 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)
        
             | HeyLaughingBoy wrote:
             | Now you're begging the question of how hard it is to break
             | it up!
        
               | thfuran wrote:
               | Significantly harder than diverting it slightly.
        
             | gremlinsinc wrote:
             | 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.
        
         | Capricorn2481 wrote:
         | 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.
        
           | slibhb wrote:
           | > 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.
        
             | suby wrote:
             | 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
        
           | progrus wrote:
           | [flagged]
        
           | Cthulhu_ wrote:
           | Slim, but not zero; we can and probably should do both.
        
       | bryanmgreen wrote:
       | 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?
        
         | not2b wrote:
         | 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.
        
         | dmbche wrote:
         | No sunlight for years, no photosynthesis - same pronostic of
         | 95% loss of life id guess
        
       | ourmandave wrote:
       | _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._
        
         | barbariangrunge wrote:
         | 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...
        
         | someplaceguy wrote:
         | Imagine an asteroid causing a glaciation event on Earth that
         | lasts 1.4 million years.
         | 
         | That's mindblowing.
        
           | jacquesm wrote:
           | 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.
        
             | someplaceguy wrote:
             | > 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.
        
               | jacquesm wrote:
               | 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.
        
           | _joel wrote:
           | 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.
        
             | localplume wrote:
             | [dead]
        
             | dsign wrote:
             | [flagged]
        
             | Cthulhu_ wrote:
             | 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.
        
               | networkchad wrote:
               | [dead]
        
               | _joel wrote:
               | Probably one of the best episodes of Trek imho -
               | https://www.imdb.com/title/tt0708803/
        
               | gloria_mundi wrote:
               | Another related Trek episode - the one I expected you to
               | link: VOY's "Distant Origin" -
               | https://wikipedia.org/wiki/Distant_Origin
        
               | CaptArmchair wrote:
               | > 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.
        
               | stOneskull wrote:
               | circle symmetry like petals round a flower a galaxy's
               | earths
        
               | samus wrote:
               | 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.
        
               | Andrex wrote:
               | > 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.
        
               | VHRanger wrote:
               | 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
        
               | pacoverdi wrote:
               | Related science fiction novel: The Ice People (La Nuit
               | des Temps) by Barjavel
               | 
               | https://en.wikipedia.org/wiki/The_Ice_People_(Barjavel_no
               | vel...
        
               | NoMoreNicksLeft wrote:
               | 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?
        
               | px43 wrote:
               | Maybe that is what happened, and we somehow managed to
               | make due without energon deposits and vibranium.
        
               | [deleted]
        
               | jacquesm wrote:
               | On those timescales plenty of natural resources would be
               | replenished, but not all. 500 million years is a long,
               | long time.
        
               | thfuran wrote:
               | 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.
        
               | goatlover wrote:
               | But life hadn't evolved on land 500 million years ago.
        
               | jacquesm wrote:
               | 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.
        
               | Retric wrote:
               | 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.
        
               | NoMoreNicksLeft wrote:
               | > 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.
        
               | Retric wrote:
               | > 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.
        
               | jacquesm wrote:
               | Carbon sink? (instead of source...) Depends on your
               | perspective I guess.
        
               | DenisM wrote:
               | If they wanted to be remembered they would encode a
               | message in the DNA.
               | 
               | Or left it on the moon, I guess.
        
               | samus wrote:
               | 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.
        
               | goatlover wrote:
               | Make use of the horseshoe crab genome then.
        
               | Jibbedeyeah wrote:
               | [dead]
        
               | xwdv wrote:
               | 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.
        
               | goatlover wrote:
               | 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.
        
               | NoMoreNicksLeft wrote:
               | > 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.
        
             | shakna wrote:
             | We're certainly setting a record at destroying this planet.
        
               | rapht wrote:
               | > 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.
        
               | hutzlibu wrote:
               | "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)
        
               | goatlover wrote:
               | 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.
        
               | Loughla wrote:
               | 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.
        
               | SamPatt wrote:
               | 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?
        
               | krisoft wrote:
               | 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.
        
               | SamPatt wrote:
               | 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?
        
               | samus wrote:
               | 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
        
               | SamPatt wrote:
               | >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.
        
               | DesiLurker wrote:
               | 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.
        
               | oceanplexian wrote:
               | > 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.
        
               | hutzlibu wrote:
               | "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.
        
             | jklinger410 wrote:
             | > 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.
        
               | prox wrote:
               | 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.
        
               | bradgessler wrote:
               | Yeah. If anything, not having our house in order is even
               | more motivation to create offsite backups.
        
               | d12345m wrote:
               | Which problems do we need to solve before you would deem
               | our species worthy of survival?
        
               | mulmen wrote:
               | 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.
        
               | JumpinJack_Cash wrote:
               | 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.
        
               | mulmen wrote:
               | We literally have satellites in space that monitor the
               | atmosphere and detect greenhouse gas emissions.
        
               | JumpinJack_Cash wrote:
               | > > 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.
        
               | javajosh wrote:
               | 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!
        
             | short_sells_poo wrote:
             | 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.
        
               | NoMoreNicksLeft wrote:
               | > 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.
        
               | [deleted]
        
               | lazide wrote:
               | 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.
        
               | oceanplexian wrote:
               | 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.
        
               | tuyiown wrote:
               | 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_.
        
               | safety1st wrote:
               | 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.
        
               | bornfreddy wrote:
               | > (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.
        
         | w10-1 wrote:
         | > 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.
        
         | [deleted]
        
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