[HN Gopher] Giant tsunami from dino-killing asteroid impact reve...
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Giant tsunami from dino-killing asteroid impact revealed in
fossilized ripples
Author : mathgenius
Score : 85 points
Date : 2021-07-19 18:16 UTC (4 hours ago)
(HTM) web link (www.sciencemag.org)
(TXT) w3m dump (www.sciencemag.org)
| pmoriarty wrote:
| For a stunning simulation of what a large asteroid impact might
| look like, see:
|
| https://www.youtube.com/watch?v=PENT_hnyO-o
| watertom wrote:
| and the only way global warming will get derailed, well, there
| are also super volcanoes....
| holler wrote:
| That video creeped me out! I mean, we'd be screwed. Luckily
| there are no known astroids, let alone moon-sized ones, heading
| towards Earth that we know of.
|
| But if we discovered one, even with ample lead time, what could
| we do?
| Retric wrote:
| Depends on the lead time. We have mapped out most possible
| asteroids for 100 years which presents something of a
| reasonable upper limit on lead time. Deflecting a 500 mile
| wide asteroid ~10,000 miles on those timescales might be
| vaguely possible. Trying to abandon earth or build some kind
| of ultra deep bunkers given 100 years seems doomed to fail,
| but it's not like a lot of other options exist.
| SllX wrote:
| Here's a version with just the impact and some music to enjoy
| it with. Used to leave this video running on various
| Macintoshes at the Apple Store on my way out.
|
| https://youtu.be/bU1QPtOZQZU
| invisiblerobot wrote:
| At least the asteroid destroyed that horrible song
| gus_massa wrote:
| Note that this is a simulation of an asteroid with a diameter
| of 500 km. The asteroid that killed the (big) dinosaurs had
| only 10 km. That's 50^3 times smaller.
| tunnuz wrote:
| I hope it can hug my daughter when this happens.
| robotresearcher wrote:
| You wouldn't rather hug her yourself?
| throwaway0a5e wrote:
| That's more like "small planet" or "very respectable moon" than
| an asteroid.
| fabiospampinato wrote:
| I enjoyed the video, although they say multiple times that an
| impact like that would kill every living thing, but we now that
| some living things survived, so I don't know how accurate that
| actually was.
|
| Edit: They are using a much larger asteroid in their
| simulation, makes sense.
| parhamn wrote:
| Heres a Kurzgesagt video with a few more details and a bit
| less dramatic: https://www.youtube.com/watch?v=dFCbJmgeHmA
| c7DJTLrn wrote:
| I hope when the next Chicxulub-scale asteroid approaches Earth
| that humanity will be ready to tackle it. If that's even
| possible. Armageddon style?
| pixiemaster wrote:
| RIP Dinosaurs.
|
| Welcome fuel!
| eloff wrote:
| Buried hydrocarbons are not really dinosaurs. They're
| prehistoric plant and microscopic life for the most part.
| Algae, plankton, etc.
|
| I believe a lot of coal harkens back to the great forests of
| the carboniferous (sp?) Period, which is special because it
| took millions of years for life to learn how to digest the
| cellulose in trees. So you can imagine millions of years of
| buried forests that could burn, but not decompose. Forest fires
| in those days must have been truly terrifying.
|
| That was a one off event in Earth's history, and has not been
| repeated. I believe it's partially responsible for why modern
| CO2 levels are much lower than historical levels. It was a
| massive natural carbon sequestration program. At least until us
| humans in our short sightedness dig it up and burn it.
| morpheos137 wrote:
| Lignin not cellulose. It was a wood crisis.
| eloff wrote:
| I'm not doing great with names today, thanks for correcting
| me.
| tejtm wrote:
| When photo-vores covered all the land the only place left
| to go was up. But Lignin was what emerged as the scaffold
| and it was amazingly successful and completely
| indigestible. It would be as if animals figured out how to
| make their bones out of Teflon or silicon dioxide, after a
| few tens of millions of years the planet would be hundreds
| of feet deep in old non decomposed skeletons.
| dzdt wrote:
| My favorite analogy is it is like trees were made of
| plastic. You know how today people say the plastic
| bottles will sit unchanged in landfills for thousands of
| years? Back then it was the same for trees. They grew,
| they fell, they sat there unchanged unless they burned.
| So if they fell in water, they stayed.
|
| Today trees rot because microbes evolved to decompose
| lignin. A million years from now maybe plastic will rot
| too.
|
| It helps to make clear how the giant carboniferous coal
| deposits were formed: plastic tree landfills.
| eloff wrote:
| That's a good analogy. There already appear to be
| bacteria evolving to eat some kinds of plastic. I don't
| think it will take millions of years. But it will also
| reduce demand for plastic, because like wood and paper,
| it can rot now.
| morpheos137 wrote:
| It would be cool if somebody could model what the
| landscape then would look like. I don't think there would
| be massive piles of wood anywhere but wet places because
| as you indicated fire is another way dead wood can be
| cleared.
| btilly wrote:
| The Carboniferous was roughly 60 million years long. And
| oxygen levels were much higher than today. This showed up in
| large insects. For example they had dragonflies over 2 feet
| wide - that's over 6x as large as the largest today.
| klyrs wrote:
| Maybe I'm reading too far into this, but are you suggesting
| that higher oxygen concentration is responsible for larger
| insects? If true, I'd love to understand why
| [deleted]
| morpheos137 wrote:
| More oxygen works better with less efficient breathing
| systems.
| tejtm wrote:
| Their lung analogs are more like holes/tubes where air
| can go and maybe slosh around a bit. So there is a
| surface area to volume trade off point that depends on O2
| concentration.
| jjk166 wrote:
| Getting sufficient oxygen is a key limiting factor in
| metabolism. The more oxygen an animal can get, the bigger
| an animal can afford to get.
|
| And it's not just insects. For example, the ancestors of
| dinosaurs evolved a highly efficient respiratory system
| towards the end of the permian period when oxygen
| concentrations were low, which likely helped them survive
| the deadliest mass extinction ever. Afterwards, oxygen
| levels skyrocketed up, and the dinosaurs, who still had
| their efficient lungs, could take advantage of it and
| became the giants we know and love. This same system is
| also key to the ability of modern birds to fly.
|
| Insects and other arthropods breathe through their skin,
| so the amount of oxygen they can get is limited by their
| surface area, whereas the amount of oxygen they need is
| determined by volume. Thus for any given oxygen
| concentration, there is some maximum surface area to
| volume ratio for insects, and in turn a size limit for
| any given body plan. This is why, for example, the
| largest species of tarantulas across multiple continents,
| despite evolving separately, are all the same size -
| being big has a lot of perks, but if they got any bigger
| they'd suffocate.
| willmadden wrote:
| Oil is mostly a renewable resource. New oil is made from
| magma heating the basement rocks of the Earth's crust. As
| the rocks heat methane gas is distilled. This combines
| with carbonates and carbon 14 to form oil. This is why
| oil wells in Saudi Arabia, Russia, and elsewhere
| mysteriously refill after being depleted.
| btilly wrote:
| Citation needed.
|
| Given how much your claim flies in the face of
| established and widely accepted scientific claims,
| preferably citations to peer reviewed research.
|
| Doubly so for the howler about C14. Oil is notable for
| its conspicuous LACK of C14, not an abundance of it.
| willmadden wrote:
| How do these "established and widely accepted scientific
| claims" explain why oil wells are filling back up?
|
| "Established and widely accepted scientific claims" are
| often nothing more than political propaganda, in this
| case propaganda originating with Standard Oil, the
| Rockefellers, and the even older money that backed that
| empire.
|
| Oil being non-renewable justifies overregulation by
| governments and price gouging by producers.
|
| I'll leave you to do your own research.
| eloff wrote:
| That's a fascinating angle on dinosaurs and birds I've
| never heard of before, thanks for sharing!
| btilly wrote:
| Oxygen is one of two factors allowing for large insects.
| Ecology is the other.
|
| As https://news.ucsc.edu/2012/06/giant-insects.html says,
| before birds you see a clear correlation between insect
| size and oxygen level. After birds, the correlation
| disappears.
| chrisco255 wrote:
| Wasn't the carboniferous period one of the most abundant
| periods for life on planet earth? The forests must have been
| incredible.
| willmadden wrote:
| I don't think we should assume it was an asteroid. It could have
| been a magnetic pole reversal and shift in the earth's rotation.
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