[HN Gopher] Ancient Earth Globe
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Ancient Earth Globe
Author : BerislavLopac
Score : 197 points
Date : 2020-09-13 10:56 UTC (12 hours ago)
(HTM) web link (dinosaurpictures.org)
(TXT) w3m dump (dinosaurpictures.org)
| pvg wrote:
| A Show HN with comments by the author:
|
| https://news.ycombinator.com/item?id=17286770
| martythemaniak wrote:
| Super cool stuff. If the author has time, it would be even
| possible to derive the major climate zones at that time using
| large scale features like latitude, mountains, etc.
|
| Here's a nice reconstruction of what Pangea looked like (200m
| years ago) https://youtu.be/VKq0pr4rbRs
| lhousa wrote:
| Things escalated pretty quickly between first flowers and fist
| primates
| Hammershaft wrote:
| Very impressive, what is a good resource for an interested layman
| to learn more about earth science and deep time?
| arethuza wrote:
| I can strongly recommend _Earth: An Intimate History_ by
| Richard Fortey.
|
| Also
|
| _Land of Mountain and Flood: The Geology and Landforms of
| Scotland_ - mind you that is obviously just about Scotland but
| it is a gorgeous and fascinating book!
| ajaalto wrote:
| John McPhee: Annals of the former world, Simon Winchester: The
| Map that Changed the World, Lutgens et al.: Essentials of
| Geology
| instakill wrote:
| How can you make it stop spinning?
| UncombedCoconut wrote:
| Display Options, [ ] Rotate globe
| jacobush wrote:
| Some serious interplanetary engineering, likely involving
| Fusion Candles on Jupiter to gather materials and fuel. Then a
| constant bombardment of Earth from the right angle should stop
| the spinning, eventually.
| myself248 wrote:
| I wonder if it could be done with nothing more than "solar
| sails" at ground level, aimed so they reflect the sunrise and
| push back against rotation, but exert no directional force
| the rest of the day.
| dmos62 wrote:
| Grass appeared 35 million years ago? At the same time as the
| first primates? And flowers 120 million years ago? After
| dinosaurs appeared (220 million years ago)? My mind is blown.
| What did landscapes look like?
| [deleted]
| rosstex wrote:
| According to science television, lots of palm trees.
| billiam wrote:
| What's really amazing is to think that it was only after
| grasses started taking over that very large land mammals could
| evolve on the vast marshy plains of North America and over 5
| million years or so as sea levels rose due climate change
| become whales and other cetaceans. I wonder if humans will do
| the same, albeit in much less nutritious oceans that we are
| busily acidifying.
| chansiky wrote:
| That's an interesting thought. I was running last week along
| the beach and was thinking about how early primates/hominids
| might have decided what plants could be eaten and what plants
| should be avoided when I saw a stalk of grass with its
| seeds/flowers. It seemed clear to me just looking at it that
| the seeds might be extremely edible, and I wouldn't be
| surprised if many other hungry hominids(and other herbivores)
| came to same conclusion. What I didn't know was how recent
| the first grass was nor did I realize how important it might
| have been for the evolution of land mammals. Here's an
| interesting fact about grass I just learned (from
| Wikipedia[1][2]):
|
| > They provide, through direct human consumption, just over
| one-half (51%) of all dietary energy;
|
| [1] https://en.wikipedia.org/wiki/Poaceae [2]
| http://www.fao.org/rice2004/en/f-sheet/factsheet3.pdf
| simonh wrote:
| We don't need to evolve much in the way of new adaptations
| anymore, we have technology. That's how come we can colonise
| environments from the frozen tundra, to tropical jungles, to
| the harshest deserts, and now even the vacuum of space.
| nurettin wrote:
| Humans didn't need much technology to live in deserts and
| tundras. But what if they run out of earth metals to cycle?
| What if they can't build sustainable energy sources? Our
| top modern "tech" lasts a couple of hundreds of years
| before totally collapsing. Humans will eventually go back
| to simpler tools, be it 10 million years or 100. I give it
| a couple of hundred thousand.
| simonh wrote:
| We've essentially built the entire modern world in a bit
| over a century. The only way we'll run out of metals to
| recycle is if we shoot it all out into space. Otherwise
| it'll still be here in one form or another. I am
| concerned about the long term sustainability of our
| current phase of civilisation. I think our current way of
| life is largely doomed, but we will develop new ways of
| life.
|
| Tens of millions of years is a long time. Who knows?
| mjklin wrote:
| From Wells and Huxley's _The Science of Life_ (1929):
|
| It is difficult to imagine this world with all its land
| surfaces lifeless; yet for more than a half of its history Life
| played out its drama under water, and the continents were
| practically barren. They were stark and bare, starker and barer
| than the utmost desert of today. Over the bare cliffs and
| desolate plains the sole breath of movement came from the wind
| and rain. A certain margin there may have been of faintly
| vitalized soil. From comparatively early times, a few simple
| algae may have trailed their filaments over the seashore or the
| moist borders of rock pools, or a few bacteria invaded the
| crumbling earth surface...
|
| The face of the land was like nothing we know today. There
| could have been no real soil, for soil is largely a product of
| plant action. There was no carpet of plants and felt-work of
| roots to hold water like a sponge, preventing rapid run-off,
| and to blanket the ground from excessive gain and loss of heat;
| and so the work of frost and wind, rain and sun, was much more
| active. The heights of the land were worn down quicker and
| sediments more actively deposited, and the scenery was more
| angular and forbidding. Even long after the first appearance of
| land-plants vast regions of the land which would now be covered
| with vegetation remained desert or semi-desert, since all the
| earliest plants demanded a good deal of moisture.
|
| Plants like grasses, which can thrive on dry steppes and
| prairies, are comparatively modern things. The Paleozoic Era
| knew nothing of them and the Mesozoic comparatively little.
| There was a desert flora and fauna in the Triassic; but
| possibly at least, the regions it inhabited would today be
| steppes or savannahs.
|
| It is a good exercise of the scientific imagination to picture
| this desolate and desert earth, its continents cyclically
| rising out of the waters and submerging themselves again,
| occasionally undergoing a spasm of mountain-building or an ice
| age, but remaining essentially lifeless for well over five
| hundred of our million-year periods, in spite of the abundant
| presence and notable progress of life in the waters. Through
| all these ages, the lands remained unconquered and must have
| seemed unconquerable.
| glial wrote:
| Lots of ferns maybe?
| fauigerzigerk wrote:
| Amazing! I wish it didn't end in the present.
| zcdziura wrote:
| Sort of off-topic: I love looking at images of how the Earth's
| continents have shifted and moved over time. They provide a lot
| of inspiration for me when making homemade maps for my D&D games.
| Whatever nature has done makes for much more compelling and
| believable maps than what I can make on my own!
|
| My latest map is based on a rotated view of what Pangaea Proxima
| will (probably) look like in a few million years. Looks pretty
| neat and provides a lot of inspiration.
| johnchristopher wrote:
| Aren't generators really good now ? I was under the impression
| they really did improve over the last years.
| mkl wrote:
| That whole site is pretty neat. So many dinosaurs!
| based2 wrote:
| http://www.scotese.com/
|
| https://vimeo.com/315907106
| DeepTimeMaps_Animation_Mollweide_Sample
| jagger27 wrote:
| Brilliant to see where some land masses stay relatively intact
| and how little they've changed. Newfoundland and Labrador in
| today's Eastern Canada stand out to me. I really want to those
| weathered ancient mountains some day.
| tremon wrote:
| What amazed me most is the relative short (recent) period in
| which the Himalayas formed. India split from Madagascar
| relavively recently, the speed with which it collided with asia
| must have been huge.
| tvalentius wrote:
| One of my favourite earth's 3D visualisation
| Aardwolf wrote:
| This is so awesome, I just wish it could go back even further to
| 1 billion, 2 billion, ... years ago! If we know enough about the
| Earth's history and tectonics to depict it...
| Rajdeep100 wrote:
| Cool
| Rajdeep100 wrote:
| pretty awesome
| tekcyb-org wrote:
| I don't understand how land masses the size of africa detaches.
| The map shows africa attached to the US, but this doesn't make
| sense. I can understand water levels changing, exposing new areas
| that might have been underwater, drying up and turning into land
| masses, as well as areas that were previously land, becoming
| filled with water.
| danielbln wrote:
| All continents rest on tectonic plates, which kind of rest on
| the liquid core and are moving around on it. Let enough time
| pass, and the plates will move around, and the continents with
| them.
|
| Check out this image of the plates:
| https://en.wikipedia.org/wiki/Plate_tectonics#/media/File:Pl...
| Rexxar wrote:
| It's tectonic plates
| (https://en.wikipedia.org/wiki/Plate_tectonics).
|
| You can currently see continent splitting in Island and in
| Africa : https://en.wikipedia.org/wiki/East_African_Rift
| phkahler wrote:
| To understand the separation of the Americas from African you
| may want to read about the mid ocean ridge:
|
| https://en.m.wikipedia.org/wiki/Mid-ocean_ridge
|
| Now how that large land mass came to be is an interesting
| question to me. The globe shown here in the title/link is
| clearly not homogeneous. The land mass on one side must be less
| dense than the rest of the earth for it to protrude above sea
| level that way.
| spionnaidh wrote:
| The continents are indeed less dense than the oceans!
|
| On average, the continental crust has a composition that is
| also seen in magmas that are produced at subduction zones
| (where denser oceanic crust is forced under continental
| crust) by the melting of the mantle. At the mid-ocean ridges,
| water is circulated through the newly produced oceanic crust,
| and the fresh basalt is metamorphosed, causing new minerals
| to grow which contain water as a part of their structure. Up
| to a few hundred million years later, this oceanic crust
| reaches a subduction zone, where it is pulled into the
| mantle. As it sinks, it is exposed to higher pressures and
| the water-bearing minerals become unstable. The water within
| them is driven off the crust and rises into the overlying
| mantle. At these pressures and temperatures, water is to rock
| what salt is to ice, and part of the mantle melts - think of
| it as a kind of 'slush'. As the magma (the liquid part of
| this slush) rises to the surface, it begins to crystallise,
| and the denser crystals (which form first) sink. Overall,
| this makes the magma less dense, continuing to drive it to
| the surface, where it may either eventually stall in the
| crust (in a pluton) or be erupted in a volcano. Now there is
| less dense material sitting on top of and within the oceanic
| crust and an island arc is born - an example today is the
| Aleutian Islands.
|
| The magmas formed at subduction zones have a distinctive
| geochemical signature called the 'calc-alkaline' trend.
| Whereas magmas at mid-ocean ridges become enriched in iron
| because of the crystallisation of plagioclase feldspar, at
| subduction zones the presence of water suppresses feldspar
| crystallisation, instead producing 'wet' minerals like
| amphibole. As a result, these magmas do not become enriched
| in iron as they rise through the crust, and instead become
| rich in sodium and potassium. These magmas also have
| distinctive radiogenic isotope ratios and trace element
| contents. The continental crust (while highly compositionally
| varied) on average has similar signatures, suggesting that it
| was formed by this kind of activity.
|
| The fun happens when two of these island arcs collide. They
| are both less dense than the underlying mantle, so neither
| will subduct easily. Instead, they coalesce into a single
| mass, and a continent is born. More common today is the
| collision of an island arc with a pre-existing continent.
| This happened before India collided with Asia to form the
| Himalayas, and the calc-alkaline plutonic rocks are visible
| at the surface in Tibet today. This is how the continents
| grow.
|
| The continents are thought to have started to form during the
| Archaen Eon, starting at four billion years ago. The rate at
| which they formed is still very much up for debate, but it is
| thought that crustal growth was more rapid back then as
| compared to today, and was mostly complete by around 2.5
| billion years ago. Today's tectonic plates are cored by
| ancient cratons, the oldest and most tectonically stable
| pieces of crust. Around these cratons are progressively
| younger strips of crust stuck on by colliding island arcs.
| Much of North America is made up of island arcs stuck to the
| Laurentian craton.
| Waterluvian wrote:
| It's a fantastic question this stuff isn't intuitive.
|
| http://mapdesign.icaci.org/wp-content/uploads/2012/04/atlant...
|
| Consider this model: the Earth is like a puzzle. Its crust is
| made up of a bunch of pieces that all fit together. But those
| pieces aren't unchanging. They all sit on top of a huge soft
| sludgey core called the mantle. And they want to slowly
| (slooooooowly) slide around.
|
| At each boundary between pieces one of three things can happen:
|
| - they slide against each other
|
| - they diverge from each other
|
| - they press into each other, often one going under the other,
| sometimes one pushing the other.
|
| A continent can move, oh so slowly, over millions of years
| through a combination of shifting along with other plates, or
| having one side of its plate grow (move away and have the new
| gap filled with the molten plasticy goo underneath), while the
| other side pushes away a plate or disappears underneath the
| other plate.
|
| The map I linked shows a massive stretch mark of the Earth in
| the Atlantic Ocean. This is one striking piece of evidence that
| the above effects have been happening over a long long time.
| It's basically the boundary between a few plates. And it shows
| all this brand new ocean floor that came flowing up from under
| the crust (then cooled and got hard) when a gap was created
| because they separated apart.
| tekcyb-org wrote:
| Wow thank you for the explanation and that picture you
| provided makes it very clear as well. I did not realize that
| the world was divided into plates.
| tremon wrote:
| There's a BBC documentary on this that's now around 25
| years old, called Earth Story
| (https://en.wikipedia.org/wiki/Earth_Story). It describes
| not only what we know, but how we know it. As documentaries
| go, it's rather in-depth but easily digestible.
| EdwardDiego wrote:
| Looking at New Zealand 35 million and 20 million years ago on
| that globe (search for one of our cities like Auckland or
| Christchurch) is really illuminating when compared to its
| current shape, most of the South Island is to the west of the
| North Island, as the plate boundary between the Indian and
| Pacific plate runs through the South Island, and the eastern
| side has been moving south-west for millennia to form the
| current shape of the land, and our Southern Alps.
| laumars wrote:
| Good explanation.
|
| To expand on that, earthquakes and volcanoes are the result
| of those plates colliding and separating.
| hooo wrote:
| Good seeing Ian's work here!
|
| http://www.ianww.com/
| zamadatix wrote:
| I could instantly recognize the map as work of Christopher R.
| Scotese. Has there been other work to create paleo maps or was
| this work from 2000 and prior so definitive nobody has felt the
| need?
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(page generated 2020-09-13 23:00 UTC)