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What did Earth look like X million years ago?

dinosaurpictures.org

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Re: What did Earth look like X million years ago?

#71

Post by rement »

jamesrcole wrote: post #25

That's pretty cool. I have two suggestions, if the developer is seeing this: - Mark the North and South poles. For someone unfamiliar with the past continental layouts, it's easy to get a bit disoriented . I would find a location on the globe, jump back in time, rotate the globe a bit to look around, then jump further back in time and then start to get disoriented as to where on earth the details I'm looking at are.…

Looks like development has been pretty dry. https://github.com/typpo/ancient-earth The repo does not contain the texture maps but you can run an instance locally

Re: What did Earth look like X million years ago?

#72

Post by Jagat »

sauravt wrote: post #27
Jagat wrote: post #13

Awesome! It's great to see India move northward between 50m and 35m years ago, and smash into the Eurasian body, creating what is now the Himalayan range.

Here's a curious question, India merged into Eurasia ~40 million years ago, Dinosaurs became extinct around 66 million years ago. When dinosaurs were around India was still an island. We know for sure about the presence of Dinosaurs in ancient India through fossils records https://en.wikipedia.org/wiki/Rajasaurus . So how did the dinosaurs populate an isolated island? Or did they evolve independently of each other in…

Like another commentator mentioned, dinosaur started appearing ~230m years ago. If you go back ~200m years, you'll see that India, Africa and the Americas are all fused together into a supercontinent.

Re: What did Earth look like X million years ago?

#73

Post by oflannabhra »

I’ve always been fascinated by the animals from the era of megafauna, specifically the Pleistocene. Wikipedia is a great start, but details like paintings, behavior, etc are a bit more scarce.

Does anyone have any recommendations for good resources that are approachable for non-scientists?

Some megafauna examples:

Megaloceros, the giant deer who had antlers 12 feet wide- https://en.m.wikipedia.org/wiki/Irish_elk

Arctotherium, the largest bear and potentially the largest land carnivore, ever - https://en.m.wikipedia.org/wiki/Arctotherium

Titanis, one of the largest carnivorous terror birds - https://en.m.wikipedia.org/wiki/Titanis

Megatherium, the giant, elephant sized sloth that dug gigantic burrows - https://en.m.wikipedia.org/wiki/Megatherium

Thylacoleo carnifex, the marsupial lion, and largest carnivorous marsupial in Australia - https://en.m.wikipedia.org/wiki/Marsupial_lion

Camelops, a family of camels native to North America - https://en.m.wikipedia.org/wiki/Camelops

Thylacosmilus, a Metatherian (similar to marsupial), Sabre toothed carnivore from South America - https://en.m.wikipedia.org/wiki/Thylacosmilus

Re: What did Earth look like X million years ago?

#74

Post by peter303 »

dluan wrote: post #17

Last week I was in the field digging dinosaurs in Montana, when one of the dig leaders mentioned there was no grass back then, just lots of ferns, because grass hadn't evolved yet. It kind of blew my mind that for most of dinosaurs, there was just a lot of leafs and ferns. Here's some pictures for context ( https://imgur.com/a/rE5wwc4 ), when you're out where most dino bones are found, you forget that it may have bee…

Not only that, but grass has a special kind of photosynthesis that can survive in a lower CO2 atmosphere than other kinds of plants. Believe it or not, one of the long term hazards for life is too little CO2 for photosynthesis, below 100 ppm. The long term driver of CO2 is geology: weathering of rocks and formation of limestone in the deep ocean remove CO2; subduction zone volcanos return it to the atmosphere. Biosphere carbon is less than one percent of geologic carbon. When the Earth cools down too much to continue plate tectonics in a billion years or so, there will be too little volcanic carbon returned to the atmosphere. Plants and algae will die and so will all animals that eat them. Only chemeotrophic microbes will remain.

Sentient life could halt this process by burning limestone to release carbon. This is how cement is made.

Re: What did Earth look like X million years ago?

#75

Post by peter303 »

sauravt wrote: post #27
Jagat wrote: post #13

Awesome! It's great to see India move northward between 50m and 35m years ago, and smash into the Eurasian body, creating what is now the Himalayan range.

Here's a curious question, India merged into Eurasia ~40 million years ago, Dinosaurs became extinct around 66 million years ago. When dinosaurs were around India was still an island. We know for sure about the presence of Dinosaurs in ancient India through fossils records https://en.wikipedia.org/wiki/Rajasaurus . So how did the dinosaurs populate an isolated island? Or did they evolve independently of each other in…

The preminent hypothesis for the end of the dinosaurs before the Alverezes found the meteoric Iridium layer 40 years ago was large volcanos in India poisoned the planets ecosystem.

Some geologists hold that dino extinction was caused by multiple factors including a meteor, volcanos, and a preceding general decline of the genus.

Re: What did Earth look like X million years ago?

#76

Post by peter303 »

GlennS wrote: post #45
dingo_bat wrote: post #2

How do we know the geography of so long ago?

Magnetic striping on the sea floor [ https://en.wikipedia.org/wiki/Plate_tectonics#Magnetic_strip... ] is probably our best clue. It's the piece of evidence that sealed plate tectonic's place as the dominant theory. Plates which are separating let molten rock from the mantle up, where it cools hardens. Any rock which can be magnetised (iron) is aligned with the Earth's magnetic field when molten, and gets fixed that…

Paleomagnetism measurement of the magnetic field direction in a rock gives the latitude of a the rock when it formed. The magnetic fields are horizontal at the equator and vertical at the poles, thereby giving latitude of the rock when is cooled from volcanic hardening or the last metamorphic squeeze. And there is a magnetic imprint when sediments settle too.

Latitude when combined with geometric constraints of seafloor strips and correlated trans-ocean rock formations build the overall picture.

In addition the oldest seafloor is 220 million years old or 5% of Earths lifetime. Paleomag measurements go back ten times longer.

Re: What did Earth look like X million years ago?

#78

Post by GlennS »

peter303 wrote: post #76
GlennS wrote: post #45

Earlier quoted context omitted.

Magnetic striping on the sea floor [ https://en.wikipedia.org/wiki/Plate_tectonics#Magnetic_strip... ] is probably our best clue. It's the piece of evidence that sealed plate tectonic's place as the dominant theory. Plates which are separating let molten rock from the mantle up, where it cools hardens. Any rock which can be magnetised (iron) is aligned with the Earth's magnetic field when molten, and gets fixed that…

Paleomagnetism measurement of the magnetic field direction in a rock gives the latitude of a the rock when it formed. The magnetic fields are horizontal at the equator and vertical at the poles, thereby giving latitude of the rock when is cooled from volcanic hardening or the last metamorphic squeeze. And there is a magnetic imprint when sediments settle too. Latitude when combined with geometric constraints of seafl…

Those are fun and interesting corrections, thank you.
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