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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?

#21

Post by toomanybeersies »

z3phyr wrote: post #10
nharada wrote: post #6

I had no idea flowers evolved so late. The first flowers were 100 million years after the first dinosaurs!

The majority of flora we see now also evolved very late. The dinosaurs probably saw and fed on Conifers, Cycadophytes and Ferns. Grass and Modern leafed flora evolved much later.

You can see what forests might have looked like 100mm years ago by going to New Zealand, which split off from the Australian landmass about that long ago.

The native flora consists of a lot of ferns, and almost entirely evergreen plants. Flowers are uncommon and primitive, most plants are pollinated and spread by birds. The only native grasses are tussocks.

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

#22

Post by dluan »

ende wrote: post #20
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…

Lots of mosses though? I imagine more primitive vegetation filled that role.

Dunno! I think most larger dinosaurs then needed larger sources of energy. Look at the teeth of an ankylosaur or most ceratopsians - they're designed to chomp and scissor through large leafy kale.

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

#23

Post by ende »

moultano wrote: post #9

When I was a kid I had a wonderful collection of magazines called "Prehistoric Zoobooks." https://www.google.com/search?q=prehistoric+zoobooks&client=... Each one in the series described an era of life on Earth from the beginning to now, with fantastic illustrations. I used to read them from beginning to end over and over again. I really want to find something similar for my kids ideally with modern reconstructions,…

I recall this series as well (in a dark green plastic case?), and the closest experience I’ve come across as an adult has continuously been the Smithsonian Natural History museum. Every era is captured in a different exhibit.

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

#24

Post by throwaway2048 »

jcims wrote: post #3

Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…

The problem is the wavelength of light puts a hard limit on angular resolution, its the same reason why a spy satellite cannot read your newspaper, or microscopes can not see atoms, its physically impossible.

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

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

#25

Post by jamesrcole »

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. Yes, you can figure it out, but I think it could be made much easier to do.

- Have a checkbox for overlaying the outlines of the present-day continents (in their present-day positions) over the globe. This would also help the user to orient what they're looking at.

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

#26

Post by geoalchimista »

dingo_bat wrote: post #2

How do we know the geography of so long ago?

And palaeontology.

There may be tens of thousand of research papers behind each map shown in the OP. It is like solving a puzzle. At location X, Scientist A finds some clues in plate tectonics, Scientist B finds something in geochemistry, and Scientist C finds something in fossil records. Then they piece them together and if these stories all tell the same thing without a serious conflict, you can construct a point on that map. Now imagine doing this for thousands of different regions involving several generations of scientists, you get nice maps like these.

This Wikipedia page would be a nice read: https://en.wikipedia.org/wiki/History_of_Earth.

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

#27

Post by sauravt »

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 different islands?

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

#28

Post by acqq »

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…

First dinosaurs appeared as early as 230 million years ago, when what later became India was a part of the huge continent:

http://dinosaurpictures.org/ancient-earth#240

India became "an island" continent only almost 100 million years later than that.

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

#29

Post by jcims »

throwaway2048 wrote: post #24
jcims wrote: post #3

Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…

The problem is the wavelength of light puts a hard limit on angular resolution, its the same reason why a spy satellite cannot read your newspaper, or microscopes can not see atoms, its physically impossible. https://en.wikipedia.org/wiki/Angular_resolution

It is my understanding that you can mitigate this to an extent by making larger scopes or employing techniques like interferometry. I haven't found an absolute 'hard limit', only a limit based on the size of the resolving device.

I'm generally a moron in this area though so I'm certainly missing large swaths of information.

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

#30

Post by mysterypie »

Teknoman117 wrote: post #11

You have to love the giant black dot on the yucatan when you set it to the extinction of the dinosaurs.

The first time I read (in school) about an asteroid hitting the Gulf of Mexico and causing the extinction of the dinosaurs, I looked at a map and sure enough the Gulf of Mexico looked like a big round hole where the asteroid must have hit.

Later I realized that the dinosaur-killing crater is much smaller and buried and hidden at the edge of the Gulf of Mexico. I also learned that the Gulf of Mexico was formed to due plate tectonics, not due to an impact. What an odd coincidence that the dinosaur-killing asteroid hit a location on the Earth that looks just like a huge crater, but isn't a crater at all.

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