
What did Earth look like X million years ago? - rport
http://dinosaurpictures.org/ancient-earth#50
======
pvg
Previously:
[https://news.ycombinator.com/item?id=17286770](https://news.ycombinator.com/item?id=17286770)

Has a bunch of comments by the author.

------
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.

~~~
mkl
It would also be really useful if night could be turned off, and if the gimbal
lock rotation issues (I'm guessing) could be avoided (with quaternions?).

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dluan
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](https://imgur.com/a/rE5wwc4)), when you're out
where most dino bones are found, you forget that it may have been a lush
landscape of riverbeds approaching the ocean coastline, or that it may have
been a dry arid desert landscape like in the land before time movies.
Regardless, it's odd to imagine all of it, with _no grass_.

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

~~~
dluan
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.

~~~
eyko
Adapted, not designed.

------
moultano
When I was a kid I had a wonderful collection of magazines called "Prehistoric
Zoobooks."
[https://www.google.com/search?q=prehistoric+zoobooks&client=...](https://www.google.com/search?q=prehistoric+zoobooks&client=ms-
android-
google&prmd=ivsn&tbm=isch&tbo=u&source=univ&fir=J_vsWDQeSzG1jM%253A%252CiYzcTvfpkeAyyM%252C_%253BUk7Y3VJCqCBx8M%253A%252C9GZcY3es-g0kpM%252C_%253BWf-
_ANS-
pgmVSM%253A%252C9CUdUGsNydlKoM%252C_%253BINn6S_YdCaMkLM%253A%252CesoYPDwRTvMRFM%252C_%253B1MahkDKA5BOixM%253A%252CZNG3x0ByNx6leM%252C_%253Bj1WUUTyPpOyCZM%253A%252C8Zu8tTB77gKSVM%252C_%253BvTHkWrPT5BUPrM%253A%252CaQx71Q4tvo6jeM%252C_%253B62gZAYdkJvNS_M%253A%252Cb84uf8bSyH1OHM%252C_%253BuRE-
eMCu3huY3M%253A%252CUINZPn77l9LhlM%252C_%253B6r81mbOpeQkUhM%253A%252Ct6MqPGoNqB9ejM%252C_&usg=AFrqEzcu4rxaRK2euDnRSfJfVgyGLdhZXQ&sa=X&ved=2ahUKEwjP5fDwy9fcAhUDYKwKHUqBB-
kQ7Al6BAgKEAI&biw=412&bih=660) 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, but can't
find anything comparable. Any recommendations?

~~~
ende
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.

------
jcims
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 Milky Way.

I sometimes wonder if we could build a telescope large enough to resolve these
photons into an image of the earth from that time. This would likely require
5,000 years of technological development and construction, but it does seem
like it's physically possible. (Maybe there's too much dust or distortion or
background noise to actually pick out the signal, dunno)

We couldn't go back XXX million years, but maybe XX thousand?

~~~
oneredoak
I have followed the same idea regarding radio waves. Would it be possible to
travel far enough out to receive radio or TV broadcasts from WWII? Presumably
all that information in the form of waves is still out there (assuming it
hasn't been too distorted by inference, or far too small of an amplitude).

~~~
oh_sigh
No, because you can't catch up with radio waves since they are going the speed
of light.

~~~
anonytrary
But using OP's idea, they could be reflected back at the earth, such that 2018
- 1942 = 2 x numLightYears away from the scattering object. I agree, you
wouldn't be able to go "in front of the waves" but you might be able to go to
a point in space where they'd eventually arrive through scattering. I think
it's very unlikely anyways since the solid angle for them to be reflected
right back at a certain point is super small.

~~~
jcims
Very unlikely indeed. I wish I was smart enough to do the math but I'm sure
it's more difficult than resolving a planet 50k light years away. Probably
more like resolving a planet in another galaxy.

~~~
anonytrary
I fixed the typo, the factor of a half should have been on the other side of
the equation. To actually calculate a realistic probability would require more
work; farther objects would imply higher attenuation, etc.

------
okket
Previous discussion from 2 months ago:

[https://news.ycombinator.com/item?id=17286770](https://news.ycombinator.com/item?id=17286770)
(59 comments, some from the author)

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

~~~
z3phyr
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.

~~~
toomanybeersies
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.

~~~
dvtv75
Head down to Curio Bay and see the remains of a forest from 180mya, too.

------
Jagat
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.

~~~
sauravt
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](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?

~~~
acqq
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](http://dinosaurpictures.org/ancient-earth#240)

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

------
sus_007
The creator himself had posted this earlier at HN.
[https://news.ycombinator.com/item?id=17286770](https://news.ycombinator.com/item?id=17286770)

------
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](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](https://en.m.wikipedia.org/wiki/Arctotherium)

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

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

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

------
arethuza
This actually answered a question I had wondered about - in the North West of
Scotland there are mountains made of a distinct sandstone - Torridonian (named
after the sea loch). I remember reading that the material that created this
sandstone came from the erosion of mountains to the North West (where the
Atlantic is now).

I looked up Scotland and 750 million years ago and there is a range of
mountains to the North West. :-)

Incidentally, one of the cool things about the North West of Scotland is that
the _original_ landscape that was buried by the sandstone has been exposed in
places.

Edit: I also seen to remember reading that the Brownstone buildings of New
York are actually made from the same stone deposited on areas that ended up on
the other side of the Atlantic when it split.

------
HoochieKoo
It would be cool if this could show what the Earth would look like in the
future too.

------
barking
Topically, I see Britain had everything sorted 150 million years ago while the
rest of Europe was in a right heap.

~~~
weinzierl
First thing I noticed as well. Joking aside: Any ideas why this is so? It's
not that the British Islands elevation is so extreme.

~~~
rement
The British Isles are away from the plate edges where most disruptive geologic
activity occurs (earthquakes, volcanoes, subduction, etc). The rest of Europe
is along the edges of the plate and was geologically active. If you look at
North West Brazil you can see very little happens for over 240 million years
(away from plate edge) while Oceania has been very active for the last 100+
million years (and is still very active).

If you look at the ocean while you go back in time you can see large swaths
that have very little detail. This is because that rock has been geologically
recycled and is no longer part of the geologic record.

------
illwrks
Brilliant, although it would be excellent if the transitions between the times
was animation.

Perhaps the time could be represented as a video. Draw a video frame to a
canvas and use as a texture for the sphere. As the time is updated just play
forward or backward to a video point and the texture would update.

------
Teknoman117
You have to love the giant black dot on the yucatan when you set it to the
extinction of the dinosaurs.

~~~
mysterypie
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.

------
RightMillennial
Are polar ice caps that rare of an event for the Earth? I only see them at 600
(N & S), 450 (S), 300 (S), 35 (S) and 20 (S) Mya.

------
JumpCrisscross
Has anyone made a large-format map (or better yet: globe) across which one can
scroll to past geographic and political maps?

~~~
Steuard
I think so! The "Magic Planet" is a digital projection globe that can display
all sorts of different datasets. I've been more interested in its planetary
science, astronomy, and geology applications, but I believe they've got lots
of political, cultural, and economic visualizations as well.

[http://globalimagination.com/](http://globalimagination.com/)

------
deanclatworthy
Is it not possible to zoom? It becomes un-viewable when I do?

------
laxd
Would be cool to have "snowball earth" pop up there around 700mya.

------
natch
Love the left-right arrow key shortcuts here.

------
freecodyx
Africa 90m years before was splitted into two giant pieces, and then merged
into one piece ??

------
dingo_bat
How do we know the geography of so long ago?

~~~
GlennS
Magnetic striping on the sea floor
[[https://en.wikipedia.org/wiki/Plate_tectonics#Magnetic_strip...](https://en.wikipedia.org/wiki/Plate_tectonics#Magnetic_striping)]
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 way. The magnetic field swaps
every 10,000 years or so
[[https://en.wikipedia.org/wiki/Geomagnetic_reversal](https://en.wikipedia.org/wiki/Geomagnetic_reversal)],
so you get a stripey effect.

Working our more precised dates for the magnetic swaps is a matter of slow and
painstaking correlation with other bits of evidence: dating of radioactive
elements, tree rings, rock layers, the temperature of the Earth, composition
of gas bubbles trapped in rock and ice.

~~~
peter303
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.

~~~
GlennS
Those are fun and interesting corrections, thank you.

