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Ancient Earth Globe

dinosaurpictures.org

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Re: Ancient Earth Globe

#51

Post by mkl »

raattgift wrote: post #28
Jupe wrote: post #16

Some time ago I had this thought: The original (single) continent was round, and about the diameter of the moon. Since the moon was much closer to the earth, it's gravitational pull would give rise to a bulge (an earth "tide" if you will), which would be roundish and about the size of the moon's visible diameter. I am definitely not a geologist, and this is probably un-provable... but, to me, it sure seemed like a pl…

> un-provable ... plausible Your idea's first hurdle is the length of day vs the length of month. How do you keep the moon over one bulged part of Earth at all times? (it's a very different story for the moon, whose 'day' is as long as its orbit, more at [1]) Additionally, there is a solar tide at work on the oceans that is visible daily, and especially at spring and neap tides. The sun's mass drives a maximum of alm…

I wondered if it was possible at some point in the past, but I don't think so. The moon's orbit has been increasing its whole existence. It started ~25,000 km away from Earth [0], and is now at ~384,000 km. That means at some point it was at the distance for a current geosynchronous orbit, ~36,000 km. Unfortunately, when the moon was formed, the Earth's day was only 6 hours long [0], so the geosynchronous orbit was much smaller at ~10,000km (based on [1]), and so I don't think they ever lined up.

[0] https://physics.stackexchange.com/questions/31429/how-long-w...

[1] https://www.dummies.com/article/academics-the-arts/science/p...

Re: Ancient Earth Globe

#53

Post by Cort3z »

Cort3z wrote: post #52

Very cool website. Would be nice with a slider in addition to the dropdown, so you could scrub backwards and forwards in time.

With the power of a little too much time before a meeting, I give to you a slider;

Add this somewhere which makes sense in the html;

``

Then, add this script in your console;

```js

const slider = document.getElementById('mySlider'); const select = document.getElementById('years-ago');

slider.addEventListener('input', () => { select.selectedIndex = Number(slider.value); select.onchange(); });

```

Re: Ancient Earth Globe

#55

Post by sgt »

Tagbert wrote: post #43
xwdv wrote: post #3

I would love to see the projection of what the landmasses would look millions of years into the future.

I’ve seen some. The most noticeable changes are Australia smashing into Southeast Asia. The Mediterranean closing up as Africa moves into Europe. East Africa splitting along the rift valley. California surfing up toward Alaska.

Will California break off and surf up towards Alaska, you say? Best news I've had all morning.

Re: Ancient Earth Globe

#56

Post by singularity2001 »

How much of that topology is speculation? I get that geologists can estimate the latitude of a location at a given time because of climate and chemical signals, plus some contemporary tectonic shift vectors. I don't get how paleomagnetism is reliable when the magnetic field can wander in the timespan of some thousand years. I'd expect the resulting equations to yield a multitude of solutions or even be unsolvable.

Re: Ancient Earth Globe

#57

Post by leohonexus »

To see life evolve from algae, one would have to live 7.5 million lifespans, assuming one has a lifespan of 100 years. Ancient Egypt is just 50 lifespans away in comparison. That's the most mind-boggling fact I learnt today.

Re: Ancient Earth Globe

#59

Post by simonh »

leohonexus wrote: post #57

To see life evolve from algae, one would have to live 7.5 million lifespans, assuming one has a lifespan of 100 years. Ancient Egypt is just 50 lifespans away in comparison. That's the most mind-boggling fact I learnt today.

For much of human history 50 years is probably a lot closer. Anyway…

https://xkcd.com/2608

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