You have to love the giant black dot on the yucatan when you set it to the extinction of the dinosaurs.
What did Earth look like X million years ago?
11–20 of 78 posts
Re: What did Earth look like X million years ago?
#12How do we know the geography of so long ago?
And geochemistry.
Re: What did Earth look like X million years ago?
#13Awesome! 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.
Re: What did Earth look like X million years ago?
#14Earlier quoted context omitted.
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).
No, because you can't catch up with radio waves since they are going the speed of light.
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.
Re: What did Earth look like X million years ago?
#15Previously: https://news.ycombinator.com/item?id=17286770
Has a bunch of comments by the author.
Re: What did Earth look like X million years ago?
#16You have to love the giant black dot on the yucatan when you set it to the extinction of the dinosaurs.
Nice catch. That dot is surprisingly small to have caused so much hoopla, but I guess it makes sense when you think about it.
Re: What did Earth look like X million years ago?
#17Last 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 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.
Re: What did Earth look like X million years ago?
#18The creator himself had posted this earlier at HN.
https://news.ycombinator.com/item?id=17286770
Re: What did Earth look like X million years ago?
#19Earlier quoted context omitted.
No, because you can't catch up with radio waves since they are going the speed of light.
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 s…
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.
Re: What did Earth look like X million years ago?
#20Last 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.