"After Earth" - what would the world look like?

[Iowan]

It used to be said that cockroaches and rats would survive a nuclear war.

The advice, then, was to get under your refrigerator if you saw a mushroom cloud.

But that's where the cockroaches and rats are...
OH! maybe that's why they survive.

[QIII]

You dun caught on quick like fer an Iowegian.

[jerryzambrano]

Nice question.
I've neither seen the movie or any of the ads/trailers/spoilers etc.
If we go by TV models such as "Revolution", the answer would be that it would take quite a while before we returned to a civilization as we know it.
However, there are other schools of thought (In the Sci-Fi world) that a new or fresh start on a distant planet would only encourage the rapid development of civilization as well as exceeding our previous understanding of it.

J.

[Paqman]

What mark have we made that would still be distinguishable?

Depends how closely you looked. Most of what we build is steel and concrete, that will only last a few hundred or thousand years at the most. The sites of most cities would be overgrown and fairly hard to distinguish fairly quickly, although some in particularly dry environments would probably stay obvious for thousands of years. Ironically, probably some of the stuff from ancient civilisations (eg: the pyramids) would outlast a lot of modern stuff. Stone may be a poor building material in a lot of ways but it is just more stable than reinforced concrete.

Plenty of things would be fairly obvious if you looked close enough. Incongruous chemical signatures would be everywhere in the soil and to a lesser extent the air, and it would be pretty hard to explain the distribution of certain species without us as the vector (eg: the presence of rats and dogs or specific European species on remote Pacific islands)

There would be a few really obvious artefacts that were there to be found. In the US the monument Mount Rushmore is expected to last for many tens of thousands of years. It's in a fairly stable bit of geology and it's cut into granite, which is seriously hard. Should be there for any alien archaeologists even if we're long gone.

The longest lasting proof of our existence won't be on Earth though. The artefacts from the Apollo missions on the moon could well last for millions of years. Galvanic corrosion will eventually break down the technological components, but that could take a very, very long time. The moon isn't particularly geologically active, so the astronauts' footprints will stay exactly the same until something disturbs them, which might not be for many millions of years.

[Moose]

History Channel had a TV show based on that: http://www.history.com/shows/life-after-people

Was pretty good.

+1. I used to watch this show and it taught me a heap of interesting stuff. This show definitely comes close as to making assumptions of a post-humane world.

[Copper Bezel]

Stone may be a poor building material in a lot of ways but it is just more stable than reinforced concrete.

The pyramids and other surviving megalithic constructions like that are also built with less of the dynamic tensions that decay could release. They're basically stacked on the ground. You couldn't well build a skyscraper out of stone, and a Great Pyramid made of reinforced concrete might outlast the original (although weathering would be a serious issue.) The fault tolerances when every square cm of ground is load-bearing seem rather higher. = )

[llanitedave]

Depends how closely you looked. Most of what we build is steel and concrete, that will only last a few hundred or thousand years at the most. The sites of most cities would be overgrown and fairly hard to distinguish fairly quickly, although some in particularly dry environments would probably stay obvious for thousands of years. Ironically, probably some of the stuff from ancient civilisations (eg: the pyramids) would outlast a lot of modern stuff. Stone may be a poor building material in a lot of ways but it is just more stable than reinforced concrete.

Plenty of things would be fairly obvious if you looked close enough. Incongruous chemical signatures would be everywhere in the soil and to a lesser extent the air, and it would be pretty hard to explain the distribution of certain species without us as the vector (eg: the presence of rats and dogs or specific European species on remote Pacific islands)

There would be a few really obvious artefacts that were there to be found. In the US the monument Mount Rushmore is expected to last for many tens of thousands of years. It's in a fairly stable bit of geology and it's cut into granite, which is seriously hard. Should be there for any alien archaeologists even if we're long gone.

The longest lasting proof of our existence won't be on Earth though. The artefacts from the Apollo missions on the moon could well last for millions of years. Galvanic corrosion will eventually break down the technological components, but that could take a very, very long time. The moon isn't particularly geologically active, so the astronauts' footprints will stay exactly the same until something disturbs them, which might not be for many millions of years.

I agree with just about all of this. A thousand years is not very long in the overall scheme of things, biologically there'd be no perceptible evolution in the remaining species. As for the footprints on the Moon, they might not last all that long after all; there's a contant rain of micrometeoroids impacting the surface, and over the eons these should wear down and flatten out the astronaut's surface markings. The occasional larger impact will splatter glass over the top of them. Those same micrometeoroids will act like a super sand-blaster on the metal artifacts left behind, grinding them back into dust. That would almost certainly require millions of years, though.

[deadflowr]

The moon isn't particularly geologically active, so the astronauts' footprints will stay exactly the same until something disturbs them, which might not be for many millions of years.

Or at least until Walmart opens up there.

[philinux]

The film in question seems to have been panned by some critics. The audience seems split too. I'll wait till it arrives via my satellite dish or aerial.

http://www.rottentomatoes.com/m/after_earth/

On the question, the earth will return to being green and blue with fantastic views of the cosmos due to no artificial light.

[Paqman]

The pyramids and other surviving megalithic constructions like that are also built with less of the dynamic tensions that decay could release. They're basically stacked on the ground. You couldn't well build a skyscraper out of stone, and a Great Pyramid made of reinforced concrete might outlast the original (although weathering would be a serious issue.) The fault tolerances when every square cm of ground is load-bearing seem rather higher. = )

Well the thing about stone is that you have to build with no tension at all. It's junk in tension, so you have to make sure it's subject to compressive forces only (which means minimising bending too).

A concrete pyramid wouldn't do as well as the real ones, concrete just insn't as stable chemically, and corrosion of the rebars would cause spalling. Not that you need rebars in a pyramid, you'd be better off using unreinforced concrete.

The Colosseum is made of concrete IIRC, so it can last a few centuries in reasonable shape.

As for the footprints on the Moon, they might not last all that long after all; there's a contant rain of micrometeoroids impacting the surface

Yeah, and the occasional big one. One near miss from a decent sized one could erase the footprints. Still an odd thought that something as normally transient as a footprint could be such an enduring artefact of our civilisation though.

I guess the gold record on the Voyager probes could last a long, long time though. Gold is super-stable, so that should last until it falls into a gravity well and gets swallowed. That could be a really long time.