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My story involves everyone in the year 2015 suddenly disappearing. What would visitors to Earth find if they arrived in the year 12015, or 10,000 years after we all disappeared? Assume none of our infrastructure has been maintained during that period.

I'm especially interested to know what would remain of our technology and infrastructure, such as roads, buildings, major installations, ships and aircraft, observatories, bridges, the pyramids, etc.

Would these things be completely gone or would there be some rubble and other evidence left? What about stuff like kitchen and laundry appliances, mobile phones, etc? Would these things completely disintegrate, or would there be some bits left? What about stuff made of stainless steel like cutlery and kitchen sinks?

I want to understand two things:

  1. Would there be any evidence on or very near the surface that our civilisation once existed?
  2. Would there be anything useful (or close to useful) left behind?

Bonus question: What would the world look like? Would climate change have raised ocean levels, or would it be close to now? Are there any parts of the world which definitely would have changed through erosion or other forces? For example, the Grand Canyon or The Twelve Apostles (rock formation in Australia).

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    $\begingroup$ I liked the expression The Administrator used in Half-Life 2: "All that would remain of humanity would be a thin layer of plastic under aeons of mud." $\endgroup$ – SF. Mar 31 '15 at 0:14
  • $\begingroup$ @Marky Mark suppose during these period of absent natural disasters are frequents, don't rule of asteroid impacts, man-made structures undergoes disintegration and biodegrading and continental shifts, winter Earth or even direct shower from a distance gamma ray burst... (1) depend of alien's archaeology see neanderthal discovery (2) recycle non-biodegradable (Bonus) speculative...see chaos theory. $\endgroup$ – user6760 Mar 31 '15 at 1:43
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    $\begingroup$ Four words: The World Without Us by Alan Weisman. It's a great book that answers exactly what you are asking. $\endgroup$ – fi12 Feb 24 '16 at 0:10
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This has been answered comprehensively in the TV series Life after People. The link goes to a wiki with a lot of information about the series, including synopses of the episodes.

To summarise very briefly in case of link rot (URLs don't always have a terribly long lifespan either), after 10,000 years, there wouldn't be very much left on the surface at all, save some items that are particularly resistant to decay, like stainless steel objects, and things in protected places such as caves or deserts. The artefacts on the moon and satellites in space would still be there, mostly unchanged save for the effects of 10,000 years of solar irradiation.

As to whether there would be anything useful left, the answer is, "Yes, but not much at all". There may be useable stainless steel objects like cutlery and kitchen sinks that could be cleaned up and used. There may be occasional objects left in protected places that have not decayed, but for the most part, not much will still work unless it is corrosion resistant and simple.

The world would be warmer, and erosion would have changed geography a little, but 10,000 years is not the timescale over which major geological changes occur, so the continents would still be recognisable, if displaced a little due to continental drift.

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  • $\begingroup$ Good answer, though I'm curious why you think it would be warmer 10k years from now...it's far enough out there and there is enough influencing our climate that it's really hard to conclusively say it'd be warmer, especially with us gone. $\endgroup$ – Twelfth Mar 31 '15 at 0:07
  • $\begingroup$ @Twelfth, I was summarising from the Life after People wiki. I'm not a climatologist, and my intuition would be similar to your own. It may have something to do with non-greenhouse climatic trends. $\endgroup$ – Monty Wild Mar 31 '15 at 0:16
  • $\begingroup$ Glacial cycles move between periods of glaciation, then retreat and warm intervals, then back. If we assume we are entering a interglacial warm period, in 10000 years things should be even warmer than now. $\endgroup$ – Oldcat Mar 31 '15 at 16:58
  • $\begingroup$ In 10k years porcelain toilets would still work but everything (left out in the elements) made with iron in it would be rust, including stainless steel. $\endgroup$ – Mazura Feb 12 '16 at 23:47
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Not sure I agree with some of the above answers; after all, how much is left and recognizable of ancient civilizations that are only a fraction of the age being postulated here? A few megastructures built of stone like the Pyramids, and that is about all.

Cities from ancient Sumer resemble eroded hills, and virtually any metallic object has corroded away except for gold (which, if it could be salvaged by grave robbers, was almost always plundered and melted down). Most of our buildings and structures are made out of metal, and (as mentioned above) most would have collapsed after about two centuries without being maintained. Our concrete structures won't last much longer, they have reinforcing rods while ancient Roman concrete does not.

Any future civilization or alien explorers will indeed find evidence that something or someone was here, mostly by digging through garbage dumps or discovering old mines (oddly, that is how we find out a lot about ancient civilization), but they won't find the towering remains on New York or Hong Kong unless they arrive only a century or two after all the humans were gone.

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Mount Rushmore probably wouldn't have changed all that much, and there would be some other buildings and places that would appear to be actually pretty close to what they do today; but for the most part and in most places it would require quite a bit of effort to find out that there had been people at all on earth, especially depending what the climate may or may not have done in 10,000 years; any current warming from our existence would have long since disappeared and there very well could have been an ice age between now and then which would further remove many evidences of prior human existence.

There would surprisingly actually be some random objects that would likely be completely usable if one knew where to look. Deep mines and landfills if they were otherwise undisturbed could be dug through for some interesting things, including usable silverware and quite possibly kitchen sinks. Not sure how a mobile phone would fare in a landfill type environment over 10,000 years, I mean it probably didn't get placed there because it was usable to begin with and it certainly wouldn't be usable after that long, but there would be bits left.

Major geological features would likely look not too very much different from how they do today for the most part.

All of the low earth orbit satellites would have fallen to earth; only the higher orbiting satellites, such as the geostationary satellites would be left.

Once archeological surveys started there would be no trouble determining that there was a major civilization.

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  • $\begingroup$ In addition to Rushmore, ruins of the largest dams (Tarbela, Fort Peck, Gardiner, ASARCO tailngs, etc.) could be expected to remain visible until subducted at a plate boundary or buried beneath a lava flow. $\endgroup$ – A. I. Breveleri Mar 19 '18 at 0:25

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