Pretty much what the title says. How long would it take for natural processes to erase the existence of humanity circa 2003?
How long does it take for Styrofoam to degrade again? 20,000 years?
How long does it take for Cher to degrade?
Hey, I like Cher…
Although you have an interesting point. It’s a shame more people won’t be fossilized… I’d love to hear the thoughts of a superintelligent cockroach paleontologist as he studied the fossil of a sillicone implant.
JS:
Seriously, you might want to define “all evidence”. That’s pretty broad. Do you mean how long before Vulcans could land on earth, do a pretty thorough search and not find out about us?
Very, very long. We routinely dig up fossils of creatures that lived 100s of millions of years ago. I would venture a guess that as long as the earth were around, intelligent ETs would be able to detect that we had been here.
There would be traces detectable even to future versions of us with “only” our current level of technology, for millions of years.
We’ve been able to find 5,000 year old graves simply due to soil disturbances, and the Pyramids are what, 3,000+ years old? Fossilized bones are sometimes ten million years old or more…
With things like modern concrete, stainless steels, titanium and carbon fiber, there’d be traces left for untold millennia.
Heck, even if all our manmade works vanished overnight, ther would still be detectable traces of excavations like strip-mines, coal mines, skyscraper foundations, cliffsides carved out for highways, and other major features that would be obvious as non-natural for eons.
I’m not sure whether I understand the OP correctly. I presume the first part of the title is a hypothetical, not a prediction, otherwise I’m not going to bother finishing this post. 
Do you mean (as the title suggests) how long until evidence of humanity is gone, or how long until evidence of civilization anno 2003 is gone? The former may take a very long time, given that the Pyramids and the Chinese wall are still very visible. For the latter I’m not sure, I wondered about that just last week.
If we are talking about ‘gone’ in the sense of irretrievably gone, even for an archaeologist, I guess it will be tens or hundreds of thousands of years. We even now manage to collect much stuff of primitive mankind, while they didn’t erect any kind of large building. OTHO a lot of modern building doesn’t seem very durable. Concrete and steel is not very durable in the long term, I guess. My guess is with durable plastics, too. It appears these will last thousands of years (not functional, but still in one piece). It may very well be that an archaeologist will one day dig up lots of CD’s and DVD’s and proclaim these to be either currency or a sacrifice to the Big God aka Bill Gates.
Humanity as in “Humans considered as a group; the human race,” and not humanity as in “The quality of being humane; benevolence.”
The Earth has an expected life of what? A couple billion years before the sun supernovas or whatever? (If you’ll allow me to verbify “supernova”…and verbify “verb” into “verbify” for that matter.) Let’s suppose that intelligent life does evolve again. Will our footprint be here until the sun explodes even if we vanish today?
According to Squink, it sounds like we will be detectable until the sun explodes.
Sorry, I didn’t make myself as clear as I should be. I meant: evidence of human civilization in full (i.e. from all ages), or evidence of human civilization anno 2003.
I agree that until the earth has molten, there will remain evidence of us humans having been around, but it will get progressively harder to detect. If you are speaking of unmistakeable signs, I’m still with the pyramids.
If you mean, enough evidence to get a clear picture of our current life-style, beliefs etc. (which after all comprise a civilization), I’m not sure whether our current civilization will leave much of a footprint. Computers and modern paper are already hard to conserve for librarians who make a real effort to do so. The building might keep up longer, at least the basic structure, but I’m really not sure whether they will stay in proper shape. Modern structures are stable only because they assume regular upkeep. Look at the way the WTC went: when the basic structure was touched, the whole building collapsed. You can’t destroy the pyramids in that way.
(No I’m not obsessed with pyramids, they are just the easiest example. And I can’t spell the names of Middle-and-South-American civilizations and their temples, or the Borobodur (?))
See, that is much more interesting than what I was asking.
Let’s see if we can rephrase it: Given humanity’s immediate extinction this instant, at what minimum point in time will a future archeologist no longer be able to reconstruct human civilization in the year 2003? Does that sound about right?
How long will it take for acid-free paper to become unreadable? That may be our first benchmark.
Who is in charge of the demise of the Human Race. If it is Rummy our evidence will go before us
Some traces will last for billions of years: namely the six Apollo lunar landers on the moon as well as Pioneer 10 and 11, and Voyager 1 and 2.
**Yeah, but they are trying to preserve the articles in usable form - in (say) that anaerobic environment of a landfill, there isn’t a lot going on.
The WTC didn’t disappear though, did it; there was a heck of a lot of debris, parts of which (especially the metal parts) are going to stay looking clearly artificial for a long time.
The pyramids? the Great Wall? A blink of the eye. The most lasting construction of mankind detectable by observers in the distant future will be the United States Interstate Highway System. These straight-line roadbed evacuations should be detectable by any archeologist (able to draw a straight line) in the immediate future (say 330,000 years) or through three ice ages of the future. That is the length of time than it would probably take for normal weathering processes to erode away and downcut the present terraine (say 60 feet, base level ) and thereby make the best of their observations a bit of a streach.
But the good news is that mankind is leaving more evidence of his culture and existence in the mud flats of our river estuaries than any low life mollusks or Paleozoic trilobites. In the dark shales of 600,000,000 years from now the cast of a plastic six pack ring holder won’t bring very much on the fossil market.
Hey! What about that spacecraft with the naked man and naked woman we sent out to say “HI!” to our sapient brothers over in the galaxy next door. Wow! If that thing doesn’t run into anything big it could last a couple of billion years. Wow!
I’m gonna vote that the immense garbage dumps in major cities will yeild up evidences of our existence at least as far into the future as dinosaurs are in the past.
Radioactive Waste.
Isotopes that cannot exist in Nature will be found there in measurable quantities for millions of years.
And our radio transmissions are echoing out into the Galaxy, clearly audible to any available listener, an archive of Human endeavour for millions of years.
[nitpick]
The Milky way galaxy is only ~100,000 light years in diameter, so those signals will pass beyond it in the blink of a geological eye.
[/nitpick]
I’m going to add that our system of cemetaries will provide evidence of our existence for millions, possibly even a billion years. If not the bones or fossilized remains, at least the pattern of disturbed soil that would show were there graves were. Any cemetary in a geologically sedate zone should last quite a while, certainly enough for a new intelligent species to arrise.
Thinking about this some more, let me clarify something. I believe that human remains or artifacts cannot be erased from the archaeological record before another intelligent species would arise to examine them because there’s so much. Something will survive thru the ages to give a clue to future intelligent species or extra-terrestrial archaeologists that we were here.