# How advanced does a civilisation need to be before it leaves a permanent record? **URL:** \ **Category:** Factual Questions\ **Created:** [October 8, 2012, 5:25pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104 "2012-10-08T17:25:23Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Teuton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/teuton/32/3864_2.png) [@Teuton](https://boards.straightdope.com/u/Teuton)\ **Post date:** [October 8, 2012, 5:25pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/1 "2012-10-08T17:25:23Z")
Inspired by another thread about how well our own civilisation would last for study by future paleontologists. The question is as it’s stated in the title, but I suppose a clearer way to ask it would be, What particular inventions and advancements would survive, say, a 60 million year time gap? And, given I suspect that they will be quite advanced, how sure can we be that some other species _hasn’t_ developed, say, agriculture, before us and been wiped out? ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [October 8, 2012, 10:58pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/2 "2012-10-08T22:58:48Z")
Nothing lasts that long. > [@](#): > > I close my eyes Only for a moment and the moment’s gone All my dreams Pass before my eyes with curiosity > Dust in the wind All they are is dust in the wind > Same old song Just a drop of water in an endless sea All we do Crumbles to the ground, though we refuse to see > (Aa aa aa) Dust in the wind All we are is dust in the wind Oh, ho, ho > Now don’t hang on Nothin’ last forever but the earth and sky It slips away And all your money won’t another minute buy > Dust in the wind All we are is dust in the wind (All we are is dust in the wind) > Dust in the wind (Everything is dust in the wind) Everything is dust in the wind (In the wind) ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 8, 2012, 11:02pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/3 "2012-10-08T23:02:43Z")
All it has to do is act up REALLY BAD, just once, and that goes on its Permanent Record. Just TRY to get it erased! Not in a million years! ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [October 8, 2012, 11:14pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/4 "2012-10-08T23:14:46Z")
I’m impressed. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 8, 2012, 11:18pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/5 "2012-10-08T23:18:25Z")
Advanced enough to make a stone tool. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [October 8, 2012, 11:20pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/6 "2012-10-08T23:20:27Z")
At least advanced enough to have an elementary school system. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [October 8, 2012, 11:40pm UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/7 "2012-10-08T23:40:55Z")
Given that we have fossils that are hundreds of millions of years old - going all the way back to bacterial colonies - technology and civilization are not really required to leave evidence. The hard thing might be interpreting whether the permanent record indicates civilization or not, but there will be plenty of records left behind. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [October 9, 2012, 12:24am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/8 "2012-10-09T00:24:37Z")
Quarrying stone was mentioned in an earlier thread on this subject. Carving a whole bunch of rectangular chunks out of a mountainside is going to be visible for a good, long time. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [October 9, 2012, 12:56am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/9 "2012-10-09T00:56:25Z")
It is ironic that some of the first tools our civilisation made will be among the longest lasting of all our relics. Knapped flint tools will continue to be recognisable as artificial for hundreds of millions of years (in the right circumstances). Other long-lived areifacts will include certain class and ceramic objects. Most metal onjects will become unidentifiable, but some- gold for instance- might perdist in some form, although they could be easily deformed so much as to resemble natural nuggets because they are so soft. I suspect that no civilisation will everleave a permanent record; planets stars and even whole galaxies eventually evaporate away into unidentifiable dust, or are swallowed by black holes, which evaporate into radiation. It would be difficult to create anything that would last longer than a supermassive black hole, but even those are fleeting events compared to eternity. ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [October 9, 2012, 1:00am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/10 "2012-10-09T01:00:46Z")
The limestone pyramids will stay there as long as they’re not quarried or nuked (or egypt gets 200 days of rain.) Ankor Wat is made of laterite (practically weather-resistant even in tropical settings.) Other relics will presist as long as they’re not intentionally destroyed. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [October 9, 2012, 1:56am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/11 "2012-10-09T01:56:44Z")
A Mickey Mouse watch. 😉 ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [October 9, 2012, 2:06am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/12 "2012-10-09T02:06:09Z")
I’d assume evidence of large scale mining would still be noticeable. Some chemicals with very long half lives would still signify we were here. All the nuclear weapons full of U-235 will signify some kind of intelligent life since U-235 occurs in very small concentrations in nature (less than 1%), while in nuclear weapons (90%) or in power plants (5%) the concentration is far higher than you find in nature. The half life of U-235 is 700 million years. Archaeologists looking around in a billion years finding stores of U-235 in concentrations of 50%, isolated from other sources of Uranium, might figure something was up. My understanding is bronze statues will last at least 10 million years. No idea if they will last far longer than that or not. ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [October 9, 2012, 2:11am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/13 "2012-10-09T02:11:48Z")
The least soluble minerals (at the surface) are oxides, so you could take a leaf from Angkor Wat. The most stable undergound environment are those salt domes. ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [October 9, 2012, 3:53am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/14 "2012-10-09T03:53:35Z")
> [@Wesley\_Clark](#): > > I’d assume evidence of large scale mining would still be noticeable. > > Some chemicals with very long half lives would still signify we were here. All the nuclear weapons full of U-235 will signify some kind of intelligent life since U-235 occurs in very small concentrations in nature (less than 1%), while in nuclear weapons (90%) or in power plants (5%) the concentration is far higher than you find in nature. The half life of U-235 is 700 million years. Archaeologists looking around in a billion years finding stores of U-235 in concentrations of 50%, isolated from other sources of Uranium, might figure something was up. > > My understanding is bronze statues will last at least 10 million years. No idea if they will last far longer than that or not. We’ve been able to find evidence of [natural nuclear fission](http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor) that took place 1.7 billion years ago just by a slightly lower (by only 0.003%) concentration of uranium-235 in ore, so I can easily see this happening. Although, if you have deposits of very high uranium concentrations (from not just bombs, but waste disposal/storage sites) scattered across the globe, one could be mislead to think that uranium naturally occurs like that, although geologists would probably easily recognize it as unnatural. Also, what about landfills? No doubt they will leave behind deposits that are clearly not natural due to the high concentrations of minerals that normally wouldn’t be found together or in such concentrations. Some of the stuff might even fossilize before it decomposed if they can still be [recognizable after decades](http://environment.about.com/od/recycling/a/biodegradable.htm): > [@](#): > > “Typically in landfills, there’s not much dirt, very little oxygen, and few if any microorganisms,” says green consumer advocate and author Debra Lynn Dadd. She cites a landfill study conducted by University of Arizona researchers that uncovered still-recognizable 25-year-old hot dogs, corncobs and grapes in landfills, as well as 50-year-old newspapers that were still readable. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [October 9, 2012, 4:26am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/15 "2012-10-09T04:26:28Z")
> [@Teuton](#): > > The question is as it’s stated in the title, but I suppose a clearer way to ask it would be, What particular inventions and advancements would survive, say, a 60 million year time gap? A lunar lander comes to mind. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [October 9, 2012, 5:21am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/16 "2012-10-09T05:21:26Z")
Considering that we have fossil evidence of soft bodied invertebrates from much longer than 60 million years ago, I think evidence of our freeway overpasses, our motor cars, our knives and forks, and perhaps even our iphones can be expected to survive for much longer than that. I don’t see why the same would not apply to the artifacts - often made of quite durable materials such as stone, ceramic and metal - of much earlier, even quite “primitive”, human cultures. ---
**Author:** ![Peanuthead](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peanuthead/32/360_2.png) [@Peanuthead](https://boards.straightdope.com/u/Peanuthead)\ **Post date:** [October 9, 2012, 8:16am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/17 "2012-10-09T08:16:43Z")
Twinkies? ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [October 9, 2012, 9:15am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/18 "2012-10-09T09:15:48Z")
> [@Der\_Trihs](#): > > A lunar lander comes to mind. No. Meteorites can and will destroy it. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [October 9, 2012, 10:07am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/19 "2012-10-09T10:07:29Z")
> [@Michael63129](#): > > We’ve been able to find evidence of [natural nuclear fission](http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor) that took place 1.7 billion years ago just by a slightly lower (by only 0.003%) concentration of uranium-235 in ore, so I can easily see this happening. So what about the 500 or so above ground Atomic tests that took place between 1945-1980? Will that still leave a trace signature that can be easily detected in 60 Million years? ---
**Author:** ![Bremidon](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@Bremidon](https://boards.straightdope.com/u/Bremidon)\ **Post date:** [October 9, 2012, 11:10am UTC](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104/20 "2012-10-09T11:10:14Z")
Most evidence of our existence would be gone within 500 years. Some of the larger, better built buildings might last a bit longer, but metal does not do well if there’s noone around to take care of things. Water is unbelievably destructive. That said, some stone buildings like the pyramids might make it for quite a bit longer. Eventually they would be destroyed by sand and wind, but it might take thousands of years. Mount Rushmore might last longer, because it is carved from granite. In any case, 10,000 years and pretty much everything is absolutely wiped out on Earth. Any evidence would have to be small things somehow conserved away from water, wind, and sand. Maybe the things we’ve squirrelled away in salt mines will last longer… re: Twinkies: If you want food that _really_ lasts, you should go for honey. If you can keep honey away from water, it might last over 1 million years. What about stuff away from Earth? Well, our signals will also be pretty much background static after 10,000 years. (Apparently 2 light years is enough distance to make all our signal indistinguishable from background noise). If we shot enough stuff out of our solar system, they should last a long time; although, someone still has to find them. I don’t know about evidence on the moon. What effect does the solar wind have on our stuff on the moon? [Next page](https://boards.straightdope.com/t/how-advanced-does-a-civilisation-need-to-be-before-it-leaves-a-permanent-record/637104.md?page=2)