Apparently the oldest 'reliably' (if you happen to believe in the reliability of science these days) dated rock art cave paintings in Oz are 28,000 years old. However, there are pictures of long extinct animals and:
"The people who drew that animal could only have seen it more than 40,000 years ago,"
Stone carvings in some rock in Australia is estimated to last for 50 to 60 thousand years:
When it comes to the future, after we're all long gone, perhaps tunnels carved into solid rock may feature art like that.
I imagine most concrete structures/tunnels will collapse though. The reinforcing steel used in modern concrete construction rusts if gets wet causing 'concrete cancer', although maybe concrete structures in very dry and low salt areas might fare better.
There is a one-time NASA/Australia deep space tracking facility in a mountainous national park near me that was used to relay messages from the lunar landings. All of the above ground structures are now gone. All that remains is the levelled mountaintop site, concrete slabs, and some steel rails and so forth for the dishes once stood.
I broke into abandoned tracking station facilities before they were demolished once as a juvenile delinquent (I can't remember which ones, there's more than one around here and I was wasted at the time). I recall though that one of my mates made off with a souvenir of some electrical component festooned with radiation warnings - not the sharpest tool in the shed that bloke. But it highlights the risk of ignorance coupled with radioactive items that may be left behind from a one-time civilization.
In a way, collapse already happened up there at the space communications sites. No more lunar landings = no more deep space communications, so all that's left are some slabs here and there and Australia's own miniature version of Machu Picchu :P
There'd be some plumbing buried there I guess. And I saw some structure and pipes left near a creek, which I presume once fed the facility, or maybe dumped its waste.
The roads and associated earthworks to the facility will probably be all that's left in time. Maybe the odd bit of metal. It's not very salty around here, so metals that might ordinarily rust away to nothing may be able to last longer around here.
no subject
"The people who drew that animal could only have seen it more than 40,000 years ago,"
Stone carvings in some rock in Australia is estimated to last for 50 to 60 thousand years:
https://www.abc.net.au/science/articles/2014/10/09/4102916.htm
But that is pure rock.
When it comes to the future, after we're all long gone, perhaps tunnels carved into solid rock may feature art like that.
I imagine most concrete structures/tunnels will collapse though. The reinforcing steel used in modern concrete construction rusts if gets wet causing 'concrete cancer', although maybe concrete structures in very dry and low salt areas might fare better.
There is a one-time NASA/Australia deep space tracking facility in a mountainous national park near me that was used to relay messages from the lunar landings. All of the above ground structures are now gone. All that remains is the levelled mountaintop site, concrete slabs, and some steel rails and so forth for the dishes once stood.
I broke into abandoned tracking station facilities before they were demolished once as a juvenile delinquent (I can't remember which ones, there's more than one around here and I was wasted at the time). I recall though that one of my mates made off with a souvenir of some electrical component festooned with radiation warnings - not the sharpest tool in the shed that bloke. But it highlights the risk of ignorance coupled with radioactive items that may be left behind from a one-time civilization.
In a way, collapse already happened up there at the space communications sites. No more lunar landings = no more deep space communications, so all that's left are some slabs here and there and Australia's own miniature version of Machu Picchu :P
There'd be some plumbing buried there I guess. And I saw some structure and pipes left near a creek, which I presume once fed the facility, or maybe dumped its waste.
The roads and associated earthworks to the facility will probably be all that's left in time. Maybe the odd bit of metal. It's not very salty around here, so metals that might ordinarily rust away to nothing may be able to last longer around here.
The Ninth Mouse