[Herman Melville]

Let's say all humans died out today, perhaps from a killer virus that was 100% lethal.

Let's say this same virus left all other lifeforms unharmed.

How many years (thousands/tens of thousands?) would it be until there was no trace of people whatsoever, i.e. nothing left of any of the buildings, cars, waste, roads, cities, etc?

Or would human traces be here forever?

[Don_1]

There was a thread on this a while ago (a trace of human beings!) I will try to find it for you.

[dentstudent]

Human traces are here for good. If you look at this question from a "cene" point of view, we are on the cusp of the "anthropocene". This is because in several million years time, geologists will be able to clearly demark the rise of homo sapiens and the changes that they made to the soil horizons.

[Herman Melville]

Human traces are here for good. If you look at this question from a "cene" point of view, we are on the cusp of the "anthropocene". This is because in several million years time, geologists will be able to clearly demark the rise of homo sapiens and the changes that they made to the soil horizons.

OK, but how long until all the buildings/cars/roads/rubbish was no longer noticable? I don't just mean hidden under trees/plants, but essentially decomposed or reduced to such a state that only archeological excavations could reveal it.

[Madidus_Scientia]

There's footprints in rock that you can still find left over from dinosaurs, and that was at least 65 million years ago, so if a footprint can last that long then think about how long a dirty great city is going to last, i'd say pretty much forever, until the earth gets incinerated from the sun becoming a red giant.

Even the pyramids are still here and don't look like they're in a hurry to go anywhere.

[Daerana]

I remember watching this documentary a while ago called 'Life After People'.  I think it will answer your question.

[Herman Melville]

There's footprints in rock that you can still find left over from dinosaurs, and that was at least 65 million years ago, so if a footprint can last that long then think about how long a dirty great city is going to last, i'd say pretty much forever, until the earth gets incinerated from the sun becoming a red giant.

Even the pyramids are still here and don't look like they're in a hurry to go anywhere.

The pyramids are only a few thousand years old. Will they survive another 10,000 years? Or 100,000 years? I don't think so. Plus, they are essentially just rock structures. Few of the things we create now will last as long.

[Madidus_Scientia]

Plastic.

[Herman Melville]

Plastic.

Surely plastic is too new for us to know for sure whether it will survive for millions of years?

[Bored chemist]

The weird distribution of radioactive elenments in a nuclear reactor would prove for a long time that we had been here.
There are things called accelerated aging tests that indicate that plastics will be around for a long while but I'm not sure if they can support a million year lifespan.

[ukmicky]

There's footprints in rock that you can still find left over from dinosaurs, and that was at least 65 million years ago, so if a footprint can last that long then think about how long a dirty great city is going to last, i'd say pretty much forever, until the earth gets incinerated from the sun becoming a red giant.

Even the pyramids are still here and don't look like they're in a hurry to go anywhere.

The pyramids are only a few thousand years old. Will they survive another 10,000 years? Or 100,000 years? I don't think so. Plus, they are essentially just rock structures. Few of the things we create now will last as long.

Provided egypt's weather remains as it is now,the pyramids may crumble on the outside but the interiors structures will be still remain relatively untouched for a lot longer than ten thousand years. 

[Don_1]

There's footprints in rock that you can still find left over from dinosaurs, and that was at least 65 million years ago, so if a footprint can last that long then think about how long a dirty great city is going to last, i'd say pretty much forever, until the earth gets incinerated from the sun becoming a red giant.

Even the pyramids are still here and don't look like they're in a hurry to go anywhere.

The pyramids are only a few thousand years old. Will they survive another 10,000 years? Or 100,000 years? I don't think so. Plus, they are essentially just rock structures. Few of the things we create now will last as long.

Provided egypt's weather remains as it is now,the pyramids may crumble on the outside but the interiors structures will be still remain relatively untouched for a lot longer than ten thousand years. 

I would say so too. The damage to the Great Pyramid so far has been largely done by man and it's still standing after more than 4.5k years, even surviving an earthquake in the 14th century.

They don't build 'em like that n'more!

[dentstudent]

On the face of it, 10,000 years is not very long in terms of how long the earth will be here...

The weird distribution of radioactive elements in a nuclear reactor would prove for a long time that we had been here.

Selenium (SE-82), which is a common by-product of copper refining, has a half-life of 1.3*1020 years which expands out to 130,000,000,000,000,000,000 years or simply 130 quintillion years.

Since this is created through human intervention, I think that we can safely say that our influence will be detectable for quite some time!

[Don_1]

130 quintillion years.

How many seconds would that be?


COME BACK!!! I was only joking

[Daerana]

130 quintillion years.

How many seconds would that be?

A LOT!!!

[Chemistry4me]

Actually 3.1556926 × 10²⁵ seconds. []

[Daerana]

Actually 3.1556926 × 10²⁵ seconds. []

 []
well done. clap clap
 []

Like I said though; a lot. []

[Chemistry4me]

All I had to do was to type it into Google and it did the calculating for me! []

[Daerana]

All I had to do was to type it into Google and it did the calculating for me! []

I thought that's what you had done.

[Chemistry4me]

Yeah well technology makes me lazy.