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General Science => General Science => Topic started by: Herman Melville on 02/06/2009 11:44:42

Title: How long would humans' mark be left on a planet with no humans?
Post by: Herman Melville on 02/06/2009 11:44:42
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?
Title: How long would humans' mark be left on a planet with no humans?
Post by: Don_1 on 02/06/2009 11:48:09
There was a thread on this a while ago (a trace of human beings!) I will try to find it for you.
Title: How long would humans' mark be left on a planet with no humans?
Post by: dentstudent on 02/06/2009 12:17:54
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 (http://en.wikipedia.org/wiki/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.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Herman Melville on 02/06/2009 15:59:48
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 (http://en.wikipedia.org/wiki/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.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Madidus_Scientia on 02/06/2009 17:33:03
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.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 04/06/2009 08:47:01
I remember watching this documentary a while ago called 'Life After People'.  I think it will answer your question.

Title: How long would humans' mark be left on a planet with no humans?
Post by: Herman Melville on 04/06/2009 09:53:48
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.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Madidus_Scientia on 04/06/2009 16:39:02
Plastic.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Herman Melville on 04/06/2009 17:11:21
Plastic.
Surely plastic is too new for us to know for sure whether it will survive for millions of years?
Title: How long would humans' mark be left on a planet with no humans?
Post by: Bored chemist on 04/06/2009 21:33:33
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.
Title: How long would humans' mark be left on a planet with no humans?
Post by: ukmicky on 04/06/2009 23:48:30
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. 
Title: How long would humans' mark be left on a planet with no humans?
Post by: Don_1 on 05/06/2009 07:58:36
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!
Title: How long would humans' mark be left on a planet with no humans?
Post by: dentstudent on 05/06/2009 08:19:38
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!
Title: How long would humans' mark be left on a planet with no humans?
Post by: Don_1 on 05/06/2009 08:42:08
130 quintillion years.


How many seconds would that be?


(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fparanoid%2F2.gif&hash=b6c89a93fcdc26f07540419a36cc278d) COME BACK!!! I was only joking (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Flol%2F4.gif&hash=dc0017defb1737ae43c0ff6efcb35b2a)


Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:36:21
130 quintillion years.


How many seconds would that be?

A LOT!!!
Title: How long would humans' mark be left on a planet with no humans?
Post by: Chemistry4me on 05/06/2009 09:38:08
Actually 3.1556926 × 1025 seconds. [;D]
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:41:47
Actually 3.1556926 × 1025 seconds. [;D]

 [:o]
well done. clap clap
 [:D]

Like I said though; a lot. [:)]
Title: How long would humans' mark be left on a planet with no humans?
Post by: Chemistry4me on 05/06/2009 09:42:34
All I had to do was to type it into Google and it did the calculating for me! [:D]
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:43:10
All I had to do was to type it into Google and it did the calculating for me! [:D]

I thought that's what you had done.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Chemistry4me on 05/06/2009 09:44:48
Yeah well technology makes me lazy.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:46:17
yay for technology!!!   [;D]
Title: How long would humans' mark be left on a planet with no humans?
Post by: Chemistry4me on 05/06/2009 09:48:00
Speaking of technology and getting back to the question: How long would humans' mark be left on a planet with no humans?

Forever! Because there'll only be robots.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:52:44
they're not quite human I don't think but anyway, human programming will still be visable in them, and they would possibly last if they evolve enough to be able to figure out how to repair  themeselves.  They could possibly form a whole new civilization!
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:53:32
Did you watch the youtube link? That has some answers I think as to times.
Title: How long would humans' mark be left on a planet with no humans?
Post by: Chemistry4me on 05/06/2009 09:54:29
They don't need to repair themselves, they just build new ones!
Title: How long would humans' mark be left on a planet with no humans?
Post by: Daerana on 05/06/2009 09:57:00
very true.  Yet, how would they know how to build themeselves if they do not know how they themeselves were built, and therefore how to repair themeselves?  It would be wasting valuable parts if they were to just start again from scratch.
Title: Re: How long would humans' mark be left on a planet with no humans?
Post by: emelymorris on 26/08/2021 14:36:19
What we now have after ourselves, our wealth, until the latter disappears, there will be a trace of a person. I think that it will take only a couple of thousand years until everything disappears, I take into account how much plastic even decays for about 1000 years. A couple of thousand years is very long for humanity, but not for the Earth and the universe, so our trail will disappear very quickly.
Title: Re: How long would humans' mark be left on a planet with no humans?
Post by: Bored chemist on 26/08/2021 15:27:48
I think that it will take only a couple of thousand years until everything disappears,
Stonehenge has been here for twice that long.
If we all disappeared, there's no reason to suppose it wouldn't survive another 4000 years, is there?

The oldest hominid fossils are very old.
There are a lot more people about today than say 50,000 years ago.
Some of us will leave recognisable skeletons which will last for at least a million years or more.
https://www.eurekalert.org/news-releases/546040

And then there's nuclear waste...