The recent History Channel special "Life After People" examined the
physical mechanisms by which human civilization -- specifically, 20cen
architecture -- would decay after our sudden vanishment. It did not
address what non-architectural remnants would *persist* for future
civilizations to discover, or structures specifically *designed* to
survive.

<http://www.history.com/minisites/life_after_people>

ObSF, one of the talking heads was David Brin.

SUMMARY

The described failure modes include things that a non-specialist
wouldn't think of. For instance, salt crystals (such as sulfates
deposited by rainwater) growing inside concrete; moisture infiltrating
reinforced concrete and rusting the rebar, causing it to expand;
windows shattering when the seals grow old, and no longer compensate
for thermal movement in the metal frame; copper lightning rods
corrode. Plus such things as plants, termites, and mussels clogging
the cooling-water intakes of Hoover Dam.

Many things collapse because they were designed for regular human
maintenance. Protective paint on steel; pumps for tunnels that lie
below the water table. The same can be said of living organic beings,
of course.

We conveniently have an example of "post-occupancy city" in the form
of the area around Chernobyl.

Once the skyscrapers of Manhattan collapse, they'll become new
vegetation-covered hills. The narrator didn't specifically say so,
but the implication is that the rubble piles are so massive that it'd
take X decamillenia for ordinary agents to erode them.

Wooden houses collapse, due largely to the depredations of termites.
The narrative didn't address things that would survive *inside* the
houses, which I expect would include: granite countertops, stone and
ceramic tile, ceramic bathroom fixtures; and on a shorter time scale,
plastic plumbing and stainless-steel cookware. Obviously toilet
manufacturers should start molding humanity's great literature onto
the unused undersides of commodes. :)

In a one-story with no cellar, these artifacts would stay basically
where they were put (short of bears shoving them around). A two-story
would have a jumble of fallen second-story plumbing. A house that
collapses into its own cellar might make a better archeological site,
since it would soon fill with silt.

IN SCIENCE FICTION

ObSF, human explorers often encounter alien artifacts that have
withstood untold ages. How? Either they're so huge that the elements
can't wear them down, they're built somewhere that doesn't *have*
erosion, they're composed of astonishingly strong materials, or
they're self-maintaining.

(The Stargate team sometimes encounter gates that have succumbed to
erosion or volcanic eruption, but usually they're sitting unencumbered
the middle of a meadow, the foundation perfectly level. In the
Pegasus galaxy, most of the gates are still in use, but back home
they're usually forgotten relics on abandoned Goa'uld colonies.)

If we were actually interested in building maintenance-free structures
that last a long, long time, and cost was no object, what would we
use? Stainless steel? Diamond slabs? Would it work to simply coat
steel and concrete with impermeable diamond instead of paint? As an
unmatched thermal conductor, is diamond immune to destructive thermal
stresses? Would it be safe fom everything short of volcanic bombs and
crowds with hammerS?

SEE ALSO

_Motel of the Mysteries_, 1979, David Macauley.
<http://www.amazon.com/Motel-Mysteries-David-Macaulay/dp/0395284252>

Yucca Mountain nuclear waste repository
<http://www.ocrwm.doe.gov/>

The Long Now Foundation
<http://www.longnow.org/>

The Svalbard Global Seed Vault
<http://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault>

On Feb 3, 11:18 am, Phillip Thorne <petho...@comcast.net> wrote:
> If we were actually interested in building maintenance-free structures
> that last a long, long time, and cost was no object, what would we
> use? Stainless steel? Diamond slabs?

Carbon does react with oxygen, although this will be slow in the form
of bulk diamond crystals. Still, alumia (aka corundum, sapphire,
ruby) could very well be preferred for this reason.

> Would it work to simply coat
> steel and concrete with impermeable diamond instead of paint?

Carbon dissolves into steel. This indicates that diamond would not be
the preferred coating for steel - in time the coating would degrade
and the surface steel would weaken.

> As an
> unmatched thermal conductor, is diamond immune to destructive thermal
> stresses? Would it be safe fom everything short of volcanic bombs and
> crowds with hammerS?

Bulk diamond crystal is brittle, and likely to have catastrophic
failure modes. Some sort of nanocyrstalline material would likely
work better, since cracks will tend to stop at grain boundaries,
improving toughness.

Luke

Phillip Thorne <pethorne@comcast.net> wrote in
news:rp2cq3d04g85b03hprt96m6t49t79tjs2h@4ax.com:

> http://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault

Thanks for a very interesting post!

And also for the link about the Svalbard Global Seed Vault - my flatmate
keeps getting nightmares (probably inspired by Greg Bear) in which she
has to wander around loads of garden centres to find enough varieties of
seed to flee to the shuttle-craft with before time runs out and the X of
Doom destroys the world; now all she'll have to do is dream about raiding
Spitzbergen. ;-)

Cheers,

Johnny T.

On Feb 3, 1:18 pm, Phillip Thorne <petho...@comcast.net> wrote:
> The recent History Channel special "Life After People" examined the
> physical mechanisms by which human civilization -- specifically, 20cen
> architecture -- would decay after our sudden vanishment.  It did not
> address what non-architectural remnants would *persist* for future
> civilizations to discover, or structures specifically *designed* to
> survive.

> <http://www.history.com/minisites/life_after_people>

One building they didn't specifically address was the Washington
Monument. I'm curious what would become of that. It's not made
of rebar, it's essentially a pure compression stone structure.

> ObSF, human explorers often encounter alien artifacts that have
> withstood untold ages.  How?  Either they're so huge that the elements
> can't wear them down, they're built somewhere that doesn't *have*
> erosion, they're composed of astonishingly strong materials, or
> they're self-maintaining.

> If we were actually interested in building maintenance-free structures
> that last a long, long time, and cost was no object, what would we
> use?  Stainless steel?  Diamond slabs?  Would it work to simply coat
> steel and concrete with impermeable diamond instead of paint?  As an
> unmatched thermal conductor, is diamond immune to destructive thermal
> stresses?  Would it be safe fom everything short of volcanic bombs and
> crowds with hammerS?

There are stones which can take weathering okay; it seems to me
the big issue is how to avoid getting covered up by sand or
vegitation.
If cost is no object, I'd say build a huge "structure" on the moon.
Maybe some sort of huge lettering legible from Earth, made of
huge piles of boulders.

Isaac Kuo

"IsaacKuo" <mechdan@yahoo.com> wrote in message
news:6f23f786-831c-46ba-b805-e3d14c4c197f@i7g2000prf.googlegroups.com...
On Feb 3, 1:18 pm, Phillip Thorne <petho...@comcast.net> wrote:
> The recent History Channel special "Life After People" examined the
> physical mechanisms by which human civilization -- specifically, 20cen
> architecture -- would decay after our sudden vanishment. It did not
> address what non-architectural remnants would *persist* for future
> civilizations to discover, or structures specifically *designed* to
> survive.

> <http://www.history.com/minisites/life_after_people>

One building they didn't specifically address was the Washington
Monument. I'm curious what would become of that. It's not made
of rebar, it's essentially a pure compression stone structure.

> ObSF, human explorers often encounter alien artifacts that have
> withstood untold ages. How? Either they're so huge that the elements
> can't wear them down, they're built somewhere that doesn't *have*
> erosion, they're composed of astonishingly strong materials, or
> they're self-maintaining.

> If we were actually interested in building maintenance-free structures
> that last a long, long time, and cost was no object, what would we
> use? Stainless steel? Diamond slabs? Would it work to simply coat
> steel and concrete with impermeable diamond instead of paint? As an
> unmatched thermal conductor, is diamond immune to destructive thermal
> stresses? Would it be safe fom everything short of volcanic bombs and
> crowds with hammerS?

There are stones which can take weathering okay; it seems to me
the big issue is how to avoid getting covered up by sand or
vegitation.
If cost is no object, I'd say build a huge "structure" on the moon.
Maybe some sort of huge lettering legible from Earth, made of
huge piles of boulders.

Isaac Kuo

HERE WE ARE, EXTRATERRESTRIAL BEASTIES!
COME EAT US!

On Mon, 04 Feb 2008, Johnny Tindalos <JamaisVu@UnrealEmail.arg> wrote:
>Thanks for a very interesting post!

You're welcome.

>And also for the link about the Svalbard Global Seed Vault - my flatmate
>keeps getting nightmares (probably inspired by Greg Bear)

_Forge of God_, right?

>in which she
>has to wander around loads of garden centres to find enough varieties of
>seed to flee to the shuttle-craft with before time runs out and the X of
>Doom destroys the world; now all she'll have to do is dream about raiding
>Spitzbergen. ;-)

Oh, c'mon. A real-world phenomenon that simplifies dream-logic? That
*never* works!

Myself, I once dreamt that the Borg were approaching Earth, so the
Federation was shipping large chunks of rainforest habitat off-planet
in giant flying shipping boxes. Which rather resembled Borg cubes in
size, shape, and their habit of hovering over the ground in much the
way bricks don't. And the UFP hadn't *told* anyone they were doing
this, which heightened the comparison.

"IsaacKuo" <mech...@yahoo.com> wrote

> One building they didn't specifically address was the Washington
> Monument.  I'm curious what would become of that.  It's not made
> of rebar, it's essentially a pure compression stone structure.

What are the foundation details? It might have a significant
possibility of toppling due to subsidence (especially given the
terrain that was there prior to the city).

> it seems to me the big issue is how to avoid getting covered
> up by sand or vegitation.

Or ice. Someplace like a rain shadow desert with little sand
(Atacama?) might be ideal, at least for a couple of 10 ky or so.

> If cost is no object, I'd say build a huge "structure" on the moon.

Although "huge" is certainly not needed for preservation. With only
the micrometeroid flux, even the Apollo artifacts will remain in place
long after we're gone (assuming we, of course, don't mess them up
first by going back. Which is looking more & more likely).

> Maybe some sort of huge lettering legible from Earth,
> made of huge piles of boulders.

Or using a Soletta to focus the solar image enough to melt large
chunks of regolith. As a very very *very* young feature, even after a
lot of late bombardment that would be clearly discernible to anybody
who can count craters, even 4 Ga from now.

Meanwhile, "Joetheone" contributed:

> HERE WE ARE, EXTRATERRESTRIAL BEASTIES!
> COME EAT US!

I was thinking of "Crunchy & tastes good with ketchup", but OK :)

--
Brian Davis

"Brian Davis" <brdavis@iusb.edu> wrote in message
news:5ab6195d-7766-42e5-97fc-2e2cfc671abc@l32g2000hse.googlegroups.com...
"IsaacKuo" <mech...@yahoo.com> wrote

> One building they didn't specifically address was the Washington
> Monument. I'm curious what would become of that. It's not made
> of rebar, it's essentially a pure compression stone structure.

What are the foundation details? It might have a significant
possibility of toppling due to subsidence (especially given the
terrain that was there prior to the city).

> it seems to me the big issue is how to avoid getting covered
> up by sand or vegitation.

Or ice. Someplace like a rain shadow desert with little sand
(Atacama?) might be ideal, at least for a couple of 10 ky or so.

> If cost is no object, I'd say build a huge "structure" on the moon.

Although "huge" is certainly not needed for preservation. With only
the micrometeroid flux, even the Apollo artifacts will remain in place
long after we're gone (assuming we, of course, don't mess them up
first by going back. Which is looking more & more likely).

> Maybe some sort of huge lettering legible from Earth,
> made of huge piles of boulders.

Or using a Soletta to focus the solar image enough to melt large
chunks of regolith. As a very very *very* young feature, even after a
lot of late bombardment that would be clearly discernible to anybody
who can count craters, even 4 Ga from now.

Meanwhile, "Joetheone" contributed:

> HERE WE ARE, EXTRATERRESTRIAL BEASTIES!
> COME EAT US!

I was thinking of "Crunchy & tastes good with ketchup", but OK :)

--
Brian Davis

We could still look to the sky and see a mass of asteroids moved together to
spell:
"WE BEASTIES. WE DO THAT THING."

Phillip Thorne <pethorne@comcast.net> wrote in
news:ehofq3huhdlbtic1ju6qr403m3kve417mo@4ax.com:

> _Forge of God_, right?

Either that or _Eon_. Possibly both...

> Oh, c'mon. A real-world phenomenon that simplifies dream-logic? That
> *never* works!

You know, the first thing my flatmate said when she saw the link on her
laptop was "Nooooooooo! Now I'll dream about wandering over endless
glaciers in a freezing blizzard trying to find the seed vault! Why did it
have to be Spitzbergen, why?"

Which was right before I read your response and laughed; I got a *very*
cross look. And a worse one when I explained! <grin>

> Myself, I once dreamt that the Borg were approaching Earth, so the
> Federation was shipping large chunks of rainforest habitat off-planet
> in giant flying shipping boxes. Which rather resembled Borg cubes in
> size, shape, and their habit of hovering over the ground in much the
> way bricks don't. And the UFP hadn't *told* anyone they were doing
> this, which heightened the comparison.

That sounds really pretty, like something a cover artist would paint.
(Complete with the tiny figures cowering in the shadows of the enormous
ecosystem-excavating cubes.... ;-)

> Phillip Thorne <pethorne@comcast.net> wrote in
> news:ehofq3huhdlbtic1ju6qr403m3kve417mo@4ax.com:
>
>> Myself, I once dreamt that the Borg were approaching Earth, so the
>> Federation was shipping large chunks of rainforest habitat off-planet
>> in giant flying shipping boxes. Which rather resembled Borg cubes in
>> size, shape, and their habit of hovering over the ground in much the
>> way bricks don't.

Oh c'mon, everybody knows that rainforests sent off into space get sent in
giant geodesic domes.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

On Wed, 6 Feb 2008 12:38:09 -0600, "Mike Combs"
<mikecombs@nospam.com_chg_nospam_2_ti> wrote:

:> Phillip Thorne <pethorne@comcast.net> wrote in
:> news:ehofq3huhdlbtic1ju6qr403m3kve417mo@4ax.com:
:>
:>> Myself, I once dreamt that the Borg were approaching Earth, so the
:>> Federation was shipping large chunks of rainforest habitat off-planet
:>> in giant flying shipping boxes. Which rather resembled Borg cubes in
:>> size, shape, and their habit of hovering over the ground in much the
:>> way bricks don't.
:
:Oh c'mon, everybody knows that rainforests sent off into space get sent in
:giant geodesic domes.

With little robot caretakers!
--
Real men don't need macho posturing to bolster their egos.

George W. Harris For actual email address, replace each 'u' with an 'i'.

Mike Combs wrote:

> Oh c'mon, everybody knows that rainforests sent off into space get sent in
> giant geodesic domes.

hah. On the spur of the moment, I just watched that in the last few
months all the way through (after not having seen it for many, many
years). Boy howdy does it not hold up.

--
Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
A man can stand a lot as long as he can stand himself.
-- Axel Munthe

On Feb 4, 1:11 pm, IsaacKuo <mech...@yahoo.com> wrote:
> On Feb 3, 1:18 pm, Phillip Thorne <petho...@comcast.net> wrote:
> > If we were actually interested in building maintenance-free structures
> > that last a long, long time, and cost was no object, what would we
> > use?  Stainless steel?  Diamond slabs?
>
> There are stones which can take weathering okay; it seems to me
> the big issue is how to avoid getting covered up by sand or
> vegitation.
> If cost is no object, I'd say build a huge "structure" on the moon.
> Maybe some sort of huge lettering legible from Earth, made of
> huge piles of boulders.
>
> Isaac Kuo

I think the Pyramids and Mount Rushmore have a shelf life on the order
of a million years or so, but someone will want to fact-check that.
Even if cost were no object, I'm thinking a big lump of rock beats the
stainless steel, diamond, and other high-tech solutions over the
really long haul. (Especially since you presumably don't want your
artifact to be looted by space pirates, post-apocalyptic gangs, damn
dirty apes, etc., for precious materials.)

On Feb 7, 7:06 pm, Damien Valentine <valen...@gmail.com> wrote:

> I think the Pyramids and Mount Rushmore have a shelf life on the order
> of a million years or so, but someone will want to fact-check that.
> Even if cost were no object, I'm thinking a big lump of rock beats the
> stainless steel, diamond, and other high-tech solutions over the
> really long haul. (Especially since you presumably don't want your
> artifact to be looted by space pirates, post-apocalyptic gangs, damn
> dirty apes, etc., for precious materials.)

Good idea. Possibly this is why Niven and Pournelle decided too make
a Thuktun out of stone rather than something like the other materials
you mention.

Knobby <knobbynobbs@hotmail.com> wrote in news:20c5cf17-32d0-4b5c-a20e-
61e45b634bdc@q77g2000hsh.googlegroups.com:


> Good idea. Possibly this is why Niven and Pournelle decided too make
> a Thuktun out of stone rather than something like the other materials
> you mention.
>

Thuktun = Predecessor instructions found by the Fithp, right? I would
have thought diamond more durable...though perhaps, as you say, merely
more lootable.

Hmmmmm....what do we Homo saps find materially valueless, yet which can
maintain a large quantity of encoded information across generations?
Besides DNA, that is (and anyway DNA kinda depends on a workable
biosphere----at least within broad definitions of such; prokaryote
survivors would do!)...any thoughts?

Cheers,

JT