Finally got an idea for an IRTC topic.

The plaque would be rather small from the intended viewport, but
now I like the (space-)weathered version so much I'm considering
throwing the original concept out of the window ;)

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I doubt the plate looks aged at all. It probably is still as shiny as it was 
when the spacecraft was launched.

No oxygen in space to corrode it (and gold does not corrode easily, anyway), 
no dust to grind it down. At the velocities involved even a small speck 
would either make a neat hole or destroy the whole spacecraft.

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> I doubt the plate looks aged at all. It probably is still as shiny as it was
> when the spacecraft was launched.
>
> No oxygen in space to corrode it (and gold does not corrode easily, anyway),
> no dust to grind it down. At the velocities involved even a small speck
> would either make a neat hole or destroy the whole spacecraft.
>
>
>


bound to slow down any deteriorarion.

Also, the plaque was placed so that it was "behind" the spacecraft as it 
traveled across the solar system.


Alain

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> Also, the plaque was placed so that it was "behind" the spacecraft as it 
> traveled across the solar system.

Interesting fact. I did not know this.

When I read your post I looked up NASA's mission page. Now I am not so sure 
about the plaque anymore... I did not expect a 6000K hot gas-cloud outside 
our solar system! Never heard of "Fluff" - strange things are out there, 
indeed.

What do you think of this?

http://science.nasa.gov/science-news/science-at-nasa/2009/23dec_voyager/

Will the gas be sufficient to melt down the spacecraft? It is quite hot, but 
is it dense enough to heat up the craft? Or will radiation cooling win?

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TC wrote:

> I doubt the plate looks aged at all. It probably is still as shiny as
> it was when the spacecraft was launched.

I looked for information on how well it would preserve
but didn't find much. In the end I suppose it's a matter
of time, even tiny and unlikely impacts would accumulate
over millions of years.

> At the velocities involved even a small speck would either make a
> neat hole or destroy the whole spacecraft.

Not necessarily, it depends on how small the speck it.
E.g. the star dust misson could capture dust particles at
extreme velocities (it used aerogel for this but that was
more for protecting the particle from being smashed).

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Alain wrote:

> Also, the plaque was placed so that it was "behind" the spacecraft as
> it traveled across the solar system.

interesting point, I didn't find information on the exact
orientation. But again, wait long enough and it will encounter
*something* which changes the direction of travel. I've got
eons to play with here ;)

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TC wrote:

> Will the gas be sufficient to melt down the spacecraft?

No you would freeze to death there. The common day usage
of words like "temperature" and "cloud" is very misleading
in that respect. The density of particles in a "gas cloud"
is smaller than in the best vacuum produced on earth. And a
single particle oscillating wildly due to high temperature
still doesn't carry an impressive total energy budget.

Even our own atmosphere exceeds 1000K above around 300km
and it doesn't fry anything, despite it being much denser
than a gas cloud. Similar with the sun: the surface is about
6000K but the corona has more than a million degrees.

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> I looked for information on how well it would preserve
> but didn't find much. In the end I suppose it's a matter
> of time, even tiny and unlikely impacts would accumulate
> over millions of years.

Well - if you wait long enough everything will perish. ;-)

It may well be that this probe and plaque will be all that remains of 
humanity in the really long run - who knows when voyager will have the 
misfortune to enter the gravity well of a distant star or a planet and not 
be able to escape? Or when it will hit something smaller?

Maybe it will still travel trough the galaxy in a few million years...

But back to your image - maybe the "brushed" look could stem from the probe 
crashing, but I suppose it would melt (explode, disintegrate, whatever) when 
it enters an atmosphere, like any other asteroid does, in the improbable 
event it would hit a planet with intelligent life to appreciate what they 
got here. Which would mean it would have to hit and survive hitting a planet 
which can support life and hitting it at a time when life is intelligent 
enough to appreciate what they got here - even on Earth it would have been 
very improbable to "time" the impact correctly. If we are generous, then out 
of the last couple of billion years on Earth only within the last few 
thousand years anybody >being able< to appreciate the plaque would have been 
in residence.

So, the final question is: why was the plaque made - apart from PR reasons? 
The only way for anybody to recover it would be to see it drifting through 
space, to own a spacecraft that could "catch" it, and finally to have the 
desire to do so. But then hope springs eternal...

I find reality rather sad. If you think about it, while it may perhaps be 
possible that there is (will be / has been) intelligent life out there, the 
chances to meet them over time and space are pretty much non-exisitent. 
Space-travel - living beings travelling between stars - is highly 
improbable, too, unless we should discover a new kind of physics... which I 
really do not see.

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>> Also, the plaque was placed so that it was "behind" the spacecraft as it
>> traveled across the solar system.
>
> Interesting fact. I did not know this.
>
> When I read your post I looked up NASA's mission page. Now I am not so sure
> about the plaque anymore... I did not expect a 6000K hot gas-cloud outside
> our solar system! Never heard of "Fluff" - strange things are out there,
> indeed.
>
> What do you think of this?
>
> http://science.nasa.gov/science-news/science-at-nasa/2009/23dec_voyager/
>
> Will the gas be sufficient to melt down the spacecraft? It is quite hot, but
> is it dense enough to heat up the craft? Or will radiation cooling win?
>
>
>

In space, things are realy different than anything you can encounter 
here on Earth.
"Very High" density clouds can count less than one atom per cubic kilometer.


stripped of any electrons and traveling at relativistic speeds. Any 
space ship traveling through that may only encounter a particle every 
few seconds, at most.

Take a look at the horse head nebulae, one of the densest you can find. 
It's density is well over 10000 times that of the surrounding space, but 
still less than 1% of that in the vicinity of the moon. Around the moon, 
the best vacuum ever acheived in any laboratoty look like high presure.

The "local fluff" mentioned in that article must have a density, at the 
dencest area of the bow shock, around 100000 to 1000000 lower than that 
of the space around the earth.



Alain



Alain

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> Finally got an idea for an IRTC topic.
>
> The plaque would be rather small from the intended viewport, but now I
> like the (space-)weathered version so much I'm considering throwing the
> original concept out of the window ;)

   Putting aside the controversy about if it should be weathered or not, I
think the corrosion looks good, only perhaps a bit exaggerated in height (if
it is a heighfield, I will scale it smaller on y).

-- 
Jaime Vives Piqueres

http://www.ignorancia.org

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