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See this Paper from Fermat’s Library
https://fermatslibrary.com/s/the-siluria...cal-record


I’ve pondered this ‘possibility’ all my length - that there have been civilisation(s) before us on Earth and that for some reason they became extinct and also that any possible archaeological evidence has long degraded and disappeared. However the paper also looks at possible civilisations from Venus or Mars. What I’ve NEVER seen discussed is why do we only look for intelligent(?) life like our own that breathes oxygen? Could there not be lifeforms that evolved that could survive on planets that needed obnoxious elements (cf to us) like Sulphur, CO2, N etc. Lifeforms that could exist under atmospheric pressures that would crush us.
Hello!

(04-23-2019 10:27 PM)Leviset Wrote: [ -> ]What I’ve NEVER seen discussed is why do we only look for intelligent(?) life like our own that breathes oxygen? Could there not be lifeforms that evolved that could survive on planets that needed obnoxious elements (cf to us) like Sulphur, CO2, N etc.

If you take a close look at the literature about astrobiology and SETI as far as intelligent life is concerned you will find that no researcher excludes anything. There are plenty of (micro)organisms on our planet who do not need oxygen or carbon but sulphur instead as you write. See for example this Wikipedia article here: https://en.wikipedia.org/wiki/Hydrothermal_vent
Future space probes to the large moons of Jupiter and Saturn will explicitely search for lifeforms which may have evolved in their oxygen-less environments.

(04-23-2019 10:27 PM)Leviset Wrote: [ -> ]Lifeforms that could exist under atmospheric pressures that would crush us.

We don't get crushed by atmosperic (or hydrostatic) pressure either. Only gas-filled cavities inside the body with no connection to the outside will. A healthy human should not have any of these, otherwise deep-sea diving (divers who service oil platforms dive beyond 300m of depth which amounts to 30x our atmospheric pressure!) and similar activities would not be possible.

Regards
Max
Bit pedantic!
Are you saying Deep Sea (which my son when he was 5 continually called them dipsy divers) Divers don’t need to be encased in an atmospheric pressure suit kept at a 1 atmosphere pressure when they go down?
Why is one of the best ‘games’ that Oceanographers like to play is that of decorating a polystyrene cup, lowering it over the side on a long string down near to the ocean bottom so that when it’s hauled back up its now the size of a thimble covered with now miniature drawings? Presumably it’s been ‘crushed’ under the pressure or is it the terminology that you object to? Should I have said if humans even could stand on the surface of Jupiter (without a suit) they wouldn’t be ‘crushed’ by the atmospheric pressure but rather they would shrink, collapse, deflate, flatten, dry up, shrivel, wilt, wither, abate, decrease, diminish, dwindle, lessen, recede or any permutation or any combination of these?
I’m pretty sure I’d still be dead.
(04-24-2019 03:14 PM)Leviset Wrote: [ -> ]Are you saying Deep Sea (which my son when he was 5 continually called them dipsy divers) Divers don’t need to be encased in an atmospheric pressure suit kept at a 1 atmosphere pressure when they go down?

No. They usually wear "soft" but watertight immersion suits whose internal pressure is the same as the outside pressure. To avoid the necessity to decompress after each dive they live inside pressure chambers when not in the water for up to one month at a time.
There are also so called "Atmospheric Diving Suits" (https://en.wikipedia.org/wiki/Atmospheric_diving_suit) which are small one-man submarines that keep the internal pressure at 1 atmosphere all the time. But they are so expensive that only the US Navy can afford some...

(04-24-2019 03:14 PM)Leviset Wrote: [ -> ]Why is one of the best ‘games’ that Oceanographers like to play is that of decorating a polystyrene cup, lowering it over the side on a long string down near to the ocean bottom so that when it’s hauled back up its now the size of a thimble covered with now miniature drawings? Presumably it’s been ‘crushed’ under the pressure or is it the terminology that you object to?


Yes, exactly. This is possible bacuse the polystyrene consists mostly of air (or maybe nitrogen) bubbles surrounded by very thin plastic. When they get compressed by the water the plastic ruptures, the gas is released and the cup will not re-inflate when brought back to the surface.
The neoprene suits worn by recrational divers are similar. There are made from small gas bubbles surrounded by rubber. In the depth the bubbles get compressed and an 8mm neoprene suit (I chose that example because mine is like that) will only be something like 3mm thick 40m below the surcace (thereby losing most of it's thermal insulation where you need it most and also losing much of it's buoyancy, thereby necessitating the use of a "BCD" or buoyancy control device, an inflatable vest). But the rubber is elastic and does not burst, so when coming back to the surface the suit will be again as thick as it was before.

(04-24-2019 03:14 PM)Leviset Wrote: [ -> ]Should I have said if humans even could stand on the surface of Jupiter (without a suit) they wouldn’t be ‘crushed’ by the atmospheric pressure but rather they would shrink, collapse, deflate, flatten, dry up, shrivel, wilt, wither, abate, decrease, diminish, dwindle, lessen, recede or any permutation or any combination of these?

Nothing of that will happen. When you descend to the surface of Jupiter (or Venus, wearing appropriate heat protection) and give the gas filled cavities inside your body (which are the lungs and the sinuses and some other bits of the respiratory system) enough time to fill with breathable gas with the same pressure as outside then you will stay exactly as before. 99 Percent of the body is either bone or some kind of liquid (or jelly or similar) which are not compressible.
The only thing to avoid is rapid compression and rapid decompression as this will damage the lungs and hollows inside one's head, causing a "barotrauma" (https://en.wikipedia.org/wiki/Barotrauma). But crushing? No.

Regards
Max
(04-24-2019 03:49 PM)Maximilian Hohmann Wrote: [ -> ]The only thing to avoid is rapid compression and rapid decompression as this will damage the lungs and hollows inside one's head, causing a "barotrauma" (https://en.wikipedia.org/wiki/Barotrauma).

That kind of trauma is easy to avoid with the breathing and pressure equalization techniques that are among the first thing any scuba diver learns. The real danger is the bends, which is what happens when you decompress too quickly after having been at high pressure for some time: gas which has dissolved into your blood and tissues comes out of solution, and when it can't escape the body quickly enough, forms bubbles which cause blood clots, and those can cause permanent injuries and even death. But even then, it's not the pressure that kills, but the decompression.
And then there was the movie "The Abyss" where they used oxygenated fluorocarbons to allow for even deeper diving. The scene with the mouse was not faked.
I don't really enjoy such speculations as it is hard to test claims. Although in this case is a bit more serious because the study come from nasa.

If it would be true it would be incredibly sad. Tons of life experiences, knowledge (and calculators!) lost for good (we already lose a ton of those things every year). Also imagine another planet where such an early progressed civilization exist. It would have a huge head start compared to us.

As last speculations: Imagine another civilization that never discontinued their 41c . I guess many here would be ready to accept them as our overlords.

Edit: the paper can raise another question. Did have so far produce something that can last millions of years as archeological evidence? I mean even bones, artifacts or the like. I'm not aware of anything that could last so long with the Earth geologically active.
Hello!

(04-25-2019 09:39 PM)pier4r Wrote: [ -> ]I don't really enjoy such speculations as it is hard to test claims.

Exoplanets were also pure speculation until 30 years ago. Speculation (at least sensible speculation) lead to research programs and research programs (sometimes) lead to discoveries. There is absolutely nothing wrong with speculation!

(04-25-2019 09:39 PM)pier4r Wrote: [ -> ]As last speculations: Imagine another civilization that never discontinued their 41c . I guess many here would be ready to accept them as our overlords.

Not me. I never liked the 41C much. In part because the LCD 16 segment display is one of the ugliest things ever invented by humankind. I am really glad that we have evolved beyond that!

(04-25-2019 09:39 PM)pier4r Wrote: [ -> ]I'm not aware of anything that could last so long with the Earth geologically active.

I think we have made quite a lot of things by now which can survive extreme conditions. Uranium-oxide pellets that serve as fuel for nuclear power plants. They melt beyond 3000°C. Nothing is naturally so hot on Earth. The same applies to some types of ceramic. And if it does not get molten by lava, gold and stainless steel can withstand almost anything our planet has to offer for many millenia. Finally there are thousands of satellites in earth and solar orbits some of which may stay there for millions of years. And all the stuff we left on the moon of course. Archeologists a million years from now have a good chance to find some of our civilisation remains.

Good night
Max
(04-25-2019 11:07 PM)Maximilian Hohmann Wrote: [ -> ]
(04-25-2019 09:39 PM)pier4r Wrote: [ -> ]As last speculations: Imagine another civilization that never discontinued their 41c . I guess many here would be ready to accept them as our overlords.

Not me. I never liked the 41C much. In part because the LCD 16 segment display is one of the ugliest things ever invented by humankind. I am really glad that we have evolved beyond that!

I will.
And you didn't like the display because you obviously had that 16 segments prototype never meant to be released. I have on all of my 41s the normal 14 segments; and it's fantastic! ;)
From the 41C Service Manual:

"The display is a 12-character, liquid crystal display (LCD). Each character position has 14 digit segments, 3 punctuation marks, and 1 annunciator space which are defined by three row lines (common to all characters) and six column lines. (See figure 2-2.) The entire display constitutes a 3-row by 72-column matrix which is activated by the display driver."

[Image: Display%20Character_s.jpg?psid=1]

So there are 18 elements for each character position.
(04-25-2019 11:07 PM)Maximilian Hohmann Wrote: [ -> ]Not me. I never liked the 41C much...

Wow, well, I suppose there is a first for everything. Probably due to the same genes that cause you to collect all those non-HP machines. Huh

I suppose beauty is in the eye of the beholder, but there was (is!) surely a lot to like about the 41C apart from the LCD display, right?

Just please tell us that you liked the half-nut display even less than the original - a chance for redemption Undecided
(04-26-2019 12:59 PM)Didier Lachieze Wrote: [ -> ]So there are 18 elements for each character position.

14 segments, 18 elements.
Hello!

(04-26-2019 01:08 PM)rprosperi Wrote: [ -> ]I suppose beauty is in the eye of the beholder, but there was (is!) surely a lot to like about the 41C apart from the LCD display, right?

Not much, I'm afraid... The keyboard I like. And the modular expansion too (but they copied that from Ti of course ;-) ) Apart from that really not much. Having to type "XEQ Alpha xyz" to access all those fancy functions is not the way I like to interact with a calculator. I much prefer the triple-shifted keys of the HP-67. Or the single shifted ones of the Ti59... And disposable batteries as standard? Really? No way I would ever have bought that calculator then ,even if I could have afforded one.

(04-26-2019 01:08 PM)rprosperi Wrote: [ -> ]Just please tell us that you liked the half-nut display even less than the original - a chance for redemption Undecided

You mean "ugly" comes in different shades :-) I could never understand why they chose this kind of display when their desktop calculators and instruments of that time were fitted with such wonderful dot matrix LED displays. So they knew what it takes to make a dot matrix!

Anyway, in the scope of this thread none of that matters much because no HP-41C will survive long enough to be of interest for any future archaeologist.

Regards
Max
(04-26-2019 02:40 PM)Maximilian Hohmann Wrote: [ -> ]Anyway, in the scope of this thread none of that matters much because no HP-41C will survive long enough to be of interest for any future archaeologist.

Regards
Max

Interesting! What would take to let them survive (if not functioning, at least physically) for a practical eternity? (say 1 million years)

The dame could be applied to every similar objective in type and size.

Burying them in a box and then concrete and them burying them somewhere but not too deep?

If it is deep, I am afraid that gelogical movements will crush the crate. Although 1 million years may be not enough for large geological movements in some parts of the world, better not to risk it.
If it is shallow, then water can slowly erode it and pulverize it.

Instead of concrete, a massive rock that is drilled and the content placed in the middle and then the hole closed with concrete? I still think it could last a bit more but not much more than the example above.

Any other idea?
 
Hi, pier4r:

(04-26-2019 07:29 PM)pier4r Wrote: [ -> ]Interesting! What would take to let them survive (if not functioning, at least physically) for a practical eternity? (say 1 million years)

Nothing, short of a genuine supernatural miracle. For example:
  • anything plastic will turn to dust in much less that 1 Myear, plastic is unstable
     
  • same for LCDs and most other non-metallic components, even glass, which is unstable too.
     
  • apart from geological activity such as earthquakes, volcanism, etc., there's the ever-present non-negligible possibility that a sufficiently sizeable asteroid or comet hits the Earth, and matter of fact within 1 Myear from now you can count on a number of cataclismic impacts that can melt considerable areas on Earth, possibly even continent-size.
In the long run, such as 1 Myear or more, the Earth's surface will surely get seriously affected by a number of phenomena whether of internal or external origin. I'd suggest you actually watch (not simply read about it) the film Melancholia, (a 2011 psychological drama science fiction art film written and directed by Lars von Trier) which carries this concept to its final consequence in its awesome ending.

It totally has to do with the ideas in your post and I heartily recommend it.

Best regards and have a nice weekend.
V.
 
Hello!

(04-26-2019 09:27 PM)Valentin Albillo Wrote: [ -> ]I'd suggest you actually watch ...

Thank you - I haven't seen that one yet. Although one has to be in a certain mood to watch Lars von Trier films without throwing oneself into the path of a train afterwards...

And regarding the possible longevity of electronics: One more factor which hasn't been mentioned is diffusion of atoms within semiconductors. Let them lie around for long enough and they will stop working on their own. Heat accelerates the process, so one might want to store them at very low temperatures. But that again will freeze the liquid inside the LCD displays and render brittle all the plastic parts.

The only way to pass on an HP-41C to a civilazation 100 generations from now is to engrave it's construction schematics in gold foil and store that in a place which is not geologically active, e.g. the moon.

Regards
Max
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