[Space] Panspermia and the Campgaign

[malloyd]

Originally Posted by whswhs

Silicon by itself doesn't seem likely to form useful information-bearing polymers. At least I don't know of anything comparable even to hydrocarbon chemistry based on it.

The hydrocarbon analogs are siloxanes. The monomer unit isn't -C- but -Si-O-, and they can form fairly long polymers, and rather complicated other structures (the 5 unit rings, and the cubane analog are both fairly stable, and give you a fine core for building elaborate structures around). Though the ones more interesting to us are silicones, mixed things with Si-O- backbones but carbon chains hanging off the other two bonds from the silicon.

[Flyndaran]

Originally Posted by whswhs

I don't understand why this is relevant. We have one known life-bearing planet and it has human-level intelligence. Why does it need to have more than one species with human-level intelligence? That seems like moving the goalposts.

Bill Stoddard

I'm not doing that. I think we're having a miscommunication rather than disagreement.
I'm saying that human intelligence is incredibly rare if it's only occurred once on a known life giving planet in 4.54 billion years. To the best of our knowledge and archaeological research.

[Flyndaran]

Originally Posted by jeff_wilson

Yes, but it was a different one than the one with supposed microbe fossils, and may have been discredited if a current grad student can't locate a reference.

The "fossils" were cylindrical structures much smaller than any known life form. And later researchers were able to induce similar structures through mundane non living chemistry of the type likely to exist on Mars.
Not absolutely conclusive, but enough to strongly suggest wishful thinking on the "pro-life" crowd.

[whswhs]

Originally Posted by Flyndaran

I'm not doing that. I think we're having a miscommunication rather than disagreement.
I'm saying that human intelligence is incredibly rare if it's only occurred once on a known life giving planet in 4.54 billion years. To the best of our knowledge and archaeological research.

I don't think "rare" is meaningful. There is only one known life giving planet, and it has human-level intelligence. You could just as well say that the observed probability of a life-bearing planet having intelligence is 100%. We're speculating with a sample of one, and probability adjectives don't really mean anything. Wait until we have close observation of a hundred or so planets with biospheres and we can talk.

It will have to be really close observation, though. Suppose you observed Earth, say, a quarter millennium ago. What signs of intelligence could you spot from a modest interplanetary distance, let along from parsecs away?

Bill Stoddard

[malloyd]

Originally Posted by whswhs

I don't think "rare" is meaningful. There is only one known life giving planet, and it has human-level intelligence.

This is a sample counting issue. Equally you could say it's been life giving for about 10,000 times as long as it has had intelligence, so the odds are about 0.01%

It will have to be really close observation, though. Suppose you observed Earth, say, a quarter millennium ago. What signs of intelligence could you spot from a modest interplanetary distance, let along from parsecs away?

From a modest interplanetary distance you might be able to see evidence for agriculture, some serious scientists thought it might be possible to see on Mars. Though the fact there are only handful of actual Martian features that seem to correlate with those maps of Mars at all suggest actual resolution wasn't anywhere close to what they *thought* it was.

[Joseph Paul]

Originally Posted by Flyndaran

I'm not doing that. I think we're having a miscommunication rather than disagreement.
I'm saying that human intelligence is incredibly rare if it's only occurred once on a known life giving planet in 4.54 billion years. To the best of our knowledge and archaeological research.

Why does it need to be 'human intelligence' for an SF RPG?

And I think "...to the best of our knowledge and archeological research..." is a huge hole in that statement.

[whswhs]

Originally Posted by Joseph Paul

Why does it need to be 'human intelligence' for an SF RPG?

The original phrase was "human-equivalent" or "human-comparable" or something like that. I think it can be read as a paraphrase of Campbell's "as well as a man, but not like a man."

Bill Stoddard

[Anthony]

Originally Posted by whswhs

It will have to be really close observation, though. Suppose you observed Earth, say, a quarter millennium ago. What signs of intelligence could you spot from a modest interplanetary distance, let along from parsecs away?

Using what level of technology? The most visible stuff is probably agriculture and mining activity, either of which could be detected at several AU by the equivalent of a high end TL 8 telescope.

[whswhs]

Originally Posted by Anthony

Using what level of technology? The most visible stuff is probably agriculture and mining activity, either of which could be detected at several AU by the equivalent of a high end TL 8 telescope.

What scale of agriculture or mining? Agriculture, for example, could be Neolithic gardens in jungle clearings, or ancient Sumerian canals, or Kansas wheat fields. I'll give you the wheat fields. But you could have intelligent, technological life that farmed and mined on quite a small scale.

Bill Stoddard

[Anthony]

Originally Posted by whswhs

What scale of agriculture or mining?

Earth 250 years ago, as you specified, though even 5,000 years ago you'd be able to detect and at least recognize as odd agricultural patterns in areas such as the Nile. TL0 wouldn't be visible from space, but TL 1+ won't hide at interplanetary distances.