Journal tomhudson's Journal: Solution To The Fermi Paradox 18
We are alone. Here's why.
One thing I never see when people talk about the Fermi Paradox ("if there are so many planets, why don't we hear anyone else?"), is that the original Earth, left alone, could never support life.
Some time in the first 100 million years, something the size of Mars gouged out enough material to create the moon. Obviously, there was more material than that in the proto-earth, since it wouldn't all go in just the right direction and speed to stay in Earth's orbit - calculations say that about 10x the lunar mass was shed
The atmosphere that would have formed without the impact would have been that deeper and denser. It would have had more of a greenhouse effect, and that would have meant higher temps, more water vapor, leading to still higher temps, more water vapor, and we get the runaway greenhouse effect that we see on Venus.
In short, earth-like planets are not just not the norm - they are extremely improbable. Even the Earth - any impact would have to occur early enough in the Earth's existence, before the Earth's water supply has been baked out (think of how much denser the air would be if all the water in the oceans was vaporized). and the hydrogen then permanently lost by dissociation of the water vapor molecules at higher altitudes by sunlight, with the hydrogen leaving the planet.
Ocean's weight: 1,450,000,000,000,000,000 tons
Total area: (land and sea) 196 939 900 square miles
= 7,362,652,260 tons per square mile.
There are 4,014,489,600 square inches in a square mile. This gives a pressure of 1.8 tons per square inch. 240 atmospheres compared to Venus' 90 atmospheres
Venus would look like a cold winter day, and Earth would be the hottest planet in the system.
Unless there are advanced life forms on the moons of Jovian-type planets around other stars (not very likely at all) it's a safe bet we're alone; almost certainly we're alone in this galaxy. We're a fluke.
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We know that the galaxy centers are not hospitable to biological life, so that takes out the majority of stars.
OUtside of sci-fi, binary systems don't work, so take off 50% of those that are left.
For the small, old stars, the band "liquid water" is so narrow, and so close to the dwarf, that it doesn't work either.
The larger ones - they don't last long enough.
Of those that are left, what are the odds that the planet will be just the right size, and just the right distance, to have liquid water (too
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I think life is reasonably common, intelligent life possibly common (thinking dolphins and such here) and life capable of making bombs and ships and tofu... not so much. Otherwise someone really would be all over the place/visiting by now.
But again, it is all wild ass speculation until we get out there and find out.
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The galaxy is 100,000 light years in diameter, and the oldest star is 13.2 billion years old. Assuming that planets around 1st-generation stars are to deficient in heavy metals to support a space-faring race, we'll assume a civilization required a 2nd-generation star or better. The 1st-generation stars were a LOT bigger than today's average [nova.org], and thus the process of seeding heavy elements went quickly, since those stars don't have
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Though now the question is, how long until we start exploring space? We could do it technology-wise, but we aren't. I keep hoping we find a hospitable planet around a "nearby" star; this might provide the kick in the ass we need to really start exploring. Of course this all assumes we don't wipe ourselves out first, or are wiped out by some disaster.
Aside from whatever our problem is with seriously getting into space, a lifeform could easily be smart but incapable of space travel. For example, dolphins are
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Mammals have been around since the Triassic, so by the time of "Jurassic Park", mammals were into everything (the dirty rats! - well, rat-like), stealing eggs, competing for food, etc.
So eventually, we (or something similar) would have evolved anyway even without the extinction event that might have ended the "reign of the dinosaurs".
As for our not going into space - I allowed an extra half-billion years in the timeline, which is longer than we will exist as a species. We've only been flying for 100 ye
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...Mammals have been around since the Triassic...
Ahh, good catch. What amazes me is how quickly we moved from rat sized mammal to human though. I've always wondered if various forms of natural radiation have an impact on mutations (and the potential for rapid evolution). For example, increased solar radiation (which could also account for some extinction events as well) causing a greater number of mutations. Which could also be another unique feature of our solar system......
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I'm with you on that one. Even when almost all mutations are harmful, that still leaves out that 1-in-a-million. Over millions of years, you're eventually going to hit the jackpot.
Of course if the rate of mutations is too high, then you don't get a stable population to start with, so you end up not being able to dependably pass on desirable traits. Like everything else, it's a fine balance, and one reason you won't find advanced life on planets that get too much radiation (the galactic center, for exampl
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Or maybe things living in the galactic center have evolved checksumming for their important bits? :-)
Meat (Score:3, Funny)
Um, no. (Score:1)
Not only are Earthlike planets common, Earthlike moons are even more common and even more hospitable to sparking life. And that's just life-as-we-know-it. For all we know some stars are self-aware, or some black holes - but they communicate in some way that's not meaningful for us - and perhaps they deem us unworthy of communicating with us because we are so small and irrelevant in their grand scheme, too ephemeral for them to take notice of. For all we know the black holes can't hear the quasars, which
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I'm a huge sci-fi fan, so I recognize all the scenarios you outline.
Unfortunately, real life is a bit harsher.
Solar intelligence - the hotter something is, the more that the effects of thermal noise interfere. The sun is just too hot - and too dense. If the sun were a brain, it would take more than the life of the human race to have a thought because it takes a long time for things to happen in the core - for example, the light we see from the sun today got it's start (iirc) a million years ago. It's th
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We're pretty sure there are dimensions we cannot measure, some say 23 dimensions in all.
Obligatory Deep Thought, by Jack Handey:
What are all these "other dimensions" I keep hearing about? To me, there's only one dimension worth anything, and that's the good ol' U. S. of A.
I think.. (Score:1)
I've finally found something I disagree with you on (well, at least something major).
First, your numbers in the OP are a little off. If that big chunk that became the moon had not been bashed away... Well, you didn't adjust for that.
Second, we (humans) do not know how the moon came about for certain. Sure, there's some great theories, some of them with a ton of data backing them. But we still don't know - it's the nature of science, unfortunately. If it wasn't directly observed, we can only get a guess
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Debating these things is how we develop some new ideas :-)
Yu're right. If that big chunk hadn't been bashed away, we would have to add about 10% to the final figures, making Earth even less hospitable, since the greenhouse effect would be a bit more efficient.
It's a good thing we lost the extra weight - it's one reason why we're not a second, but even hotter, Venus. Mercury [hypertextbook.com] is cooler than Venus [hypertextbook.com] despite being much closer to the sun only because it doesn't have an atmosphere, so no greenhouse effect.
Peale's take (Score:2)
I saw a talk by Stan Peale (who taught me graduate classical mechanics) in about 1992 or so. In that talk, he suggested that the conditions for intelligent life might be significantly less common than was believed at the time. He focused on the importance of a big moon and a huge planet (Jupiter) in the same solar system to protect Earth from impacts by large objects long enough for intelligent life and then technology to develop.
Peale got famous when he published a paper just before the Voyager probes ar
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That is the sort of course it's too bad nobody had a camcorder for ... though it must have been even better sitting in on it. Colour me jealous :-)
It's the old "you can't get there from here" problem. Sure, mechanical intelligences could populate the galaxy, but who makes them in the first place - and why haven't they done so already? Biochemical intelligence? If we could figure out what "intelligence" is in the biological context ... but we don't even know how things like consciousness work. We know it