Earlier quoted context omitted.
This... isn't a discussion about copyright though?
It wasn't, until https://news.ycombinator.com/item?id=45477785
That is about piracy, not copyright.
Earth was born dry until a cosmic collision made it a blue planet
251–260 of 279 posts
Re: Earth was born dry until a cosmic collision made it a blue planet
#252What I don’t understand is how you define a single point (even if the point spans a million years) of “when the solar system formed.” They say the chemical composition of the Earth solidified “only 3 million years after the solar system formed” — isn’t the formation of the planets itself part of the formation of the solar system? How does one define the moment of formation? Or does this mean that we know with certain…
> How does one define the moment of formation? We don't. It's usually within a range. My illustrated book shows the timeline with more context and detail. Note that the events are provided on a timeline with some uncertainty (e.g., ± 1 million years): https://impacts.to/downloads/lowres/impacts.pdf
That’s what I was thinking but I guess the uncertainty is less than I assumed.
Btw your book is AMAZING!
Re: Earth was born dry until a cosmic collision made it a blue planet
#253Earlier quoted context omitted.
One approach is to give each variable a probability distribution. The greater our uncertainty about possible values, the wider the bell curve. Drexler and colleagues did that, and found "a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological…
Probability distributions based on a single data point (of where we know there is life) aren’t reliable distributions.
No, it’s just a starting point. We do need more data.
Re: Earth was born dry until a cosmic collision made it a blue planet
#254Earlier quoted context omitted.
It's 45 years old and the author is deceased. I assume you would be untroubled by a link to a copy of Macbeth . Where do you draw the line?
An obvious line would be when copyright expires. In fact, drawing that line is exactly what copyright expiry is intended to do.
Copyright has far exceeded sane limits a long time ago.
Re: Earth was born dry until a cosmic collision made it a blue planet
#255Earlier quoted context omitted.
Exactly. Some of the biggest explanatory factors for the Fermi paradox are likely to be economics and politics: interstellar travel is unreasonably expensive, unimaginably slow, and has negative ROI unless your time horizons are beyond anything that's ever been used on Earth. Consider that in some countries on Earth, we can't even get consensus that obtaining energy directly from the Sun via solar panels is a good id…
Also, people vastly underestimate how hostile space is: colonizing Mount Everest, the Antarctic or the continental plateau under sea would be far easier than colonizing Mars. And Mars is the most hospitable extraterrestrial place we know of.
I don't think we would colonizing Mars, free floating colonies akin to O'Neil Cylinders orbiting Earth would probably be the more logical option. And with increasing robotic automation capabilities, it's not improbable to see these being built in the future.
Re: Earth was born dry until a cosmic collision made it a blue planet
#256Earlier quoted context omitted.
Yes, I think that will never happen. My prediction is that generational ships are super rare in the universe, and may only happen ones or twice in the entire history of a civilization, and for a tiny portion of civilizations. Meaning by far majority of all civilization will have zero generational ships. Maybe a single civilization somewhere in a distant galaxy will have hundreds, but nowhere near enough to cover an e…
It doesn’t matter how rare it is to get started once it starts. Every ship is a new civilisation that is created, one predisposed culturally and perhaps genetically to spreading out. Especially once you reach the “hundreds” level then given the technology exists and the people exist why would it stop, until there’s nowhere else to go. There is the light cage issue where a civilisation can only spread so far with expo…
von Neumann probes are a fantasy. I see no reason why any civilization in the entire universe will ever build a successful self replicating probes, let alone ones that are still replicating dozens of millennia later. The reasons include that targeted probes and telescopes can give you pretty much the same amount of knowledge for far cheaper and much quicker then random walking probes across the galaxy. There is also a technical limitation to self replicating probes, even if a civilization will build one, we cannot expect the self-replicating mechanism to last dozens of millennia. Some generations will fail to replicate, and in the vastness of space that may mean the entire lineage will go extinct.
I think you may be expecting an exponential growth when population dynamics almost always favor logistical growth. At some point your machines, or your colonial behavior hits a limit and your growth starts to slow down. I suspect that limit is within the solar system for the vast vast vast majority of civilization. And even if one escapes their own solar system and starts anew on a new home world, they most likely will not colonize another. The space is just so big, and habitable worlds so far away from each other that I find it extremely improbable that any civilization (and their ancestor civilization) will survive more than 5-6 colonization (by far most will see 0).
> Living beings are the same.
They are not. You are describing living beings like viruses (fair enough; viruses are worthy to be considered lifeforms) that spread from host to host until they infect everybody. But viruses don‘t behave like that. The vast majority of them only infect their closest neighbors, and those that do spread towards the limit of all members of the species (like Covid) still fall short and eventually start to slow down their spread in a logistical manner. Growth only looks exponential while you are at the initial stages of spread. This behavior is not only common among viruses, but in fact most population dynamics can be described with logistical growth.
Re: Earth was born dry until a cosmic collision made it a blue planet
#257Re: Earth was born dry until a cosmic collision made it a blue planet
#258Earlier quoted context omitted.
One approach is to give each variable a probability distribution. The greater our uncertainty about possible values, the wider the bell curve. Drexler and colleagues did that, and found "a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological…
Probability distributions based on a single data point (of where we know there is life) aren’t reliable distributions.
Which is why they set very wide ranges on the things we know little about. Doing that is less unjustified than guessing specific values, as people have usually done.
It's nowhere near a precise estimate of the probability of life. What it mainly shows is that the Fermi "paradox" is no such thing. It can look that way if we guess specific parameter values, but if we fully account for our uncertainty on the various parameters, then the result is a decent chance that we are alone, given the knowledge we have so far.
Re: Earth was born dry until a cosmic collision made it a blue planet
#259Related, a recent study suggests up to 1% of our mantle is water trapped within rock that gets released as subduction increases to higher heat and pressure. This water could account for three times the amount of water on the surface and may represent a whole-Earth water cycle. https://www.bnl.gov/newsroom/news.php?a=111648 I wonder how this ties in with the submitted link about Theia. And it will be interesting if we…
There are structures in Earth's mantle which are believed to be leftover chunks of Theia, which makes the connection feel quite plausible.
https://www.newscientist.com/article/2400567-bits-of-an-anci...
Re: Earth was born dry until a cosmic collision made it a blue planet
#260Earlier quoted context omitted.
It doesn’t matter how rare it is to get started once it starts. Every ship is a new civilisation that is created, one predisposed culturally and perhaps genetically to spreading out. Especially once you reach the “hundreds” level then given the technology exists and the people exist why would it stop, until there’s nowhere else to go. There is the light cage issue where a civilisation can only spread so far with expo…
von Neumann probes are a fantasy. I see no reason why any civilization in the entire universe will ever build a successful self replicating probes, let alone ones that are still replicating dozens of millennia later. The reasons include that targeted probes and telescopes can give you pretty much the same amount of knowledge for far cheaper and much quicker then random walking probes across the galaxy. There is also…
> von Neumann probes are a fantasy.
Well pack it up folks, we've been told what would be possible for any alien civilization, even given millions of years of effort.