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Earth was born dry until a cosmic collision made it a blue planet

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Re: Earth was born dry until a cosmic collision made it a blue planet

#241

Post by lazide »

DennisP wrote: post #154
buran77 wrote: post #45

Earlier quoted context omitted.

The equation itself makes no assumptions. But anyone trying to calculate something with it must. The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link: ne = the average number of planets that can potentially support life per star that has planets. fl = the fraction of planets that could support life that actually develop life at some poi…

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.

Re: Earth was born dry until a cosmic collision made it a blue planet

#242

Post by me-vs-cat »

squigz wrote: post #178
LeifCarrotson wrote: post #125

Earlier quoted context omitted.

That's "Dragon's Egg" by Robert L. Forward, a classic Sci-fi story: https://annas-archive.org/md5/4c381ac344506d10037fc8e7747098... The cheela lived on the surface of a neutron star, and they lived faster because the nuclear physics that powered their metabolism are far faster than the chemical and mechanical physics that power our own.

I'm not against piracy, and I love Anna's Archive... but publicly linking directly to a pirate source for something like this seems wrong. Could've just linked the Wikipedia page and let people acquire however they prefer. Anyway, sounds interesting, gunna add that to my list

My initial reaction was the same, then I thought: "no, we need more of this".

We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.

Re: Earth was born dry until a cosmic collision made it a blue planet

#243

Post by dreamcompiler »

LeifCarrotson wrote: post #125
dotancohen wrote: post #115

Earlier quoted context omitted.

About forty years ago I read a terrific book about life forms that live on a star. Maybe Starquake was it called? Did to the abundance of energy on the surface of a star, they live their lives a million times faster than humans. Thus for both them and the humans who discover them, communication is difficult. I think the humans push these life forms to develop civilization, which from the human's perspective had them…

That's "Dragon's Egg" by Robert L. Forward, a classic Sci-fi story: https://annas-archive.org/md5/4c381ac344506d10037fc8e7747098... The cheela lived on the surface of a neutron star, and they lived faster because the nuclear physics that powered their metabolism are far faster than the chemical and mechanical physics that power our own.

And "The World at the End of Time" by Frederik Pohl.

https://en.wikipedia.org/wiki/The_World_at_the_End_of_Time

Re: Earth was born dry until a cosmic collision made it a blue planet

#244

Post by dotancohen »

me-vs-cat wrote: post #242
squigz wrote: post #178

Earlier quoted context omitted.

I'm not against piracy, and I love Anna's Archive... but publicly linking directly to a pirate source for something like this seems wrong. Could've just linked the Wikipedia page and let people acquire however they prefer. Anyway, sounds interesting, gunna add that to my list

My initial reaction was the same, then I thought: "no, we need more of this". We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.

Promoting copyright infringement in order to initiate a conversation about copyright is about as moral as murdering civilians to initiate a conversation about human rights.

Re: Earth was born dry until a cosmic collision made it a blue planet

#245

Post by andrewflnr »

8bitsrule wrote: post #224
andrewflnr wrote: post #57

I've tried reading the paper, which is obviously less hand wavy than this mess of a blog post but pretty tough going for a layman. I still don't see how they conclude that the water arrived all at once instead of in a bunch of comets... https://www.science.org/doi/10.1126/sciadv.adw1280

>this mess of a blog post It's that. Just one more in a long line of wild-eyed 'the Earth collided with' theories. > Scientists have shown that Earth’s basic chemistry solidified within just three million years ... They haven't 'shown' anything. They may have evidence to support part of one model ... if they can demonstrate that a Theia probably existed in the first place. Try to read it? Thick going . https://www.sc…

Water wasn't hard to get in the outer solar system. You know, where all the ice balls are?

They're not here to "demonstrate" the Theia impact theory, because there's already tons of other work doing that.

Re: Earth was born dry until a cosmic collision made it a blue planet

#246

Post by raverbashing »

antonvs wrote: post #238
raverbashing wrote: post #234

Earlier quoted context omitted.

Yup The fundamental problem with the Drake equation is that it's frequentist, not Bayesian Hence why you get too high sensitivity to parameters you have no way of having an estimate with a small margin of error We "don't care" about how many civilisations are out there, we care to the point where we can interact with them. As mentioned, it has several assumptions. "Rate of birth of sun like stars" means nothing. You…

> star too bright but with a hot Jupiter tidally locked in front of your moon, shielding it It seems unlikely that such exceptions would amount to more than part of a reasonable margin of error.

It is very likely that Earth itself is the exception of the exception and is part of a "margin of error"

Re: Earth was born dry until a cosmic collision made it a blue planet

#247

Post by squigz »

me-vs-cat wrote: post #242
squigz wrote: post #178

Earlier quoted context omitted.

I'm not against piracy, and I love Anna's Archive... but publicly linking directly to a pirate source for something like this seems wrong. Could've just linked the Wikipedia page and let people acquire however they prefer. Anyway, sounds interesting, gunna add that to my list

My initial reaction was the same, then I thought: "no, we need more of this". We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.

This... isn't a discussion about copyright though?

Re: Earth was born dry until a cosmic collision made it a blue planet

#248

Post by me-vs-cat »

dotancohen wrote: post #244
me-vs-cat wrote: post #242

Earlier quoted context omitted.

My initial reaction was the same, then I thought: "no, we need more of this". We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.

Promoting copyright infringement in order to initiate a conversation about copyright is about as moral as murdering civilians to initiate a conversation about human rights.

Is that really the equivalence you want to make?

That's a rather severe escalation to me.

Re: Earth was born dry until a cosmic collision made it a blue planet

#249

Post by me-vs-cat »

squigz wrote: post #247
me-vs-cat wrote: post #242

Earlier quoted context omitted.

My initial reaction was the same, then I thought: "no, we need more of this". We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.

This... isn't a discussion about copyright though?

It wasn't, until https://news.ycombinator.com/item?id=45477785

Re: Earth was born dry until a cosmic collision made it a blue planet

#250

Post by littlestymaar »

antonvs wrote: post #239
littlestymaar wrote: post #152

Earlier quoted context omitted.

> With sublight velocities achievable today, I recall it would only take around a million years for a Von Newmann probe to cover the entire galaxy. Such a probe is quite conceivable, so why isn't there more evidence of such probes everywhere? What are the incentives to build and deploy such a thing though? We as a civilization fail to fund things that have a ROI of more than a few years, how are you going to fund som…

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.
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