The Astronomy Thread

pharmakos · Sep 27, 2019

Olebass said:
It is fairly safe to assume many worlds have some form of life on them. Maybe even trillions.
What is crazy to me is when you think how much life exists on Earth, yet only 1 type can create iPhones.

With the rules of biology being what we know, it's pretty much inevitable that one species will rise to the top of any given ecosystem and destroy any competition it might have. Yeah, can't assume it's be the same on alienworld, but if it is then yeah

iannis · Sep 27, 2019

khorum said:
Sure, but again we can't anthropomorphize the motives of hypothetical aliens. We can't assume their need for lebensraum or planets with liquid water or whatever. So the idea is to use systems that are universal to predict behavior. Things like how the laws of thermodynamics would apply to all civilizations and it scales into thermoeconomics, which predicts how things redistribute energy, from sub-cellular organelles to big corporations to civilizations.

WE might want to colonize Alpha Centauri because cow farts destroyed our ecosystem, but aliens might just be attracted to shiny space lights.

The critical weakness of the Kzin was not laser weapons, but rather laser pointers.

Oldbased · Sep 27, 2019

pharmakos said:
With the rules of biology being what we know, it's pretty much inevitable that one species will rise to the top of any given ecosystem and destroy any competition it might have. Yeah, can't assume it's be the same on alienworld, but if it is then yeah

It's not that. I agree, we should eat everything. It's just that only one was capable of saying, I need a house. Bird says me too. Wasp says me too. Ant says yo, what about a cave. We all move into cave. Years later we say yo cave sucks, we need a house. Bird says me too. Wasp says me too. We build a house. Then suddenly man is like, yo I need a steam engine. Bird says WTSplat, Wasp says WTsplat Man drives around world in massive steam engine. Man says yo I need porn, computers, space shuttles, porn, iPhones, computers, porn. All other life on Earth is like yo I need a worm.

khorum · Sep 27, 2019

It could just be spores that survive in the vacuum of space. It doesn't have to be intelligent in a way we understand intelligent at all. There could just be a planet where the dominant species is a clonal colony of trees who evolved a way to let their spores float out into space and eventually spread to other planets. Point is, we don't anthropomorphize what the hypothetical civilizations are, we just need to look at the universal systems and constraints that would make it possible.

If you think, "whoa but those spores can't blast kerolox and jet to other stars in a human lifetime that's worthless". The problem isn't with the spores, it's with your assessment that it would need to succeed in its task measured in HUMAN LIFETIMES. The spores could evolve membranes that act as solar sails and use constant acceleration that'll result in speeds that is orders of magnitude faster than our rockets----but only after decades of slow acceleration.

A few years ago a couple mathematicians pubished a paper about their simulation that said any civilization with the ability to travel at speeds that WE HAVE LONG SURPASSED with our shitty rocket tech would have colonized the entire Milky Way galaxy in less than 50 million years:

https://www.fgcu.edu/cas/departments/math/files/Spatial-Dispersion.pdf

Paper said:
Conclusion In 250 iterations (250 Kyr), a civilization with the highest proclivity to emigrate (c=1) will travel approximately 500 light years, about half the distance possible, although the results vary somewhat from graph to graph. This rate of expansion is approximately one-fourth of the maximum travel speed of Spatial dispersion of interstellar civilizations At this modest rate, a civilization could still span the Milky Way in less than 50 Myr.The model shows that in the 5 Gyr the Universe has been able to support intelligent life, the first civilization to emerge could have colonized the Galaxy 100 times over and done it long before the second civilization even evolved.

So in the 5 billion years since the earth has formed, any prior intelligent species who arrived at the technological level we were at in 1969 could've colonized the entire galaxy 100 times over. No need for warp drives, just time.

pharmakos · Sep 27, 2019

The more I've thought about it over the years, the more I've started to believe the "we're the first" answer to the Fermi Paradox. IMO it explains more than any other answer.

pharmakos · Sep 27, 2019

Olebass said:
We build a house. Then suddenly man is like, yo I need a steam engine.

I suppose 3 million years is roughly "suddenly" in astronomical timelines, so I can't really argue with that in this thread

Oldbased · Sep 27, 2019

pharmakos said:
I suppose 3 million years is roughly "suddenly" in astronomical timelines, so I can't really argue with that in this thread

Could be worse. Think of the first dude that demanded twinkies be a thing

Ukerric · Sep 27, 2019

Cybsled said:
You're right, it just takes one. But on a cosmic scale, you need more data. You can't draw a conclusion with 50 years of extremely limited data/observational capabilities out of billions.

No, but you can put a reasonable cap.

A mathematical paper came out a couple years (a decade?) ago. They ran monte-carlo models, and put a cap on the numbers of technological civilizations expected on our Galaxy. 8. If there were more than 8 active civilizations in our light cone across the Milky Way, we had more than 50% chance of having detected them.

(vs the tens/hundreds of thousands that the Drake Equation predicted originally)

Ukerric · Sep 27, 2019

Cybsled said:
Right, a civilization that has completely exhausted/is close to exhausting all local resources basically has to look elsewhere or die/risk collapse.

So if we look at vast timescales, eventually you have to look outside your solar system, although such a move with limited speed would be more like exodus than expansion.

It's more like reproduction than exodus. Unless there's scientific/technological advances far beyond what we expect, you will never emigrate any meaningful % of a civilization to another planet, in this system or another.

The only thing you can do is create a daughter civilization somewhere than continues your cultural legacy (with the inevitable variation) from a necessary small pool of colonists.

For interstellar colonies, the most plausible model at the moment is automated probes with artificial wombs (a technology that's probably less than 2 decades away) and frozen embryo, with an initial generation raised by machines and fed "earth" libraries until they develop on their own. Hardly an exodus.

Kirun · Sep 27, 2019

pharmakos said:
The more I've thought about it over the years, the more I've started to believe the "we're the first" answer to the Fermi Paradox. IMO it explains more than any other answer.

In terms of the timescales we're talking about and the sheer unimaginable size of the known universe, it taking 9 billion"ish" years for a singular happenstance to finally, "get it right", isn't that far fetched. We probably are, in fact, "first".

pharmakos · Sep 27, 2019

Kirun said:
In terms of the timescales we're talking about and the sheer unimaginable size of the known universe, it taking 9 billion"ish" years for a singular happenstance to finally, "get it right", isn't that far fetched. We probably are, in fact, "first".

most experts would say that the fact that it took so long is the least believable thing about the idea, tho with a sample size of one it is literally impossible to know. maybe life truly is that rare (and if so, the state we've got the planet in now is infinitely more sad, but i digress...)

Ukerric · Sep 27, 2019

Aldarion said:
I agree. I just find it an important semantic distinction. The filter metaphor only makes sense for factors that end species. But no disagreement about its impact.

That's because you tend to think of the filter as something ahead. Each filter ends more stuff than a civilization; the first ends entire worlds. It's just hard to think about it because we obviously have passed it.

My personal two "old" filter candidates:

- Complex life. Life arose fast, chemistry tend to create biological components with ease, and we have no less than three different orders of life (some parts of which use RNA instead of DNA) that tend to suggest that life might be easy. By comparison, there's mounting evidence, genetic and otherwise, that the procaryote->eucaryote jump occurred exactly ONCE in our history. Now, maybe it did occur multiple times, and some latecomers got outcompeted because eucaryote evolve scare fast. Or maybe it couldn't, and we got lucky to get complex cells, and the rest of the Galaxy is covered in bacterial mats.

- Intelligence. Khorum alluded at extinctions, but even without extinctions, there's lots of evidence that evolution is not teological (goal-driven), and that intelligence is not an ecological niche that a species has to fill. Meaning that sapients are maybe the conjunction of a significant number of random factors (we have a number of pre-sapient species around, primates, corvids and possibly cetaceans, but they all lack stuff, even if we didn't outcompete them - except probably primates). So we might be the lucky ones to get high tool-making intelligence. After all, our most significant evolutionary advantage isn't that we're intelligent, it's that we're the Terminators of the natural kingdoms. When any other creature ends up panting after running for an hour, we keep coming after them. When they can no longer run because their body heat is above all limits... we still run to them. And kill them. And eat them.

Kirun · Sep 27, 2019

pharmakos said:
most experts would say that the fact that it took so long is the least believable thing about the idea, tho with a sample size of one it is literally impossible to know. maybe life truly is that rare (and if so, the state we've got the planet in now is infinitely more sad, but i digress...)

I don't think the random chemistry needed for "life" is probably all that rare in the universe. Getting a chicxulub meteor at the precise right time, with the precise right conditions, to bring the precise mammalians to prominence is a completely different story, however. It taking only 9 billion years to bring about that random circumstance is actually the "amazing" part of life, in my opinion. Even considering the sheer size of the universe.

pharmakos · Sep 27, 2019

Ukerric said:
- Intelligence. Khorum alluded at extinctions, but even without extinctions, there's lots of evidence that evolution is not teological (goal-driven), and that intelligence is not an ecological niche that a species has to fill. Meaning that sapients are maybe the conjunction of a significant number of random factors (we have a number of pre-sapient species around, primates, corvids and possibly cetaceans, but they all lack stuff, even if we didn't outcompete them - except probably primates). So we might be the lucky ones to get high tool-making intelligence. After all, our most significant evolutionary advantage isn't that we're intelligent, it's that we're the Terminators of the natural kingdoms. When any other creature ends up panting after running for an hour, we keep coming after them. When they can no longer run because their body heat is above all limits... we still run to them. And kill them. And eat them.

it's possible that the number of mass extinction events that have happened in Earth's history is precisely what led evolution towards intelligence. it's probably at least what led towards that "nature's Terminators" development. would be a bit of a mind fuck if one of the requirements for "heir to the stars"-level life is a fragile planet.

pharmakos · Sep 27, 2019

Kirun said:
I don't think the random chemistry needed for "life" is probably all that rare in the universe. Getting a chicxulub meteor at the precise right time, with the precise right conditions, to bring the precise mammalians to prominence is a completely different story, however. It taking only 9 billion years to bring about that random circumstance is actually the "amazing" part of life, in my opinion. Even considering the sheer size of the universe.

the cosmologists would ask you what it is about the current state of the universe that made it happen now rather than sometime in the past, since the current age of relative "calm" on the astronomical scale has been going on for awhile. of course, the answer could just be "that's just when the dice finally landed right," but yeah... "phase states" of the universe and yada yada is where this aspect of the conversation usually ends up going.

khorum · Sep 27, 2019

pharmakos said:
it's possible that the number of mass extinction events that have happened in Earth's history is precisely what led evolution towards intelligence. it's probably at least what led towards that "nature's Terminators" development. would be a bit of a mind fuck if one of the requirements for "heir to the stars"-level life is a fragile planet.

It's absolutely one of the requirements. Ironically, one of the arguments against Kardashev's scale is that he assessed human energy density in 1964---when the overwhelming majority of human energy production was from FOSSIL FUELS. So the question is what would emergent intelligences do if they were unlucky enough to evolve on a planet where their surface IS NOT layered with half a billion years' worth of mass extinctions converted into the most energy-dense liquid resource we've ever discovered.

So for a civilization to achieve what we have achieved in 1969, they wouldn't just need intelligence, they would have needed at least FIVE mass extinction events to convert more than 85% of all life on the planet into ready fuel to power an industrial civilization five hundred million years in the future.

pharmakos · Sep 27, 2019

khorum said:
It's absolutely one of the requirements. Ironically, one of the arguments against Kardashev's scale is that he assessed human energy density in 1964---when the overwhelming majority of human energy production was from FOSSIL FUELS. So the question is what would emergent intelligences do if they were unlucky enough to evolve on a planet where their surface IS NOT layered with half a billion years' worth of mass extinctions converted into the most energy-dense liquid resource we've ever discovered.

So for a civilization to achieve what we have achieved in 1969, they wouldn't just need intelligence, they would have needed at least FIVE mass extinction events to convert more than 85% of all life on the planet into ready fuel to power an industrial civilization five hundred million years in the future.

Yup, wow, makes sense, but damn that's a lot to take in. Really adds to the likelihood that we're the first.

pharmakos · Sep 27, 2019

Ukerric said:
For interstellar colonies, the most plausible model at the moment is automated probes with artificial wombs (a technology that's probably less than 2 decades away) and frozen embryo, with an initial generation raised by machines and fed "earth" libraries until they develop on their own. Hardly an exodus.

just saw this post. wow, that's terrifying. sounds like an initial generation full of sociopaths.

Malakriss · Sep 27, 2019

pharmakos said:
just saw this post. wow, that's terrifying. sounds like an initial generation full of sociopaths.

how's that any different than some places on Earth

pharmakos · Sep 27, 2019

Malakriss said:
how's that any different than some places on Earth

and how. some places on earth terrify me too.

The Astronomy Thread

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