Space, the Final Frontier: It Gazed Into My Open Refractor

The Something Awful Forums > Discussion > Debate & Discussion > Space, the Final Frontier: It Gazed Into My Open Refractor

«‹›215 »

Lightning Knight: Feb 24, 2012; Pray for Answer

Hello D&D! This thread is a spin off of a discussion that happened in USPOL. Originally, we were discussing the Fermi Paradox and the prospect of distant alien life that may or may not exist, but feel free to discuss and debate other weird space poo poo like Nemesis Theory (probably not real) or whatever here. As long as it's about space or aliens or somehow adjacent to that, it's kosher itt.

If you want to go to bat for the idea that aliens have visited Earth and there's government conspiracies to cover it up then more power to you I guess but I will lol at you.

Please be respectful, I expect that this topic should be less controversial and high blood pressure inducing than your average D&D affair. :colbert:

Also don't be a weird gross dick about your evopsyche theories on human evolution or other racist poo poo, and try to root your arguments in good science please.

Haystack posted:

Aliens don't have interstellar civilizations for exactly the same reason humans never will: it costs way, way, waaaay too much energy, and is way too slow. A physicist on another forum I frequent broke it down like this:
quote:
Everyone thinks that space is big, but they're wrong. It isn't big, it's big. People don't comprehend the scale. When I hear people talking about 'fast space travel' I start to itch a little bit. People that say that sort of thing don't mean 'fast' in the sense of being able to send a tiny unmanned probe to the nearest exoplanet in 'only' a few million years, they mean being able to hop a space-bus and have a family vacation in Betelgeuse. And that isn't going to happen, not ever. I don't care what kind of weird future technology and vast oceans of clean cheap energy you postulate. We are stuck on Sol forever, and let me show you why.

The closest terrestrial planet we know of is Gliese 876 d, which is 15 light years away. Sure, the atmosphere is well above boiling, but we are not very picky space travelers. Let's say that we have perfect technology. Our engines are 100% efficient, fuel weighs nothing, and accelerations are instantaneous. This is the thermodynamic limit. It cannot get better than this. What would it cost us to send someone or something to Gliese?

Here's a table. I have listed the energy cost of the voyage in units that I call 'Globes.' Globes are the percentage of the entire world's energy production per year. I chose three different masses for your edification. Use the globes per kilogram if you want to quickly calculate the cost of sending your favorite sci-fi starship on a 15 light-year journey at the speed of your choice. Use the 1,000 kilogram table if you want to launch your Honda Civic into space. Use the 500,000 kilogram table if you want to use the International Space Station as your ship (which by the way, is terribly cramped and unpleasant).
pre:
+--------------------------------------------------------------------------------------------------------------------------+
|Velocity (c)|Time, Earth's Frame (years)|Time, Ship's Frame (years)|Globes per kg|Globes per 1000 kg|Globes per 500,000 kg|
+--------------------------------------------------------------------------------------------------------------------------+
|0.01        |1500                       |1499.92                   |0.0000000095 |0.0000095         |0.0047               |
|0.1         |150                        |149.25                    |0.00000096   |0.00096           |0.48                 |
|0.2         |75                         |73.48                     |0.00000392   |0.00392           |1.96                 |
|0.3         |50                         |47.7                      |0.00000917   |0.00917           |4.58                 |
|0.4         |37.5                       |34.37                     |0.000017     |0.017             |8.65                 |
|0.5         |30                         |25.98                     |0.000029     |0.029             |14.69                |
|0.6         |25                         |20                        |0.000047     |0.047             |23.73                |
|0.7         |21.43                      |15.3                      |0.000076     |0.076             |38.00                |
|0.8         |18.75                      |11.25                     |0.000127     |0.13              |63.29                |
|0.9         |16.67                      |7.26                      |0.00025      |0.25              |122.86               |
|0.99        |15.15                      |2.14                      |0.0012       |1.2               |578.05               |
|0.999       |15.02                      |0.67                      |0.0041       |4.1               |2028.44              |
|0.9999      |15                         |0.21                      |0.0132       |13.2              |6618.27              |
+--------------------------------------------------------------------------------------------------------------------------+
There's a lot I want to unpack here.

Generous Assumptions

I can't emphasize enough how nice I'm being here. I'm granting instantaneous acceleration, which is huge. If you have to actually worry about thrust, the times become much, much longer, while still requiring the same amount of energy. I am also granting zero weight fuel, which is nuts. On top of that, we have perfect efficiency. We lose nothing by charging the engines nor by firing them (In contrast, we lose about 60-70% of the energy generated from burning coal by the time it reaches our homes). These numbers are also for fly-by arrivals. If you want to actually stop when you get there, then double the energy cost.

Scale: Earth Time

This is the only part of the chart that scales in a simple, intuitive manner. If you double your ship's speed, the guys on the ground have to wait half as long for it to get there. Nice and simple.

Scale: Ship Time

For the ship, things are a bit weirder. As velocity increases, relativity becomes impossible to ignore. At 0.8c, it actually takes the ship less than 15 years to travel a 15 light-year distance. This might sound like FTL travel, but it's really nothing of the sort. Space is contracting for the ship. The distance between objects is shrinking. The 0.99c ship gets to Gliese in 2.14 years because in its frame, Sol and Gliese are only about 2.14 light-years apart.

Notice that the scaling becomes extremely non-linear towards the end. Increasing your velocity from .9c to .99c is only a 10% boost, but it cuts the travel time (for the ship) by about 70%. Welcome to space-time, you fuckers.

This also causes out-of-synch issues with your earth buddies. I was going to get into the heartbreaking consequences of this, but I'm not going to bother because the next section is going to render that moot.

Scale: Energy

And now we come to my point. Classically, energy scales by the square of the speed. So doubling your velocity doesn't double your energy cost, it quadruples it. That would be bad enough, but then relativity adds in an asymptotic scaling factor that goes berzerk as you start to approach c. Just look at those numbers. Really, look at them.

I chuckle a bit when I hear about space tourism. We aren't going to other planets. Not ever. The cost of sending even a small ship to our closest (and totally uninhabitable) terrestrial neighbor and having it get there before the crew dies of old age has to be measured in multiples of the earth's annual energy output. I don't care what kind of future tech that we have. How much more energy are we gong to be producing with our tri-lithium anti-phasing widgets? A hundred times as much? A thousand? Those both sound like wildly unrealistic numbers, and they both totally don't solve the problem. If you have to deal with issues like real acceleration, real efficiencies, and real fuels, then a million-fold increase probably wouldn't rescue the project.

We're not claiming other planets. We only have the one that we're on. We need to take care of it.

LtStorm posted:

In USPOL there was mention of alien microbes living among us, including the idea that tardigrades are that. Tardigrades are definitely from Earth, but, there's still potential that microbes of an alien source could be hiding all over Earth and we just haven't spotted them yet. More likely, but also yet unproven, is the idea there is life that evolved on Earth alongside the life we know, but that we haven't noticed yet--it'd all be microbial also, most likely.

The reason this is a question is because of how we study microbial life. To discover a new species of microbe a scientist has to:

1. Spot it in a microscope
2. Spot many of it
3. Figure out how to grow a colony of it
4. Study its biochemical and genetic composition

Right now the way we tend to study microbial life is by looking for biochemistry that works the same as it does in the macro life we can study much more easily; almost all microbes we know of have very similar biochemistry to us and all plants and animals. I say "almost" because recently scientists have nailed down an organism that is, to our knowledge, of Earth, but also differs more from all known life than we differ from fungi. The organism is hemimastigote and was first spotted in a microscope back in the 19th century but were only studied under a microscope before modern biochemistry had arisen which didn't reveal how truly weird they were until they were re-discovered now.

So where could alien (extraterrestrial or terrestrial) life be hiding on Earth? It could be anywhere in our biosphere. Say you were to collect a random sample of matter--much like what was done that lead to the hemimastigotes being rediscovered--and separated out the abiotic parts (which could also be where you accidentally throw out the evidence of alien microbes because it looks abiotic to you). What you were left with that you are sure was a living organism or came from an organism would include a portion of biological dark matter.

Biological dark matter includes things like junk DNA--which we can find even in our own bodies, but could also potentially contain remnants or genetic material of organisms with completely different biochemistry from us. As I mentioned before, most of our ability to study microbial life relies on it having the same biochemistry as us, which our cutting edge ways of analyzing biological material rely on more and more heavily. This all leads to a hypothesis that there could be a shadow biosphere that contains microbial life that works so differently than what we've identified and studied that it could be hiding in plain sight without us identifying it.

Of course, so far there's scant evidence to support this, which could be because it doesn't exist, but much like aliens not on our planet, could also be because we just haven't discovered it yet. And hemimastigotes are still having their biochemistry studied, they could still contain surprises even more amazing than they already do.

mycomancy posted:

Great topic LK! Here's my opinion as a molecular and synthetic biologist: there are three Great Filters of consequence, the Nucleosynthesis filter, the Intelligence filter, and the Synthetic Biology filter.

The Nucleosynthesis filter is the apparent requirement of heavy elements to do biochemistry. While life is made out of a skeleton of hydrogen, oxygen, nitrogen, and carbon, elements like phosphorous, sulfur, iron, manganese, magnesium, copper, and other elements are found everywhere and are essential to basic enzymatic function. Planets that form too early will have concentrations of these elements that are too low for complex biochemistry to evolve. This Filter means that life can only evolve once enough first and second generation stars have died to produce these elements.

The Intelligence filter is based on the fact that we've seen intelligence involve only once on our planet. Like many adaptations, intelligence evolved in response to a specific environment encountered by a specific species. The odds of this happening is likely very low, as the physiological cost and prerequdited of intelligence is high.

The Synthetic Biology filter is the one we're going through right now. We can't survive in any meaningful way in space, and evolution is too slow. We have to redesign ourselves to get off the planet, and now we have the tool to do it in RNA-guided nucleases like Cas9 and Cpf1. If an intelligent species evolved such that they could not engineer themselves for whatever reason, they'd be homebound.

Well, that's my two cents on the topic.

mycomancy posted:

Did you put my dumb, sleep deprived spelling error in there too?

To answer your question, here's the short list of animals we think of as being at least somewhat intelligent: us, pigs, dogs, elephants, various cetaceans, various apes, various corvids, and maaaaaaybe octopi. So we aren't crowding out intelligence at low levels. Despite these numerous examples of "low level intelligence," we don't seen other intelligence peers on the planet even though presumably the apes at least are as smart as our common ancestors were. So why?

There's a certain level of anthrocentricism when we discuss the evolution of human intelligence. WE'RE intelligent, and we see the good in it, so we think it'd be good for any organism to evolve. To borrow from Larry Niven's Known Space books, Finagle Was Right: The Perversity Of The Universe Tends Towards Maximum aka the Universe doesn't give a gently caress about what humans want, need, or think, and it's gonna do what it does without consideration towards us.

So, my expert opinion is that we're probably the first intelligent species in the observable universe, and likely we're the last. The spark of intelligence dies with us. And, with the way the world is going, that'll be in about 20 years.

VitalSigns posted:

Space predators being the resolution to the Fermi paradox seems unlikely to me because why would an alien species that doesn't share common descent like all life we've heretofore observed on Earth be able to naturally digest anything it finds here, let alone everything.

Even if you assume that only carbon-based life is possible and sugars are the building block of energy storage/release in every possible lifeform (or at least lifeforms complex enough to invent interstellar travel), there's still a bunch of proteins and possible carbohydrate configurations that you can't break down unless you evolved alongside the organisms making it so you have the enzymes you need.

There's an enzyme in our spit that breaks down the carbohydrates in starchy foods like crackers and potatoes, if you don't have that you can't get the glucose out of them, you just have to poo poo out all that energy untouched like we do with cellulose. The energy in cellulose is enough to sustain cows and even giant fat-rear end elephants if they eat enough of it, but even their bodies can't break it down, they rely on symbiotic organisms in their gut to ferment the cellulose down into something their bodies know how to produce the enzymes to handle.

Even to eat another mammal or even a nearly-identical human, I can't break down and use their proteins without special enzymes produced in my liver and a low-pH environment for the reaction to take place in, and of course all that needs to happen in a protected enclosed area of my body so the enzymes and acid don't get out and I don't digest my own muscles and organs. If you're born without one of those critical enzymes then eating meat literally poisons you. Or one of the most common dietary restrictions on earth is lactose intolerance where your body says "okay I'm not a baby anymore time to stop wasting energy on an enzyme to break down milk sugars since I probably won't encounter any" and so most people on earth can't eat the same food they ate as a baby unless they're from a few subpopulations of humans whose ancestors lived in a culture that depended so much on animal husbandry for survival that persistence of lactose tolerance into adulthood was selected for.

And all those problems exist among creatures that have evolved to eat each other, planet earth is filled with organisms with weird proteins and strange sugars and other chemicals that might as well be alien compounds from another planet because you can't do anything with them, at best you excrete them out untouched, or maybe they blister your skin or maybe they just kill you, or maybe they mimic or block neurotransmitters and do weird things to you like make you hallucinate or get you high or paralyze your nervous system and suffocate you to death.

Even if everything goes well you can have unexpected problems if your environment provides too little of an important nutrient (iodine deficiency was common in isolated landlocked areas before we added it to salt to supplement everyone's diet) or too much (if you eat a dog's liver you will die from too much vitamin A, this was a problem when early arctic expeditions ran into trouble and started eating their pack animals).

When you look at how digestion works you have to conclude it's hilariously impossible that a predator alien could show up and just start eating earth life. Even if we don't lack a single element they need nor contain any elements in lethal overdoses for them, their bodies wouldn't be able to digest the life they found here just like we can't digest a lot of life we find here. And digestion has to evolve this way. Energy efficiency is extremely important, if you can expend 1% less energy than the neighboring species to obtain the same food you're going to outcompete them. The purpose of enzymes is, like all chemical catalysts, to lower the input energy required for a chemical reaction. You can't carry around a reactor in your stomach to incinerate everything you eat into its constituent parts because the energy requirement would be enormous and you'd lose out to the animal using specialized enzymes to break down food at cold temperatures (and how would you protect your own body from it, we can coat our stomach in pus that the acid and enzymes can't break down, but a universal digestor by definition would break down anything organic it touches). And you can't make enzymes for every conceivable energy-rich molecule you might ever encounter because (a) if you've never been exposed to a given molecule there's no selection pressure to create a way to digest it, and (b) creating enzymes costs energy so making ones you never use makes you less competitive than the next guy who only makes the ones they need for the food they eat (again why most humans become lactose intolerant at ages when their ancestors stopped drinking breastmilk, or why humans are the only animal susceptible to scurvy. Most animals make their own Vitamin C, but at some point in our and our great ape cousins' history we lost that ability because we stopped making a critical enzyme in the chain, most likely Vitamin C was so readily available in our immediate environment that apes who didn't bother to make the enzymes survived better than the ones who did).

It makes for a fun creepy sci-fi premise, but practically speaking it's biologically impossible that we would make a good food source for a lifeform that evolved from an independent line of descent, and that's before you even get to the practical problems of the insane amount of energy expenditure it takes to come here versus just growing food on your home planet or in artificially constructs in your own solar system or manufacturing it from base elements or whatever (these are the same problems behind theories that aliens would conquer us for our natural resources, all of which are more plentiful and easily found in space without having to lift them out of a planet-size gravity well)

LtStorm posted:

I take issue with your issue. There's no guarantees silicon-based life would be rock anemones or stuck at the bottom of oceans. Well, no more guarantee than it'd be anything because we haven't met it yet. Now I get to talk about what I think about silicon chemistry!

Carbon is super-flexible, you are correct, but silicon is the second most flexible atom next to it (and is literally next to it on the Periodic Table meaning their properties are similar). Silicon is flexible enough to make macromolecules just like carbon, which is possibly the most important thing for it plausibly being a cornerstone of life and why we talk about silicon-based life. Macromolecules are, as the name suggested, large molecules; at their low end a macromolecule contains hundreds of atoms while at the high end it contains thousands of atoms. Small molecules, like the nucleic acids in our bodies (dozens of atoms each), come together due to their chemistry to form macromolecules such as DNA (thousands of atoms). The proteins in our bodies and any polymer we use in our lives are composed of macromolecules.

Making macromolecules requires a flexible atom able to form lots of bonds (lots in this context being four) as a base. Both carbon and silicon can form four bonds with four different atoms; they're both about equally good at that. One important feature of these flexible atoms is how they form long chains. Carbon has no problem forming long chains of itself; if you have a long chain of carbon with only hydrogens in every other available bonding position, you have a hydrocarbon; modifying them can make things important to our biochemistry like fatty acids. The silicon equivalent is a silane, which is hilariously flammable like hydrocarbons, but not nearly as stable. So while silanes, which are highly reactive in general, may be important to the biochemical reactions of a silicon-based life form, it's probably not going to around as a stable molecule. What silicon can do that carbon can't is form silicones. A silicone, as in the polymer we see in our every day lives, is a chain of alternating silicon and oxygen atoms. Silicones are highly stable and flexible with the theoretical ability to modify each silicon in the chain with up to two other atoms. Carbon doesn't form an exact equivalent of silicone--alternating carbon with oxygen in a chain makes an ether functional group which has its own complex chemistry. You can put ether functional groups in a chain but they tend to form a loop instead of a straight chain, which oddly enough is important to how Febreze and other odor eliminating products work.

Another thing you would need for life is a set of functional groups that have a variety of chemical properties they can imbue macromolecules with. For our carbon-based life, most atoms used in our functional groups are near carbon in the Periodic Table: nitrogen, oxygen, phosphorous, and sulfur. Other atoms used in our biochemistry are on the left side of the Periodic Table (hydrogen, sodium, magnesium, etc.) or near the center (iron, zinc, manganese, etc). While we don't know exactly what other atoms silicon-based life would use in its functional groups, it's easy enough to speculate it would share a lot of the atoms with us based on what we know about basic chemistry, the chemistry of silicon, and our own biochemistry. We know, for instance, that in our own biochemistry the elements carbon, nitrogen, and sulfur have a complex interlocked chemistry. Silicon does not interact with nitrogen directly, but has chemistry with carbon and sulfur. So functional groups for silicon-based life would have access to nitrogen as a key micronutrient much like we need iodine--or they may not use nitrogen at all. With carbon, we know silicon can form some functional groups and that they have a complex chemistry with each other because of the study of organosilicons. With sulfur, we know silicon can polymerize with it in a way that carbon can not, which would be an important difference in how silicon-based life works. Silicon does not interact with phosphorus much at all under Earth-like conditions, so if we found silicon-based life using phosphorous we'd probably learn something new about that chemistry. Lastly, one thing silicon is hands-down worse at than carbon is the ability to form double and triple bonds. Carbon is very good at both of those things which means they're a big part of the functional groups in our own biochemistry.

So silicon is flexible enough to plausibly build large macromolecules with, and we know from basic research into the chemistry of silicon that it can form functional groups with carbon, oxygen, and sulfur at the least. Once you have functional groups you need a set of molecular building blocks using those functional groups that fit together in a flexible way to build a macromolecule. As that macromolecule gets bigger it will start demonstrating unique properties due how its functional groups interact with each other and with functional groups in other small and macromolecules. In carbon-based life this would be where you building blocks like nucleic acids that are assembled to make a self-replicating macromolecule like DNA and RNA which is able to facilitate the synthesis of other macromolecules like proteins and other structures that make up the cells organisms are composed of.

So from this perspective there's nothing clearly standing in the way of silicon-based life being just as complex as carbon-based life. Silicon has its own bag of tricks to offer but we only poorly understand them because we haven't studied silicon and its ability to form macromolecules (this is something basic research would do, FYI) nearly as much as we've studied carbon and most importantly our own biochemistry. Most of our research into organosilicons is due to polymer research--so how to make different and better plastics (this is something applied research does, FYI).

The bigger hurdles to us imagining silicon-based life, from our perspective as carbon-based life, is what their basic building blocks and fundamental chemical reactions for them would be--which we have to completely guess at. For example, their biochemistry would definitely have several reduction-oxidation reactions somewhere in it (which doesn't have to involve oxygen in spite of the name of the reaction); for us one of those is carbon (solid) and oxygen (gas) forming carbon dioxide (gas). The equivalent for a silicon-based life form would be silicon (solid) and oxygen (gas) forming silicon dioxide (solid). So how they use that reaction would have to be completely different than how our form of life uses the equivalent. And of course because silicon reacts well with carbon it may just be that they use the same carbon and oxygen redox reaction as us.

When we think about silicon-based life we need to remember it doesn't have to exist at the same conditions as we do. What if they were on a planet halfway between Earth and Venus in conditions? I say this because one idea is that silicon-based life could exist at much hotter temperatures than carbon-based life. Going to a much higher temperature and pressure would mean changes to chemistry that would both make some reactions we benefit from unfavorable and unusual and vice verse. One other big question that also relates to the reactions that make this life possible is what solvent that silicon-based life would use as at a higher temperature water isn't going to work. Sulfuric acid is one suggestion because it boils at 300 C; so if silicon life using that would exist somewhere just below that temperature. Using sulfuric acid as a solvent would also make the chemistry happening completely different than how our life works and might have the benefit of making silicone-based macromolecules much more stable. An example in the difference of conditions is silicon nitride, an inert industrial chemical under Earth-like conditions. On a hot planet covered in sulfuric acid, silicon nitride would not exist as a compound--it would be dissolved so nitrogen would not risk being locked up in an inert compound and would go elsewhere in their environment and be available for biochemical reactions.

Living at a higher temperature than us hardly would stop a silicon-based life from space-faring anymore than we do from the perspective of life support--it's trivial to make a hotter box than what we do for traveling the delightfully insulating depths of space where you have more trouble getting rid of heat than generating it.

Of course, what kind of technology is possible on the planet they might live on is another question. The important thing is that if silicon-based life could form from abiogensis, there's nothing fundamental that we know of standing in its way of being as complex as us.

Citations: A lot of chemistry textbooks I've read because I'm a chemist. I like this one which is about supramolecular chemistry, the study of molecules--especially macromolecules--interacting with one another.

Lightning Knight fucked around with this message at 17:18 on Dec 10, 2018

# ? Nov 29, 2018 15:28

Adbot: ADBOT LOVES YOU

# ? Apr 28, 2024 17:27

Lightning Knight: Feb 24, 2012; Pray for Answer

https://www.youtube.com/watch?v=wdJvFMAbPF8

Bill Nye's take on the Fermi Paradox.

# ? Nov 29, 2018 15:34

VH4Ever: Oct 1, 2005; by sebmojo

Well now that we have our own thread for this, I'm going all in because I actually spent most of my youth devouring stuff on aliens and Area 51 and poo poo so I do have some viewpoints on this. But I think the simple one, adding onto Fermi a bit, is this: the universe is just unendingly, mind bendingly, soul crushingly huge and we're just one tiny, likely unremarkable part of it. If anything, the idea that aliens would come visit us instead of billions of other solar systems is just as self absorbed as thinking our star was the center of the entire universe. Who the gently caress are we? That may be part of it. But old, pre-9/11 X-Files stories of visits and coverups still sort of excite me just like they did back then. I do think it's interesting though, how "pilot saw something" is now a legit story that gets reported in the news, not something that causes the pilot to be laughed out of his job anymore.

# ? Nov 29, 2018 15:40

Zoph: Sep 12, 2005

Great thread idea. One of my favorite resources is Isaac Arthur's Youtube channel/audio podcast, where he makes long-form videos breaking down the science behind insterstellar travel, building superstructures/massive, interstellar projects, and he also spends a ton of time on the Fermi Paradox. Each video can be 45 minutes long, but you get clearly organized videos that walk you through the theories, the scientific principles under-girding them, and even the calculations needed to make it happen.

https://www.youtube.com/watch?v=rDPj5zI66LA

The short version of his outlook is that he's an endless, Utopian optimist about the possibilities of mankind in space, but also makes very convincing arguments to the effect that there is no real answer to the Fermi Paradox other than intelligent life being ridiculously rare.

edit: link fixed! sorry.

Zoph fucked around with this message at 15:53 on Nov 29, 2018

# ? Nov 29, 2018 15:41

BigglesSWE: Dec 2, 2014; How 'bout them hawks news huh!

My (very unscientific) take:

It seems to me that life on Earth pops up wherever life is conceivably possible, no matter the odds.

This would imply that IF life (as we understand it) behaves the same outside of Earth, all we really need to find it is to find habitable environments; if a place can harbor life, it WILL harbor life.

# ? Nov 29, 2018 15:42

Triskelli: Sep 27, 2011; I AM A SKELETON
WITH VERY HIGH
STANDARDS

Continuing the arguments about the Great Filter from USPOL (for the uninitiated, Filters are basically hurdles that life has to cross getting from chemicals to star-hopping), I�m going to make a totally unresearched claim that the Filter to Civilization is being able to throw poo poo overhanded. Birds are capable of speech, there�s evidence that elephants have culture, but beaning a sabertooth in the noggin requires a good overhand chuck. And humans happily found that �chucking poo poo� is a field with boundless potential for innovation that something like termite fishing or oyster cracking just doesn�t match.

# ? Nov 29, 2018 15:42

Lightning Knight: Feb 24, 2012; Pray for Answer

Zophar posted:

Great thread idea. One of my favorite resources is Isaac Arthur's Youtube channel/audio podcast, where he makes long-form videos breaking down the science behind insterstellar travel, building superstructures/massive, interstellar projects, and he also spends a ton of time on the Fermi Paradox. Each video can be 45 minutes long, but you get clearly organized videos that walk you through the theories, the scientific principles under-girding them, and even the calculations needed to make it happen.

https://www.youtube.com/watch?v=channel?UCZFipeZtQM5CKUjx6grh54g

The short version of his outlook is that he's an endless, Utopian optimist about the possibilities of mankind in space, but also makes very convincing arguments to the effect that there is no real answer to the Fermi Paradox other than intelligent life being ridiculously rare.

Your link gives me an error, just FYI.

# ? Nov 29, 2018 15:49

Demon Of The Fall: May 1, 2004; Nap Ghost

space aliens ate my balls OP

# ? Nov 29, 2018 15:50

Zoph: Sep 12, 2005

Lightning Knight posted:

Your link gives me an error, just FYI.

Thanks, should work now.

# ? Nov 29, 2018 15:53

Lightning Knight: Feb 24, 2012; Pray for Answer

Zophar posted:

Thanks, should work now.

Yup!

Demon Of The Fall posted:

space aliens ate my balls OP

Did they at least share a smoke with you after the fact?

# ? Nov 29, 2018 15:53

Kerning Chameleon: Apr 8, 2015; by Cyrano4747

Intelligent aliens exist, but like us, are constrained to their own solar systems because you cannot innovate away the laws of physics no matter what Star Trek may have led you to believe. Relativity and radiation are a bitch, yo.

This is also a good thing, because it prevents horrible space empires from ever being a thing.

# ? Nov 29, 2018 15:58

Violator: May 15, 2003

�Aliens don�t exist because we have millions of camera phones and no photographic evidence� doesn�t make sense. Most UFO sightings last seconds and camera phone sensors are about 1/4 the size of your pinky finger nail. I feel like I can�t even get a good photo of my cat unless the conditions are right, getting something in the sky 30 miles away during a fleeting sighting with likely suboptimal lighting is basically impossible.

# ? Nov 29, 2018 15:59

Olpainless: Jun 30, 2003; ... Insert something brilliantly witty here.

I suspect the great filter is probably multicellular life, probably the mitochondria step. It's the only thing in the history of life in this world that took a LONG TIME to happen, as opposed to being basically taking over every niche as fast as possible.

# ? Nov 29, 2018 16:05

Total Party Kill: Aug 25, 2005

There is intelligent life in the universe beyond us, because they built the simulation we are all living as lines of code within.

# ? Nov 29, 2018 16:32

Owlofcreamcheese: May 22, 2005; Can't post for 9 years!; Buglord

Threads like this always devolve into "literally whatever political problem earth has right now, that is the great filter" 100% of the time.

My answer to the fermi paradox is that without a clean alien free universe to compare to we have no way of knowing what minor meaningless anomalies we know about mean anything until some alien tells us and we retroactively know we detected tons of aliens all the time.

Like an uncontacted tribe right now could see plane contrails every day but why jump to the conclusion "flying men are in that thing" when a sane person would just go "oh, guess that is one of the types of clouds that exist" like no one is out there telling them that rainbows are a regular part of nature, contrails aren't, the longer hotter summers are a thing people did somewhere but the earthquake is just a thing that happens sometime. Without context it's never going to be easy to know what is or isn't fully natural and thats stuff you could figure out eventually but there is literally no mystery in astronomy that has existed so long or so deep that we are even 1% of the way to saying "oh, it must be aliens, we studied this so in depth there is no way it couldn't be" even if ultimately something somewhere was.

Like there is less than 1/3rd the amount of lithium in the universe current models say there should be, we should spend like at least a hundred years of trying to figure out how our model is wrong before ANYONE goes "an alien ate it" which is good science, but applies to everything and like, if an alien did eat it we aren't gonna know till we really really really exhaust every other way better possibility.

# ? Nov 29, 2018 16:42

Toaster Beef: Jan 23, 2007; that's not nature's way

The podcast The End of the World with Josh Clark talks a whole bunch about the Fermi Paradox and what the next Great Filter might be. It's a great listen, though I think it gets a little less interesting as it goes on. It's only ten parts, and it's just about done.

# ? Nov 29, 2018 16:44

The_Doctor: Mar 29, 2007; "The entire history of this incarnation is one of temporal orbits, retcons, paradoxes, parallel time lines, reiterations, and divergences. How anyone can make head or tail of all this chaos, I don't know."

Oh hey, what�s going on in here?

# ? Nov 29, 2018 16:49

Owlofcreamcheese: May 22, 2005; Can't post for 9 years!; Buglord

Like here is a short list of some currently unsolved problems in astrophysics. You could write a sci-fi story about any of these being caused by aliens, but anyone suggesting that seriously should rightfully be kicked out of science, no one anywhere is anywhere near that stumped that anyone should be jumping to that conclusion, but that means humans are not actually far enough along to detect aliens at all. Our knowledge is way too simple to be anywhere near the point that we ruled out everything to the point we could look at something weird and go "yup, must be aliens". Maybe in a thousand more years of trying and failing to answer questions with more realistic answers.

We need to know a hell of a lot more about the universe to be anywhere near the point we could see anything but bleep blorp the alien personally to detect something and say "yes, only explanation for this is aliens did it". We detect things we can't currently explain constantly, even knowing if anything meant anything is way beyond where we are. Even if something did.

----------

Astrophysical jet: Why do only certain accretion discs surrounding certain astronomical objects emit relativistic jets along their polar axes? Why are there quasi-periodic oscillations in many accretion discs?[33] Why does the period of these oscillations scale as the inverse of the mass of the central object?[34] Why are there sometimes overtones, and why do these appear at different frequency ratios in different objects?[35]

Diffuse interstellar bands: What is responsible for the numerous interstellar absorption lines detected in astronomical spectra? Are they molecular in origin, and if so which molecules are responsible for them? How do they form?

Supermassive black holes: What is the origin of the M-sigma relation between supermassive black hole mass and galaxy velocity dispersion?[36] How did the most distant quasars grow their supermassive black holes up to 1010 solar masses so early in the history of the universe?

Rotation curve of a typical spiral galaxy: predicted (A) and observed (B). Can the discrepancy between the curves be attributed to dark matter?

Kuiper cliff: Why does the number of objects in the Solar System's Kuiper belt fall off rapidly and unexpectedly beyond a radius of 50 astronomical units?

Flyby anomaly: Why is the observed energy of satellites flying by Earth sometimes different by a minute amount from the value predicted by theory?

Galaxy rotation problem: Is dark matter responsible for differences in observed and theoretical speed of stars revolving around the centre of galaxies, or is it something else?

p-nuclei: What astrophysical process is responsible for the nucleogenesis of these rare isotopes?

Ultra-high-energy cosmic ray:[17] Why is it that some cosmic rays appear to possess energies that are impossibly high, given that there are no sufficiently energetic cosmic ray sources near the Earth? Why is it that (apparently) some cosmic rays emitted by distant sources have energies above the Greisen�Zatsepin�Kuzmin limit?[4][17]

Rotation rate of Saturn: Why does the magnetosphere of Saturn exhibit a (slowly changing) periodicity close to that at which the planet's clouds rotate? What is the true rotation rate of Saturn's deep interior?[37]

Origin of magnetar magnetic field: What is the origin of magnetar magnetic field?

Large-scale anisotropy: Is the universe at very large scales anisotropic, making the cosmological principle an invalid assumption? The number count and intensity dipole anisotropy in radio, NRAO VLA Sky Survey (NVSS) catalogue[38] is inconsistent with the local motion as derived from cosmic microwave background[39][40] and indicate an intrinsic dipole anisotropy. The same NVSS radio data also shows an intrinsic dipole in polarization density and degree of polarization[41] in the same direction as in number count and intensity. There are several other observation revealing large-scale anisotropy. The optical polarization from quasars shows polarization alignment over a very large scale of Gpc.[42][43][44] The cosmic-microwave-background data shows several features of anisotropy,[45][46][47][48] which are not consistent with the Big Bang model.

Space roar: Why is space roar six times louder than expected? What is the source of space roar?

Age�metallicity relation in the Galactic disk: Is there a universal age�metallicity relation (AMR) in the Galactic disk (both "thin" and "thick" parts of the disk)? Although in the local (primarily thin) disk of the Milky Way there is no evidence of a strong AMR,[49] a sample of 229 nearby "thick" disk stars has been used to investigate the existence of an age�metallicity relation in the Galactic thick disk, and indicate that there is an age�metallicity relation present in the thick disk.[50][51] Stellar ages from asteroseismology confirm the lack of any strong age-metallicity relation in the Galactic disc.[52]

The lithium problem: Why is there a discrepancy between the amount of lithium-7 predicted to be produced in Big Bang nucleosynthesis and the amount observed in very old stars?[53]

Ultraluminous pulsar: The ultraluminous X-ray source M82 X-2 was thought to be a black hole, but in October 2014 data from NASA's space-based X-ray telescope NuStar indicated that M82 X-2 is a pulsar many times brighter than the Eddington limit.

Fast radio bursts: Transient radio pulses lasting only a few milliseconds, from emission regions thought to be no larger than a few hundred kilometres, and estimated to occur several hundred times a day. While several theories have been proposed, there is no generally accepted explanation for them. The only known repeating FRB emanates from a galaxy roughly 3 billion light years from Earth.[54][55]

# ? Nov 29, 2018 16:59

axeil: Feb 14, 2006

This thread is great and the Fermi Paradox is a legit fascinating thing. I read a great book on it last year:

If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

The book covers a whole bunch of potential solutions to the Fermi Paradox from the super trivial (God is real and it only made humans) to the more complex (we live in the equivalent of the boonies of the galaxy) to the meta-physical (reality is simulated).

Personally I think it's either that the universe is simulated, that space is really, really big and we just aren't close enough, or that we currently lack the method of communicating with other species and they don't care enough to use our methods to talk to us.

The Great Filter is a rather scary prospect though and every time we find indications of life on other planets my heart sinks. At this point the only Great Filter candidate in the past is probably the development of eukaryotic life or the development of general, human-level intelligence. Everything else seems fairly common. And if the Great Filter hypothesis is correct, it's more likely it's in our future than our past which...isn't very reassuring.

Anyway, go read that book I linked if you wanna learn about the Fermi Paradox.

Also when I get some more time I'll write an effort posts about Our Mathematical Universe which had a very, very good explanation of known science about the Universe's formation and a pretty good hypothesis on how things fundamentally work that's a bit mind-blowing.

edit: for those unfamiliar the Great Filter postulates that there is a "filtering" event that prevents most life from colonizing nearby places. Basically there's a process for making a space-faring civilization which is roughly:

1. Have the right star system (including organics and potentially habitable planets)
2. Star system must create reproductive molecules (e.g., RNA)
3. Simple (prokaryotic) single-cell life must be created
4. Simple life must evolve into complex (eukaryotic) single-cell life
5. Complex life must evolve to use sexual reproduction
6. Multi-cell life must evolve from sexually reproducing single-cell eukaryotic life
7. Tool-using animals with big brains must come into existence
8. Tool-using animals must make it to where humans are now
9. Colonization explosion happens

If the Great Filter exists in steps 1-7 it means it's very likely that humans are alone. However if it's in steps 8 or 9 that's very, very bad for continued human existence. At this point the only early steps that look unlikely are 4 and maybe 7.

edit 2: And for those not familiar with the Fermi Paradox, here it is laid out in the Drake Equation.

The Drake equation is:

N = R ∗ fp * ne * fl * fi * fc * L

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);

and

R∗ = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
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 point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

If you do out the math based on what we know, N should be a very, very high number and yet right now our observed N is 1 (us). So if that's the case one of the numbers here must be spectacularly low and it's unlikely its R, fp, or ne just based on what we've discovered in the last 20+ years. Which means you need at least one very low number for the equation to work out and some of them being low (e.g. fc) implies that humans are extremely likely to destroy themselves.

The "good" news is that L is most likely the value that's really, really low as we already have seen our civilization move away from releasing detectable signals into space as things like terrestrial radio/TV are being deprecated.

axeil fucked around with this message at 17:31 on Nov 29, 2018

# ? Nov 29, 2018 17:10

Haystack: Jan 23, 2005

Every single alien civilization has lived and died in its own home system. Even if FTL travel were possible (which it almost certainly is not), the resource costs of operating in space are too high. Gravity wells are a bitch, to say nothing of the radiation.

Haystack fucked around with this message at 17:22 on Nov 29, 2018

# ? Nov 29, 2018 17:19

axeil: Feb 14, 2006

Haystack posted:

Every single alien civilization has lived and died in its own home system. Even if FTL travel were possible (which it almost certainly is not), the resource costs of operating in space are too high. Gravity wells are a bitch, to say nothing of the radiation.

What about von Neumann probes?

https://en.wikipedia.org/wiki/Self-replicating_spacecraft#Von_Neumann_probes

Why don't we see them? You'd only need 1 civilization around our tech level in the galaxy to decide to make them for us to likely see evidence of their existence.

# ? Nov 29, 2018 17:29

feedmyleg: Dec 25, 2004

As just some idiot on the internet, I've found the idea quite compelling that as the universe expands, the distance between galaxies increases at such a speed that it makes even near-light speed travel between systems prohibitively difficult. I believe I picked up this idea from a Kurzgesagt video on YouTube, but is there anything more to this?

# ? Nov 29, 2018 17:31

axeil: Feb 14, 2006

feedmyleg posted:

As just some idiot on the internet, I've found the idea quite compelling that as the universe expands, the distance between galaxies increases at such a speed that it makes even near-light speed travel between systems prohibitively difficult. I believe I picked up this idea from a Kurzgesagt video on YouTube, but is there anything more to this?

There is more "space" in between everything in the universe in general as time goes on but on a local scale you have our galaxy generally occupying the same space and things are still moving toward us (e.g. the Andromeda galaxy) even as the universe on average moves away from us.

The constant expansion of the universe is a good reason why everything will end up very cold and lonely in a trillion years, but I don't think it's a good explanation for why we're so lonely now.

# ? Nov 29, 2018 17:33

A Wheezy Steampunk: Jul 16, 2006; High School Grads Eligible!

This is an older article but I share it whenever this topic comes up because it's a good summary of the various outcomes of the Great Filter:

https://waitbutwhy.com/2014/05/fermi-paradox.html

I'm personally a fan of the "we're first" outcome. There's another article (I don't remember enough details to find it and I might be getting some of these details wrong) where someone graphed the "complexity" of life on Earth and worked backwards to find that the origin "should" be before the universe formed, another point in favor of "we're first".

# ? Nov 29, 2018 17:34

axeil: Feb 14, 2006

A Wheezy Steampunk posted:

This is an older article but I share it whenever this topic comes up because it's a good summary of the various outcomes of the Great Filter:

https://waitbutwhy.com/2014/05/fermi-paradox.html

I'm personally a fan of the "we're first" outcome. There's another article (I don't remember enough details to find it and I might be getting some of these details wrong) where someone graphed the "complexity" of life on Earth and worked backwards to find that the origin "should" be before the universe formed, another point in favor of "we're first".

Yeah that Wait But Why article is good and it's before the author completely lost his marbles talking about cryo-freezing his head and how Elon Musk is our savior.

I'd be interested in reading that 2nd bit you talk about as it sounds interesting and lines up with the theory that you need a star of at least the 3rd generation to generate life because you need heavier elements.

# ? Nov 29, 2018 17:36

Owlofcreamcheese: May 22, 2005; Can't post for 9 years!; Buglord

Haystack posted:

Every single alien civilization has lived and died in its own home system. Even if FTL travel were possible (which it almost certainly is not), the resource costs of operating in space are too high. Gravity wells are a bitch, to say nothing of the radiation.

Say the opposite, say that aliens are flying around everywhere in ships the size of buildings nonstop every day.

Unless one was like, right here right now, why would we detect that? How would we detect that? If someone DID detect it why would "aliens" be a reasonable explanation instead of literally any other explanation.

Like if there was a billion spaceships flying between random stars right this second what exactly are we supposed to have detected? radio waves? anonymous mass distribution? high energy particles? unexpected element distributions? we detect that sort of stuff all day every day and simply do not have any sort of information to determine why. We aren't gonna get a picture of an alien holding a sign or something.

# ? Nov 29, 2018 17:36

A Wheezy Steampunk: Jul 16, 2006; High School Grads Eligible!

axeil posted:

I'd be interested in reading that 2nd bit you talk about as it sounds interesting and lines up with the theory that you need a star of at least the 3rd generation to generate life because you need heavier elements.

Found it after more searching! Here's the summary: https://www.technologyreview.com/s/513781/moores-law-and-the-origin-of-life/ and the original: https://arxiv.org/abs/1304.3381. I did have some of the details wrong, it wasn't before the universe formed, it was before the Earth formed:

quote:

Sharov and Gordon say that the evidence by this measure is clear. �Linear regression of genetic complexity (on a log scale) extrapolated back to just one base pair suggests the time of the origin of life = 9.7 � 2.5 billion years ago,� they say.

And since the Earth is only 4.5 billion years old, that raises a whole series of other questions. Not least of these is how and where did life begin.

[I]f life takes 10 billion years to evolve to the level of complexity associated with humans, then we may be among the first, if not the first, intelligent civilisation in our galaxy. And this is the reason why when we gaze into space, we do not yet see signs of other intelligent species.

# ? Nov 29, 2018 17:45

zoux: Apr 28, 2006

feedmyleg posted:

As just some idiot on the internet, I've found the idea quite compelling that as the universe expands, the distance between galaxies increases at such a speed that it makes even near-light speed travel between systems prohibitively difficult. I believe I picked up this idea from a Kurzgesagt video on YouTube, but is there anything more to this?

They also have a very popular video on the Fermi paradox, which looking at that waitbutwhy article, may be heavily based on it.

https://www.youtube.com/watch?v=sNhhvQGsMEc

Cool idea for a thread op.

# ? Nov 29, 2018 17:47

MSDOS KAPITAL: Jun 25, 2018

Here's what I wrote about this in the other thread:

We're at the point in our technological development where we can reason about harnessing the energy of entire stars and colonizing an entire galaxy. The sort of stuff that is really easy to notice if anyone's done it, or has ever done it. Moreover we don't need a lot more technological advancement to get there: the biggest hurdle in fact is probably modifying our own bodies both to survive the trips between stars and to live long enough to make making the trip worthwhile for a single individual (and the second part is optional, strictly speaking, though we'd probably want to do it and almost certainly could do it provided we've already solved the first bit). Our actual space travel technology is pretty rudimentary but suitable for purpose, or nearly so, if we had more rugged bodies.

Point being that even if we do destroy ourselves, we can conceive of another species similar to ourselves but a little less self-destructive and tribal, and consequently a little bit better at global civilization, which doesn't destroy itself. Instead, they build themselves better bodies and use space travel technology not much better than our own, to travel to other stars and within a few million years or so colonize an entire galaxy. And they build up their industry to the point that they can feasibly build Dyson spheres or Dyson swarms or what-have-you over the course of a few hundred thousand years or something, which is peanuts to an immortal species of intelligent life which has adapted itself to living in space.

If we were to look at such a galaxy with a telescope, it would be immediately apparent to us that that galaxy was populated with intelligent life. We have found no such galaxy, in spite of a lot of looking. My guess is that if there is intelligent life like us in the universe it must occur only once in every several hundred thousand galaxies or so. Or maybe it's never occurred and we're the first.

It doesn't mean that there will never be other intelligent life. There are a lot of red dwarf stars in the universe, and the planets orbiting them in their habitable zones have hundreds of billions or even in some cases a few trillion years to develop intelligent life. There may come an age of the universe where it is teeming with intelligent life all growing up and discovering one another, but it seems like that age is far off. Like "several multiples of the current age of the universe" far off.

1glitch0 posted:

I think you might be looking at this from a very human-perspective. It's a very child-like analogy, but sixty years ago a computer took up an entire room and couldn't do a lot, now we all have one in our pockets that is infinitely more powerful. While we're looking for Dyson spheres or whatever, an advanced civilization might have the equivalent of an iPhone that can orbit a sun and give them all the energy they need. Or maybe colonization of entire galaxies with a large population isn't even the best path for an intelligent species to take. We only look for, and can only really look for, what we would consider advanced or can imagine. Maybe another species' environment or biology or technological path led them somewhere that we can't even comprehend. Dark matter is a complete mystery. And there's probably other many other mysteries we haven't even discovered that could go a long way to explain where everyone else is.

And if you want to go a route more similar to us there's now two "super structures" around distant stars that we can't properly explain.

As much as we like to pretend we have a grasp on what's happening in the universe we still live on a planet where last week a guy took a boat to an island to tell people about his belief in a supernatural entity and got shot to death by arrows by the locals because they don't like outsiders.

Could be. My post is my thinking on it currently but it's not like I'm super certain of it. Another thing I'll point out though, since you mention the human perspective on things: the universe is very, very young. It has been around for 13 billion years yet trillions of years lie ahead during which conditions will remain roughly as favorable to the formation of intelligent life as they are now. The present age of our star is about 40% of the age of the universe itself. Meanwhile, as I already mentioned, there are planets orbiting red dwarfs right now which have many, many multiples of the current age of the universe on which to develop life at an entirely leisurely pace, compared to our own history. In light of that I would say that even if we are not the only life in the universe, we are certainly among the first, and furthermore we probably have a home star system that will eventually be considered atypical as a host of intelligent life.

Honestly I think part of the insistence that there must be other intelligent life out there is borne of a desire not to be human-centric just for the sake of not being human-centric. But unless we have a really, really flawed understanding of physics, we really are at essentially the very beginning of the history of life in the universe. Even if intelligent life formed immediately after the Big Bang, in the grand scheme of things humans arose not too long after that. The other consequence of this desire to not be human-centric is the idea that, well intelligent life exists it's just so advanced that it's really all around us and we can't possibly comprehend it. But it seems unlikely that all intelligent life would evolve technologically in such a way that they would be utterly imperceptible to us. That's a sort of hubris on it's own kinda, IMO :colbert:

I guess the point I'm driving at is this: I can step outside my front door, and see all around me incontrovertible evidence of the existence of life on Earth. If I stepped outside my front door and saw nothing but land devoid of any evidence of life no matter where I looked, I might start to guess that I was alone. Why would the universe be any different in this regard?

e: also lmao get a load of this dickhead:

i am harry posted:

MSDOS KAPITAL posted:
Oh I suspect there is probably a lot of simple life, actually. But probably nothing much more complex than prokaryotic life almost anywhere, or literally everywhere else in the universe, that is habitable to it. I.e. think the Great Filter is behind us. I am an optimist.

You mean you're a narcissist.

# ? Nov 29, 2018 17:50

Fister Roboto: Feb 21, 2008

My personal bullshit theory is that there has to be something else besides us humans out there, because the universe might as well not exist if there's nothing capable of observing it.

# ? Nov 29, 2018 18:00

Kerning Chameleon: Apr 8, 2015; by Cyrano4747

MSDOS KAPITAL posted:

Here's what I wrote about this in the other thread:

We're at the point in our technological development where we can reason about harnessing the energy of entire stars and colonizing an entire galaxy. The sort of stuff that is really easy to notice if anyone's done it, or has ever done it. Moreover we don't need a lot more technological advancement to get there: the biggest hurdle in fact is probably modifying our own bodies both to survive the trips between stars and to live long enough to make making the trip worthwhile for a single individual (and the second part is optional, strictly speaking, though we'd probably want to do it and almost certainly could do it provided we've already solved the first bit). Our actual space travel technology is pretty rudimentary but suitable for purpose, or nearly so, if we had more rugged bodies.

Point being that even if we do destroy ourselves, we can conceive of another species similar to ourselves but a little less self-destructive and tribal, and consequently a little bit better at global civilization, which doesn't destroy itself. Instead, they build themselves better bodies and use space travel technology not much better than our own, to travel to other stars and within a few million years or so colonize an entire galaxy. And they build up their industry to the point that they can feasibly build Dyson spheres or Dyson swarms or what-have-you over the course of a few hundred thousand years or something, which is peanuts to an immortal species of intelligent life which has adapted itself to living in space.

If we were to look at such a galaxy with a telescope, it would be immediately apparent to us that that galaxy was populated with intelligent life. We have found no such galaxy, in spite of a lot of looking. My guess is that if there is intelligent life like us in the universe it must occur only once in every several hundred thousand galaxies or so. Or maybe it's never occurred and we're the first.

It doesn't mean that there will never be other intelligent life. There are a lot of red dwarf stars in the universe, and the planets orbiting them in their habitable zones have hundreds of billions or even in some cases a few trillion years to develop intelligent life. There may come an age of the universe where it is teeming with intelligent life all growing up and discovering one another, but it seems like that age is far off. Like "several multiples of the current age of the universe" far off.

Could be. My post is my thinking on it currently but it's not like I'm super certain of it. Another thing I'll point out though, since you mention the human perspective on things: the universe is very, very young. It has been around for 13 billion years yet trillions of years lie ahead during which conditions will remain roughly as favorable to the formation of intelligent life as they are now. The present age of our star is about 40% of the age of the universe itself. Meanwhile, as I already mentioned, there are planets orbiting red dwarfs right now which have many, many multiples of the current age of the universe on which to develop life at an entirely leisurely pace, compared to our own history. In light of that I would say that even if we are not the only life in the universe, we are certainly among the first, and furthermore we probably have a home star system that will eventually be considered atypical as a host of intelligent life.

Honestly I think part of the insistence that there must be other intelligent life out there is borne of a desire not to be human-centric just for the sake of not being human-centric. But unless we have a really, really flawed understanding of physics, we really are at essentially the very beginning of the history of life in the universe. Even if intelligent life formed immediately after the Big Bang, in the grand scheme of things humans arose not too long after that. The other consequence of this desire to not be human-centric is the idea that, well intelligent life exists it's just so advanced that it's really all around us and we can't possibly comprehend it. But it seems unlikely that all intelligent life would evolve technologically in such a way that they would be utterly imperceptible to us. That's a sort of hubris on it's own kinda, IMO

I guess the point I'm driving at is this: I can step outside my front door, and see all around me incontrovertible evidence of the existence of life on Earth. If I stepped outside my front door and saw nothing but land devoid of any evidence of life no matter where I looked, I might start to guess that I was alone. Why would the universe be any different in this regard?

e: also lmao get a load of this dickhead:

You mean you're a narcissist.

I love how your post can literally be boiled down to "Okay, BUT WHAT IF everything physicists have observed about our universe so far is 100% wrong and my favorite pulp fiction comic is right? What then, smartie pants?!?"

Some people really don't like the idea that intelligent life in general, and humanity in particular, have far, far shorter shelf lives than they want to believe.

We are not special, we will never be special, and we will all die out without having amounted to even the equivalent of a gnat's fart in terms of impact as far as the universe is concerned. Get over it, and yourself.

Outer space is where everything goes to die, including and especially your hopes and dreams.

Kerning Chameleon fucked around with this message at 18:13 on Nov 29, 2018

# ? Nov 29, 2018 18:08

VH4Ever: Oct 1, 2005; by sebmojo

Kerning Chameleon posted:

I love how your post can literally be boiled down to "Okay, BUT WHAT IF everything physicists have observed about our universe so far is 100% wrong and my favorite pulp fiction comic is right? What then, smartie pants?!?"

Some people really don't like the idea that intelligent life in general, and humanity in particular, have far, far shorter shelf lives than they want to believe.

We are not special, we will never be special, and we will all die out without having amounted to even the equivalent of a gnat's fart in terms of impact as far as the universe is concerned. Get over it, and yourself.

Outer space is where everything goes to die, including and especially your hopes and dreams.

This is a more doomsaying way than I would have put it but you have a point here: in the cosmic timeline of planets and stars forming and etc, our overall lifespan is a mere blip on the heart monitor. We'll have been around a few thousand years if we're lucky in a universe where millions of years can pass without anything notable happening nearby. The sheer odds of our short existence overlapping with some other spacefaring species' are long indeed.

# ? Nov 29, 2018 18:22

sean10mm: Jun 29, 2005; It's a Mad, Mad, Mad, MAD-2R World

When you look at distant galaxies you're not seeing them as they are now, but as they were millions or even billions of years ago. It's impossible to know what the rest of the universe is like "now."

# ? Nov 29, 2018 18:29

Adar: Jul 27, 2001

Here's a horror movie type take on it:

-Let's assume that life is extremely common and intelligent life is only slightly less common.
-Let's further assume that the technological curve of any given civilization is similar to our own, i.e. an Industrial Revolution type event can make a military from the year 2000 completely obliterate every military combined on an 1800-era planet.
-Let's also assume technology doesn't ever entirely stall out / there will always be some advancements to be made.
-This means no two civilizations will ever be at the same stage of development and the more advanced civilization is extremely likely to technologically and militarily dominate the weaker one. Insert colonialism comparison here.
-This also means the weaker civilization can never catch up without immense effort.
-Based on the law of large numbers, any given civilization is vanishingly unlikely to be the most senior. Unless you're leading the Galactic Council and have personally checked, you can never be sure.
-It is also vanishingly unlikely that all civilizations have the same benevolent mindset. Wholly benevolent civilizations could happen, but they themselves would never be sure there isn't a Big Bad out there. A Big Bad would also never know whether it was the biggest. Game theory suggests a preemptive arms race of some type is a certainty by at least some civilizations; even if they don't run into the Biggest Bad they could always come across an only slightly inferior and hyper militarized force.
-If you don't have galactic FTL scanners and cannot check everything, how do you deal with this? What happens when you can build Dyson sphere type monuments but they're a galactic broadcast to anyone who uses the visual spectrum? Aren't you eventually marking yourself for death?

If you're a sufficiently unified and late stage civ, I think the answer is that you pick a planet, build a big shell around it, put giant thrusters on it and sail off away from the galaxy into the deepest, darkest corner of space possible, trusting the unlikelihood of anyone checking that exact region for the next few trillion years. The only way to compete in a game like that is to remove yourself from the board and make sure no one ever finds you.

# ? Nov 29, 2018 18:30

A Wheezy Steampunk: Jul 16, 2006; High School Grads Eligible!

VH4Ever posted:

The sheer odds of our short existence overlapping with some other spacefaring species' are long indeed.

This is why I think the "we're [among the] first" is the most likely explanation to the Fermi paradox. Prokaryotes were on their own for two billion years before eukaryotes came about, then another two billion to get to us. The universe is only around 14 billion years old and the early universe didn't contain any heavy elements as axiel pointed out. I don't think enough time has passed for intelligent life to bridge the vast distances of the universe, if that's even possible under the current physical laws governing the universe.

# ? Nov 29, 2018 18:34

zoux: Apr 28, 2006

Adar posted:

Here's a horror movie type take on it:

-Let's assume that life is extremely common and intelligent life is only slightly less common.
-Let's further assume that the technological curve of any given civilization is similar to our own, i.e. an Industrial Revolution type event can make a military from the year 2000 completely obliterate every military combined on an 1800-era planet.
-Let's also assume technology doesn't ever entirely stall out / there will always be some advancements to be made.
-This means no two civilizations will ever be at the same stage of development and the more advanced civilization is extremely likely to technologically and militarily dominate the weaker one. Insert colonialism comparison here.
-This also means the weaker civilization can never catch up without immense effort.
-Based on the law of large numbers, any given civilization is vanishingly unlikely to be the most senior. Unless you're leading the Galactic Council and have personally checked, you can never be sure.
-It is also vanishingly unlikely that all civilizations have the same benevolent mindset. Wholly benevolent civilizations could happen, but they themselves would never be sure there isn't a Big Bad out there. A Big Bad would also never know whether it was the biggest. Game theory suggests a preemptive arms race of some type is a certainty by at least some civilizations; even if they don't run into the Biggest Bad they could always come across an only slightly inferior and hyper militarized force.
-If you don't have galactic FTL scanners and cannot check everything, how do you deal with this? What happens when you can build Dyson sphere type monuments but they're a galactic broadcast to anyone who uses the visual spectrum? Aren't you eventually marking yourself for death?

If you're a sufficiently unified and late stage civ, I think the answer is that you pick a planet, build a big shell around it, put giant thrusters on it and sail off away from the galaxy into the deepest, darkest corner of space possible, trusting the unlikelihood of anyone checking that exact region for the next few trillion years. The only way to compete in a game like that is to remove yourself from the board and make sure no one ever finds you.

Isn't this similar to the Three Body Problem take? I've only read a summary. There's a lot of sci fi that uses malicious conquering races or all devouring Von Neumann machines as the solution for the Fermi paradox.

# ? Nov 29, 2018 18:38

Owlofcreamcheese: May 22, 2005; Can't post for 9 years!; Buglord

MSDOS KAPITAL posted:

If we were to look at such a galaxy with a telescope, it would be immediately apparent to us that that galaxy was populated with intelligent life.

How? Name a single measurement we could make that any sane scientist in 2018 would look at and say "gotta be aliens". We already have galaxies that are wrong or against our predictions in every way imaginable, but that is because we are still very new to astrophysics and have a very very basic understanding of what the numbers even SHOULD be. Declaring anything aliens at this point would be madness. We literally do not have the tools to see an alien at this point or to know if anything we could see could even be a sign of an alien.

Like we need like 500 more years of astrophysics to have any numbers solid enough to know something is wrong.

The answer to the fermi paradox is "welp, we've looked no where and found nothing, time to give up" before even knowing enough to even know if we found something.

# ? Nov 29, 2018 18:44

Ytlaya: Nov 13, 2005

My guess is that it's more likely that any sort of "filter" is just related to interstellar space travel being impossible (or impractical to the point of uselessness) for complex life, rather than something related to the development of life itself, or aspects of civilizations.

I can pretty confidently say that simple life is virtually guaranteed to be extremely common, to the point where I wouldn't be surprised if it even exists elsewhere in our solar system. Complex life is trickier, because it took a very long time to develop on our own planet, and when you're talking about time periods on the order of "billions of years" the universe is actually pretty young. There's also the fact that, IIRC, a lot of the heavier elements necessary for life as we know it to exist didn't exist for the first couple generations of stars, limiting the time frame further.

edit: I think it's still likely that other intelligent organisms confined to their own solar systems exist, though.

Ytlaya fucked around with this message at 18:52 on Nov 29, 2018

# ? Nov 29, 2018 18:48

Adar: Jul 27, 2001

zoux posted:

Isn't this similar to the Three Body Problem take? I've only read a summary. There's a lot of sci fi that uses malicious conquering races or all devouring Von Neumann machines as the solution for the Fermi paradox.

A little but not quite. Sci fi tends to focus on one race being conquered by another or an automated threat like von Neumanns. But even in those cases the conquerer or probe is not going to be the Biggest Bad, because across the entire universe the probability of that is effectively 0. In fact no sane race would ever deploy a von Neumann voluntarily because a Bigger Bad, which the probes will eventually always encounter, will trace them back to their source. The law of large numbers is a real bitch when you think in those terms.

For the same reason, the simplest and possibly single most probable take on why we've seen nothing unusual is that everyone is hiding from everyone else.

# ? Nov 29, 2018 18:49

Adbot: ADBOT LOVES YOU

# ? Apr 28, 2024 17:27

DrSunshine: Mar 23, 2009; Did I just say that out loud~~?!!!

axeil posted:

This thread is great and the Fermi Paradox is a legit fascinating thing. I read a great book on it last year:

If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

It is swell, and I read this book too! It's a fascinating read and less full of woo than other books on the same subject.

[quote]
The Drake equation is:

N = R ∗ fp * ne * fl * fi * fc * L

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);

and

R∗ = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
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 point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

If you do out the math based on what we know, N should be a very, very high number and yet right now our observed N is 1 (us). So if that's the case one of the numbers here must be spectacularly low and it's unlikely its R, fp, or ne just based on what we've discovered in the last 20+ years. Which means you need at least one very low number for the equation to work out and some of them being low (e.g. fc) implies that humans are extremely likely to destroy themselves.

The "good" news is that L is most likely the value that's really, really low as we already have seen our civilization move away from releasing detectable signals into space as things like terrestrial radio/TV are being deprecated.

One thing which I've never really seen discussed is running the Drake Equation backward, an idea that came to me a couple years ago. Of the constants we see in it, there are a bunch for which we we now have fairly decently known values - R, fp, ne. Setting N=1, we could back out a value for the product of the remaining constants that should give us a ballpark estimate of what the terms must at least work out to be.

https://arxiv.org/ftp/arxiv/papers/1705/1705.07816.pdf

This paper gives values for R≈7/yr, fp=1, ne =0.2. The other terms are the "unknowns" that are kind of sociological in nature, we can call them "λ". Setting N = 1 gives us: 1/(R*fp*ne) = λ ≈ 0.714

So (fl*fi*fc*L) must work out to be greater than or equal to 0.714, because below that we can't account for our own existence.

# ? Nov 29, 2018 18:54

The Something Awful Forums > Discussion > Debate & Discussion > Space, the Final Frontier: It Gazed Into My Open Refractor

«‹›215 »