So, is it safe to say that extraterrestrial sentient life is almost non-existent...

Actually, the bulk of rocky planets form around red dwarfs, which live a whole lot longer than yellow dwarves (like our sun), and are more prone to forming rocky planets... and there's a lot more red dwarves than yellow dwarves, being among the most common types of stars.

No, given how little we can see, and how little we know, and where we are in the galaxy. Life could be pretty damned common, and we wouldn't know it.

Assuming biological immortality (or near to), comes before interstellar space travel (and that seems to be the direction we're going here - and it may even be a requirement for said) every interstellar civilization is going to have a population cap from the get go. They thus won't be using huge amounts of resources, leaving industrial footprints you could see from light years away, building super structures for nigh infinite energy, or even expanding beyond a few systems... As once you've done that, colonizing more doesn't improve your species's odds of survival anymore - lest you can cross into another galaxy, which is probably not possible.

We could be surrounded by such civilizations, and even if there was on the closest star to us, we wouldn't know it.

All we do know is that no interstellar species was bent on infinite expansion within the past hundred million years or so... As if there were, we'd probably be a colony.

The first ten minutes of the extended cut are.

...after that it becomes a race to see which idiot dies first, like any b-slasher.

Unless there were multiple ancestors, and our ancestor prokaryotes out competed the competition.

Red dwarfs are not stable like our sun. They churn and bubble and flare constantly. This process keeps helium from building up in their cores, but it makes them deadly as well. It is not likely they would allow planets around their habitable zones to form atmospheres or remain unmolested by intense radiation. Most light from red dwarfs is infra red, too. All plants use viable and ultra violet light. We want to see complex life that gives rise to intelligent critters. A red dwarf may not output the right amount of energy to get that going.

1) it took 5 billion years for us to evolve
2) the universe is 13 billion years old
3) the younger the universe, the more chaotic and energetic the environment
4) evolution needs a stable environment

How about this: we may be the first.

Assuming FTL travel is impossible, I am fairly certain that as long as we don't go looking for it, we will be far more advanced than alien life that comes looking for us.

Possible. But there's no evidence, not even contingent evidence, for that position. That abiogenesis is the Big Filter That Matters™ is the most Occamish solution to the Fermi paradox.

It's a comedy. None of the characters act like normal people with common sense. They refuse to carry guns on an expedition to see new life (something even Charles Darwin did to protect himself from potentially dangerous animals).

So you're saying that life formed in just one exact location on earth. Nowhere else?

the unlikelihood of ever interacting with an intelligent extraterrestrial species greatly dwarfs the unlikelihood of them even existing.

meaning that regardless of whether they exist or not isn't really relevant because we would never find them anyway. even if they existed then for all intents and purposes they wouldn't exist as far as we're concerned because we would never know.

but for the sake of argument, in the vastness of the universe with all manner of matter roaming around it seems likely that somewhere, at some point the right combo of chemicals and elements came together in the right environment somewhere to produce self-replicating entities that we would probably consider "life"

Meh, get lucky enough to have a molten core and a magnetic field and you're good for most of that. They certainly provide enough UV, with the habitable zone being closer and brighter. More to the point, they each provide a lot more opportunities for a whole lot longer, and there's a whole lot more of them.

I suspect that if another species has a suicidally curious SETI program such as our own, they'd never bother pointing it at yellow dwarves. Granted, they probably wouldn't bother pointing it in our direction in general, as we're way out here on the rim where stars are relatively few and far between - all the real action's at the center.

Kinda neglecting how many solar systems there are existing at the same time, especially since it seems stars with planets are the rule rather than the exception.

We might be among the first in the grand scheme of the lifetime of the universe - but it's likely that includes a whole lotta company.

Yeah, why not? Everyone agrees the origin of life was an astronomically improbable event - far more improbable than most people realize (see ). So it makes sense that this massive fluke happened only once, in one corner of one sea on one planet among hundreds of billions in the galaxy. It had to happen at least once, somewhere, otherwise you wouldn't be on this South Sudanese second hand monocle collectors' board. The principle of mediocrity doesn't apply, obviously, as we do seem to be unique: the Fermi Paradox is a thing.
(unless you want to go
>simulation argument
but that's a meme argument bordering on unscientific; we've gotta work with the information we've got.)

>The center

You're kidding, right? That's not where you want to be if you want stable conditions. The core is a dangerous place. You are more likely to find life around stars that stay away from the core. Not just ones that are currently out of it, but ones that don't have an elliptical orbit and stay away from it all together.

It's not perfect, but it's decent.

At the very least enjoy the cinemetography which was pretty well done.

Not him... But it could be that life is indeed rare. Complex life capable of technology as we understand it, that might be even rarer.

However, the components we're made up of are all among the most common in the universe (and hell, we even find RNA in meteors once in awhile). There's nothing particularly unusual about this solar system, and in many ways, it seems it's not even the most optimal for supporting life, and the types that are seem to be much more common.

The most popular abiogenic theories suggest that were probably several million LUCA all in one place, bits of churning RNA trapped in natural mud shells, that competed and merged with one another until finally one began making its own cells and outbred all the rest. You can create recombinating proteinoid microspheres in a lab, and you sometimes find them in nature, near underwater volcanoes, so it maybe that abiogenesis is an ongoing process. At the same time, however, fish feed on that stuff, so it's unlikely to ever get the chance to come to fruition again.

If you were break up the number of steps needed to reach intelligent life into 50 steps, with each step having a generous chance of 50%, then the odds of life forming around any random star would be 0.5^50. That's a couple galaxies worth of stars. Life may only show up once per galaxy in this case. If the odds of each step being passed is 33%, life only happens once in a universe.

I think a big problem in this debate is how we're defining life.

is there anything else in the universe where entities are comprised of carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur and also self replicate just like life on earth does? maybe not

is there some collection of matter out there that could be considered "life" by some definition regarding it's complexity and ability to compute in the most basic sense of the term? maybe

personally I don't think the unlikelihood of our existence precludes similar forms of life from developing elsewhere in the unfathomable vastness of the universe but at the same time there's not remotely enough information to suggest that it's also likely that they exist as well. It's one of those unknowns that almost becomes philosophical because of how abstract some of the arguments become, both in favor and against

Aww hell naw, most of the stars you see in that center clump are every bit as stable as our own. They look close together from here, but are still light years apart, even if they, on average, have less space between them.

I mean, yeah, you don't want to be at the dead center, as there is that little hazard of Sagittarius A, but otherwise, most all the stars we can see there, from here, are as safe as our own.

>RNA in meteors
Really? seems unlikely, unless they are meteorites kicked up from earth by larger impacts. Sauce? (I googled, only found 'building blocks' of DNA/RNA which is not even close to being the same thing)
>recombinating proteinoid microspheres
Not a biochemist, but sounds juicy. Care to explain?

That's assuming there's only one way to skin a cat. There's so many viable abiogensis theories about, life may happen in a number of different ways, and that's only considering carbon based life much like our own.

Civilization and/or interstellar travel, similarly, there's a myriad of paths and systems to achieve the same effect.

All things being equal, I do rather suspect there is a lot of primitive life out there, structured much like our own, but interstellar civilizations, yeah... I could easily see those being one to a hundred galaxies. Biological advancement maybe inevitable once the ball is rolling - but that's not necessarily the case once information based advancement takes over. Still, who knows, shit could just as easily be everywhere and we could still very easily not be aware of it.

It is understood by evolutionary biologists as "an evolutionary spandrel" or an accident that for whatever reason didn't get weeded out (usually that means peacock feathers that got so large they became a hindrance)

You do realize this is what started the whole exo-biogenesis craze? I was sure everyone had heard about this.

scientificamerican.com/article/were-meteorites-the-origi/

I really don't think so. There is a far greater chance of nearby stars causing gravitational disturbances that will do things like tug on the oort cloud and send extinction size meteors into the inner solar system. It only takes one to wipe out an up and coming species of sentient raccoons. Not to mention the increased risk of being too close to other exploding stars. Our nearest star is only something like 6 light years away and thankfully it is a red dwarf. Imagine how hard we would be sweating if that star was beetlejuice.

There are also a myriad of paths that don't lead to this effect, which is were cumulative probably stacks up and tells you the odds of intelligent (keyword) life evolving may be once-in-a-galaxy events.

Alpha centauri is 4 light years away, and bound with another star, both of which affect us gravitationally. That's still closer than the average distance between stars in the core (which average 8). But that's a whole lot denser than the stars out here (averaging 20).

Granted, you don't want to be within 600 years of a potential super nova... But well, we are (Betelgeuse), so that doesn't make it any safer here.

>compute
>complexity
Computation is only possible on the basis of complexity, and complexity only possible by a process of natural selection. Unless we're talking intelligently designed entities (or Boltzmeme brains), natural selection is the only process we know of capable of producing vastly more complexity in a localized region of the universe. Whether that region is the body of a carbon-based lifeform on a rocky planet, or something that lives in a sun or on the surface of a neutron star, the key to natural selection is reproduction and mutation. So reproduction - a complex process that itself could not have originally arisen by natural selection - is the most fundamental criterion for life. And I would argue that Earth is fairly likely to be the only place where that criterion has been met.

Which I guess makes your estimate more optimistic than mine.

It's all incredibly speculative though.

>Other researchers say the finding appears to be solid, although some are skeptical of its significance. Robert Shapiro, a professor emeritus and senior research scientist in chemistry at New York University, says that because of their low concentration, extraterrestrial nucleobases were unlikely to have played much of a role in kick-starting life. "They're a subunit of a subunit of DNA," he says. "My opinion is that their amounts were utterly unimportant and insignificant." He says he would be more impressed if whole nucleosides—bases plus sugars—were found in meteorites in concentrations similar to those of amino acids.

Nucleotides are simple building blocks, again. It's an interesting finding, but hardly extraterrestrial RNA any more than random, individual space rocks indicate an extraterrestrial Stonehenge.

Imagine the generation of life on Earth. Now imagine if the only reason life began was because one meteorite with the exact building block to kick-start life was included on it, at a particular spot on the meteorite to survive entry, and this particular meteorite struck the Earth at exactly the right spot, in fact the only spot on Earth that would lead to life at that exact time point.

An event with such an infinitesimally small probability is unlikely to occur more than once, in an entire universe. And our evolution has required many of these events to line up.

We are alone.

If the average is just 8, then that means a hell of a lot of stars are closer than that.

Also, last I heard, Betelgeuse wad 640 light years away and is not considered a threat. It's not predicted to produce a gamma ray burst aimed at us.

Well ya need something capable of storing vast amounts of information through varied permutations that is self replicating.

There's some theories regarding silicon based life, but beyond that things get very fanciful.

The universe is big, but there is a limited amount of matter in it, and further, anything outside of our galaxy, which contains less than a comparative grain of sand on a beach of said matter, effectively doesn't exist to us (assuming extreme FTL isn't a thing). So your possibilities are limited.

Plus, you get into definitions. "Life, but not as we know it", could just as easily be defined as not life.

On the other hand, yes, various factors of the Fermi paradox and Drake equation seem to assume that all the aliens are really just humans, but not. So even within the scope you have available, there are probably several possibilities we've not dwelt on much.

Yeah, but even both Alpha Centauri and Proxima were yellow dwarves, we'd still be safe. Four light years is plenty of spacing.

Sure, you're more likely to have stellar conflicts towards the center, but they aren't that much more common than they are out here. Most of the systems grow up just fine - so much so that any one that doesn't becomes the target of extreme astronomical interest. And there's just a whole lot more potentials there than out here.

It's just a shame that it's all too far away for us to send a SETI signal too. (Though, maybe that's a good thing, as I did describe that program as suicidally curious.)

Just as an FYI, if FTL never happens, that matter that lies between stars and galaxies is very important to us. Interstellar asteroids and ejected planets make for excellent pit stops. It may be more feasible to hop along them to other stars than it would be to pack enough fuel to make the trips in one go. The so called Steppenwolf planets.

Traveling to another galaxy might also be as simple as looking for a star that is about to be ejected, catching up to it and settling its solar system. Then you ride it into intergalactic space for billions of years and leave when you get close enough to another galaxy.

>Traveling to another galaxy might also be as simple as looking for a star that is about to be ejected, catching up to it and settling its solar system. Then you ride it into intergalactic space for billions of years and leave when you get close enough to another galaxy.
That doesn't work because the galaxies are all moving away from each other at an accelerating rate. (With the exception of the few blue shifted ones that we'll eventually merge with.)

Even if you traveled at ten times the speed of light, you'd never reach the nearest red shifted galaxy, universal expansion is simply too fast. You'd need outright teleportation (which, who knows, might be a thing, just seems unlikely).

All those most distant rare stray stars will eventually be stranded and alone.

Universal expansion isn't strong enough to pull apart close clusters of galaxies. The local group is going to stick together. I believe there is also another cluster that is coming to us because of the great attractor. I am aware that the great attractor is not actually pulling most things together and is actually just slowing them down as they move away, but some things are moving towards it.

No, it is - only for the blue shifted galaxies is this not the case. We're never going to reach The Great Attractor, and it is indeed moving away from us.

Within 100 billion years, only the local group will be visible. Within 450 billion years, we'll all be one galaxy, and no other galaxies will be visible, nor will the CMB or any solid observational evidence that there ever was anything besides this new galaxy.

>Universal expansion isn't strong enough to pull apart close clusters of galaxies.
It'll eventually be so strong it'll pull apart not just galaxies, but solar systems, planets, and atoms. Granted, all the stars will be long dead by then, so I guess no one will be around to see it.