Aliens probably long dead, say scientists

[EastEnder]

Well the thread is about Aliens, and so the film I linked to is relevant to the thread title, but that doesn't mean it's my main interest. If folk on here are more interested in ET then watch the film at face value.

I'm very interested in ET, but I imagine I would find the film more annoying than interesting. I like documentaries that are scientific, present a range of perspectives, allow for commentators with different views, express opinions as such and not as fact, which give equal weight to argument and counterargument, and which don't reject hypothesises solely on the basis that they contradict a prior assumption.

If you can assure me that it satisfies those criteria, I'll give it a go!

 

[nuffsaid]

I'm very interested in ET, but I imagine I would find the film more annoying than interesting. I like documentaries that are scientific, present a range of perspectives, allow for commentators with different views, express opinions as such and not as fact, which give equal weight to argument and counterargument, and which don't reject hypothesises solely on the basis that they contradict a prior assumption.

If you can assure me that it satisfies those criteria, I'll give it a go!

Well, I've only seen the first half hour or so on a youtube version. It was entirely comprised of witness testimony. So face-to-camera, people describing events, documents, meetings. A mixture as mentioned of military and government officials, pilot testimony, air traffic control testimony, screenshots of some actual radar occurrences backing up the testimony, etc. So very dry, you either believe the veracity of those detailing their testimony or you don't. A lot of the testimony was obviously taken a long time ago as much looked recorded over the decades, stuff that's already on Youtube elsewhere so not exactly a load of people rocking up for a paycheck in the last 12 months. There wasn't much time for alternative views as that would double the length of the film. But what do you say to a cockpit crew of a 747 freight plane who say they saw an object the size of 2 aircraft carriers follow them and track them when they changed course, and air traffic control are able to verify it. You're all on drugs, please stop flying anymore aircraft....and you radar controller...go home and don't come back.

 

[Gromit]

Aliens are dead, alive and yet to be born. All at the same time.

Those that believe aliens would die before they'd reach us are basing conclusions on human life spans.
The AI theory assumes other life forms could not be immortal or incredibly long lived. Like all assumptions it is only an assumption.

 

[EastEnder]

Well, I've only seen the first half hour or so on a youtube version. It was entirely comprised of witness testimony. So face-to-camera, people describing events, documents, meetings. A mixture as mentioned of military and government officials, pilot testimony, air traffic control testimony, screenshots of some actual radar occurrences backing up the testimony, etc. So very dry, you either believe the veracity of those detailing their testimony or you don't. A lot of the testimony was obviously taken a long time ago as much looked recorded over the decades, stuff that's already on Youtube elsewhere so not exactly a load of people rocking up for a paycheck in the last 12 months. There wasn't much time for alternative views as that would double the length of the film. But what do you say to a cockpit crew of a 747 freight plane who say they saw an object the size of 2 aircraft carriers follow them and track them when they changed course, and air traffic control are able to verify it. You're all on drugs, please stop flying anymore aircraft....and you radar controller...go home and don't come back.

I would say: "That sounds very interesting, perhaps it's aliens. Perhaps it's something else. In light of our struggle to explain it any other way, shall we just go with aliens then?"

There are always problems when people reach for fantastical answers to things that are hard to explain. That's why primitive man first invented God.

I'm not saying it's not aliens, just that extraordinary claims require extraordinary evidence. Considering your example of the 747 encounter - does the film consult a range of other experts, physicists, meteorologists, etc, to provide a range of alternative theories, or is the aliens conclusion the only one on the table?

 

[Signal 11]

But what do you say to a cockpit crew of a 747 freight plane who say they saw an object the size of 2 aircraft carriers follow them and track them when they changed course, and air traffic control are able to verify it.

I'd tell them to at least check the wikipedia article about it.

After a three-month investigation, the FAA formally released their results at a press conference held on March 5, 1987. Here Paul Steucke retracted earlier FAA suggestions that their controllers confirmed a UFO,[13] and ascribed it to a "split radar image" which appeared with unfortunate timing. He clarified that "the FAA [did] not have enough material to confirm that something was there", and though they were "accepting the descriptions by the crew" they were "unable to support what they saw".[12]

 

[nuffsaid]

I would say: "That sounds very interesting, perhaps it's aliens. Perhaps it's something else. In light of our struggle to explain it any other way, shall we just go with aliens then?"

There are always problems when people reach for fantastical answers to things that are hard to explain. That's why primitive man first invented God.

I'm not saying it's not aliens, just that extraordinary claims require extraordinary evidence. Considering your example of the 747 encounter - does the film consult a range of other experts, physicists, meteorologists, etc, to provide a range of alternative theories, or is the aliens conclusion the only one on the table?

Maybe watch the film, and make up your own mind. The US just brought that mini-shuttle drone thingy back from a 2 year mission no-one knew about, I'm sure there's a lot more we're not shown.

 

[EastEnder]

Maybe watch the film, and make up your own mind. The US just brought that mini-shuttle drone thingy back from a 2 year mission no-one knew about, I'm sure there's a lot more we're not shown.

I'm sure there's loads of stuff we're kept in the dark about. Much of which goes to fuel the conspiracy theories.

I'm just a big believer in the importance of balance. In the absence of incontrovertible evidence, any valid investigation should attempt to consider all possibilities. It's how good science is done - you present your case then open up the floor to allow others the opportunity to refute it.

If the film was divided into two halves, with the first being arguments for, and the second being arguments against, thereby offering the viewer a well balanced discussion, I'd be a lot more enthusiastic! If no opposing theories are ever proposed, I'd seriously question the validity of the entire exercise.

 

[existentialist]

No need for the internal combustion engine. Planes, ships, cars, lorries - redundant overnight, (of course it would take time to replace those - but you get the meaning).

That wouldn't sort out climate change overnight. It might (eventually) stop us spewing out more carbon dioxide, but the damage is arguably already done.

 

[existentialist]

Maybe watch the film, and make up your own mind.

 

[2hats]

Doubtless Trump has already demanded to see the files and will spill the beans in due course...

 

[Signal 11]

The US just brought that mini-shuttle drone thingy back from a 2 year mission no-one knew about, I'm sure there's a lot more we're not shown.

X-37B Space Plane maneuvers into Lower Orbit, likely Precursor to Landing – Spaceflight101

In the hush-hush nature of X-37B, no information on the craft’s orbit is provided through official channels, but the amateur satellite tracking community kept close watch over the first three OTV missions and the fourth would be no different. Satellite watchers got a fix on the spacecraft’s orbital trajectory within six days of launch

 

[2hats]

Maybe watch the film, and make up your own mind. The US just brought that mini-shuttle drone thingy back from a 2 year mission no-one knew about, I'm sure there's a lot more we're not shown.

It was spotted barely 5 days after launch by amateur astronomers in South Africa using public predictions issued by a seasoned observer of NROL launches who nailed the target orbit before the launch based on various launch constraints and activities. Details of several of the payloads have been placed in the public domain.

 

[ferrelhadley]

It was spotted barely 5 days after launch by amateur astronomers in South Africa using public predictions issued by a seasoned observer of NROL launches who nailed the target orbit before the launch based on various launch constraints and activities. Details of several of the payloads have been placed in the public domain.

Many Kerbals died to bring us this knowledge. /sadface.

 

[ferrelhadley]

If "they" exist and are interested in space travel they were here a long time ago watching us. Since our atmosphere went oxygen rich about 2 billion years ago, this place has been marked as special in giant letters any technologically advanced civilisation will be able to read. It would only take a couple of million years for a civilisation to reach every corner of the galaxy using von neumann probes. Our planet would likely be a high priority target for anyone looking for multi-cellular life. This was all pretty much worked out by the 60s. They even made a film about it.

 

[DotCommunist]

using von neumann probes.

I can see many reasons, both practical and or religious as to why that might never happen even for a highly advanced species

but what do I know, trying to guess the mind of an alien from the perspective of a human being is just sci fi really.

 

[ferrelhadley]

I can see many reasons, both practical and or religious as to why that might never happen even for a highly advanced species

Butlerian Jihad.

 

[Signal 11]

I can see many reasons, both practical and or religious as to why that might never happen even for a highly advanced species

It has to be true for every one of them if it's to be the explanation.

 

[DotCommunist]

Butlerian Jihad.

touche

 

[EastEnder]

I can see many reasons, both practical and or religious as to why that might never happen even for a highly advanced species

but what do I know, trying to guess the mind of an alien from the perspective of a human being is just sci fi really.

The beauty of von neumann probes is that it only has to happen once. The real question is, are we the only intelligent life in this galaxy, either now or in the past? If we're not, then it would seem odd if there was only one other intelligent race out there - either we're alone, or presumably there's many other sentient species. It would seem highly unlikely that there were exactly 2 or 3. So, hypothetically, if there's lots of intelligent ETs, many of which, presumably, are much older & more advanced as a species than us, only one of them needs to set about exploring the galaxy via von neumann probes. Even if most races are religious zealots or prime directive advocates, it would only take one of them to get the ball rolling. The idea that out of many advanced alien races, absolutely none of them thought of sending von neumann type probes out to explore the galaxy, seems a tad implausible.

So the fact that we've not detected any evidence so far either means their technology is so alien we can't even recognise it as such, or they're not out there in the first place. My hunch is for the latter - the universe is still relatively young, with respect to the duration over which it will be capable of supporting life - there's many billions, possibly trillions, of years left over which other intelligent species could arise. We might just be one of the early adopters, so to speak.

 

[kabbes]

it would seem odd if there was only one other intelligent race out there - either we're alone, or presumably there's many other sentient species. It would seem highly unlikely that there were exactly 2 or 3.

This just isn't right. It's a horrible logical fallacy, in fact. The most likely number of sentient species depends on how likely it is for intelligence to form. We have no idea what the chances are of this, but we do know that:

• Earth was formed 4.6 bn years ago
• Water turned up 4.4 bn years ago
• Simple life arrived 0.1bn years after that. OK, 100 million years is a long time but in the scheme of things, that's pretty quick. A tick for life forming relatively easily.
• It then took a billion years before prokaryotes appeared. That's really quite a long time to go from something of ultimate simplicity to something still really very simple.
• Another 1.5 billion years before eukaryotes appeared. Blimey, it's taken 2.5 billion years just to get some other simple one-celled organisms
• Another billion years before we get to multi-cellular organisms. So simple life: 0.1bn years. Multi-cellular life: another 3.5 billion years!
• Everything else is pretty fucking quick, all things considered. That to creatures as we know them in about 0.3 billion years.

Now, I find that interesting because when we think of the development of sentient life, I think we as laypeople tend to focus on (a) the likelihood of finding life, and then (b) the evolution from, like, squirrels and shit to us. But actually this tells us that the difficult bit is going from "life" to "really, really simple but slightly more complex life". It takes literally billions and billions of years. That's how long it took for the couple of random things to happen that made really basic multi-cellular life possible.

So we know that the odds on the necessary random things happening are really stacked against, even if the planet is perfectly set up to create and sustain life in the first place. And then of all the planets we know, how many are really even vaguely set up to create and sustain life?

So maybe 1/1000 planets can get to sustainable life and the typical return period for such life to become multi-cellular is 4bn years. Or maybe we got lucky and the return period is actually 100bn years.

If so, it could well be that across the whole galaxy (say) of 100 billion terrestrial-like planets the odds are such that the mode of the distribution of planets with multi-cellular life is zero but with a mean of, say, 0.5. I'm thinking of something like an Overdispersed Poisson distribution such that you'd mostly simulate 0 but sometimes get 1, very rarely get 2, super-rarely get 3 and basically never get 4+.

 

[EastEnder]

This just isn't right. It's a horrible logical fallacy, in fact. The most likely number of sentient species depends on how likely it is for intelligence to form. We have no idea what the chances are of this, but we do know that:

• Earth was formed 4.6 bn years ago
• Water turned up 4.4 bn years ago
• Simple life arrived 0.1bn years after that. OK, 100 million years is a long time but in the scheme of things, that's pretty quick. A tick for life forming relatively easily.
• It then took a billion years before prokaryotes appeared. That's really quite a long time to go from something of ultimate simplicity to something still really very simple.
• Another 1.5 billion years before eukaryotes appeared. Blimey, it's taken 2.5 billion years just to get some other simple one-celled organisms
• Another billion years before we get to multi-cellular organisms. So simple life: 0.1bn years. Multi-cellular life: another 3.5 billion years!
• Everything else is pretty fucking quick, all things considered. That to creatures as we know them in about 0.3 billion years.

Now, I find that interesting because when we think of the development of sentient life, I think we as laypeople tend to focus on (a) the likelihood of finding life, and then (b) the evolution from, like, squirrels and shit to us. But actually this tells us that the difficult bit is going from "life" to "really, really simple but slightly more complex life". It takes literally billions and billions of years. That's how long it took for the couple of random things to happen that made really basic multi-cellular life possible.

So we know that the odds on the necessary random things happening are really stacked against, even if the planet is perfectly set up to create and sustain life in the first place. And then of all the planets we know, how many are really even vaguely set up to create and sustain life?

So maybe 1/1000 planets can get to sustainable life and the typical return period for such life to become multi-cellular is 4bn years. Or maybe we got lucky and the return period is actually 100bn years.

If so, it could well be that across the whole galaxy (say) of 100 billion terrestrial-like planets the odds are such that the mode of the distribution of planets with multi-cellular life is zero but with a mean of, say, 0.5. I'm thinking of something like an Overdispersed Poisson distribution such that you'd mostly simulate 0 but sometimes get 1, very rarely get 2, super-rarely get 3 and basically never get 4+.

Whilst I don't disagree with what you're saying, I would point that the only timeline of evolution we have available for study is our own, therefore we inevitably make certain assumptions. I would definitely agree that the most challenging part of evolution is making the huge leap from extremely simple life, to something even vaguely more complex. However, it has been suggested that the leaps in complexity may be highly dependent on major environmental shifts. Ancient life on the early earth languished in evolutionary torpor for aeons, it would seem that evolution needs a periodic shock to the system, such as the last global glaciation event that preceded the cambrian explosion. The conclusion I would be inclined to draw from that is that placing too much emphasis on earth's evolutionary timeline as a yardstick to measure others may be imprudent. Whether it's the effects of nearby super nova, meteorite impacts, passing stars, or whatever, predicting when in the course of evolution events of such magnitude occur that they dramatically affect the rate of change is problematic.

Additionally, I was considering the existence of sentient species now or in the past, with respect to whether any of them would have sent out von neumann probes. The Milky Way is believed to be nearly as old as the universe itself, maybe 12+ billion years, and stars of high metallicity such as our sun are thought to have existed for anything up to about 10 billion years. So it's entirely plausible that solar systems such as ours have existed for far longer than our own. Entire civilisations could've emerged, sent off their von neumann probes, then been irradiated by a quasar. Maybe on a planet that formed 8 billion years ago it only took 1 billion years for complex life to form. Or maybe it takes, on average, longer than the length of time a planet is hospitable for life for complex life to emerge, so it almost never does. Basing it on our own evolutionary timeline is assuming that we're typical, which would seem unlikely in a chaotic universe.

 

[littlebabyjesus]

So maybe 1/1000 planets can get to sustainable life and the typical return period for such life to become multi-cellular is 4bn years. Or maybe we got lucky and the return period is actually 100bn years.

Or, of course, we got relatively unlucky and the return period is actually much less than that.

Another unknowable is what ways there may be for life to evolve into complexity other than the way that it happened here - through the symbiosis that created eukaryotes, for instance. Necessarily, we only know of what succeeded here, but that doesn't tell us what other processes might have succeeded.

I think we can learn a lot more about these chances even just by discovering very simple single-celled life somewhere - on Europa perhaps. If it looks very much like the simple life on Earth, then that provides evidence that this is a typical way for our kind of life to evolve. If it looks very different, that will suggest that there are lots of different pathways.

Also, you may be doing something of a disservice to the progression of life towards eukaryotes. They're not really 'simple' at all.

 

[NoXion]

This just isn't right. It's a horrible logical fallacy, in fact. The most likely number of sentient species depends on how likely it is for intelligence to form. We have no idea what the chances are of this, but we do know that:

• Earth was formed 4.6 bn years ago
• Water turned up 4.4 bn years ago
• Simple life arrived 0.1bn years after that. OK, 100 million years is a long time but in the scheme of things, that's pretty quick. A tick for life forming relatively easily.
• It then took a billion years before prokaryotes appeared. That's really quite a long time to go from something of ultimate simplicity to something still really very simple.
• Another 1.5 billion years before eukaryotes appeared. Blimey, it's taken 2.5 billion years just to get some other simple one-celled organisms
• Another billion years before we get to multi-cellular organisms. So simple life: 0.1bn years. Multi-cellular life: another 3.5 billion years!
• Everything else is pretty fucking quick, all things considered. That to creatures as we know them in about 0.3 billion years.

Now, I find that interesting because when we think of the development of sentient life, I think we as laypeople tend to focus on (a) the likelihood of finding life, and then (b) the evolution from, like, squirrels and shit to us. But actually this tells us that the difficult bit is going from "life" to "really, really simple but slightly more complex life". It takes literally billions and billions of years. That's how long it took for the couple of random things to happen that made really basic multi-cellular life possible.

So we know that the odds on the necessary random things happening are really stacked against, even if the planet is perfectly set up to create and sustain life in the first place. And then of all the planets we know, how many are really even vaguely set up to create and sustain life?

So maybe 1/1000 planets can get to sustainable life and the typical return period for such life to become multi-cellular is 4bn years. Or maybe we got lucky and the return period is actually 100bn years.

If so, it could well be that across the whole galaxy (say) of 100 billion terrestrial-like planets the odds are such that the mode of the distribution of planets with multi-cellular life is zero but with a mean of, say, 0.5. I'm thinking of something like an Overdispersed Poisson distribution such that you'd mostly simulate 0 but sometimes get 1, very rarely get 2, super-rarely get 3 and basically never get 4+.

So multicellular life takes time. What of it? The galaxy has plenty of time, being 13.2 billion years old. Even if you restrict potential life-bearing planets to Population I stars, they can be as old as 10 billion years. Hundreds of billions of rolls of the dice, and more than twice as much time as needed for multicellular life to form. Sounds like there could be millions of planets - if not more - with multicellular life on them, not just a handful.

 

[littlebabyjesus]

So multicellular life takes time. What of it? The galaxy has plenty of time, being 13.2 billion years old. Even if you restrict potential life-bearing planets to Population I stars, they can be as old as 10 billion years. Hundreds of billions of rolls of the dice, and more than twice as much time as needed for multicellular life to form. Sounds like there could be millions of planets - if not more - with multicellular life on them, not just a handful.

I think it's reasonable to suspect from our history that the vast majority of the places with cellular life in the Universe will only contain single-celled life forms.

But that other stat in kabbes's list - the 100 m years for some kind of life to appear in conditions favourable to it - suggests strongly that life will appear wherever the ingredients for it persist for any length of time, unless we got very lucky indeed with the speed it appeared here.

Given the growing evidence that earth-like planets in habitable zones are very common across the Universe, it seems very unlikely to me that simple life has not appeared on a great many of them, perhaps even the majority of them. Where that simple life then goes, if anywhere, is very hard to say, I would think. One thing that strikes me about the evolution of complex life on Earth is that the mechanisms enabling it seem really very hard to predict, seemingly circuitous, and very occasion-dependent, reliant on serendipity. Who knows what other processes can also happen?

 

[kabbes]

So multicellular life takes time. What of it? The galaxy has plenty of time, being 13.2 billion years old. Even if you restrict potential life-bearing planets to Population I stars, they can be as old as 10 billion years. Hundreds of billions of rolls of the dice, and more than twice as much time as needed for multicellular life to form. Sounds like there could be millions of planets - if not more - with multicellular life on them, not just a handful.

Could be. But by my speculative effort above, it ended up as a 4 trillion-to-1 shot. So hundreds of billions of rolls of the dice and twice as much time as needed still only results in an expectation of less than 1 planet with multicellular life.

Speculation is a bitch though. Maybe it's 400 billion to 1. Or 40 billion to 1. Or 4 quadrillion to 1. Who knows?

I'm just disagreeing with the concept that it's either 1 planet or it's loads. That really doesn't follow at all. It could easily be 2 or 3 planets.

 

[DaveCinzano]

Aliens probably long dead, say scientists

They should try telling that to Ridley Scott

 

[DotCommunist]

Who knows what other processes can also happen?

life...finds a way

 

[NoXion]

Could be. But by my speculative effort above, it ended up as a 4 trillion-to-1 shot. So hundreds of billions of rolls of the dice and twice as much time as needed still only results in an expectation of less than 1 planet with multicellular life.

Speculation is a bitch though. Maybe it's 400 billion to 1. Or 40 billion to 1. Or 4 quadrillion to 1. Who knows?

I'm just disagreeing with the concept that it's either 1 planet or it's loads. That really doesn't follow at all. It could easily be 2 or 3 planets.

Where are you getting the 4 trillion to one figure from? That seems way too high. Especially since you talked about time being the limiting factor, not whether life forms in the first place. If only 1/1000th of 100 billion planets now existing have ever had life evolve on them, that's 100,000,000 planets with life. Assuming that these planets all orbit Population I stars, then the age range is 0-10 billion years which suggests that a majority of life-bearing planets will have multicellular organisms, especially given that the average age of a star in the Milky Way is 10 billion years, which suggests that the majority of stars to ever form in the galaxy have already done so.

So, 50 million, maybe 25 million to be conservative. A handful doesn't seem likely given the numbers involved.

 

[kabbes]

Where are you getting the 4 trillion to one figure from? That seems way too high. Especially since you talked about time being the limiting factor, not whether life forms in the first place. If only 1/1000th of 100 billion planets now existing have ever had life evolve on them, that's 100,000,000 planets with life. Assuming that these planets all orbit Population I stars, then the age range is 0-10 billion years which suggests that a majority of life-bearing planets will have multicellular organisms, especially given that the average age of a star in the Milky Way is 10 billion years, which suggests that the majority of stars to ever form in the galaxy have already done so.

So, 50 million, maybe 25 million to be conservative. A handful doesn't seem likely given the numbers involved.

I'm not saying that time is the (only) limiting factor. I'm saying (well, actually totally speculating) that it's a really long shot even over a typical 5 billion year life span of a planet of a planet that can support life.

 

[EastEnder]

I think it's reasonable to suspect from our history that the vast majority of the places with cellular life in the Universe will only contain single-celled life forms.

But that other stat in kabbes's list - the 100 m years for some kind of life to appear in conditions favourable to it - suggests strongly that life will appear wherever the ingredients for it persist for any length of time, unless we got very lucky indeed with the speed it appeared here.

Given the growing evidence that earth-like planets in habitable zones are very common across the Universe, it seems very unlikely to me that simple life has not appeared on a great many of them, perhaps even the majority of them. Where that simple life then goes, if anywhere, is very hard to say, I would think. One thing that strikes me about the evolution of complex life on Earth is that the mechanisms enabling it seem really very hard to predict, seemingly circuitous, and very occasion-dependent, reliant on serendipity. Who knows what other processes can also happen?

If there's other life out there, I would imagine it's mostly unicellular, although that assumption is merely based on what happened on Earth. Although to take the speculation one step further - whatever form any potential alien life takes, it's possibly likely that its evolution would be significantly limited by its environment. If you consider all the types of planetary bodies that may be hospitable to life, most of them are probably ocean worlds with thick global ice coverage - much like Europa. The conditions required for a world with both water & land under a thick, but not too thick, atmosphere are quite specific. Whereas a small ice covered world doesn't need a strong magnetic field, doesn't need to worry about an atmosphere & has excellent protection from impacts, super nova, etc. And given that small, long lived stars such as red dwarfs are far more numerous than Sun types stars, the combination of small, ice covered ocean worlds, orbiting close in to red dwarfs, potentially offers far greater prospects for the emergence of life than terrestrial type bodies. But it would also, most likely, provide quite a dull environment, without many of the dramatic effects that influenced evolution on earth.