Is the Fermi Paradox becoming more acute?

Great Debates
1

Seth Shostak, Senior Astronomer and Director at the Center for SETI Research said in 1914: “”One in five stars has at least one planet where life might spring up. That’s a fantastically large percentage. That means in our galaxy there’s an order of tens of billions of Earth-like worlds.” He predicts that extraterrestrial life will have been discovered by 2040.

I think that if we haven’t discovered extraterrestrial life by 2040, chances are we never will.

About half a century ago physicist Enrico Fermi was surprised by the apparent contradiction between the lack of evidence and high probability estimates for the existence of extraterrestrial civilizations. Given the billions of stars in our galaxy and the billions of years since life could have thrived in so many places, the Milky Way should be bustling with alien activity. “Where is everybody?” Fermi asked.

“We still have plenty of time to discover alien civilizations,” optimists say.

Maybe. The problem is most of the action in the universe has already happened. The first generation of galaxies appeared when the universe was about 400 million years old. Early galaxies were only several thousand solar masses but they increased in size through successive merges until they were reached the size of up to billions of solar masses. Certain scientists (such as David Sobral) think that fifty percent of the stars ever created were already born nine billion years ago. For nine billion years the universe has been producing the other half. At the moment the rate of star formation has diminished dramatically – only a number equal to a twentieth of the total number of today’s existing stars could still be generated until the end of time.

Plus, the dark energy that makes up over 2/3 of the universe’s energy causes the universe to expand at an accelerating rate. It’s been quite a while since dark energy has superseded other forms of energy and galaxies themselves – matter started to become quite dilute billions of years ago. Since the effect of dark energy increases as the space expands, one of its consequences is that new structures are less and less likely to form from now on. That is, gradually dark energy will become so strong that it will rip apart galaxies, stars and even atoms.

I think the heyday of extraterrestrial civilizations is now or has already passed. If we still want to discover them, we’d better hurry.

2

Just to head off some obvious jokes, I presume the OP means the Fermi Paradox.

3

:smack:

You presume well. :smack: :smack:

I wonder if somebody could edit the title accordingly.

4

It’s worse than you think.

“Life” doesn’t necessarily mean life as we know it. We may not even recognize different life forms. And he’s referring to planets where life MIGHT spring up, not that it necessarily will . . . or has. And none of this implies “Earth-like worlds.”

But I agree, the Universe is probably teeming with life. If the chances of us discovering them by 2040 are remote, the chances of them discovering us (if they haven’t already) are much, much greater.

5

At least until it invades our space homes. “Honey, remember that funny rock I found? Did you move it?”

“No, dear.”

“And I don’t recall the floor being so slimy.”

“Maybe if you washed it once in a while.”

6

‘By 2040, or we never will’?

Laughable. We will keep looking no matter what and we will just find it when we find it. If we ever do, then we will keep looking anyway.

7

We all take it for granted after having read and watched tons of sci-fi that we’re going to figure out how to do FTL travel one day. It’s just assumed that if there were advanced life in the universe, they’d be all over the place. But I think it’s pretty likely that there is life out there, and we’ll never meet it simply because of the distances involved.

People also overestimate our detection methods. They’ve bought into the meme that we’ll be able to see everyone’s radio and TV broadcasts. But those signals diminish with the cube of the distance. You’d need an antenna network bigger than the solar system to detect radio signals from more than a few light years away.

It seems to me the way we’ll discover life will actually be pretty anticlimactic - we’ll probably detect a world far away to which we apply some sort of spectroscopy and decide that the combination of elements in their atmosphere very probably indicates life, but not quite for sure.

8

I forget the name of the theory, but there is a theory that life couldn’t arise for the first 9 billion years of the universe because stars had a different % of heavy metals in them, and as a result there were more gamma rays. So life couldn’t develop because gamma rays were a bigger threat. However I don’t know if this theory meant that intelligent life couldn’t develop, or that all life would die. Also, in the 600 million years of multicellular life we have had 5 natural extinction events and life has always recovered and kept going. In fact oneof the 5 major extinction events could’ve been due to a gamma ray.

Anyway, forget the name of the theory, but life seems to have arisen 4.1 billion years ago on earth, which is within a billion years of the time when gamma rays became less of a threat.

However, it would only take an alien civilization traveling at 10% the speed of light a million years to colonize the galaxy. That is a rounding error at the timeframes being discussed. We can probably achieve 10% the speed of light with nuclear pluse ships which were theoretically possible back in the 1950s.

I really don’t know the answer.

9

I’d never heard that one, but there is a similar argument that it required a few generations of stars, to cook up heavier elements, which are conducive to life, if not absolutely necessary. Chlorophyll has that odd Magnesium atom. Maybe plant life could have developed some other sunlight-gathering molecule, but good old chlorophyll is mighty important to life as we know it.

ETA: Okay, atomic number 12 isn’t all that heavy. But, still, it wouldn’t have been around before a generation of nucleosynthesis.

10

Life as we know it existed quite happily without chlorophyll for 500 million years.

11

I think the putative notion that there must be extraterrestrial contact in order for life beyond Earth to exists, is a fallacy and one that’s been perpetuated, exacerbated and, indeed, inculcated by [science fiction] entertainment media.

Firstly, who is to say how long a species survives for? Perhaps species die out before they can harness technologies that permit them to travel to other worlds (…even if such an endeavour was an explicit desire in the first place). A destiny that’s been postulated for our own kind, by more than one luminary.

Secondly, who is to confirm that intergalactic space travel is even possible for flesh-based organisms? The assumption that “E.T.'s” are all flying about in cloaked U.F.O.'s, is predicated upon “Area-51” silliness and has scant scientific substrata, only rumination, to buttress it. Even getting to the mere neighbouring planet, in Mars, is a massive feat of preservation – with ramshackle solutions posited of travellers requiring to be hid behind stowed cargo in order to avoid the potential deadly cosmic rays. Reaching literal galaxies, would likely require the realisation of “A.I.” and what we now dub “machines”, sent in place of our organic selves (…that, or some kind of ‘cryo-storage’ of the crew). Assuming that “A.I.” would not expunge us altogether… or that we do not commune with it and are no longer “human”, in the sense we consider ourselves now. But, I digress…

Lastly, why would a far-advanced species - which is a given presumption for interstellar space travel to be reconcilable without fanciful deus ex machina intervention - have any desire to commune with what would comparatively be akin to humans “communing” with insects? Sure – they may want to “study” us and perhaps simple enact intergalactic diplomatic relations. However, travelling literal light years would not be some off-the-cuff pursuit they could undertake just to fill a couple of petri dishes and for a handshake – of which, the former ‘analysis’ could surely be conducted remotely, given their implied, available technology.

Bonus rumination:
What if aliens are not corporeal ‘beings’; rather, energy-based entities that we cannot directly contact? What if contact could only be enacted through other energy-harnessing conduits – e.g., computers? (See: The Astronaut’s Wife (1999))

In summation:
I believe this Protagoras’ bias - viewing the universe through an anthropoidal prism - is what leads us to the quandary of why we have yet to make contact with aliens; despite all our efforts and the mathematical proofs that seem to bear out the probability of ‘contact’ being quite high. If we step outside the square and consider the scenario from an alien species’ angle, it’s actually quite logical that we have not, and perhaps will not, ‘meet’ an E.T. outside of a moonshine-fuelled, Bible Belt hoedown.

Our “A.I.” successors, on the other hand - if it comes to that - may have a better chance at bridging the aforementioned ‘galaxy of gaps’. But by then, perhaps expansion theory would have the skies empty, with nothing to aim for anyway.

12

If they even use that any more (or not yet).

Heck there is also the assumption that a species may exist (as itself or in closely incremental enough evolutionary steps as to maintain civilizational continuity) long enough before plain old extinction catches up with it as to make some sort of significant interstellar progress.

Plus there is the possibility that that civilizations with both actual interstellar potential AND the interest in doing it are not too common on either value, and combined even rarer, and that on top of it either they don’t last or can’t maintain effort as long as it takes or would at some point just stop because, well, they had enough (as suggested in a different thread). We like to think that all it takes is just one with enough drive to do it. Well, maybe we’re wrong.

My purely speculative instinct is that even in the best of cases a vast majority of civilizations come and go without ever making contact, or even finding compelling evidence of life beyond their own stellar system. Nothing to be depressed about in that – there’s 7 billion people on Earth and are we going to say every one of them who did not become Bill Gates or Pope Francis or Kenneth Branagh or Narendra Modi was a failure?

13

For certain definitions of “as we know it.” Life as I know it exists in a very rich ecological environment, made up a a web of thousands of species. Early life, B.C. (before chlorophyll) was bacterial soup and algae mats.

(Even that is kind of impressive. Any form of self-organizing life – throwing energy into the face of entropy – is remarkably cool.)

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Here is a good article from Wait but Why about the fermi paradox.

This is good too.

16

Why would they want to colonize the galaxy?
To spread out that far, you have to make a lot of babies.
But we now know that people don’t like to make babies.
Every country on earth (with first-world technology and lifestyle) is declining in population, as new births are below replacement level.

So, based on the only scientific evidence we have (i.e. ourselves) we have proof that when an intellligent species becomes advanced, it stops breeding.

Fermi’s parodox is solved.
The aliens are sitting at home quite comfortably, with their door closed.

17

There are a few more issues with that theory. As technology advances, data compression improves. When you compress data, you mostly do it by removing redundancy and patterns. Any pattern can be exploited to shrink the data by simply defining the pattern, where it appears, and maybe how that instance deviates from the norm. You end up with, what looks like, random noise.

Also, as technology advances, the efficiency of the system improves. Why beam signals strong enough to go into space if you can use more, local transmitters or directional transmissions or less lossy transmission mediums?

So, you quickly end up with a situation where there are no significant signals going into space, the ones that are look like random background noise, and they are falling off at a cubic rate.

18

‘Beings composed of pure energy’ is a popular and fun SF trope, but has anyone ever come up with a remotely plausible framework for how that would work?

Energy doesn’t tend to interact with other energy directly, and energy doesn’t tend to stay in one place without dissipating or dispersing.

Never mind a sentient being. How can you make any complex system out of pure energy?

19

chappachula writes:

> Every country on earth (with first-world technology and lifestyle) is declining in
> population, as new births are below replacement level.

This is exaggerated and speculative. Most of the world is somewhere close to replacement level, a little above or a little below. The big drop in fertility rates has really gone on only since the mid-twentieth century. To predict that this means that human beings will quit breeding and die out is pushing it. Most trends don’t last forever:

20

If FTL travel is possible … where are all the tourists?

I think the most likely thing we’ll find out there that presumes to be biological in origin will be an atmosphere with a profound amount of O[sub]2[/sub], something we’ll detect when we can image the spectrum of these atmospheres … and that technology is a ways off still.