The great silence: Just 4 in 10k galaxies may host intelligent aliens

https://www.space.com/plate-tectonics-intelligent-alien-life-rare

by bookofjoe • 2 years ago

21 63 2 years ago

cratermoon2• 2 years ago

Recent studies suggest there are 2 trillion galaxies in the observable universe. That works out to roughly 8 billion galaxies with intelligent life. There are untold trillions more galaxies beyond our observable horizon. Intelligence may be scattered sparsely, but there's probably a lot of it in absolute terms. Maybe in some corner of the universe two intelligent civilizations arose in the same galaxy, within a few tens of light years from each other.

What is lonelier, having no other intelligence for millions of light years, or knowing there's another civilization tantalizingly close, but still far enough to make the possibility of in-person contact daunting under known laws of physics.

vessenes3• 2 years ago

My mind goes to: do we want an outside context problem to be our problem or a neighbour’s problem? I choose neighbour’s problem unless they are extremely benign. Like, extremely.

engineer_222• 2 years ago

There are intelligent beings on planet earth with language and culture that we have no idea how to communicate with.

Roll the in the idea we'll communicate with them with messages encoded in radio waves, and they'll understand, and it sounds hopelessly optimistic.

babypuncher2• 2 years ago

What alternative technology do you propose aliens would be using to communicate wirelessly across vast distances? Even if something new is eventually discovered (like Star Trek's "subspace"), it stands to reason that any civilization advanced enough to explore their own solar system would have been using radio long before then.

itishappy2• 2 years ago

What makes you assume aliens are communicating wirelessly across vast distances?

Earth is home to just one species who've developed wireless communication, and we don't broadcast across astronomical distances if we can help it these days.

atrus• 2 years ago

The issue isn't them using radio, it's that it's on top of another encoding.

If someone sent you raw radio data, what's it modulated by? Frequency? Phase? Amplitude? A combination of the three? Is it multiplexed with other data? And then, if you magically figure that out, it's not even in a language you speak? If it's even a spoken language!

Good luck haha.

upon_drumhead• 2 years ago

https://en.m.wikipedia.org/wiki/The_Hole_Man Had a fun thought experiment around using a micro black hole to use gravity for communications

cratermoon2• 2 years ago

any civilization advanced enough to explore their own solar system would have been using radio long before then.

Perhaps we just missed the signals?

Let's ponder some timescales. The Earth has been around ~4.5 billion years, life began a half billion to a billion years later. It wasn't until about 2 million years ago that the species that was to evolve into modern humans started to use fire. That's 3.498 billion years or so of life before what we might considered civilization.

Humans first started using radio about 125 years ago. An instant in cosmic timescales. Powerful broadcast radio signals first showed up in 1930s. We are already starting to transition to lower power point-to-point wireless transmission. That means our radio waves are become far less detectable at stellar distances. Give it another 25 or 50 years and humans might well have gone silent, for all practical purposes, to hypothetical aliens.

To have another advanced civilization arise both within detection distance of Earth and in an overlapping instant of time where we might detect each other? The odds are unfathomably tiny.

TheLoafOfBread2• 2 years ago

Try to demodulate QAM64 without knowing what it is. It will look just like little bit elevated noise. Now imagine that aliens will be using as effective as possible modulation. There is close to zero chance to figure out what is being transferred.

Furthermore it also makes no sense to just scream in all directions so you will use highly directed microwave beam or laser. If you are not in the path of such communication, you will hear silence.

Loughla• 2 years ago

What beings have language and culture other than human?

nilamo2• 2 years ago

Dolphins, ants, most birds, wolves...

jasonpeacock• 2 years ago

Whales, elephants, birds, octopus, ...

wahern• 2 years ago

It all depends on how you define language and culture, and that's before you delve into a host of other unstated assumptions. The whole debate is driven by unstated assumptions, or assumptions and thresholds which are more-or-less pulled out of thin air, notwithstanding any associated quantifications. And these assumptions are constantly in flux.

For example, once upon a time "tool use" was considered a unique capability of humans, and from that was derived definitions of intelligence, etc. Well, turns out lots of other animals use tools, at least under that original, somewhat simplistic definition. But what's the significance of that fact--that other animals use tools? Does it mean they're also intelligent, just like humans? People have argued as much, but the "tool use" test was basically pulled out of someone's butt to begin with; the fact we all agree other animals use tools, now, doesn't actually imply much of anything.

People draw conclusions where none can be drawn. And people establish presumptions and definitions to fit their preferred conclusions.

vessenes3• 2 years ago

The Drake equations are the most convincing assessment of where we’re at and why that I’ve read — upshot, the fact that nobody is near us is a GREAT sign that we’re likely going to have time to expand out of our solar system before some dominant civ just eats us maybe without even noticing us.

That said, so many of these ‘intelligent life’ things have so many baked in assumptions, I’m constantly frustrated: “Must be water based, since that’s what we know,” “Must communicate via radio like we do in ways that we could recognize”, … The assumptions are legion.

VagabundoP• 2 years ago

Exactly, there’s alien and there’s alien alien.

We can’t even imagine alien alien.

bsder• 2 years ago

“Must be water based, since that’s what we know,”

This one is an assumption, but it's a pretty good one.

Equilibrium chemistry has a fairly narrow band of energy in which things can be pushed to one side or the other without completely dissociating. A solvent is almost always required as a medium and water is about as "simple" as that gets.

Sub-zero chemistries might work, but they would be much slower than water--life might take longer than the age of the universe to evolve. Molten chemistries don't seem to be able to hang together long enough to be reversible.

While the "building blocks" of life might be different, given our current knowledge of physics, the probability that the solvent for life is water is likely very high.

vundercind• 2 years ago

Chemistry’s the limiting factor for most of it.

You’ll need a lot of energy for complex life. The list of things that can naturally provide enough without having extremely-hostile side effects is pretty much limited to stars, and then only if you get really lucky in a whole bunch of ways.

Then you need to turn that into chemical energy to actually do anything with it.

That’s gonna turn useful chemicals from the environment into waste you can no longer use. If you’re lucky the waste is chemically useful, and if something can evolve to use it, maybe it can turn it back into what you need (happened with oxygen). If the waste isn’t useful, you better hope your planet’s recycling it somehow. Ideally with some kind system that adjusts with a feedback-loop so it doesn’t limit your growth too much.

Our one example sure looks extremely fragile, in that if you mess with any of several things a little bit, you might still get life, but it’ll cyclically wipe itself out, or never be able to harvest enough energy to support complex life, or any number of other problems that end in not seeing intelligence arise.

poikroequ• 2 years ago

However, it should be noted that the Drake equation is more of a thought experiment to highlight what we know and what we don't know about the evolution of technological life, rather than an absolute guide to the number of civilizations out there.

I fully agree with your second paragraph though.

Beijinger• 2 years ago

"is a GREAT sign that we’re likely going to have time to expand out of our solar system before some dominant civ just eats us maybe without even noticing us."

This is a bold interpretation. Could be a sign of many things. Like that life is much rarer than we assume. Could be that all civilizations run into some kind of energy trap or that civilizations tend to destroy themself with technology

“Must be water based, since that’s what we know,”

No scientist says that they MUST be water based, but water based would be a decent assumption since we know life can be water based. To look for life in general: look for entropy sources.

https://www.sciencealert.com/entropy-could-be-the-secret-to-...

vessenes3• 2 years ago

I think your possible scenarios -- very rare life, energy trap or great winnower / cliff -- actually are all pretty positive in terms of Drake - to me the major point the equations make is just this: if you see any aliens at all, it is likely that you are late to the game of getting extrasolar, and due to the timescales involved, it is most likely that you are very very late to the game.

That said, if, say in a billion years, we survive as a race, and still haven't met anyone, then some of those drake choices are very different than we imagine them -- and we must have somehow gotten really lucky, or there is something else very strange going on. Regardless, it would likely be pretty bad news to a single-planet lifeform to meet us at that point, or at least tectonic, depending on how altruistic society as a whole would be at the time of the meeting.

raxxorraxor• 2 years ago

I would think radio waves to be quite sensible here compared to other-dimensional ghost-aliens roaming the skies.

Given radio waves being the primary marker for our own existence and looking at the distance those artificial signals already travelled compared to the size of the cosmos, I believe not having any form of indication for intelligent or any alien life is a surprise.

saomcomrad56• 2 years ago

Sounds like more than enough

dyauspitr2• 2 years ago

Imagine if we are the only life in the universe. A million years from now we will have seeded life across multiple galaxies if we’re still around. What a crazy life that would be.

cgriswald• 2 years ago

If we left today, instantaneously at the speed of light, it would still be another 1.5 million years before we arrived at the nearest galaxy.

knowitnone• 2 years ago

according to relativity, if we could travel at the speed of light, we would arrive instantaneously. you're thinking about it from the observer point of view.

dgrin91• 2 years ago

Our nearest galaxy is only ~25k light years away (Canis Major)

dyauspitr2• 2 years ago

Yeah but the people traveling would barely have aged.

postalrat• 2 years ago

Probably already happened.

OutOfHere2• 2 years ago

The article is not about life, but about intelligent life. It says so right in the title. I do not consider humans to be particularly intelligent, as they can't even come together to address global threats like climate change that could mean the difference between a universe with intelligent life versus a universe that's barren. To address the risk, we first have to acknowledge this universal risk.

cosmotic• 2 years ago

Why not say 1 in 2.5k?

moralestapia• 2 years ago

Nice! That's billions of them, then.

Ekaros2• 2 years ago

An other aspect I have been thinking is fraction of planets that have sufficient metal richness for life or advanced civilizations in first place. So you could have intelligent life that just doesn't get advanced due to lack of resources...

exe342• 2 years ago

water worlds - easy to evolve life, much harder to evolve technology.

bookofjoe• 2 years ago

Stephen Wolfram predicts liquid computers

topspin• 2 years ago

Given the number of galaxies, this ratio means "intelligent aliens" are common.

TheBlight2• 2 years ago

It seems like application of the Copernican principle should be the default and the burden is on others to show that the Earth and its observers are somehow extraordinary.

kcplate• 2 years ago

Intelligent life isn’t even common on the one planet where we know it exists. You have maybe a dozen species that could go beyond their basal instincts out of millions of forms of life and only a single species has the intelligence to make itself known outside the biosphere.

Life might be common, but “intelligent” life? That seems to be exceedingly rare.

kachapopopow• 2 years ago

So basically, aliens are all around us? Just very very far away.

TheBlight2• 2 years ago

"Just very very far away."

Many of them have probably had ample time to travel the galaxy.

yobid20• 2 years ago

They are already here.

marmaduke• 2 years ago

C'mon, call it dark forest already

fuzzythinker• 2 years ago

Poor title, 4 in 10k is in the low side of estimate.

"by plugging this value into the Drake equation, Stern and Gerya arrive at a value for the number of extraterrestrial civilizations as somewhere between 0.0004 and 20,000".

EDIT: If we take a number near the middle, say 1, we have ~1 per galaxy. Near the high side, we have ~10k per galaxy.

ant6n• 2 years ago

Hey that's us! We're like a terrestrial civilization inside a galaxy!

effed3• 2 years ago

Or maybe actually this is a measure of the fact we are still quite deaf (and blind) about what is, in wide sense, life, not event about intelligent one. Plate tectonics, water and dry land are really necessary? And some intelligent beings will radio-shout everywhere? Maybe they not know radio, and still are intelligent, or know the radio and being even more intelligent do not use it...

lukan• 2 years ago

The assumption here is, plate tectonics are required for intelligent life. Which is an interesting theory, but not much more I think. We don't even know what is required for the formation of life at all.

tconfrey• 2 years ago

I've often wondered how important the tides are to the migration of fish onto land and our subsequent evolution. Our moon's relative size is another earthly anomaly and without the moon tides would be solar driven and pretty minimal (AFAIK).

yabatopia• 2 years ago

A fingerprint is unique. A snowflake is unique. But for some reason we find it difficult to face the possibility that intelligent life - on planet earth - is in a similar way unique.

OutOfHere2• 2 years ago

If we are alone or among the very few in the universe, this makes it all the more important for us to shed selfish behaviors and come together to resolve global threats such as climate change and many others. Yet, we continue in the opposite direction, treating life in the universe as disposable.

TheLoafOfBread2• 2 years ago

That means lot of space for Human race to expand in.

The great silence: Just 4 in 10k galaxies may host intelligent aliens

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