Author Topic: So let's talk SETI.  (Read 890 times)

Re: So let's talk SETI.
« Reply #15 on: December 20, 2020, 11:33:39 PM »
There a series on YouTube that discusses the possibilities of alien life. I particularly find this one incredibly interesting:



Both of the currently two videos in the series discuss different topics, so you don't have to watch part one before this one. What this video discusses is the question of if alien life exists, what might it look like? They consider various environments, and how they might affect the evolution of life. For example, a bright blue star might have vegetation that is red in color instead of green, while a planet near a dim brown dwarf might have black vegetation that is designed to absorb as much light as it possibly can.
"Oh, wearisome condition of humanity,
Born under one law, to another bound;
Vainly begot, and yet forbidden vanity,
Created sick, commanded to be sound."
--Fulke Greville

Offline Hydra009

Re: So let's talk SETI.
« Reply #16 on: December 21, 2020, 12:26:33 AM »
Also important is the relative gravity, thickness of the atmosphere, and presence of moon(s).  There could be some low-gravity worlds with some amazing leaping predators.  Or flying creatures that can stay in flight virtually their entire lives.

And something that doesn't get talked about enough is just how bizarre Earth's history has been - we probably had a huge impact that permanently sundered off our moon (an abnormally large one relative to the planet, too), the Great Oxygenation Event (not only allowed for a bunch of new kinds of life, but also new minerals), endosymbiosis that created eukaryotes (how the hell did that happen??), several snowball Earths, the asteroid impact that killed the dinosaurs, etc.  This isn't how things could've turned out at all.  It's amazing that we're even here to talk about this stuff.

Offline Baruch

Re: So let's talk SETI.
« Reply #17 on: December 21, 2020, 01:28:57 AM »
John Carter on Mars could also jump far, but because he grew up on Earth ;-)
Ha’át’íísh baa naniná?
Azee’ ła’ish nanídį́į́h?
Táadoo ánít’iní.
What are you doing?
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Don't do that.

Re: So let's talk SETI.
« Reply #18 on: December 21, 2020, 11:27:16 AM »
I have the Five Tones as my ringtone.
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline Baruch

Re: So let's talk SETI.
« Reply #19 on: December 21, 2020, 11:38:32 AM »
I have the Five Tones as my ringtone.

So your true form is a Big Eyed alien? ;-)  Cool!  But stop playing with your mashed potatoes ;-))
« Last Edit: December 21, 2020, 12:12:05 PM by Baruch »
Ha’át’íísh baa naniná?
Azee’ ła’ish nanídį́į́h?
Táadoo ánít’iní.
What are you doing?
Are you taking any medications?
Don't do that.

Re: So let's talk SETI.
« Reply #20 on: December 21, 2020, 04:36:07 PM »
Also important is the relative gravity, thickness of the atmosphere, and presence of moon(s).  There could be some low-gravity worlds with some amazing leaping predators.  Or flying creatures that can stay in flight virtually their entire lives.

And something that doesn't get talked about enough is just how bizarre Earth's history has been - we probably had a huge impact that permanently sundered off our moon (an abnormally large one relative to the planet, too), the Great Oxygenation Event (not only allowed for a bunch of new kinds of life, but also new minerals), endosymbiosis that created eukaryotes (how the hell did that happen??), several snowball Earths, the asteroid impact that killed the dinosaurs, etc.  This isn't how things could've turned out at all.  It's amazing that we're even here to talk about this stuff.

I was reading yesterday about a study of simulated planets trying to determine how long various planets might remain habitable for the billions of years needed to evolve complex intelligent life. Turns out it's largely due to random chance that Earth's climate has remained habitable as long as it has, so liquid water was always available somewhere on the surface. Most planets weren't so lucky.
« Last Edit: December 21, 2020, 04:38:40 PM by Unbeliever »
God Not Found
"There is a sucker born-again every minute." - C. Spellman

Offline Baruch

Re: So let's talk SETI.
« Reply #21 on: December 21, 2020, 04:59:25 PM »
The Earth was a snowball with its original atmosphere.



So the water here wasn't always liquid.



Since all animals are descended from a common ancestor we share with the sponges, that explains human behavior ;-)
« Last Edit: December 21, 2020, 05:33:36 PM by Baruch »
Ha’át’íísh baa naniná?
Azee’ ła’ish nanídį́į́h?
Táadoo ánít’iní.
What are you doing?
Are you taking any medications?
Don't do that.

Offline Hydra009

Re: So let's talk SETI.
« Reply #22 on: December 21, 2020, 05:44:57 PM »
I was reading yesterday about a study of simulated planets trying to determine how long various planets might remain habitable for the billions of years needed to evolve complex intelligent life. Turns out it's largely due to random chance that Earth's climate has remained habitable as long as it has, so liquid water was always available somewhere on the surface. Most planets weren't so lucky.
Our neighbors, Venus and Mars, are proof of that.  Though Mars does have some residual liquid water.  Various Jovian moons as well.  Hell, even our moon has some water and that's about as barren as they come.

Yes, in our solar system, Earth is the only one with water huge amounts of surface water and has maintained it for billions of years, which appears to bode poorly for complex extraterrestrial life.  And although we don't yet know much about extrasolar planets other than their existence, and we're likely overlooking a ton of small, rocky planets due to technical limitations, we do know of several planets that are likely to have large amounts of water.  So maybe water, especially stable oceans, isn't as rare as it first appears.
« Last Edit: December 21, 2020, 07:40:51 PM by Hydra009 »

Offline SGOS

Re: So let's talk SETI.
« Reply #23 on: December 21, 2020, 06:19:44 PM »
There are a lot celestial bodies in the universe. So rare is kind of a relative term.  With numbers that big, things that are rare are still likely to occur many times.  Also, if Earth is so unique that there is no other planet like it, the universe is always evolving, and sooner or later another Earth like orb is bound to show up.  It is not just the vastness of the universe that allows for things similar to us.  Eternity may be an even a bigger contributing factor to more Earth like planets.   Although, we are probably unlikely to find them let alone be here when they are.

Offline trdsf

Re: So let's talk SETI.
« Reply #24 on: December 21, 2020, 09:35:24 PM »
Well, while we're on the topic of aliens, I've had a rather intense debate with a friend of mine about whether or not it's wise for us to send out radio broadcasts and do other things that could make first contact with aliens.

She maintains that aliens are likely predatory and aggressive, much like us.  So such signals are tantamount to ringing the dinner bell.  Think about what our own explorers did when they made contact.  It would be much the same for us.

I agree that aliens would vaguely be like us, denizens of a planet or large moon - likely omnivorous generalists like us.  They'd likely have a similar aggressive streak as us, though I'd like to think that total war is an alien (get it?) concept to them.  And like us, they might've somewhat tempered their belligerent streak as they became more high-tech and learned to be a little bit more compassionate.  Because a superbelligerent alien race would never make it into space at all - they'd simply bomb themselves into oblivion.

Given the vastness of space (space is really BIG), they would have plenty of resources and territory of their own (as would we), so we wouldn't necessarily have to fight over it.  This galaxy is big enough for the both of us; neither of us would have any need to fight the other.  In fact, we would literally have to go light years out of our way to fight each other.  A rather absurd, though not impossible, situation.

Aliens wouldn't truly want our raw resources, the real treasure trove is in our life and its byproducts - culture and technology.  Because that's certainly what we're interested in.  Why come all that way to destroy when you can study?

And besides, our first contact would likely not be between us personally - but through our machine intermediaries - our probes - who definitely have no harmful intent.

So, instead of fearing aliens and going silent, we should do everything we can to be loud and noticeable to make first contact happen asap.  Because any first contact would likely enable a huge technological leap for us, potentially saving countless lives.  Imagine a new power source or new medical technology or new spaceflight technology.  It's such a massive boost that it's worth betting that the aliens we do meet aren't genocidal.
I think dinnerbell is the wrong idea -- we'd need to be the same biology to be nourishing and the odds of evolution doing the same chemical thing twice are nearly, but not quite, zero.

Stephen Hawking was on the 'we should keep our heads down' side of the debate, of the opinion that we shouldn't draw attention to ourselves on the basis that the sort of aggression, tribalism and territoriality that still lurks (overtly or covertly) in the human animal might be evolutionarily common to sentient species, and the last thing we need is to meet an alien race as unpleasant as we are but with higher technology.

The fault with his reasoning is that it presupposes that they are nearby, and/or that they have broken the interstellar travel problem, either by circumventing the speed of light or by having a stardrive that pushes up close enough to c that shipboard travel time is tolerable (and that you don't ever plan on going home again).  Those are two really big ifs.

Unless the galaxy is thickly populated, we're highly unlikely to be within thousands or even tens of thousands of lightyears to our nearest sapient neighbor.  Now keep in mind that we ourselves have only been detectable for two hundred years (by spectrographic analysis of our atmosphere -- industrial pollution, ironically, would be the marker of "intelligence"), and broadcasting for one hundred.  With the advent of cable, satellite, fiber optic, and other more finely focused data transmission means, our radio footprint is growing smaller.  You don't need an AM antenna blasting 250,000 watts from just over the Mexican border to be heard nationwide anymore, you just need a wifi hotspot or a 3, 4 or 5g connection.

So instead of just blasting out a sphere across the electromagnetic spectrum, the Earth's radio signature is an expanding bubble about a hundred light-years thick, slowly attenuating into noise the further out it gets.  A civilization fifty light years away that doesn't tumble across radio until 100 years from now will have missed us -- the easily-detectable stuff will have long since passed them by. 

I am not convinced that as technology advances, races become more civilized.  I mean, look at us.  We may be risen apes, but we're still apes deep inside our brains.

Of course, as you point out, space is really big.  And the light barrier isn't an engineering problem like the sound barrier was -- it's built into the way reality works.  Any first contact by radio will be a long, drawn out affair of slowly working out a mutual language to communicate with, and then gaps of centuries between questions and answers.  The vastness of space makes for a quite efficient social condom.  We would be way out of the way for anyone to mount an expedition to come beat us up, enslave us, eat us, rob us, whatever, and the resources gained would not make up for the resources expended.

So I generally agree, we shouldn't worry about being heard.  Besides, we're listening.  Every argument against us making contact can be made by any other sentient race out there.
"My faith in the Constitution is whole, it is complete, it is total, and I am not going to sit here and be an idle spectator to the diminution, the subversion, the destruction of the Constitution." -- Barbara Jordan

Offline trdsf

Re: So let's talk SETI.
« Reply #25 on: December 21, 2020, 09:44:40 PM »
What if the aliens are enormous? Looking sort of like humpback whales; filter-feeding on stars, planets and asteroids as they slowly consume entire galaxies. We would get a few decades to figure something out.
We would see that, though: stars just winking out and not coming back, rather than exploding or just fading away, unless there were only a small handful feeding on the far side of the galactic core.  Eventually one of the automated swky surveys would go, "Hey, HD612468 isn't there anymore, someone take a look at this."
"My faith in the Constitution is whole, it is complete, it is total, and I am not going to sit here and be an idle spectator to the diminution, the subversion, the destruction of the Constitution." -- Barbara Jordan

Re: So let's talk SETI.
« Reply #26 on: December 21, 2020, 10:10:23 PM »
I heard recently about a supermassive black hole they can't find...
God Not Found
"There is a sucker born-again every minute." - C. Spellman

Offline Hydra009

Re: So let's talk SETI.
« Reply #27 on: December 21, 2020, 10:14:45 PM »
I think dinnerbell is the wrong idea -- we'd need to be the same biology to be nourishing and the odds of evolution doing the same chemical thing twice are nearly, but not quite, zero.
The dinnerbell is figurative.  :P

Quote
I am not convinced that as technology advances, races become more civilized.  I mean, look at us.  We may be risen apes, but we're still apes deep inside our brains.
Subjectively, it may appear at first glance that humanity has gotten increasingly violent and nasty.  After all, every bad thing that happens gets blasted all over the news and social media.

But objectively, we have gotten better, although some parts of the world have definitely improved more than others.



Steven Pinker deals with this subject in a far more comprehensive way than I possibly could, but the long and short of it is that we live in a much more peaceable age compared to the 20th century and before.  Though I note that while armed conflicts between countries have declined sharply, more decentralized conflicts - riots, insurrections, etc - are still a worrying trend.

Quote
So I generally agree, we shouldn't worry about being heard.  Besides, we're listening.  Every argument against us making contact can be made by any other sentient race out there.
We're listening and we have no harmful intent (I hope) and yet people assume that others are listening and they have harmful intent.  It just doesn't jive with me.  And we also have to consider the cost of silence is missing out on potential aid.  People who favor silence consider the ultimate bad outcome and argue against the risk (humans are naturally risk adverse), but we actually risk a lot with silence, too.

It's like being stranded on an island and not trying to make contact with outside people under the assumption that they'd row over and murder us all.  It's certainly a possibility.  But so is every other outcome.  People illogically assign the highest weight to the most negative outcome.
« Last Edit: December 21, 2020, 10:21:35 PM by Hydra009 »

Re: So let's talk SETI.
« Reply #28 on: December 22, 2020, 07:51:42 AM »
ge amounts of surface water and has maintained it for billions of years, which appears to bode poorly for complex extraterrestrial life. 
No.

https://en.wikipedia.org/wiki/Extraterrestrial_liquid_water
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline Baruch

Re: So let's talk SETI.
« Reply #29 on: December 24, 2020, 05:43:49 PM »
"HUGE Fireball Falls From Sky In China, Are These ALIENS??" ... aliens already report that Chinese people taste like sesame chicken ;-)
Ha’át’íísh baa naniná?
Azee’ ła’ish nanídį́į́h?
Táadoo ánít’iní.
What are you doing?
Are you taking any medications?
Don't do that.