The evolution of complex life

[Doc Dutch]

I never said that. I don't think intelligent life requires the ability to generate radio frequency broadcasts. In fact the VAST majority (probably about 99.999999%) of the time humans have been on the earth we didn't broadcast any electromagnetic signature and certainly not in sufficient quantity to be a detectable coherent signal light years away.

We clearly disagree on what counts as "life" and even what counts as "advanced lifeforms". I take a broader view that radio communication is not a necessary component of a life form to still count as an advanced complex life form.

Sure, it took Earth lifeforms about 4.5B years to generate radio signals. As mentioned before, the oldest starts in our galaxy are over 13B years. Seems like they've had enough time.

"So long and thanks for all the fish!"

[Cypress]

It actually kind of does, though. You are correct most of them are probably from inorganic sources, but indeed they are a sign that the building blocks of life are ubiquitous. The only thing missing is their coalescence into a life form which is trivial compared to the compounds themselves. It's how they react naturally.



Not really. Condensation of amino acids into proteins happens spontaneously and protein's complexity mostly rises from the secondary structures (alpha helices, beta sheets,etc) which are a function of the arrangement of the molecules in the protein and hydrogen bonding between the various regions.




I totally agree that it has yet to be done using "estimated starting processes" in the lab but it is most assuredly done every single day in PCR machines all over the world.




But you just noted that things like methane are ubiquitous and not necessarily related to life.

It is mostly handwaving to assume spectroscopy can solve all the problems. It can't. That isn't how it works. Spectroscopy of an entire planet would be of limited utility unless it somehow showed an atmosphere completely filled to the brim with DNA molecules. I think we can both agree that's not a sign of life and it's unlikely even if life existed on the planet that the atmosphere would have enough DNA to show up on a spectroscopy analysis of the planet viewed from several light years away.

I think the unusual properties of carbon and water make it seem like the universe is primed for life.

Between carbon, water, amino acids, nitrogen, phosphorus we have 95 percent of the building blocks of life. But what we don't really have is a fix on the process that puts it all together.

[Saint Guinefort]

Sure, it took Earth lifeforms about 4.5B years to generate radio signals. As mentioned before, the oldest starts in our galaxy are over 13B years. Seems like they've had enough time.

"So long and thanks for all the fish!"

That's an arbitrary goal, though. Why would anyone necessarily produce radio waves? As I said humanity existed for the vast majority of its time without any electromagnetic signature. So why do you think that radio and tv broadcasts (or even microwave broadcasts) would be somehow EXPECTED just because we developed it?

I'm saying the universe may be TEAMING with life that is as advanced as say...the 18th century. That's pretty advanced life, wouldn't you agree? How would we detect that? The fact is we can't.

And it doesn't mean that no life exists out there, it just means no life that has developed the ability to generate radio waves and had sufficient time for those waves to make it all the way to us has been discovered.

That is a VERY narrow sub-species of the concept of "complex life". It's even a sub-sub-sub-species of a "technologically advanced society".

[Cypress]

You're leaping to conclusions again, Perry PhD.

Yes, life can exist without intelligence and radios. However, life continues to evolve over time. Given enough time, those evolving lifeforms will advance enough to leave their planet, which means they'll use the natural laws of the Universe to communicate.

You are free to believe that out of 100 thousand million stars, only humans invented radio communications, but I disagree.

I don't think is an inevitable foregone conclusion that intelligent life capable of technology is automatically a consequence of evolution. Life has existed for 3.5 billion years. Radios have existed for 100 years.

And the dominance of mammals and their progeny, the primates, might be a consequence of a lucky asteroid strike 66 million years ago

[Doc Dutch]

I don't think is an inevitable foregone conclusion that intelligent life capable of technology is automatically a consequence of evolution. Life has existed for 3.5 billion years. Radios have existed for 100 years.

And the dominance of mammals and their progeny, the primates, might be a consequence of a lucky asteroid strike 66 million years ago

The Earth has experienced at least five mass extinction events. Without anything to compare it to, it's impossible to know if that is average, above average or below average.

Even so, our solar system is young at less than half the age of other stars in our galaxy. Either we are very, very lucky or life is very, very rare.


https://www.discovermagazine.com/pla...ss-extinctions

https://www.livescience.com/mass-ext...ped-Earth.html
The 5 mass extinctions

Ordovician-Silurian extinction: ~ 440 million years ago
Species made extinct: 85%

Late Devonian extinction: ~ 365 million years ago
Species made extinct: 75%

Permian-Triassic extinction: ~ 253 million years ago
Species made extinct: 96% marine life; 70% terrestrial life

Triassic-Jurassic extinction: ~ 201 million years ago
Species made extinct: 80%

K-Pg extinction: ~ 66 million years ago
Species made extinct: 75%

[NiftyNiblick]

The Earth has experienced at least five mass extinction events. Without anything to compare it to, it's impossible to know if that is average, above average or below average.

Even so, our solar system is young at less than half the age of other stars in our galaxy. Either we are very, very lucky or life is very, very rare.


https://www.discovermagazine.com/pla...ss-extinctions
The 5 mass extinctions

Ordovician-Silurian extinction: ~ 440 million years ago
Species made extinct: 85%

Late Devonian extinction: ~ 365 million years ago
Species made extinct: 75%

Permian-Triassic extinction: ~ 253 million years ago
Species made extinct: 96% marine life; 70% terrestrial life

Triassic-Jurassic extinction: ~ 201 million years ago
Species made extinct: 80%

K-Pg extinction: ~ 66 million years ago
Species made extinct: 75%

Here' the thing, Uncle Doc.

Life isn't rare enough, because if the rewards don't adequately compensate the travails in sentient life,
which is the case in an awful lot of such life,
life is then a net-negative experience.

Only average intellectual acuity is required to recognize that, but being willing to accept it requires a little bit more..

[Doc Dutch]

Here' the thing, Uncle Doc.

Life isn't rare enough, because if the rewards don't adequately compensate the travails in sentient life,
which is the case in an awful lot of such life,
life is then a net-negative experience.

Only average intellectual acuity is required to recognize that, but being willing to accept it requires a little bit more..

What are you drinking, neef?

[NiftyNiblick]

What are you drinking, neef?

Dunkin Donuts K Cup coffee, well fortified with sambuca, as I do every night since they invented the Keurig machine.

Congrats on finding a new user name, by the way.

You DO have skills, such as they are.

[Doc Dutch]

Dunkin Donuts K Cup coffee, well fortified with sambuca, as I do every night since they invented the Keurig machine.

Congrats on finding a new user name, by the way.

You DO have skills, such as they are.

Is it laced with Jameson's or Baileys?

Thanks. I'm having fun with it.

As many women have said before you.

[NiftyNiblick]

Is it laced with Jameson's or Baileys?

Thanks. I'm having fun with it.

As many women have said before you.

I'm pretty sure I said Sambuca.
I do have both Jameson's and Baileys on the bar, along with a lot of other stuff that never gets touched,
but I'm partial to the beverages of my own people.

[Doc Dutch]

I'm pretty sure I said Sambuca.

I do have both Jameson's and Baileys on the bar, along with a lot of other stuff that never gets touched,

but I'm partial to the beverages of my own people.

Thanks. I missed the reference...and have never drank it.

Both are great in coffee.

I like to branch out.

[Cypress]

The Earth has experienced at least five mass extinction events. Without anything to compare it to, it's impossible to know if that is average, above average or below average.

Even so, our solar system is young at less than half the age of other stars in our galaxy. Either we are very, very lucky or life is very, very rare.


https://www.discovermagazine.com/pla...ss-extinctions

https://www.livescience.com/mass-ext...ped-Earth.html
The 5 mass extinctions

Ordovician-Silurian extinction: ~ 440 million years ago
Species made extinct: 85%

Late Devonian extinction: ~ 365 million years ago
Species made extinct: 75%

Permian-Triassic extinction: ~ 253 million years ago
Species made extinct: 96% marine life; 70% terrestrial life

Triassic-Jurassic extinction: ~ 201 million years ago
Species made extinct: 80%

K-Pg extinction: ~ 66 million years ago
Species made extinct: 75%

My two cents.

If intelligence is an inevitable consequence of evolution,
and not a random consequence of a perfect storm of events, whyy didn't it ever happen before? Why did it take 3 billion years?

As for 12 billion year old stars: those stars and their stellar systems are depleted in heavy elements. No heavy elements, no life. Heavy elements in any significant abundance was a relatively late introduction to the universe, because they are only created in Type I supernovae. The early universe and the early generation stars were virtually completely hydrogen and helium.

Life is not possible in a hydrogen and helium environment. Life needs carbon, oxygen, nitrogen, iron, etc.

Our stellar system got lucky. We have a relatively young star which formed from nebula enriched in heavy elements.

[NiftyNiblick]

Our stellar system got lucky. We have a relatively young star which formed from nebula enriched in heavy elements.

Again, we're making the value judgement that having environs conducive to life was lucky.
There is no misery on lifeless planets.

It always boils down to the same thing:

Do the rewards adequately compensate the travails?

Every instance where the answer is 'No" is an example where life was a negative event.

[Doc Dutch]

My two cents.

If intelligence is an inevitable consequence of evolution,
and not a random consequence of a perfect storm of events, whyy didn't it ever happen before? Why did it take 3 billion years?

As for 12 billion year old stars: those stars and their stellar systems are depleted in heavy elements. No heavy elements, no life. Heavy elements in any significant abundance was a relatively late introduction to the universe, because they are only created in Type I supernovae. The early universe and the early generation stars were virtually completely hydrogen and helium.

Life is not possible in a hydrogen and helium environment. Life needs carbon, oxygen, nitrogen, iron, etc.

Our stellar system got lucky. We have a relatively young star which formed from nebula enriched in heavy elements.

Agreed on intelligence. It goes with the Red Queen Hypothesis. The extinction events may be part of the answer on why intelligence didn't evolve faster.

Also agreed on Type I/II stars. Still, the oldest Population I stars are 10B years, about twice our Sun's age.

https://www.astronomynotes.com/ismnotes/s9.htm

The Population I stars are in the disk component of the Galaxy. They have a wide range of ages, from 0 to 10 billion years old. The youngest ones are in the spiral arms. Population I star orbits are orderly: roughly circular orbits close to the mid-plane of the galactic disk. Young star clusters made of Population I stars are called open clusters because the stars are loosely bound together, in contrast to the old, concentrated globular clusters.

[Cypress]

Again, we're making the value judgement that having environs conducive to life was lucky.
There is no misery on lifeless planets.

It always boils down to the same thing:

Do the rewards adequately compensate the travails?

Every instance where the answer is 'No" is an example where life was a negative event.

Let's just say it was unusual that our solar system formed out of a nebula that was relatively enriched in heavy elements, making life here possible.