Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Milky Way is probably full of dead civilizations

livescience.com

Post reply on HN
Print view View original

41–50 of 62 posts

Re: The Milky Way is probably full of dead civilizations

#41

Post by JoeyJoJoJr »

vikingerik wrote: post #13
thomassmith65 wrote: post #2

It seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently. Radio waves take time to travel; there could be many civilisations out there whose signals haven't had time to reach us. If that's the case, we're just the first intelligent civilisation to evolve in our immediate vicinity.

This isn't likely. The Milky Way is 100k light years in diameter. That's tiny relative to the age of life. Animals comparable to humans in complexity have existed for something like 250 million years on Earth, and could have on planets of stars that formed billions of years before our sun. The possible timespan for signal-emitting life to have developed is many multiples of the timespan that signals take to cross the…

This is tangential to what you are saying, but does it blow any else’s mind that we just so happen to exist right at the start of the universe’s existence? If the universe is going to have a habitable window of however many quadrillion years, what are the odds that it just so happens that our existence falls within the first blink of that timeframe. If life is abundant in the universe it would stand to reason that it will continue to be abundant for a very, very long time. Further, if I am to spawn in the universe as a self conscious being, wouldn’t it be likely I would spawn at a random point on (almost) the total timeline of the habitable universe? So then the odds of existing (basically) right at the beginning of the timeline is exceptionally small, unless there is some factor that influences where on the timeline we must exist.

Re: The Milky Way is probably full of dead civilizations

#42

Post by Qem »

CheeseFromLidl wrote: post #28
thomassmith65 wrote: post #2

It seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently. Radio waves take time to travel; there could be many civilisations out there whose signals haven't had time to reach us. If that's the case, we're just the first intelligent civilisation to evolve in our immediate vicinity.

From our 1 datapoint set I’m leaning towards the “earth is an aberration” theory. This was a dinosaur planet. There was a reset some time ago that cleared the path for mammals. It’s unlikely that this timing is common.

It was recently proposed the hypothesis we suceeded at developing intelligence while dinosaurs failed because humans evolved under the lowest levels of atmospheric CO2 in the entire history of Earth, allowing brain upscaling, at least until we botched it in the last 2 centuries. See https://www.qeios.com/read/IKNUZU

Re: The Milky Way is probably full of dead civilizations

#43

Post by Balgair »

The composition of the universe is:

~5% matter and energy. The stuff you and I, dollhouses, dogs, and sugarcubes are made up of. Of that about 99.9% of it is very hot stars.

~20% dark matter. This is currently under investigation, but really all we know about it is that it is incredibly sparse and falls down.

~75% dark energy. We know nearly nothing about it except that it falls up (?!)

Point is, if there are other civilizations out there, and they have been existing for even a few thousand years longer than our has, a cosmic eyeblink, they are probably not just using matter and energy anymore. Heck, their understanding of physics is so much more than ours, even comparing us to Plato and them to Devoret is an insult.

Re: The Milky Way is probably full of dead civilizations

#44

Post by Sil_E_Goose »

JoeyJoJoJr wrote: post #41
vikingerik wrote: post #13

Earlier quoted context omitted.

This isn't likely. The Milky Way is 100k light years in diameter. That's tiny relative to the age of life. Animals comparable to humans in complexity have existed for something like 250 million years on Earth, and could have on planets of stars that formed billions of years before our sun. The possible timespan for signal-emitting life to have developed is many multiples of the timespan that signals take to cross the…

This is tangential to what you are saying, but does it blow any else’s mind that we just so happen to exist right at the start of the universe’s existence? If the universe is going to have a habitable window of however many quadrillion years, what are the odds that it just so happens that our existence falls within the first blink of that timeframe. If life is abundant in the universe it would stand to reason that it…

Mr. Shabadoo, you might be interested in the doomsday argument if you are not already familiar.

https://en.wikipedia.org/wiki/Doomsday_argument

Re: The Milky Way is probably full of dead civilizations

#45

Post by gregbot »

intended wrote: post #12
amanaplanacanal wrote: post #3

Looks like a bullshit paper. This big question mark is: assuming life evolves on a suitable planet, what are the odds that something like an intelligent technological species would ever evolve? We only have one example: us. You can't extrapolate from that, so they just made up numbers.

By this criteria - all papers that extrapolate are BS papers. There’s a ridiculous number of stars in the sky - no matter how low you put the odds of intelligent life, you will still end up with more than 1 civilized species in the universe. This is, at least for me, the primary utility of such extrapolations. And eventually - extrapolations will be tested.

Extrapolating from multiple good data points and making up a number based on zero examples are absolutely not the same thing.

Re: The Milky Way is probably full of dead civilizations

#46

Post by d4rkn0d3z »

jiggawatts wrote: post #39
d4rkn0d3z wrote: post #30

I read a paper a long while back that used purely numerical arguments to first show a common rate in the growth of complexity across biological and non-biological systems under similar conditions. It then plotted this exponential growth backwards in time, showing that life's origins were prior to the formation of earth by about 1.5 billion years. No guesswork, it was quite solid; the same math applied to human techno…

Obligatory: https://xkcd.com/605/ That paper used a horribly faulty logical argument because it has been well known for quite a while that most of the time evolution is quite slow, but there are short bursts of rapid change. For example: https://en.wikipedia.org/wiki/Cambrian_explosion See: https://en.wikipedia.org/wiki/Punctuated_equilibrium

The "obligatory" doesn't apply since that paper did not extrapolate. It would be the exact opposite.

I'm pretty sure the issue you raise is averaged away quite neatly by the math.

Re: The Milky Way is probably full of dead civilizations

#47

Post by ahazred8ta »

pols45 wrote: post #5
thomassmith65 wrote: post #2

It seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently. Radio waves take time to travel; there could be many civilisations out there whose signals haven't had time to reach us. If that's the case, we're just the first intelligent civilisation to evolve in our immediate vicinity.

Not really. Microbes have been around for a long time. And there are more of them today than there are stars in the sky. No intelligence required. Plus they change so fast that what Life looked like yday can look totally different tomorrow. As Lynn Margulis would say the chimps aren't the main show. Intelligence maybe an over rated and very buggy feature of Life. And the bugs get amplified as the minds interact with…

"The anthropologists got it wrong when they named our species Homo sapiens ... In reality, we are Pan narrans, the storytelling chimpanzee." ― Terry Pratchett

Re: The Milky Way is probably full of dead civilizations

#48

Post by jiggawatts »

d4rkn0d3z wrote: post #46
jiggawatts wrote: post #39

Earlier quoted context omitted.

Obligatory: https://xkcd.com/605/ That paper used a horribly faulty logical argument because it has been well known for quite a while that most of the time evolution is quite slow, but there are short bursts of rapid change. For example: https://en.wikipedia.org/wiki/Cambrian_explosion See: https://en.wikipedia.org/wiki/Punctuated_equilibrium

The "obligatory" doesn't apply since that paper did not extrapolate. It would be the exact opposite. I'm pretty sure the issue you raise is averaged away quite neatly by the math.

They literally extrapolated backwards in time. Extending your data in time is extrapolation, whether that’s forward or backward!

Re: The Milky Way is probably full of dead civilizations

#49

Post by JoeyJoJoJr »

Sil_E_Goose wrote: post #44
JoeyJoJoJr wrote: post #41

Earlier quoted context omitted.

This is tangential to what you are saying, but does it blow any else’s mind that we just so happen to exist right at the start of the universe’s existence? If the universe is going to have a habitable window of however many quadrillion years, what are the odds that it just so happens that our existence falls within the first blink of that timeframe. If life is abundant in the universe it would stand to reason that it…

Mr. Shabadoo, you might be interested in the doomsday argument if you are not already familiar. https://en.wikipedia.org/wiki/Doomsday_argument

Oh cool, this is interesting!

Re: The Milky Way is probably full of dead civilizations

#50

Post by gizajob »

Panzerschrek wrote: post #33
gizajob wrote: post #32

Earlier quoted context omitted.

It’s not really possible to say that it is certain given we haven’t looked very hard or for very long. We don’t even know if there’s life in nearby places like Enceladus.

We don't need to look hard. If interstellar travel is possible and someone in our Galaxy have developed it in the past, the whole Solar System including Earth should be already colonized.

There are many other answers to why it isn’t outside of “they should have done this but haven’t and therefore cannot exist”.
Post reply on HN