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Aliens on 1k nearby stars could see us, new study suggests

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Re: Aliens on 1k nearby stars could see us, new study suggests

#101

Post by Baeocystin »

saas_sam wrote: post #95
tsimionescu wrote: post #92

Given that life only appeared once on earth in 3.5 billion years on Earth, the Milky Way is around 14 billion years old, we don't really have a good reason to believe there were more than a handful of abiogenesis events in the history of the galaxy. Of course, its possible this is completely wrong, perhaps the Earth was completely unlucky, or perhaps there have been many abiogenesis events and they have just failed f…

Is "life only appeared once on earth" an accepted fact at this point? There was clearly at least one occurrence that led to a subsequent successful reproductive pattern from which we evolved, but prior to that, or alongside that, it strikes me as pretty unlikely that we would be able to discover other fleeting abiogenesis events. We just discovered new salivary glands in human heads. Organs. Not microscopic ones. The…

No. We have a Last Universal Common Ancestor, but that says nothing about whether or not there were other independently-formed branches that were competing at the time.

My personal opinion is that life under early Earthlike conditions was/is almost a guarantee. There is compelling evidence that life already existed in and survived the Late Heavy Bombardment- that's very early in our planet's history. If it was truly a rare event that sparked things off, I would expect it to have occurred much later in the planet's history.

https://en.wikipedia.org/wiki/Late_Heavy_Bombardment#Geologi...

Re: Aliens on 1k nearby stars could see us, new study suggests

#102

Post by Baeocystin »

tsimionescu wrote: post #86
deeeeplearning wrote: post #71

Earlier quoted context omitted.

Given the age of the Milky Way, a civilization using even slow sub light travel with generation ships or autonomous probes could have colonized the entire galaxy many times over. Why has no one done that? Hence the paradox.

There are problems of resiliency and energy storage that could be more or less fundamental problems. It could take millions if years of technological civilization to produce a machine capable of sustaining life for the hundreds of thousands of years necessary for interstellar travel, and civilizations may tend to collapse for various reasons before reaching such technological peaks. It's also entirely possible that w…

>Think about the fact that in 3.5 billion years there hasn't been any new abiogenesis on the only planet in the universe we know for sure can sustain life, and in this billion years a single life form has ever evolved from a single-cell to multi-cellular life, aren't the priors pretty decent that life is an extremely rare phenomenon?

Any freshly-evolved life would have to compete with organisms that have already been honing their survival strategies for literal billions of years. There's no reason to think such a thing is possible, and the lack of it doesn't speak one way or another to the difficulty of it happening in a virgin environment.

Re: Aliens on 1k nearby stars could see us, new study suggests

#103

Post by njarboe »

buran77 wrote: post #60
beamatronic wrote: post #41

Earlier quoted context omitted.

That’s why the best thing any species can do for the other species is to leave signs that we were once here.

We still need to leave a heck of a collection. On a living, evolving planet if all civilizations are gone the signs get wiped out pretty fast in geological time (geology, weather), and in space the signs are usually traveling in the emptiness with little chances of being spotted. The best probes will eventually fail and will just add to the countless objects floating never to encounter anything. I know it sounds depr…

On the other hand, large objects made by us on the Moon could last for 100's of millions of years. Especially if the object was designed to last that long.

Re: Aliens on 1k nearby stars could see us, new study suggests

#104

Post by godelski »

koheripbal wrote: post #49
Madmallard wrote: post #40

Earlier quoted context omitted.

If you didn't know what ants were already they probably would be interesting

Sure, but if you were a billion years old and had seen ants before, it's unlikely that you'd take interest in any specific ant hill you walk by.

Idk, there are still people that study ants. Both professionally and as a hobby. Just because you don't care doesn't mean someone doesn't. I don't know why the same wouldn't be true for aliens. Unless those aliens are ant like (hive mind...ish)

Re: Aliens on 1k nearby stars could see us, new study suggests

#105

Post by bena »

deeeeplearning wrote: post #91
bena wrote: post #83

Earlier quoted context omitted.

Yes, I know the paradox. It's simple. It's too simple. It has huge assumptions. Namely the assumption that the current problems to colonization can be solved in a cost-effective manner. The longest continuous length of time spent in what limited space flight we have is just under 440 days. Not to mention, all of it was spent in low Earth orbit. Once we go beyond that, we lose all protection from the Earth's magnetosp…

You talk like this is all expected to be done by 21st century humans when in reality if there were civilizations out there capable of doing this colonization they would likely be millions of years our elders and its incredibly foolish to try to guess their intentions or the capabilities of their technology. Your view is painfully anthropocentric. Just to add, there are plenty of valid criticisms or plausible solution…

You talk like this is all a forgone conclusion. Technology is not magic. Time is not a salve that solves all issues.

You say that my view is "painfully anthropocentric", but how?

It seems your only response is "but aliens". That is not good enough.

You want to say that it is foolish of me to try and guess their intentions and capabilities, but that's what the paradox does as well. It assumes their intentions are to colonize and their capabilities allow it. With no proof. The only life we have to base anything off of is right here.

And if you think I haven't identified a single valid criticism of the Fermi paradox, then I'm just going to assume you aren't aware of the criticisms.

I've basically touched on this one https://en.wikipedia.org/wiki/Fermi_paradox#Economic_explana...

So no, I'm not saying that just because it can't be done now, it can't be done ever. I'm saying the Fermi Paradox is basically saying "Once you solve these incredibly hard problems, this becomes easy."

I think the Fermi Paradox is phrased wrong. It should state that if it were possible to colonize the galaxy, it would have been done by now.

Re: Aliens on 1k nearby stars could see us, new study suggests

#106

Post by Baeocystin »

e12e wrote: post #99
eloff wrote: post #74

Earlier quoted context omitted.

I don't know why this got down-voted. The milky way is 100K light years across. It's 13.5 billion years old. It's entirely possible to blanket the whole galaxy with probes, without even getting into self replicating probes.

You have to make an assumption about speed - it certainly won't be more than a tiny fraction light speed. Eg voyager appear to travel now at less than 0.00006 c (16 km/s). Than turns 100k light years into ballpark 150 M year journey (no it doesn't its 1.8 bn years as mentioned in reply) . Still possible to cross 10.000 times - but that would be a straight line. I suspect the distances will grow somewhat fractally if…

To traverse 100k light-years at 16km/s would take approximately 1.8 billion years. FWIW.

Re: Aliens on 1k nearby stars could see us, new study suggests

#107

Post by mistersquid »

e12e wrote: post #99
eloff wrote: post #74

Earlier quoted context omitted.

I don't know why this got down-voted. The milky way is 100K light years across. It's 13.5 billion years old. It's entirely possible to blanket the whole galaxy with probes, without even getting into self replicating probes.

You have to make an assumption about speed - it certainly won't be more than a tiny fraction light speed. Eg voyager appear to travel now at less than 0.00006 c (16 km/s). Than turns 100k light years into ballpark 150 M year journey (no it doesn't its 1.8 bn years as mentioned in reply) . Still possible to cross 10.000 times - but that would be a straight line. I suspect the distances will grow somewhat fractally if…

> Than turns 100k light years into ballpark 150 year journey.

Forgive my confusion.

If 100K light years is 100K years at c, how can

> 0.00006 c

yield 0.00150K (150) years?

Re: Aliens on 1k nearby stars could see us, new study suggests

#109

Post by e12e »

Baeocystin wrote: post #106
e12e wrote: post #99

Earlier quoted context omitted.

You have to make an assumption about speed - it certainly won't be more than a tiny fraction light speed. Eg voyager appear to travel now at less than 0.00006 c (16 km/s). Than turns 100k light years into ballpark 150 M year journey (no it doesn't its 1.8 bn years as mentioned in reply) . Still possible to cross 10.000 times - but that would be a straight line. I suspect the distances will grow somewhat fractally if…

To traverse 100k light-years at 16km/s would take approximately 1.8 billion years. FWIW.

Thanks, not sure how I got to just 150 mill years.

Re: Aliens on 1k nearby stars could see us, new study suggests

#110

Post by baja_blast »

tsimionescu wrote: post #92

Given that life only appeared once on earth in 3.5 billion years on Earth, the Milky Way is around 14 billion years old, we don't really have a good reason to believe there were more than a handful of abiogenesis events in the history of the galaxy. Of course, its possible this is completely wrong, perhaps the Earth was completely unlucky, or perhaps there have been many abiogenesis events and they have just failed f…

Why would there be multiple abiogenesis events? It seems once life evolves it can survive a lot and has all extinction events. The fact life occurred almost immediately after it formed suggests abiogenesis is common and more the rule as opposed to the exception. Multicellular life on the other hand could be much rarer since it took billions of years to happen.
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