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Author Topic:   Other civilisations in the Galaxy - are they really that likely?
Omnivorous
Member
Posts: 3978
From: Adirondackia
Joined: 07-21-2005
Member Rating: 7.3


Message 46 of 77 (234644)
08-18-2005 7:29 PM
Reply to: Message 31 by Chiroptera
08-17-2005 4:19 PM


Chiroptera:
quote:
quote:
2Gyr is 1/7 of the age of the universe!
Not to mention that it took half the lifetime of the sun for intelligent life to finally come about.
Perhaps our solar system/planet is inimical to the emergence of intelligent life.

This message is a reply to:
 Message 31 by Chiroptera, posted 08-17-2005 4:19 PM Chiroptera has replied

Replies to this message:
 Message 48 by Chiroptera, posted 08-18-2005 8:16 PM Omnivorous has replied

  
Monk
Member (Idle past 3924 days)
Posts: 782
From: Kansas, USA
Joined: 02-25-2005


Message 47 of 77 (234645)
08-18-2005 7:40 PM
Reply to: Message 45 by Omnivorous
08-18-2005 7:21 PM


Hi Omni
We cannot assume that every civilization that can broadcast, will.
Very true. One of my conditional "ifs" in Message 14 was that "they" would want to contact us. You've given a few good reasons why they may not want to. It's a big assumption to attribute motivations of aliens as being similar to our own. We can only hope that there is at least one alien civilation that was as careless with their signal generation as we have been over the last 50 years so that we might hear their carelessness.

This message is a reply to:
 Message 45 by Omnivorous, posted 08-18-2005 7:21 PM Omnivorous has not replied

  
Chiroptera
Inactive Member


Message 48 of 77 (234654)
08-18-2005 8:16 PM
Reply to: Message 46 by Omnivorous
08-18-2005 7:29 PM


Perhaps our solar system is inimical to the emergence of intelligent life, yet also unusually conducive, compared to other solar systems, to the emergence of intelligent life.
Not too far fetched, seeing how little we know about solar systems in general.
Here's a strange thought that just occurred to me. A lot of evolutionary advance occurred after mass extinctions. Maybe life cannot "advance" too quickly if a planet is too stable. Maybe the emergence of intelligent life requires just the right balance of "instability" -- frequent enough mass extinctions to periodically reopen niches and further evolutionary innovation, but not so many that you end up losing what "gains" have already been made.

This message is a reply to:
 Message 46 by Omnivorous, posted 08-18-2005 7:29 PM Omnivorous has replied

Replies to this message:
 Message 49 by Omnivorous, posted 08-18-2005 8:21 PM Chiroptera has not replied
 Message 53 by cavediver, posted 08-19-2005 4:38 AM Chiroptera has not replied

  
Omnivorous
Member
Posts: 3978
From: Adirondackia
Joined: 07-21-2005
Member Rating: 7.3


Message 49 of 77 (234657)
08-18-2005 8:21 PM
Reply to: Message 48 by Chiroptera
08-18-2005 8:16 PM


Lush Life
quote:
Here's a strange thought that just occurred to me. A lot of evolutionary advance occurred after mass extinctions. Maybe life cannot "advance" too quickly if a planet is too stable. Maybe the emergence of intelligent life requires just the right balance of "instability" -- frequent enough mass extinctions to periodically reopen niches and further evolutionary innovation, but not so many that you end up losing what "gains" have already been made.
A sort of planetary punctutated equilibrium.
I was just wondering myself if a planet too conducive to life might be inimical to intelligence.
You know, like the suburbs.

This message is a reply to:
 Message 48 by Chiroptera, posted 08-18-2005 8:16 PM Chiroptera has not replied

  
Nighttrain
Member (Idle past 3994 days)
Posts: 1512
From: brisbane,australia
Joined: 06-08-2004


Message 50 of 77 (234667)
08-18-2005 8:41 PM


Puppies to bed
What if other civilisations got a headstart on us, were transmitting around a million years in our past and got no replies?
Q^6vzz: No answers?
Ogz99l: Not a peep
Q^6vzz: Let`s shut this puppy down. There`s no other intelligent life in the universe

Replies to this message:
 Message 51 by Omnivorous, posted 08-18-2005 8:45 PM Nighttrain has not replied
 Message 55 by cavediver, posted 08-19-2005 4:51 AM Nighttrain has not replied

  
Omnivorous
Member
Posts: 3978
From: Adirondackia
Joined: 07-21-2005
Member Rating: 7.3


Message 51 of 77 (234670)
08-18-2005 8:45 PM
Reply to: Message 50 by Nighttrain
08-18-2005 8:41 PM


Let's blow this popsicle stand
Nighttrain writes:
What if other civilisations got a headstart on us, were transmitting around a million years in our past and got no replies?
Q^6vzz: No answers?
Ogz99l: Not a peep
Q^6vzz: Let`s shut this puppy down. There`s no other intelligent life in the universe.
All the smart money is on the other side of the future event horizon.

This message is a reply to:
 Message 50 by Nighttrain, posted 08-18-2005 8:41 PM Nighttrain has not replied

Replies to this message:
 Message 52 by cavediver, posted 08-19-2005 4:16 AM Omnivorous has not replied

  
cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 52 of 77 (234718)
08-19-2005 4:16 AM
Reply to: Message 51 by Omnivorous
08-18-2005 8:45 PM


Re: Let's blow this popsicle stand
All the smart money is on the other side of the future event horizon.
Always a safe bet

This message is a reply to:
 Message 51 by Omnivorous, posted 08-18-2005 8:45 PM Omnivorous has not replied

  
cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 53 of 77 (234720)
08-19-2005 4:38 AM
Reply to: Message 48 by Chiroptera
08-18-2005 8:16 PM


frequent enough mass extinctions to periodically reopen niches and further evolutionary innovation, but not so many that you end up losing what "gains" have already been made.
This is a great point. It makes the "mean-free-path" from eukaryote to civilisation much much longer. My question is then, what is the shortest this path can be? We've done it in 2Gyr... is that good?
BTW, to all those saying we don't know enough to talk about any of this, one data point and all that... I think the discussion itself throws up all sorts of issues and ideas, some of which may be new and useful. We're not going to find the answer, but we may progress an extra 1% towards understanding the question.

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 Message 48 by Chiroptera, posted 08-18-2005 8:16 PM Chiroptera has not replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 54 of 77 (234721)
08-19-2005 4:40 AM
Reply to: Message 40 by Monk
08-18-2005 1:49 PM


Yes, they are. But there's two problems:
1. We couldn't detect the signals we produced unless they came from a very near star (one source quoted it at 100 lyrs, but I don't have a source for that).
2. 50, or even 100, years is a tiny, tiny window of opportunity.

This message is a reply to:
 Message 40 by Monk, posted 08-18-2005 1:49 PM Monk has replied

Replies to this message:
 Message 57 by Monk, posted 08-19-2005 11:46 AM Dr Jack has not replied
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cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 55 of 77 (234723)
08-19-2005 4:51 AM
Reply to: Message 50 by Nighttrain
08-18-2005 8:41 PM


Re: Puppies to bed
What if other civilisations got a headstart on us, were transmitting around a million years in our past and got no replies?
This is related to my reply to Chirop. When could the first civilisations arise? I'm going to track down times for the first Pop I stars.

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cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 56 of 77 (234724)
08-19-2005 4:53 AM


How long have we got?
Back to the Drake eqn... for how long is any civilisation expected to survive?
Ok, how long have we got if we do not colonise off-planet? At a max, it's red-giant phase, but I'm certain it is much much sooner than that.
If we list all the civilisation endangering (and extinction) events with their probabilities, we should be able to get an "expected time before wipe-out".

  
Monk
Member (Idle past 3924 days)
Posts: 782
From: Kansas, USA
Joined: 02-25-2005


Message 57 of 77 (234813)
08-19-2005 11:46 AM
Reply to: Message 54 by Dr Jack
08-19-2005 4:40 AM


We couldn't detect the signals we produced unless they came from a very near star (one source quoted it at 100 lyrs, but I don't have a source for that).
As time marches on, is it reasonable to assume that our signal detection technology would improve? Is there an upper physical limit to the range of detection? Hold that thought and consider the following scenarios:
  1. An advanced civilization has detected our existence and sends a message that we can detect.
  2. An advanced civilization maturing technologically along similar paths sends out uncompressed signals such that we can detect those signals without their knowledge.
  3. An advanced civilization, exploring the galaxy, stumbles upon our existence and decides to visit.
All are extremely unlikely, but how would they rank in order of probability of success?

This message is a reply to:
 Message 54 by Dr Jack, posted 08-19-2005 4:40 AM Dr Jack has not replied

  
randman 
Suspended Member (Idle past 4899 days)
Posts: 6367
Joined: 05-26-2005


Message 58 of 77 (235182)
08-21-2005 2:05 AM
Reply to: Message 38 by coffee_addict
08-18-2005 12:40 PM


Re: IPU
Jesus said preach the gospel to every creature. By that, I believe either or both, intelligent life similar to our's exists in the universe, and/or we will create such intelligent life either via genetic manipulation or artificial intelligence or a combination.
Either way or both ways, Jesus seems to envision a time where "creatures" that can hear and receive the gospel will exist side by side with natural humans.

This message is a reply to:
 Message 38 by coffee_addict, posted 08-18-2005 12:40 PM coffee_addict has not replied

  
riVeRraT
Member (Idle past 416 days)
Posts: 5788
From: NY USA
Joined: 05-09-2004


Message 59 of 77 (272781)
12-26-2005 6:09 AM
Reply to: Message 38 by coffee_addict
08-18-2005 12:40 PM


Re: IPU
The bible specifically states that water is essential for all life.
Where?
But the bible also says that God created the universe. So if anything else exists out there, then it is from him.
I often wonder about the timing. Will Jesus come back before we ever have a chance to find life? So it may be out there, but we will never know.
But I have read nothing in the bible that would exclude the rest of the universe from having life.
After all, it used to be a popular belief that American Indians couldn't breed with a Christian white person.
Well that probably EVOLVED from the verse that says something about like kind marrying like kind. I can't find it right now.
But just exactly what does that mean?
Being a white/Italian, and marrying a Puerto Rican, I can see how cultural difference can interfere with a marriage. It adds a challenge to the marriage, something that you won't really know until it's too late. But Love can conquer all.
It is from that perspective that I can start to understand that verse.

This message is a reply to:
 Message 38 by coffee_addict, posted 08-18-2005 12:40 PM coffee_addict has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 60 of 77 (272803)
12-26-2005 10:23 AM
Reply to: Message 54 by Dr Jack
08-19-2005 4:40 AM


Radio Evolution
Just a note: means of transmissions, means of conveying information over them are two different things.
Radio waves fill the universe, the question is whether information is conveyed with it.
We are currently seeing the change in both tv and radio signals from analog to digital, and this results in a different "footprint" on the radio waves. I expect future changes as well.
But what the future holds for radio usage is unpredictable -- except that the trend to condense the information as much as possible to provide enhanced reception and reduce errors will likely continue in much the same vein as the trend to increased computing power within ever smaller units.
Future radio broadcasts could be bursts of information packets similar to the way information is conveyed over the internet.
The likelyhood of path directed broadcasts is also something to consider: why waste energy broadcasting where there are no receivers?
We also see a trend of direct cable linkage that is growing and replacing broadcast radio -- radio may only be an temporary means of communication.
Then there are other possibilities:
Information can be carried by lasers as well as radio waves, the limitation for our usage is the power needed to broadcast a light show versus using it as a beam of communication. (but see burst broadcast and directed broadcast above).
Then there may be other wave systems that can be used to carry information.
Physics talks about gravity waves, and we have shown that we can modify the waves of anything in the electromagnetic spectrum to carry information. What do the physics gurus think about using gravity waves for communication? Perhaps there would be less "interference" in those waves, so more advanced civilizations would use them (and using them may be the real "test" of advanced intelligence -- proof of mastering the physics and living to take advantage of it).
Just my thoughts.
ps -- here's an interesting short story on the fermi paradox issue:
http://www.davidbrin.com/lungfish1.html (enjoy)

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This message is a reply to:
 Message 54 by Dr Jack, posted 08-19-2005 4:40 AM Dr Jack has not replied

Replies to this message:
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