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Author Topic: Where are the extraterrestrials ?  (Read 13029 times)

Offline Pmb

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Re: Where are the extraterrestrials ?
« Reply #25 on: 20/02/2013 19:33:53 »
Amoung many other very important factors I think that the most imporotant factor is that intelligent life is so rare that its two species living so close togther in interstellar space is next to zero. It's just too difficult to comminicate over those distances with any technologym, even ones that we haven't been exposed to at all.
 

Offline CliffordK

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Re: Where are the extraterrestrials ?
« Reply #26 on: 20/02/2013 20:22:11 »
If someone is trying to publish the DNA sequence of Sasquatch, we should next see a publication of the DNA of "Aliens", and alien-human hybrids, showing startling similarities to the researcher's own DNA.

The prerequisite for intelligent life is just life.  And, unfortunately we don't know how common either one is, or whether it is possible for life to be something other than hydrogen/carbon/oxygen/water based. 

"Nearby" is all relative, astronomically speaking.  There about 260,000 stars within 250 light years of Earth. 

The two-way communication delay would be quite extraordinary between systems 250 light years apart, but one could imagine sharing data streams over moderate astronomical distances, even if direct travel is not practical.

The question is whether "life" or "intelligent life" is more common than 1:260,000
 

Offline syhprum

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Re: Where are the extraterrestrials ?
« Reply #27 on: 20/02/2013 21:15:20 »
I sometimes wonder if the extra-terrestrials have a different conception of time to us so that instead of looking for signals in a 1 Hz bandwidth we should be looking at a 0.001 Hz bandwidth. 
 

Offline CliffordK

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Re: Where are the extraterrestrials ?
« Reply #28 on: 20/02/2013 22:49:38 »
The bandwidth of the signal would depend somewhat on one's ability to decode the signal.  I'm not real familiar with computer communications, but it would not be too surprising to use multiple channels for parallel communication, using as tight of frequency separation as could be discerned.  Perhaps adding a timer signal to correct for frequency shifts.  To an outsider, such parallel data transfers might look like "noise".

Our radio signals, of course, incorporate both amplitude modulation (AM) and frequency modulation (FM).

If one wished to initiate "first contact" with an alien species, say 250 light years away, I would think one would choose a very simple signal until one could ascertain that both parties were listening, then choose a more complex pattern.  Or, perhaps both transmit a simple AM signal, as much to get attention as anything else, as well as a much more complex data transfer signal.  Could you embed the key for the complex signal in the simple AM signal?

Of course, if one was just intercepting communication such as we use to voyager, and various satellites and deep space probes, then that would depend on the technology at the time of manufacture.

Anyway, a "first contact" signal should also be transmitted continuously, or as continuous as possible, just to increase the possibility that someone is listening.
 

Offline evan_au

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Re: Where are the extraterrestrials ?
« Reply #29 on: 21/02/2013 10:45:18 »
Dolphins live in the sea, so that makes them non-terrestrial.
Why can't we learn to communicate with them, first?
 

Offline yor_on

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Re: Where are the extraterrestrials ?
« Reply #30 on: 25/02/2013 20:04:02 »
You know Evan. I think we do know how to communicate with other animals here. We just don't notice that we do. And sometimes we don't want to notice it either, consider how many cultures that treat animals as less than humans, then consider how we use them for our food industries. To do the same with humans would indeed be inhuman, but seems acceptable when it comes to other species.
 

Offline Pmb

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Re: Where are the extraterrestrials ?
« Reply #31 on: 26/02/2013 01:10:00 »
I think spending millions of dollars on trying to contact something in space is rediculous. .
It's hardly ridiculous since it would answer a question that we've all been asking since the man walked the Earth: Are we alone?

It would make an immense difference to everyone on the planet. Hardly a ridiculous effort.
 

Offline syhprum

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Re: Where are the extraterrestrials ?
« Reply #32 on: 26/02/2013 07:57:14 »
I do not think SETI ridiculous but rather futile if we did find evidence of intelligent life the distance would probably be so great that with the large time delay any conversation would be impossible 
 

Offline imatfaal

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Re: Where are the extraterrestrials ?
« Reply #33 on: 26/02/2013 09:40:54 »
Syhprum - I agree with Pete, it would be an incredibly important moment in world history, finally knowing we are not alone.  I think it would alter the way we approach many things
 

Offline CliffordK

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Re: Where are the extraterrestrials ?
« Reply #34 on: 26/02/2013 18:14:07 »
If we wished to establish communication with aliens, perhaps the best thing to do would be to broadcast a "here we are" signal.

The likelihood that a single burst sent towards a neighboring star would be picked up would be low.

Earth, of course, "leaks" some radio waves, but not at a power or design to attract attention of extraterrestrials.  Perhaps communication satellite uplinks, but even those would tend to sweep around the sky on a 24 hour basis, and not give continuous coverage anywhere.

What we really would need is a powerful omnidirectional broadcast antenna sending out, a simple, but unmistakably artificial signal.  Then on a different frequency, perhaps a weaker signal carrying a digital photo dictionary, uncompressed, of course, and other selected communication.  Embed information to find the second signal in the first one.  And, if a response is received, to expect to send directed communication on a 3rd frequency.

And the signal pair would have to be continuously maintained for thousands, or perhaps millions of years, while always scanning for a response.

If we are unable to, or unwilling to invest in initiating contact, why would one think that an alien race would be doing it?
 

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Re: Where are the extraterrestrials ?
« Reply #34 on: 26/02/2013 18:14:07 »

 

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