Alien Life, Coming Slowly Into View

[Torplexed]

Originally Posted by August

What would it take to broadcast a signal that can be read on a distant planet? Power obviously. Lots and lots of power, but in what form?
Radio Frequency, Light, Microwave?

No matter what form one uses signal attenuation is gonna be a bear.

Actually, it was purposely done once here on Earth that I know of from the giant Arecibo radio telescope in Puerto Rico. Although, arguably more as a PR stunt than anything else.

http://en.wikipedia.org/wiki/Arecibo_message

The Arecibo message was broadcast into space a single time (not repeated) via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close collection of stars that was available in the sky at the time and place of the ceremony.The message consisted of 1679 binary digits, approximately 210 bytes, transmitted at a frequency of 2380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 1000 kW. The "ones" and "zeros" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes.

The binary 'message' consists of:

1. The numbers one (1) through ten (10)
2. The atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up deoxyribonucleic acid (DNA)
3. The formulas for the sugars and bases in the nucleotides of DNA
4. The number of nucleotides in DNA, and a graphic of the double helix structure of DNA
5. A graphic figure of a human, the dimension (physical height) of an average man, and the human population of Earth
6. A graphic of the Solar System
7. A graphic of the Arecibo radio telescope and the dimension (the physical diameter) of the transmitting antenna dish

However, the chances, even if our galaxy is teeming with life, of someone listening, at the right frequency, at the right time, in the right direction is so mathematically remote as to be barely worth considering.

[Sammi79]

Originally Posted by August

Don't be so sure. People who witnessed the Wright Brothers first flight were on hand to watch man land on the moon.

Well it is certainly not impossible, and I would be overjoyed if it were to happen within my lifetime, however - the problems of the vastness of the universe compound the calculations, for a start the observable part extends for roughly 13.7 billion light years. For us to 'hear' a signal from another intelligent transmitter we need to be close, within our own galaxy at least (a few hundred light years max). The probablity (given the physical vastness of what we can see) that this might happen is an infintesimal or very very close to 0. Then we have the problem of time. How big or long is time? even if the universe is teeming with life, the probability that 2 intelligent lifeforns evolve within the same window of time (a few thousand or possibly 10s of thousands of years)- is again an infintesimal. Multiply these 2 probabilities together, because we need to be not only physically close but also close enough in time and the result you get (even if as we suspect life is common in the universe) is so close to 0 as to be not really worth thinking about. Even if life is common (and we have no proof that it is yet) It is very likely that right now in our time, no other life exists within our universe.

Still, here's to hoping. No reason to stop looking.

[Gerald]

Originally Posted by Torplexed

Actually, it was purposely done once here on Earth that I know of from the giant Arecibo radio telescope in Puerto Rico. Although, arguably more as a PR stunt than anything else.

http://en.wikipedia.org/wiki/Arecibo_message

However, the chances, even if our galaxy is teeming with life, of someone listening, at the right frequency, at the right time, in the right direction is so mathematically remote as to be barely worth considering.

Interesting reading on the Arecibo message, it is truly an amazing versatility that you can not take on

[Torplexed]

And then you've got physicists like Stephen Hawkins who advocate that, than rather than trying to establish contact, humankind should try to avoid contacting alien life forms. "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans." However, he doesn't seem to be opposed to interstellar eavesdropping.

[Gerald]

Originally Posted by Torplexed

And then you've got physicists like Stephen Hawkins who advocate that, than rather than trying to establish contact, humankind should try to avoid contacting alien life forms. "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans." However, he doesn't seem to be opposed to interstellar eavesdropping.

In the previous post here, discussed the form in which the signal can come from, and it could be basically anywhere, then our references are severely restricted, to reasonably speculate as to new technology or similar equipment get permission, to get a "perspective" which is difficult to take you mentioned the people like Stephen Hawkins does not see potential in this kind of signals intelligence

[August]

Originally Posted by TLAM Strike

Radio and Microwaves are light.

Electromagnetic energy actually, which includes visible "light". All have different frequencies which affect propagation.

Space is a wonderful medium for radio signals. Those involved in SETI seem confident that the signals we sent on purpose to some near by stars could be read if someone was there.

I was reading somewhere awhile back that there is some doubt that those signals could be distinguished from background noise.

[Gerald]

Originally Posted by August

Electromagnetic energy actually, which includes visible "light". All have different frequencies which affect propagation.



I was reading somewhere awhile back that there is some doubt that those signals could be distinguished from background noise.

Possible with the right equipment and qualified personnel, which is not an easy task, when there is always a constant audio stream

[danlisa]

Doesn't the active search for ET Life seem a little pointless?

Correct me if I'm wrong but I understand the following:

Signals we send out: These take an inordinate amount of time to reach anywhere, receiving a response would take double that. Within the transit time it's conceivable that the replying world would no longer exist by the time the signal reached us. This also applies to listening to space 'signals'.

Identifying habitable planets: Again, the time involved is mind boggling. We can ID a planet that's billions of light years away and say that's a possible earth clone but that image we captured has taken billions of years to reach us. The originating planet would now probably be a hunk of space rock.

What am I missing and how much funding is put to this?

[Gerald]

Not a lot of money relating to this, unfortunately, but the future may provide a different perspective

[TLAM Strike]

Originally Posted by danlisa

Doesn't the active search for ET Life seem a little pointless?

Correct me if I'm wrong but I understand the following:

Signals we send out: These take an inordinate amount of time to reach anywhere, receiving a response would take double that. Within the transit time it's conceivable that the replying world would no longer exist by the time the signal reached us. This also applies to listening to space 'signals'.

Identifying habitable planets: Again, the time involved is mind boggling. We can ID a planet that's billions of light years away and say that's a possible earth clone but that image we captured has taken billions of years to reach us. The originating planet would now probably be a hunk of space rock.

What am I missing and how much funding is put to this?

For perspective there are 7 star systems in 16 light years that feature stars like our sun or close to it. The closest confirmed Extrasolar planet is 10 light years away (it orbits Epsilon Eridani a star similar to our own). The distances involved might not be that big on a cosmic scale.

[Gerald]

To mention just one example, as to our sun, it takes "only" 8 light minutes, and there is ZERO in the context