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Lt. Colonel Halt: Strange. One again left. Let's approach the edge of the woods at that point. Can we do without lights? Let's do it carefully, come on... OK we're looking at the thing, we're probably about 2-3 hundred yards away. It looks like an eye winking at you, it's still moving from side to side and when we put the star scope on it, it's sort of a hollow centre right, a dark centre, it's...
Lt. Englund: It's like a pupil...
Lt. Colonel Halt: It's like the pupil of an eye looking at you, winking...and the flash is so bright to the Star scope, err.... it almost burns your eye.
[Break in tape]
Click for Source Thread(It is worth reading it whole).
originally posted by: tanka418
originally posted by: Harte
Some of the microwaves we receive from space start out around 20 Gw. That's not Jiggawatts.
Harte
Most signals received from space originate within a star...so, the power is a wee bit more than mere gigawatts. And most of those are rather weak.
So even in the best possible case, it's unlikely still that we will ever receive anything we can verify as a legitimate signal.
originally posted by: intrptr
a reply to: Harte
So even in the best possible case, it's unlikely still that we will ever receive anything we can verify as a legitimate signal.
Then why do they monitor? They have a big array of telescope dishes and computers monitoring 'millions' of channels…
Because we ourselves purposefully broadcast a powerful enough omnidirectional signal that a civilization as far away as several thousand light years with similar equipment that SETI uses would be able to detect.
originally posted by: intrptr
a reply to: Soylent Green Is People
Because we ourselves purposefully broadcast a powerful enough omnidirectional signal that a civilization as far away as several thousand light years with similar equipment that SETI uses would be able to detect.
A Thousand years from now. They'll have Ralph Cramden as our dignitary.
originally posted by: Harte
The are excited by the stars nearby, but they come from the gas and start out around 20 GW.
originally posted by: moebius
a reply to: tanka418
From my undersanding SETI looks for narrowband/pulsed signals. They are not looking to pick up any encoded data.
According to this paper ( arxiv.org... ) our planetary radars (Arecibo, GBT) should be able to pick up extraterrestrial planetary radar signals at a distance of 15 parsec (~50 light-years) with 10 minutes max integration time. Which is not too bad I'd think.
originally posted by: tanka418
originally posted by: Harte
The are excited by the stars nearby, but they come from the gas and start out around 20 GW.
Just to place this in proper perspective: 20GW at 1 ly is aprox. 20e-21 watts when it is received...oh wait, that signal is far to small to receive, We will need some serous amplification technology, way more than a simple amplifier...
You see normally a signal like that would be received by a high gain antenna, perhaps 20db or so...about 10X (this will make our signal 20e-20 watts)...we will still need to amplify (apply gain) the signal more than ten trillion times to make it detectable to today's electronic systems.
And after we do all this...we have ourselves a rather nice "natural occurring" radio signal. If, by some remote chance we manage to receive a signal that had "intelligence" on it at onetime...that "intelligence" is for ever gone, lost in our attempts to receive the signal.
originally posted by: Harte
How did they receive it?
originally posted by: netbound
To be honest, I don’t know what SETI’s methodology/protocol is for analyzing the signal data received by their equipment. Attempting to decode “intelligent” signals would seem to me a futile endeavor and waste of time and money. A more fruitful effort (it would seem to me) would be attempting to detect biosignatures eminating from some targeted region of space (Kepler-452b, for ex.); something highly probable of being biological in origin, and also highly improbable of emanating from a nonbiological source. After fine-tuning the process, and including additional nonbiological chemical spectral analysis, it may then be soon possible to make “educated guesses” as to the evolutionary stage of the detected signatures; ie. microbial single-celled organisms/macro scale organisms/signs of technology, etc. As our instruments become more and more sensitive, this may be one approach. Listening for a “Hello” signal makes no sense to me.
originally posted by: Soylent Green Is People
While other intelligent life almost surely exists somewhere else in the universe just due to the shear size of the universe, I do think that life that exists "right now" may be rare, and may not really be close enough to us for us to have an occasion to find them (or them find us).
Let's consider just our part of our galaxy -- let's say our quarter of it, or our "quadrant" of it, in Star Trek terms. Sure -- there may be thousands and thousands of places in our quadrant where life had a good chance to emerge. Maybe some life did emerge, and went on to become intelligent and technological.
However, "Time" is also a factor here. Maybe one of those civilizations emerged 200 million years ago (a very short time in cosmological terms, but a long time for biology). It could have flourished for 2 million years (again, a long time for biology as we know it) and then died out. Then another might have come along elsewhere, and then eventually died out...
...There could have been several hundred technological civilizations just in our quadrant of the galaxy that lived and died in the cosmologically short span of the past 200 million years, but maybe there are none, or maybe only one or two, that are around today.
That could be why we haven't had an occasion to meet them. The possible time frame during which they existed and died out is just too large.