10 Jul 17
Originally posted by FabianFnasI know a bit about radar, 4 years in the USAF and one of my jobs was airborne radar.
Radiocommunication is one thing. Levels are quite low compared to radar.
An other thing is radar waves. They are strong and expose us very effectively. There is nothing natural about radar, only an 'intelligent' race could be the source of this.
If we would see a signal resembling our radar signature from extraterrestrial sources, then we would know, beyond any 'WOW', that there are someone out there.
There a signal that would average 30 watts would be pumped up by the fact that power was concentrated in microsecond bursts putting the instantaneous power up in the megawatt region and that was just a skinny little airborn job. The big guys say at Arecibo would put out gigawatt pulses say 1 kw tucked into a pulse a nanosecond long resulting in a power level in the gigawatt range at least for that nanosecond time frame.
But on the down side (or up side depending on your POV) those signals are highly directional and vary in galactic plane angles so the signals would be shooting off at odd angles and not going to be broadbanded physically so statistically much less able to be in the path of a high tech civilization and those signals are maybe only 50 light years in radius so a wavefront much less than the 200 odd light year diameter sphere of our RF into space. It would be beamed out to the galaxy and would have to hit at the right time a tech civilization to be detected. Not so likely but I guess scans go on at all angles so maybe it would be a physically large angle of beams, lots of beams but still they represent at this point in time a spherical wavefrong only about 100 light years across.
Originally posted by @sonhousePerhaps it is so, I'm sure you know what you're talking about - but yet these signal are very non-natural in its very nature.
I know a bit about radar, 4 years in the USAF and one of my jobs was airborne radar.
There a signal that would average 30 watts would be pumped up by the fact that power was concentrated in microsecond bursts putting the instantaneous power up in the megawatt region and that was just a skinny little airborn job. The big guys say at Arecibo would put out ...[text shortened]... ll they represent at this point in time a spherical wavefrong only about 100 light years across.
If we detected another solar system with the same radio emission, from lowest possible frequency to highest possible frequency, as is currently emitted from Earth, don't you think we would scratch our heads trying to find out from what natural source this would come from. (Writing 'wow' in margin.) When all possible natural explanations are exhausted, don't you think we would lean on an non-natural, an artificial, source, emitted by sentient creatures?
The emissions from our solar system is a very peculiar emission. No natural cause can emit such a signal signature.
This 'wow'-signal was in fact from a comet that happened to be in the direction of the telescope.
08 Sep 17
Originally posted by @fabianfnasOur wavefront is only 200 light years across now and if there were aliens say 1000 ly away, it would take 800 more years for our signal to reach them and another thousand to answer, not a good way to communicate, wait 1800 years for Howdy. Even if someone heard our signals now we would have to wait 200 years for a reply. And of course that time delay only gets worse for stars further out, 10,000 light years away, nearly 20,000 years for a reply, by that time we may all be in caves again.
Perhaps it is so, I'm sure you know what you're talking about - but yet these signal are very non-natural in its very nature.
If we detected another solar system with the same radio emission, from lowest possible frequency to highest possible frequency, as is currently emitted from Earth, don't you think we would scratch our heads trying to find out f ...[text shortened]... his 'wow'-signal was in fact from a comet that happened to be in the direction of the telescope.
Originally posted by @sonhouseWho is talking about communication? SETI is not about communication. SETI is about search for extraterrestrial intelligence.
Our wavefront is only 200 light years across now and if there were aliens say 1000 ly away, it would take 800 more years for our signal to reach them and another thousand to answer, not a good way to communicate, wait 1800 years for Howdy. Even if someone heard our signals now we would have to wait 200 years for a reply. And of course that time delay only ...[text shortened]... 00 light years away, nearly 20,000 years for a reply, by that time we may all be in caves again.
Anomalies in radio (and other EM radiation) from another star might reveal artificial non-natural emissions indicating existence of an extra terrestrial intelligence. If another civilization study our solar system, they may also conclude that our system is populated with a technological civilization.
Radio signals, radar, EM-pulses from atomic explosions, etc, are tellers for technology for those who listen. This doesn't imply that they want to communicate with us.
08 Sep 17
Originally posted by @fabianfnasJust saying if we wanted to it would be practically speaking, impossible. You can't wait 20,000 years for a reply.
Who is talking about communication? SETI is not about communication. SETI is about search for extraterrestrial intelligence.
Anomalies in radio (and other EM radiation) from another star might reveal artificial non-natural emissions indicating existence of an extra terrestrial intelligence. If another civilization study our solar system, they may also ...[text shortened]... s for technology for those who listen. This doesn't imply that they want to communicate with us.
Originally posted by @sonhouseYou're quite right there. We will never communicate with ETs, ever, with any technology known to man.
Just saying if we wanted to it would be practically speaking, impossible. You can't wait 20,000 years for a reply.
Perhaps they are communicating with us, right now, with a technology we don't know about. Like with tachyons, or by some unknown field vibrations. And they cannot understand why we're not responding. Yet, quite unlikely though.
Originally posted by @fabianfnasI would think, surely, if they are smart enough to know how to send the signal, they are smart enough to know we may not be smart enough to both detect it and understand it?
...And they cannot understand why we're not responding. ...
Alternatively, they see it as a huge deliberate insult by us to not answer, like a two finger gesture, and now they are just about to take their revenge...
Originally posted by @humyForgive my ignorance, but what is a common "two finger gesture" which conveys impoliteness?
I would think, surely, if they are smart enough to know how to send the signal, they are smart enough to know we may not be smart enough to both detect it and understand it?
Alternatively, they see it as a huge deliberate insult by us to not answer, like a two finger gesture, and now they are just about to take their revenge...
Originally posted by @freakykbhhttps://stronglang.wordpress.com/2015/10/08/up-yours-the-gesture-that-divides-america-and-the-uk/
Forgive my ignorance, but what is a common "two finger gesture" which conveys impoliteness?
Originally posted by @freakykbhYou have two hand, yes?
Forgive my ignorance, but what is a common "two finger gesture" which conveys impoliteness?
Originally posted by @fabianfnasOf course: one hands on the left, one hands on the right.
You have two hand, yes?
Otherwise, I think most people wouldn't have a clue regarding anything offensive about the gesture; even less likely E.T. would get it, either.
Originally posted by @humyI think (without actually knowing) that if they try to contact us they would use the same technology that we use to reveal ourselves. And they would do it efficiently.
I would think, surely, if they are smart enough to know how to send the signal, they are smart enough to know we may not be smart enough to both detect it and understand it?
Alternatively, they see it as a huge deliberate insult by us to not answer, like a two finger gesture, and now they are just about to take their revenge...
We haven't seen any such signal and therefore I conclude that they are not interested in us.
Originally posted by @fabianfnasOr they might just be dead. Or using tech so advanced we cannot detect it. If the latter, it would seem to me there would be lots of such communications going on and it would probabaly be related to tech of faster than light travel so all that could be going on right in front of our noses and we wouldn't have a clue. We could also be under quarantine, judged not civilized enough to warrent communications.
I think (without actually knowing) that if they try to contact us they would use the same technology that we use to reveal ourselves. And they would do it efficiently.
We haven't seen any such signal and therefore I conclude that they are not interested in us.