Another thought:
Everybody talks about aliens can receive our radio/TV signal in sphere about 80lightyears, but nobody realises that we cannot receive anything like that, if aliens were advanced further that have developed technology that they can come here, they had to invent such things like TV/radio many years before us, where is the signal ? Stephen Hawking is scared in his introvert complexes, he doesn't pay attention at natural technical evolution in a society similar to humans. Let nobody tells me that bullshit that aliens broadcast at so different frequency that we cannot receive anything.
Stephen Hawkings clever as anything, would rather listen to him than someone who thinks they have a ghost in their house ;)
Another thought:
Everybody talks about aliens can receive our radio/TV signal in sphere about 80lightyears, but nobody realises that we cannot receive anything like that, if aliens were advanced further that have developed technology that they can come here, they had to invent such things like TV/radio many years before us, where is the signal ? Stephen Hawking is scared in his introvert complexes, he doesn't pay attention at natural technical evolution in a society similar to humans. Let nobody tells me that bullshit that aliens broadcast at so different frequency that we cannot receive anything.
People are looking for extraterrestrial signals www.seti.org. However it is a volunteer effort. Humans do not now possess the capability to look in all directions at all times and at the entire EM spectrum. We have problems with atmospheroc interference, earth-origin signals bouncing back at earth, ground based equipment sensitive to only a narrow band, etc. We are a long, long way from being able to say definitely no alien signals are passing by the earth on this day. These seti people are hoping they get lucky with the limited resources they have.
There are many problmes with detecting interstellar communication. Signals lose power as the square of distance and will easily get swamped by other noise sources in long distances. They will be distored by intervening matter and gravity. Even worse, as communication technology improves you start using source coding methods that make the signal look like noise unless you know what you are looking for. However what seti hopes to find is not evidence of TV or radio, which is vert unlikely to be detected except at very short distances, but a deliberate attempt at interstellar communication. A deliberate attempt would not be coded so as to look like noise like our broadcasts are beginning to be. A deliberate attempt would be made in a frequency band that ensures it is not natural or can be easily distinguished from natural phenomena. It is worthy to note that we are not yet broadcasting a deliberate attempt at communication. Who knows if we ever will?
This notion of the mathematical likelihood of alien life has been around for decades. The original formulation is called the Drake Equation. It is very likely that there is intelligient life somewhere out there but it is unlikely that we will ever make contact or see evidence of it I would think. The universe and even our galaxy is unimaginably big.
Another interesting idea is the Fermi paradox which suggests that once lifeforms reach a certain level of achievement, they destroy themselves. If this is true maybe intelligent life doesn't last long enough to search the stars for others.
AFAIK, our galaxy is about 50 000 lightyears in diameter, if in this space would evolve an intelligent life, we must have some evidence of them as we got in current technology status, we must have some signals caught out of this space. Otherwise there is no intelligent lifeform in our galaxy and thus we can say we are safely hidden in universe, the distances between galaxies are so big, that I don't believe any lifeform can pass them.
the problem is that the signals from an alien race (or from earth for that matter) is not an ever expanding sphere, it's a shell, a century or so wide.
we are already sending out a lot less radiation than we used to, not more as you might expect. Any signals that radiate off into space is wasted energy, and as a civilisation gets more technologically advanced it moves to shorter and shorter wavelength radio systems that don't go as far. The other thing is that we use cables for long distance transmission now. The days of transmitting high power shortwave radio signals across the atlantic are more or less gone (yes I know there is ham radio, and the various national shortwave stations) We used cables, then optic fibre for our long distance communication, and the short distance stuff is all microwaves and UHF, being directed in the direction we want the signal to go, not indiscriminately fired off into space as before.
In 100 years I doubt we'll be radiating any sizeable amount of signals into space any more. This means that an alien civilisation needs to be listening out for our signals, in the right direction, in a window just a couple of hundred years wide... In the whole lifetime of the universe, that's quite a narrow window.
I hope, SETI doesn't search for analogue signals :)
all signals are analogue... they might have data modulated onto them, but they're all the same radiation.
/me waits for a pedant to come along and tell me what super stupidly high frequency a radio signal consists of individual photons and all that quantum malarkey
Comments
Stephen Hawkings clever as anything, would rather listen to him than someone who thinks they have a ghost in their house ;)
Can you say something on topic ?
People are looking for extraterrestrial signals www.seti.org. However it is a volunteer effort. Humans do not now possess the capability to look in all directions at all times and at the entire EM spectrum. We have problems with atmospheroc interference, earth-origin signals bouncing back at earth, ground based equipment sensitive to only a narrow band, etc. We are a long, long way from being able to say definitely no alien signals are passing by the earth on this day. These seti people are hoping they get lucky with the limited resources they have.
There are many problmes with detecting interstellar communication. Signals lose power as the square of distance and will easily get swamped by other noise sources in long distances. They will be distored by intervening matter and gravity. Even worse, as communication technology improves you start using source coding methods that make the signal look like noise unless you know what you are looking for. However what seti hopes to find is not evidence of TV or radio, which is vert unlikely to be detected except at very short distances, but a deliberate attempt at interstellar communication. A deliberate attempt would not be coded so as to look like noise like our broadcasts are beginning to be. A deliberate attempt would be made in a frequency band that ensures it is not natural or can be easily distinguished from natural phenomena. It is worthy to note that we are not yet broadcasting a deliberate attempt at communication. Who knows if we ever will?
This notion of the mathematical likelihood of alien life has been around for decades. The original formulation is called the Drake Equation. It is very likely that there is intelligient life somewhere out there but it is unlikely that we will ever make contact or see evidence of it I would think. The universe and even our galaxy is unimaginably big.
Another interesting idea is the Fermi paradox which suggests that once lifeforms reach a certain level of achievement, they destroy themselves. If this is true maybe intelligent life doesn't last long enough to search the stars for others.
Write games in C using Z88DK and SP1
I hope, SETI doesn't search for analogue signals :)
I bet bohusks' ghost typed that message!
we are already sending out a lot less radiation than we used to, not more as you might expect. Any signals that radiate off into space is wasted energy, and as a civilisation gets more technologically advanced it moves to shorter and shorter wavelength radio systems that don't go as far. The other thing is that we use cables for long distance transmission now. The days of transmitting high power shortwave radio signals across the atlantic are more or less gone (yes I know there is ham radio, and the various national shortwave stations) We used cables, then optic fibre for our long distance communication, and the short distance stuff is all microwaves and UHF, being directed in the direction we want the signal to go, not indiscriminately fired off into space as before.
In 100 years I doubt we'll be radiating any sizeable amount of signals into space any more. This means that an alien civilisation needs to be listening out for our signals, in the right direction, in a window just a couple of hundred years wide... In the whole lifetime of the universe, that's quite a narrow window.
all signals are analogue... they might have data modulated onto them, but they're all the same radiation.
/me waits for a pedant to come along and tell me what super stupidly high frequency a radio signal consists of individual photons and all that quantum malarkey