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Aliens can`t hear us, says astronomer
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Aliens are less likely to be able to pick up signals from Earth and make contact. Photograph: Colin Anderson/Getty Images/Blend Images
Human beings are making it harder for extraterrestials to pick up our broadcasts and make contact, the world's leading expert on the search for alien life warned yesterday.
At a special meeting on the search for extraterrestrial intelligence (Seti), the US astronomer Frank Drake - who has been seeking radio signals from alien civilisations for almost 50 years - told scientists that earthlings were making it less likely they would be heard in space.
Astronomers assumed that a standard technique for any alien intelligence trying to pinpoint other civilisations in the galaxy would involve seeking signals from TV, radio and radar broadcasts, Drake told the meeting at the Royal Society in London.
Scientists on Earth have been using this method, without success so far, to find evidence of intelligent aliens. The theory is that elsewhere in the galaxy other civilisations would probably be doing the same.
An example of this interstellar eavesdropping is dramatised in the Jodie Foster film Contact. Based on a novel by the US astronomer Carl Sagan, it tells the story of an alien civilisation that makes contact after picking up TV broadcasts from Earth.
"The trouble is that we are making ourselves more and more difficult to be heard," said Dr Drake. "We are broadcasting in much more efficient ways today and are making our signals fainter and fainter."
In the past, TV and radio programmes were broadcast from huge ground stations that transmitted signals at thousands of watts. These could be picked up relatively easily across the depths of space, astronomers calculated.
Now, most TV and radio programmes are transmitted from satellites that typically use only 75 watts and have aerials pointing toward Earth, rather than into space.
"For good measure, in America we have switched from analogue to digital broadcasting and you are going to do the same in Britain very soon," Drake added. "When you do that, your transmissions will become four times fainter because digital uses less power."
"Very soon we will become undetectable," he said. In short, in space no one will hear us at all.
What is true for humans would probably also be true for aliens, who may already have moved to much more efficient methods of TV and radio broadcasting. Trying to find ET from their favourite shows was going to be harder than we thought, Drake said.
Most scientists at the meeting said they were sure that life existed on other worlds.
Lord Rees, president of the Royal Society and the astronomer royal, said it should soon be possible to detect planets no bigger than Earth orbiting other stars and determine whether they had continents and oceans.
"Although it is a long shot to be able to learn more about any life on them, then it's tremendous progress to be able to get some sort of image of another planet, rather like an Earth, orbiting another star. And were we to find life, even the simplest life, elsewhere that would clearly be one of the great discoveries of the 21st century.
"I suspect there could be life and intelligence out there in forms that we can't conceive. And there could, of course, be forms of intelligence beyond human capacity - beyond as much as we are beyond a chimpanzee."
http://www.guardian.co.uk/science/2010/jan/27/aliens-cant-hear-us-astronomer
/``-_-´´
2010-02-22 06:08
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Re: Where do these "experts" get their ideas from?
I couldn`t agree with you more Astus, I have always thought there is something fishy about SETI. One should especially question things which are used by too many "sheeples". If SETI had the slightest chance of succeeding, "they" would never have allowed it to be used, after all they are doing their best to hide the truth from the general public.
/``-_-´´
(2010-02-22 22:13)
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Where do these "experts" get their ideas from?
If we take the length of time, from the birth of the solar system to the development of a technological civilisation on Earth, and we assume this to be a representative average of the length of time it takes for a civilisation to develop anywhere in the Universe, then we can estimate that there have been intelligent life forms with highly developed technologies in existence for around 8 billion years before we turned up.
These "experts" seem to think that Alien civilisations would still use technology that, to them, would be unthinkably ancient, if they even remembered it after such a length of time.
It also stands to reason, that any younger civilisation, reaching out to the stars, would meet up with other civilisations in the early days of their exploration and would gain access to the knowledge of the older civilisations. In a comparatively small way, this is what happens in our schools - we didn`t have to do the research to find out how radio works, we just had to read the book.
So even the most recent starfaring civilisation would have access to technology billions of years in advance of our own.
Are we then to believe that Alien youth would still be walking around with transistor radios held to their ears?
Get real!
As for SETI intercepting radio signals, whose idea was that?
Let`s be logical for a minute or two, eh? If radio waves were still the preferred means of communication between civilisations on different star systems, they would surely try to use a high capacity "tight" beam to reduce interference and losses due to distance. Low frequency radio waves have low capacity and are difficult to focus, but require low power at source. High frequency radio waves have high capacity and are easier to focus, but need high power at source.
So the higher the frequency, the easier it is to get lots of data going exactly where you want it to, the only downside being that you may need to melt a small asteroid to absorb the waste heat from transmitters powerful enough to beam a coherent signal across light years of space.
We must also remember that both source and target are moving, relative to each other, and we are moving relative to both of them.
So what chance of intercepting a tight beam signal between two civilisations in separate star systems?
Imagine you are taken up to the edge of space and you jump out to parachute back to solid ground. Somewhere else on the planet, there are two planes, location not disclosed to you, which are sending tight beam radio signals to each other using a frequency you have not been informed of.
You have in your hand a radio receiver, which continuously scans some "likeley" wave bands for radio signals.
Your task is to intercept the radio signals, passing between the two planes, as you drift gently earthward.
How do you rate your chances?
I rate them as "vanishingly small".
You don`t know where the signals are coming from or going to.
You don`t know what frequency they use.
You have no control over the direction and speed of your movement, or your location.
You have no control over the direction and speed of the planes, or their location.
If you did intercept a signal, by some freak chance, it would only be for a brief moment.
If you recorded your latitude, longitude and height, at the time, and went back there in a helicopter, you would not hear the signal again, because both transmitter and receiver would have moved and the track of the signal would be somewhere else entirely.
So you would never be able to establish where the signal came from, or where it was headed, so you would never be able to get in touch with the sender or receiver.
I`d call that a waste of time, wouldn`t you?
Mind you, whoever it is that negotiates funding for SETI has a great future ahead of them, in the world of commerce, if they ever decide to do something useful with their lives.
/Astus Rodinga, Astus Rodinga., Owfa Pitissake
(2010-02-22 13:45)
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