Human electrical transmission & detecting aliens


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sirzerp
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Message 1094364 - Posted: 7 Apr 2011, 17:31:14 UTC - in response to Message 1094131.

I’m a physicist, I assure you that all EM waves can be viewed as discreet packets with discreet energies. hc/wavelength no matter if it is 60nm or 60km.

I have done some research and I'm starting to think the universe is kind of quite below 1000 hz. Solar wind plus magnetic field equals RF, but most of these frequences seem to be in megahertz and some in kilohertz. I find no references to 10 hz at all.

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Message 1094379 - Posted: 7 Apr 2011, 18:23:50 UTC - in response to Message 1093884.
Last modified: 7 Apr 2011, 18:55:04 UTC

Michael(sirzerp),

Hi Johnney,

Well, your heart is in the right place but science isn’t based on intuition alone. We need hard numbers. For example, the three phase transmission scheme does self cancel quit a bit of noise, that’s the reason we use it.


Michael, my background is in electrical engineering but i have studied several other related discipline's. No, i have not carried out any extensive scientific investigation into the science discussed in this thread. So i must admit, some of the science is speculative. But the theory is solid science. Yes, you are correct that we try to balance the 3 phases, hence this would neutralize some of the EM radiation. But due to electrical inductance and something called "power factor", the balance is never perfect. Another point is that 3 phase a.c. transmission lines are not "screened" like a co-axial cable. They run in free air to cool them. The fact that they are not screened means that even though the 3 phases balance the current flow, there is a massive RF transmission from the lines at 50Hz in Europe and 60Hz in the US. The balancing or power factor correction wont prevent the lines transmitting RF signals 120 degrees apart. So in theory, each of the three lines will act as individual dipole antennas between the Earth and the copper or aluminum wire, if the transformer has been grounded to earth. If the transformer is not grounded, as is the case with some transmission systems, the dipole antenna would be from wire-to-wire, horizontally. or phase-to-phase.

Another person made an argument about AM radio being reflected by our atmosphere which is a good argument. Thought I’m not sure it applies. Most of the time AM radio is broadcasted vertically but our power grid is aligned horizontally. Meaning any leakage would be in the normal direction to the atmosphere ‘up’ and I would guess it would escape.


In the case of the horizontal power lines, you could think of it like an antenna lying flat on the ground instead of being on a vertical mast. With our power line, half the "lobe" of EM radiation will be absorbed into the ground. The other half will propagate vertically out into space. I'm not sure, but you might be right, maybe some of the EM wave will bounce off the ionosphere. But most of it will propagate into space. Think of a radio telescope dish on the ground. The dish faces up into space of thats where you are transmitting too. So really, our transmission lines are pointed in the best possible direction, they face into space, they just don't have a radio dish underneath them to amplify and direct the signal.

The third issue is the size of wavelength itself. It is in the 60,000,000 meter range. I don’t think anyone knows the propagation characteristics of a wavelength this large. It isn’t like anyone has went to space to measure it. We assume it propagates like AM radio but the wavelength is larger than our planet.


The wave should propagate just like any other EM wave.
I’ll show you an example why we can’t assume things. We know black holes eat photons. That’s simple to understand, but what if the black hole has a 1000 km radius and the photon has a 60000 km wavelength? Can a black hole capture a photon much larger than its light consuming radius?

I’m just pointing out there’s lots of things here we don’t know.

This is the way i see it Michael. The black hole is a bad analogy. The wave will propagate just like any other wave. And it does not matter if the wavelength is larger than the planet. If you want to detect massive wavelength EM radiation, you just build your detector to measure and detect a small part of the wave. Its easy to just build your antenna to match 1/60,000,000th of the wavelength. So ET would only need a 1 meter antenna and some clever software to detect our electrical grids.

No, your right Michael, this is just a forum message to chat about the topic. So no quotes or references are needed, its light hearted. But the science i have discussed here is very valuable. In general, before you arived Michael, i tried to keep heavy electrical and technical detail out of the discussion cos i know the folks reading the message might not understand. So i was keeping it timid :) The fact remains, our planet stands out like a sore thumb in space because of our heavy use of electricity through distributed electrical grids. ET could spot us a 100,000 light years away because of this. Of coarse, we only have the grids for about 1 hundred years, so ET will get the signal when it arrives. I have never heard any SETI researcher even mentioning this as a possible way to detect ET. Sometimes science misses the most obvious things. Or maybe i just see things that other people don't see.

John in Ireland.
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Message 1097562 - Posted: 15 Apr 2011, 18:18:52 UTC - in response to Message 1094379.

Thanks for addressing my points. I agree there is promise here, just not sure how much.

Another thing is that I found some references that the solar wind can not propagate frequencies below 100 Khz. This seemed very odd to me since I assume all frequencies can propagate in space. This was mentioned in two or three papers as the local ionization cutoff frequency.

Anyone know about this? Is there a lower frequency limit in our solar system???

The two papers listed at the bottom are some very good reading, you should be able to find these papers with google. Did you know earth's aurora borealis power is 1E8 watts with freqencies between 100 Khz and 1 Mhz? Also each magnetic field of planet, has a unique freqency? That means if you could listen in space between 100 Khz and 1 Mhz, each planet you could hear would have slightly different signal! We can't hear this on earth because of the ionosphere.

Also, I found there are NO sky surveys at 10Mhz and below from space. We got no idea what this band looks like in space.

I don't think our 50/60 hz power leakage is in the 1E8 watt range :) We should listen for aurora frequencies first, then maybe we would get lucky with finding lower freqencies.

Magnetically-Driven Planetary Radio Emissions and Application to Extrasolar Planets Philippe Zarka

Low Frequency Radio Astronomy & Extrasolar Planet Detection Jonatan Danielsson


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Message 1097638 - Posted: 15 Apr 2011, 22:34:34 UTC - in response to Message 1097562.

Very low frequencies have been used for communications by our Nations submarines. These are propagated in water and basically are sound waves.

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Message 1097674 - Posted: 15 Apr 2011, 23:38:59 UTC - in response to Message 1097638.

Very low frequencies have been used for communications by our Nations submarines. These are propagated in water and basically are sound waves.


That may well be the case now but that is communication by mechanical compression waves, more commonly known as sound.

You can have electro-magnetic radiation at low frequencies that are still "radio waves". One very good transmitter is the earth itself due to ducting through the ionosphere powered by lightning strikes to give 7.8 Hz. See Schumann resonance.


Some Radio Hams record ELF/VLF radio to pick up disturbances in the Earth's (EM) environment.

The military have played with such low EM frequencies but I don't know if anything practical was achieved.


I wonder if any other planets or stars 'transmit' a characteristic resonance at radio frequencies that can then be picked up?...

Keep searchin',
Martin

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Message 1098106 - Posted: 16 Apr 2011, 17:28:32 UTC

Hmmmm, sirzerp made a very good point there. sirzerp i read the shorter of the two papers, the other one was 50 pages long.

If we want to "see" pictures of exoplanets around other stars, its real difficult with telescopes operating in the optical or IR wavelengths. But, as suggested in those science papers, if different planets with different magnetic field's emit different radio wave patterns, then that could be the future for exoplanet hunting!! And searching for ET!!

Pretend for one moment that an earth size planet with a similar magnetic field as our own might emit radio waves at, lets say 5,580Hz. Well then as suggested by sirzerp, maybe a radio antenna array like the new LOFAR in Holland might be able to take a radio image of the sky without any stars, just the exoplanets in the 5,580Hz range for instance.

Now that would be a massive break through for exoplanet hunters!!

John.
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Message 1098110 - Posted: 16 Apr 2011, 17:34:36 UTC - in response to Message 1097638.

Does SETI reports any potential ETI signals?

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Message 1098113 - Posted: 16 Apr 2011, 17:38:05 UTC - in response to Message 1098110.
Last modified: 16 Apr 2011, 17:39:21 UTC

Does SETI reports any potential ETI signals?

No, they tell us nothing!

I've been posting messags in this forum for about 5 years now and i've never heard a peep out of the SETI scientists. If they have ET signals, i didn't hear anything about it! To be honest, i think they stopped looking about a year and a half ago.

John.

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Message 1098142 - Posted: 16 Apr 2011, 19:30:14 UTC - in response to Message 1098113.

That is very disapointing, i wonder if SETI scientits ever read the comments in this forum. The SetiHome is a wonderfull experiment for us non-astronomers to participate in nevertheless.

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Message 1098146 - Posted: 16 Apr 2011, 19:39:36 UTC - in response to Message 1098113.

... To be honest, i think they stopped looking about a year and a half ago.


Oh no...!

We haven't scared them away have we?!

(Or are we too primitive for them to be disturbed from their own searches?)


Keep searchin',
Martin


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Message 1098438 - Posted: 17 Apr 2011, 15:53:14 UTC
Last modified: 17 Apr 2011, 16:01:08 UTC

C Olival,
Don't be put off, i'm just being sarcastic. This SETI@home project is not a completely fruitless venture even if the project isn't currently detecting any ET signals!

Let me tell you why!!

By the very nature of science itself, SCIENCE CHANGES when new research is published!! Thats critical!! What does that mean?? It means that you never know what new scientific research will come onto the scene that changes the whole ball game. Tomorrow, next week, next year or whenever, some scientists somewhere could find a new way to detect ET. Maybe at a different radio frequency or something that the SETI@home scientists are not currently aware of!

So for that reason alone, NEVER give up hope. Science does, and always will change. New science is just around the corner! You just need to be patient. And we can chat and discuss our hopes and dreams right here in this SETI science forum!

I will never loose faith that new science is on its way! I'm really glad the SETI scientists who run this project allow us to participate in the science and chat here on this forum! We are very lucky to be part of this. We just need to allow the scientists to do their job. Maybe they read the messages, maybe not, i really don't know :) Sometimes i post smart comments and hope one of the scientists does read the message. You never know.

John.
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Message 1098579 - Posted: 18 Apr 2011, 2:38:40 UTC - in response to Message 1098438.

The cosmos is a big place, our own galaxy has over 200 billion stars, perhaps more, just a question of time until life is found outside Earth. Will that be achieved via Kepler and ground telescopes? A combination of both for certain. More likely life will be detected when telescopes are powerful enough in picking up bio marks in the atmosphere of an exoplanet; more likely that will happen first before SETI does find ETI signals. Does SETI and Paul Allen Array ever points their radio dishes to the stars that currently Kepler is observing?

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Message 1098696 - Posted: 18 Apr 2011, 12:16:35 UTC - in response to Message 1098579.

Does SETI and Paul Allen Array ever points their radio dishes to the stars that currently Kepler is observing?

Yea, they can point the ATA at any target they choose.

John.
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Message 1098698 - Posted: 18 Apr 2011, 12:25:26 UTC - in response to Message 1098113.
Last modified: 18 Apr 2011, 12:26:08 UTC

Does SETI reports any potential ETI signals?

No, they tell us nothing!

I've been posting messags in this forum for about 5 years now and i've never heard a peep out of the SETI scientists. If they have ET signals, i didn't hear anything about it! To be honest, i think they stopped looking about a year and a half ago.

John.


They don't tell us anything, because there is nothing to tell. I would need to do some research, but I am pretty sure a few crunchers got credit for their computers discovering a few pulsars (I recall a few news pieces about that). And from time to time rumors circulate that they did find something, and it turns out to be untrue. That may have been the case with the pulsar story I recall too.

I also interviewed a scientist with this program in an article I wrote. It can be seen here: Searching for asteroids, extraterrestrial life a little more rocky: Budget cuts threaten to close Arecibo, world's largest radio telescope

So they do pay attention and sometimes comment when it's necessary. But they aren't going to scream WE FOUND SOMETHING...if nothing has yet been found. Even if they did find ET or something, then it would take time and research before an announcement is made.
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Message 1098787 - Posted: 18 Apr 2011, 19:12:52 UTC - in response to Message 1098698.

I also interviewed a scientist with this program in an article I wrote. It can be seen here: Searching for asteroids, extraterrestrial life a little more rocky: Budget cuts threaten to close Arecibo, world's largest radio telescope.

Jason,
Nice article, well written :)

John.
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Message 1098817 - Posted: 18 Apr 2011, 21:40:10 UTC - in response to Message 1098787.

I also interviewed a scientist with this program in an article I wrote. It can be seen here: Searching for asteroids, extraterrestrial life a little more rocky: Budget cuts threaten to close Arecibo, world's largest radio telescope.

Jason,
Nice article, well written :)

John.


Thanks! I was slightly wrong though. It was Einstein@home which discovered the pulsars: Citizen Scientists Make First Deep Space Discovery With Einstein@Home. Still cool though. It also proves that our work here will eventually yield something.
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