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Cellular Phone Spectra and Earth's SETI Invisibility
astrobio writes: "How long will the Earth's technology be detectable to other worlds? From an article today by the Chairman of the SETI Institute: 'Not long, with shared transmission spectra. To transmit ever-increasing amounts of information, portions of the spectrum must be shared. This is only possible if signal strengths are reduced so that transmissions on the same frequency do not interfere with one another. The textbook example of this paradigm is the cellular phone system. This signal reduction means we are well on our way to becoming invisible.'"
The point of this is that a signal may only propagate outwards until the total mass behind it exceeds a critical value (the location of this is called the "event horizon" in an analogy to black holes). At that point its deflection will equal more than 90 degrees...i.e. it will not go any farther from its point of origin.
This new research is controversial but nobody's found any rebuttal to it so it will probably become the convential wisdom in the next few years. Sorry, alien-finding dudes.
Maybe now the three-eyed, ten-tongued aliens of Vega will be able to get some rest once we turn the noise down.
Bad intergalactic neighbors, that's what we are.
SETI researchers have known this for a good while now. As we move from broadcast television and radio to digital formats, we will essentially be reducing and eventually completely shutting off runaway transmissions out into the cosmos. This is actually included in probability calculations in the success of SETI: you only have about 200 years in a given civilization in which to find them through their leftover radiation... after that time frame, there are certain signals (radio telescopes, for instance) that are detectable, but which don't travel in every direction.
One of the goals/projects of SETI is to keep transmitting data that appears to be from intelligent creatures... Prime numbers in binary is one proposed method. A simple SOS is even possible... anything that would look nonrandom.
If you go to SETI's website, the first heading you see reads Working together to continue the Search for Extraterrestrial Intelligence. Is it just me, or does cloaking the Earth's technology from worlds with possible life counterproductive to the very things that SETI stands for?
This is ingenious technology, I am just confused as to why SETI of all organizations would propose it as it seems against their very nature.
Sounds like it could be the death knell for SETI...
Because do we really want to let the universe know we're here? Contact with a more advanced civilisation might have unfortunate repercussions for us - look at the impact contact with the West had on so many indigenous cultures during the ages of exploration and imperialism.
And that's just assuming the ETs are benevolent and simply can't help having the effect on us that we have on a newly contacted tribe in the Amazon. What if the ETs are paranoid about competitor intelligences arising and have a policy of wiping out any new civilisation that pops its head up over the electro-magnetic parapet? That's one of the more pessimistic explanations for the Fermi Paradox.
Our major communication may be invisible, but TV and radio will continue to bounce into space for a while. Also, a radio telescope would release tons of radiation on a somewhat small area. Wouldn't this be easily found by any non-earthly people? And also, if this theory is true for other alien civilations, we may never find them!
So, will this be the end of anal probing or will it just limit it to fetish vidoes?
GOOOD, now I can continue my ooops "our" plans to dominate the universe uniterupted by the galactict justice league finding out :)
True, being radio quiet makes us a much smaller needle in a bigger haystack, but we are starting (or starting to think about, anyway) our own surveys for oxygen in extrasolar planetary atmospheres, for the same reason.
If we were ants living on a Rubik's cube, differential geometry would be a little more confusing.
I thought of this years ago. Then realized I was wrong. How much power does your local AM radio station put out? 50,000 watts. Will the ammount of power required to broadcast to three states ever drop? Nope. How many 50,000 watt radio stations are there in the US alone? Over 8000.
Will XM sattelite radio change that? Has linux been able to break Microsoft's monopoly?
If voting were effective, it would be illegal by now.
"Can you hear me now?"
"I am an invisible planet. No, I am not a Kamino like that which eluded Obi-Wan Kenobi; nor am I one of your Hollywood-movie hurtling asteroids. I am a planet of substance, of soil and bedrock, forests and oceans -- and i might even be said to possess a voice. I am invisible, understand, simply because bug-eyed aliens refuse to listen to my... erm... reduced-power, shared-spectrum, electromagnetic transmissions."
I don't think that we have to worry about being a silent planet if these guys keep it up.
What we need is a screensaver that will turn a monitor into a directional antena. Then everybody can then turn their monitor towards the heavens when their computers are not at work and let the screen saver then broadcast a message. This would be much more effective and much cheaper. This way we can do the broadcasting for a change and let those free-loading, beer swilling aliens take a turn trying to decode noise from space for a change. Why should we do all the work?
Wow! I thought the neighbors described in the article were whining until I got to this part. This is a staggering amount of radiation that they are pumping out.
I once spoke to some Air Force dudes about this sort of stuff, and they said that the big concerns were over endocerine systems. It would be very interesting to see if there are any problems with diabetes or other such diseases in the area. Sounds like a perfect test bed to see if e-mag emissions really can be harmful.
Of course the complication here is that if someone there gets sick, they can rest assured that the pope will be praying for them. It is probaly a bit tough to add such complications into your statistical models.
I don't think they will invade the Earth though. The amount of energy needed to come over means that it wouldn't make sense to come over for resourses and they don't need us for slaves if they can develop artifical intelligence technology.
The best reasons for contact would be curiosity and to share knowledge of mathematics and what not.
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A Sicilian friend of mine once visited Rome and said that, even from outside the walls, the buzzing was almost deafening on some days.
With worldcom's demise, maybe ET can finally hear us because of reduced signal noise and higher local intensity.
Sure, sure, since you're so much smarter than every cosmologist in the world who says that the universe has a finite age.
They laughed at Gallileo when he said an orange and a cannon ball would fall at the same rate. Besides I said "I think this" not "I know this". I am entitled to my own observations. I was trying to engage you on the subject, not start a flame war...elitist.
Time is not measured by how particles move relative to each other. If everything is stationary time continues to march on.
Huh? If our galaxy and all the matter in it stopped moving, so would time. We would have no way to measure it, at least that is what relativity states. The photons we rely on for reference would not be moving, neither would we. Relativity is the same theory they use to come up with the age of the universe model you espouse, it's not wrong per-se, just incomplete. Time is a human concept, there is no time/space. Time is an effect of gravity and space interracting, and is wildly subjective. It changes depending on were you are in the universe.
Also, you're assuming the universe has a preferred centre. It doesn't.
What's the big bang then? They gauge the current estimate of the universe's age by it's rate of expansion from a single point. I make other assumtions, but not on this point.
Also, if "energetic particles leave the center of the universe and travel out", how does this mesh with "...the particles that make [the universe] up DO NOT move relative to each other..."? Please reconcile this.
As the particle moves away from the center, it moves slower. Thus, the particles relative movement is slower at the edges than in the center. I'm basically saying that in our layer of the expanding explosion known as the universe, light moves slower than it does closer to the center. Thus time seems to move faster.
Also, how do particles lose quantum spin? Can you explain this to me, and correlate it with the Standard Model that has been hammered out through years of extensive observations, calculations, and theories and show absolutely no support for this hypothesis?
What standard model are you talking about? One doesn't exist. Super String theory seeks to find out how sub-atomic particles exist without mass. They could be tiny knots were several dimesions meet. When 1 or more of these dimensions become unentangled, the particle ceases to interact in 3 dimensions. It is not quantum anymore, not in several places at once.
I think you should leave the thinking up to people who actually can. Don't pretend to know something when you so clearly do not.
I didn't 'think' this up. Read 'The Elegant Universe' by Brian Greene (NYT bestseller!). He is one of leading physicists of our time. Super string theory upsets assumtions made in relativity, which is why it is unpopular with the old egg-heads who have invested their lives into an incomplete observation. Einstein had no idea that sub-atomic particles existed (like quarks). So he had to make up shit to fill the holes in his theories. He even admitted relativity wasn't a complete explaination.
You're right, we don't understand gravity and time well enough. However, you understand it even less (to the point, one might add, where you don't understand it at all), so you're the least qualified to say anything even remotely resembling intelligent about it.
Seems your definition of intelligence precludes reading books, and comes from TV. I've cited my sources, you've cited none. See if you can pull your ego and your common sense apart and get back to me with rational logic.
Huh? If our galaxy and all the matter in it stopped moving, so would time. We would have no way to measure it, at least that is what relativity states.
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The lack of a way to measure something does not mean it does not exist. Do you think that because people could not measure the mass of an electron in the 1600s means it didn't exist then?
Time is a human concept, there is no time/space.
So you're saying that if humans did not exist, there would be no time?
What's the big bang then? They gauge the current estimate of the universe's age by it's rate of expansion from a single point. I make other assumtions, but not on this point.
It's called the cosmological principle. There is no preferred centre of the universe. The Big Bang happened everywhere in the universe, not at one point in the universe.
Think of the "raisin bread" model of the universe. Suppose you're a raisin in an expanding loaf of bread. According to you, all the other raisins are moving away at a speed proportional to their distance from you. From this you would assume that you're at the centre of the loaf. However, if your friend is on another raisin, he too sees all the other raisins (including the one you're on) moving away from him at a speed proportional to their distance from him. From this he would assume that he's at the centre of the loaf. There is no preferred raisin.
As the particle moves away from the center, it moves slower. Thus, the particles relative movement is slower at the edges than in the center. I'm basically saying that in our layer of the expanding explosion known as the universe, light moves slower than it does closer to the center. Thus time seems to move faster.
Proof, please. Light always moves at the same speed.
What standard model are you talking about? One doesn't exist.
The Standard Model. The Standard Model is the name given to the current theory of fundamental particles and how they interact. Nowhere in this model do particles lose spin over time. They're not like small tops in space, they have discrete, quantized spin.
Seems your definition of intelligence precludes reading books, and comes from TV. I've cited my sources, you've cited none. See if you can pull your ego and your common sense apart and get back to me with rational logic.
My intelligence comes from reading books and lecture notes, including (but not limited to) those I used when I obtained my degree in physics and astronomy.
You seem to have this idea that the universe is exploding into space. That could not be further from the truth. The universe is not expanding into space, it is space expanding. There's a huge difference there, and a very profound one. One of the consequences of the expanding universe is that there is no physical edge of the universe. If you flew in a space-ship you could not reach the physical edge of the universe because it does not exist.
I only have two links to suggest to you because I am too busy at the moment (busy working at a major astronomical observatory).
http://calspace.ucsd.edu/edout/calforum/universe/
http://www2.slac.stanford.edu/vvc/theory/model.ht
And yes, I am the same AC as above.
What the heck is stopping us from setting up a transmitter station on the far side of the moon which beams out as powerful a message as we want without interfering with terrestrial communications one bit.
You'd be able to broadcast a hemispherical signal in all the transmission windows no problem. You could broadcast with as much power as you can provide, and the moon would sheild earth-bound and even orbital communications systems.
if ($it != $onething) {$it = $another;}
I know. But my point was, time is an arbitrary concept. It has different values depending on your motion through space relative to whatever you want to measure time from. So therefore, the universe has no age. It just always was, and always will be. Unlocking the secrets of dark matter will show that the universe recycles space and motion, there is no time.
>Time is a human concept, there is no
>time/space.
So you're saying that if humans did not exist, there would be no time?
No, I'm saying that time is a way humans measure motion through the universe. It is not constant however, and makes a lousy yardstick. Einstein says that photons move through space but not time, Which is why I think he was wrong to conclude that time must be a separate dimension.
It's called the cosmological principle. There is no preferred centre of the universe. The Big Bang happened everywhere in the universe, not at one point in the universe. Think of the "raisin bread" model of the universe.
Right, space occupies different distances depending how fast you move through it...special relativity.
From our point of view, your statment makes sense. However, the raisins have no idea that they are actually moving through the bread, from they're point of view everything else is moving away from them, and they are still. They have no way to tell that everything around them is moving in one direction, away from a singular point, (think spheres expanding, not planer motion).
>..light moves slower..
Proof, please. Light always moves at the same speed.
Lets say some bubbles in a fishtank rise at a constant rate. The fish observe that the bubbles go the same rate no matter how fast they swim toward or away from them. The bubbles appear to slow down and speed up, but the fish realize this is a doppler effect, and is due to their motion, not the bubbles motion.
Now take the fishtank and chuck it out of the window of a 100 story building. The fish would still draw the same conclusion about the bubbles even though they, and the bubbles, are both in motion. They are just moving in a way they can't detect, becuase they can ONLY measure their speed relative to that of the rise of the bubbles. It's the paradox of special relativity.
Nowhere in this model do particles lose spin over time. They're not like small tops in space, they have discrete, quantized spin.
Right, and from our point of view, that spin is static. But since we MOVE at such discreet distances, we cannot gauge this decay, becuase the speed at which we move and the rate of decay, are relative.
The universe is not expanding into space, it is space expanding. There's a huge difference there
Right, if space is expanding, then all the particles in it would move relative to the rate of expansion. Even though they can move about in space, the space itself is changing, so the velocity available to relative movement is changed depending how much quantum momentum you have used up.
Thanks for the links (anon-coward). And I hope you can see now, why I think that the universe cannot have an "age". I could be wrong, but it's still has merit to consider before casting it away for what we think we already know.
Proof, please. Light always moves at the same speed.
When I was doing a research on light, I learned that in the deep seas, radiation was mooving faster than light due to the high pressure of the water. This was making radiation (something totally invisible normally) having a blue halo. Thus.. you could actually see the radiation.
Take it for what it's worth, I can't give you any source.. and this is all based on memory...
Menzoberranzan Networks
Oh wait.. that didn't proove that light was moving at a different speed, but more that something can travel faster than light..
:)
sorry..
Menzoberranzan Networks
Even if some extra-terrestrials can pick up our wireless communications, their ability to decipher it from noise may be limited because of new technologies, notwithstanding the power of our transmissions.
Consider the 2.4GHz range and frequency hopping. There's no way anyone picking up the earth's aggregate transmissions in that band would be able to decipher them, (frequency hopping is designed that way)... TV and AM/FM broadcast signals are relatively simple to decipher, having carrier signals that are quite regular.
I also understand that radio waves are fairly common in the universe, although not being at all the astronomer, I have no idea why. If our airwaves get too muddled, I imagine we won't look much different to a radio telescope than some other radio-prolific celestia.
Another question is, has this already happened somewhere else? I think I remember hearing that SETI's work, particularly their distributed computer search software would probably miss wide spread-spectrum FH radio technology and consider it white noise. Any word on that?