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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.'"
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.
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.
m l
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.