Why does SETI require this?

[karlp295]

I've been wondering about SETI's requirement that a signal must repeat before it is considered as proof of an alien or artificial source.

If a signal, and we have apparently received several, does not repeat could it not be worth further investigation?

 

[Maui]

I believe that a signal which is replicated is more likely to have been purposely transmitted; one that is not replicated could be from a random emission source that occurs naturally.

 

[billslugg]

Not only does it have to repeat but it must be an independent observer that sees it repeat. Too many "one time" observations have proven to be error, deliberate fabrication, natural cause, etc.

 

[Turtle]

I think it would really depend on what the signal is. The Wow! signal didn't last long enough, didn't repeat and didn't show much signs of being deliberately made.

If for instance we received a rerun of "I Love Lucy" from "Out
There" we might figure it was some kind of radio reflection and
discount it as from an alien civilization although speculation might last a century.

However, if a significantly long signal of an alien TV broadcast was received and left us waiting for the next installment which never repeated, we probably could safely believe after rechecking our radio telescopes that it was of alien origin.

It is, for me, difficult to believe that a sufficiently developed,
intelligent alien species would be watching television in the first place, other than "Star Trek" of course.

 

[billslugg]

The problem is that whoever is the first to detect alien intelligence will carry home a Nobel Prize. If any one signal, no matter how complex, could be taken as proof then any one person could fake it. Science requires independent corroboration. Until then, the original report is considered "tentative".

 

[Turtle]

The problem is that whoever is the first to detect alien intelligence will carry home a Nobel Prize. If any one signal, no matter how complex, could be taken as proof then any one person could fake it. Science requires independent corroboration. Until then, the original report is considered "tentative".

Question about independent corroboration? If the Wow! signal had had more substance to it, would the staff at Arecibo, who were there at the time have been considered to be enough independent corroboration? They are certainly not to be taken as lye-rs (sp)

 

[billslugg]

There are lots of rules about claiming a new discovery. Generally it must be a separate group of researchers to rule out cheating, it must be a separate piece of equipment to rule out equipment failure, It must be statistically significant to 5 sigmas. I am sure there are others.
Had the researchers at Arecibo been able to receive it also then the receipt of that signal would have been proven. This is a long ways away from proof it was an intelligent signal though. It was simply a narrow band unmodulated carrier. It may have been from one of our satellites, it may have been a naturally occurring signal.
I remember the short lived excitement in 1967 when the first pulsar was discovered. For a short while they termed it "LGM" for "Little Green Men", but soon realized it was a neutron star.

 

[Classical Motion]

Our emissions, even our on purpose ones, won't travel very far before they are deep under the static floor. To get someone's attention one would have to modulate a star. In an unnatural pattern. One needs lots of power to even have a little chance of someone spotting it.

My oldest light structures(radio) are 50 LY in diameter now. But I doubt there's enough there to detect. But theoretically they are still expanding.

 

[Turtle]

How far would a 100 KW signal go before it is undetectable? And what frequency, AM, FM, Spread Spectrum, would have the best chance. Say it's a parabolic antenna?

The Voyagers still seem to be doing well.

 

[billslugg]

The distance a signal can go is determined by the power, the antenna, the bandwidth and the noise out there. The narrower the bandwidth the farther it can go.
I have read that a 50 KW AM radio signal, sent out by an omnidirectional antenna and received by such would be buried in the noise at the distance of Jupiter.
A 1 MW narrow band radar signal sent by Arecibo antenna and received by such could be detected at about 10 ly.
So, the idea of "I Love Lucy" episodes now being in a shell that is 70 ly in radius is not true, simply because the power is too low, the bandwidth too high and the noise floor is too high.

 

[Turtle]

So, if we received a radio signal that was definitely alien and not
particularly aimed for us as the audience it would most likely
be from within out solar system?

So even if their transmitters and receivers were that much better than ours they would still have similar limits? Other than for short range communications they would be using something other than radio.

 

[billslugg]

We can tell if a signal is from an intelligent source by its content. It would be pulsing on and off in such a way that nature could not. An example might be a series of pulses 1,2,3,5,7,11,13,17,19.... Nature could not do the list of prime numbers.
We could, by moving the antenna back and forth that it was coming from a particular spot in the sky but it might be possible to be a satellite. Eventually they could rule it out but it would take awhile.
Their radio waves would obey the same limits ours do. They would know enough to use narrow bandwidth, high power, directional antennas, etc.
There are certain frequencies that are fairly noise free they might use.
It is also possible they might be communicating via laser, xrays or gamma rays. Maybe even neutrinos.

 

[Ken Fabian]

I expect a clear and unambiguous signal, even a short and non-repeating one, will almost certainly be taken seriously within the scientific community... so long as everything was recorded and those records are released for independent examination. Ambiguous "signals" not so much.

 

[billslugg]

Yes, any clear signal will be taken very seriously by the scientific community. But the discoverer will not be credited with the find until it is repeated using a different telescope and different researchers. If, for example, the Wow! signal is found to repeat by another group on another telescope, and is found to be extraterresrial, the original discoverers will get the Nobel Prize. Until then it is labelled "tentative".

It is the first to detect it that counts. Penzias and Wilson first detected the CMBR but didn't know what it was. Dicke knew what it was but he didn't do the detection. Penzias and Wilson got the Nobel Prize.

Ed Teller boycotted Ivy Mike at Enewetak because he was upset at being denied a promotion at Los Alamos. He went to a seismograph in SF at Cal Tech, noted the ground motion and was first to notify the group at Los Alamos. He got the credit. (No Nobel here, they are not real big on nukes)

 

[karlp295]

One thing that has not been mentioned but seems fairly important, is that the most important aspect to all this is having the technology to detect and analyse an alien signal. This may answer the Fermi Paradox because we just may not be able to recognize or find those signals yet and even if we do we may not be able to decode them and so may put such signals down to natural causes. Who knows how an alien civilisation way ahead of us in technology would choose to communicate?

 

[Turtle]

The problem with the Fermi Paradox is that it is not based on a whole truth. Why haven't we heard or encountered any aliens?

Well if one were to meet an impressive person at say a bus station and had an enjoyable conversation with them that would be a believable encounter if it was then told to someone else. The scientific problem with this is that it is not a repeatable experiment. One could wait years at the same bus station and never see that person again. It could and would, if it were important enough, be discounted as anecdotal, and not worthy of further consideration.

There is a great amount of anecdotal evidence of encounters with aliens. All not repeatable. I believe that most modern people would now know better than to report it. People who report such things are ridiculed
and often become the butt of some joke or derision. Airline pilots were chastised for reporting, so I heard and evidence as in photos of close up UFOs was confiscated. I heard this from someone who was there when such a UFO appeared. The US air force investigators claimed they never had the film, then just quit responding.

If you want to know how rotten it can get then check out Travis Walton (Fire In The Sky) . I believe he and the others in his work crew are in truth. A person would be a fool to report it. His crew were being accused of possible murder so they had to.

But once one has encountered an alien the Fermi Paradox becomes moot. SETI has to come up with something different than radio.

 

[Classical Motion]

At the present time, we know of no other method to signal thru space except for EM radiation. Two problems with EM radiation. First, it's slow, compared to the wanted distances. And second, it requires very high power, AND very high power control, to control that power. Our power is but a drop, within a drop, within many more drops.....of the power needed. For transmission. For reception, the only thing that changes, IS, the EM radiation we detect from space. All the object positions in space change slowly and periodically.

We have started to play with entanglement. This appears to change state in an instant, depending on the paired state at another location. It seems to be immune to distance. And like EM, there are other problems with entanglement. Physical pairing is required.....we think. And then there is the encoding problem. After pairing, we don't know which is which. So that has to be worked on. And there might be un-forseen problems. What if the same gravity field is needed for this dynamic to function the way it does?

If there is another instant parity of this cosmos that we have not recognized, maybe aliens are using that.

But for now, EM is what we can detect. They are working on gravity detectors, but the consensus there is, that these waves travel at c also. Not to mention, how hard it would be to make a gravity wave.

If there is another communication channel in this cosmos, everybody would love to know what it is.

 

[Turtle]

At the present time, we know of no other method to signal thru space except for EM radiation. Two problems with EM radiation. First, it's slow, compared to the wanted distances. And second, it requires very high power, AND very high power control, to control that power. Our power is but a drop, within a drop, within many more drops.....of the power needed. For transmission. For reception, the only thing that changes, IS, the EM radiation we detect from space. All the object positions in space change slowly and periodically.

We have started to play with entanglement. This appears to change state in an instant, depending on the paired state at another location. It seems to be immune to distance. And like EM, there are other problems with entanglement. Physical pairing is required.....we think. And then there is the encoding problem. After pairing, we don't know which is which. So that has to be worked on. And there might be un-forseen problems. What if the same gravity field is needed for this dynamic to function the way it does?

If there is another instant parity of this cosmos that we have not recognized, maybe aliens are using that.

But for now, EM is what we can detect. They are working on gravity detectors, but the consensus there is, that these waves travel at c also. Not to mention, how hard it would be to make a gravity wave.

If there is another communication channel in this cosmos, everybody would love to know what it is.

If everyone found another communication channel it would get glutted like AM radio and become just
as useless. Smart aliens would do best to keep it to themselves.

 

[karlp295]

I really wonder why any aliens would send a repeatable signal. If they are far advanced in terms of technology they must have solved many issues we haven't such as the answer to the question of alien life out there and would therefore be aware of the risks of sending messages to others.

It is more likely they are listening and watching, or maybe they are already here in plain sight. In any case, if these aliens exist and want to be hidden they can hide, if they want their presence to be known they can reveal it.

All is conjecture but as the above poster has said there is a lot of evidence already but it is not proof under scientific conditions.

 

[billslugg]

We have started to play with entanglement. This appears to change state in an instant, depending on the paired state at another location. It seems to be immune to distance. And like EM, there are other problems with entanglement. Physical pairing is required.....we think. And then there is the encoding problem. After pairing, we don't know which is which. So that has to be worked on.

There is no way to transmit information faster than the speed of light.
"...you cannot encode a preferred outcome into a quantum measurement."

No, We Still Can't Use Quantum Entanglement To Communicate Faster Than Light (forbes.com)

 

[Turtle]

The equations of state that maintain the physical world are quantum equations. Every quantum event has its associated equations. They may not be human equations but they are there. Quantum entangled events such as photons that have traveled many miles apart do not have a phone line or any physical connection between them. They are however created at exactly the same time and travel at the speed of light and exist in their reference at exactly the same time. Time is not their connector but their equations are connected.

Equations don't have a speed limit.

 

[billslugg]

Yes, photons can be entangled instantaneously but no information can be transmitted.

 

[Classical Motion]

No information is transmitted? Why is that? We entangle locally. Then separate the pair. Then we change state of one, and the other changes instantly. Does that not qualify as a transfer of information? It just that we can't encode that information. The information is exchanged in an instant. If one doesn't like the term information....then the un-known link, the unknown bond, the unknown mechanism of entanglement, of the pair, is broken in an instant. I would call that instant exchange in state, an information vehicle. Whether we can encode it or not. As a matter of fact, relative to the pair........IT IS encoded. This is the potential value of this. The encoding is there. We just can't set that encoding, yet.

When we learn more about this, I believe there is a possibility to set this encoding. But there is still a price to pay.....they have to be paired.

And we don't know how gravity plays a role. Let's encode a few billion Flippers. And we send then to our space station in orbit around Neptune. For real time communications with our new encoding method.

As the 1/2 uni-pair is transported out there, there will be un-equal g fields applied. This might affect the pairing. No one knows what entanglement is balanced on. It has to be balance on some property.

It might be a spin property. For instance, negative and positive charges are always the same numbers. They are actually left handed and right handed spin particles. We have some kind of L and R handed spin law. I don't believe many realize this yet. This would not be a law of force. It would be a law of symmetry. Structure symmetry.

Symmetry and asymmetry properties might be fundamental properties. The energy of the left vs the right particles is most asymmetric. As is physical size.

Some symmetries are balanced and others are not. Gravity is so weak, many propose it comes from symmetry.....or the lack of.

If we can nullify our inherent measurement errors, there is much more to learn of this physicality. The unknown mechanism of entanglement is very temping and has great potential other than communication. For sampling, like a gamma ray, like we sample audio today. What could be better than an instant switch?

And instant direction switch, and an instant on instant off switch, would be man's greatest apparatus ever made. It's worth lot's of study and lot's of experiments.

For me......just the mystery alone is worth it.

 

[billslugg]

The quantum state of the first photon to be read is determined randomly. We cannot control what it is going to be. All we know is that the other guy got the opposite of what we got. There is no way you can transmit a message that way.

 

[Classical Motion]

I agree and understand that. But the change is instant. And the time of the change is controllable. So it's worth while to remove that random choice for input. We have to learn how to select the polarity. There's probably a lot a work being done on this, much more than alluded to.

Why work on faster switches when we have an instant one?

Entanglement is the second example of true natural digital dynamics with propagation being the first.