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Should SETI Be Looking For Lasers Instead?
colonist writes "Frank Drake, creator of SETI's famous equation, says the detection of extraterrestrial radio signals won't work, because Earth's own radio signal will only be around for 100 years. More and more of Earth's communications use cable and satellites, with no radio-frequency leakage to space. Instead, we should be looking for intentional signals in the form of high-powered lasers that could 'outshine the sun by a factor of 10,000'. Meanwhile, Paul Davies writes that we should be conducting SETI in our DNA. In turns out that an alien message designed to last millenia should be 'inside a large number of self-replicating, self-repairing microscopic machines programmed to multiply and adapt to changing conditions', otherwise known as living cells. Are we the message?"
Optical (ie: laser detection) SETI has been up and running for a while now (see Optical SETI overview for example). Drake ought to declare an interest though, since he's one of the investigators on the project.
It's a reasonable argument, but it's far harder to set up optical "listening" posts than radio ones. It cost me about 1000 uk pounds (WHY is the pound symbol banned from
The counter argument of course is that to detect laser light, the remote civilisation have to be pointing their laser at us, whereas with radio it doesn't matter since it's not a directed beam. Against that you have to offset the time-period over which transmissions of either kind could be made...
The chances of getting a radio contact may be a few orders of magnitude lower than getting an optical contact, but since the chances of me setting up an optical SETI station are precisely 0, the chances of getting 'the' signal with radio is infinitely greater than with optics, at least for me
Simon
Physicists get Hadrons!
Is a message allowed to read itself?
is in our mitochondria.
I think we would probably be able to program organisms from scratch by that point, so what kind of organisms would you send to establish life on a distant planet? It would probably start off small, or virus like, but would need to be preprogrammed to evolve into something more complex. Since the evolution would be random, you really couldn't determine the outcome after billions of years.
Then it occurred to me that if we were going to go through all this trouble for a slight chance that these packets of life might just thrive and grow some brains, we would probably put some kind message in there. Then it occurred to me that we could possibly be the product of such a plan.
It is possible that the structure of the genetic code itself is an artificial creation of an advanced race. Maybe we should examine the fossil record to look for patterns in the earliest life on the planet. Maybe humans got an evolutionary speed pass to intelligence. Who knows? At any rate understanding the underlying structure of genetic programming would be necessary for understanding the rational behind choosing one structure over another. Just like programmers develop an understanding of the language they program in, perhaps we'll see some calculated order to it all.
With the promise of quantum communication, it is conceivable that (if Quantum communication is indeed feasible) we should be focussing our optical light search on specific photons of light.
Anyone know about beam splitting entangled pairs etc. Many moons ago, Einstein, Podolski, and Rosen carried out there unusual experiment whereby the they observed what is now known as quantun weirdness. A photon in an entangled state could be split using a sophisticated 50:50 beam splitter. Each split photon could travel off in opposite directions and appear to be twins, in the sense that any change in behaviour of one would instantly (exactly synchronized regardless of distance!!!) be felt by the other, its twin.
Evidence that this was no fluke is gathering thanks to continuing experiments, yet it is still not in stone.
My reasoning is that if this phenomenan is genuine, it could be one way extraterrestrials would chose to contact us. Why not. They send a conventional optical signal, only this time encased in a surrounding cylindar of light, thus allowing for the entangled photons charateristic properties to be influenced only by this cylinder of light. Allot can till go wrong so conceivably, the 'ET's' would send a large stream of such light cylinders- the centre of which is a stream of entangled photons. That way any measurement of the entangled photon would cause an immediate change to its twin (The twin photon - of entangled pair)would presumably be archived on the alien world bouncing back and forth in a cavity (not unlike the cavities we use today - only presumably far more advanced.) So, once change is observed, an immeditae alarm bell is triggered. The ET's can know instantly someone/something has comeinto contact with their signal. Just like Earth SETI, the ET SETI would categorise all their findings and have mant false positives. They would probably already have chartered the area of space to which they send a signal. They may know the only objects (meteorites, stars, planets, commets...) that are likely influences over the transmitted light signal. Hence, if we Earthlings intercept the light in a very manufactured manner (i.e fire a encoded light signal of our own into theres, they are likely to get some unusual data back at there end - instantly.
Anyway, lets face you can't have an interest in SETI without being imaginative.
All Im tring to say is.
1) If I were a highly advanced ET, I would use Quantum entaglement (if it is indeed feasible) to transmit photons of light.
2)I believe we should start sending entangled photons of light, encased in our own manufactured cylinders of background light, out into space.
3)I hope SETI read this.
Now from the car's perspective, the light is moving away from it at C, but it's moving forward at .5C, so the light is only getting closer to the observer at .5C. Hence it takes two minutes to reach the observer. At T+1 minute, the light has not reached the observer. So the guy in the car is surprised by the announcement that it has, and sends back an instant communique for confirmation.
"Confirmation?" asks the observer, "I haven't sent you anything yet!" After all the light has not yet reached the observer, so how could he have sent the communication?
You're assuming there's such a thing as absolute time, which Special Relatively disproved.
So there is no such thing as T time. There is O(T) - Observer time. And R(T) - caR time. Let T0 be the time when the car flashes its headlights, and T1 be the time when the light from this flash reaches the observer.
So the car flashes it's headlights at R(T0). The observer sees the flash at O(T1). The observer then immediately sends an instantaneous message to the car, which is recieved at R(T1).
To both parties, at the time T1, the light ray from the headlights has reached the observer. The difference is that (R(T1) - R(T0)) > (O(T1) - O(T0)).
Your thought experiment assumes that there is a "universal time". So that one minute for the car is the same as one minute for the observer. This is incorrect.
... light-speed communication at least, is a lot of patience!
Unless the first ETs we encounter live in a different time dimension. What we consider couple of thousand years, might be a few minutes for them, who knows?
The purpose of life is to find the purpose of life.