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ToSeek
2004-Sep-08, 04:33 PM
Message in a Bottle
Calculations Show Energy-Efficient Aliens Would Write, Not Phone (http://abcnews.go.com/sections/SciTech/US/alien_message_040902-1.html)


Physicists have calculated that inscribing information on an asteroid or comet or other kind of matter and shooting it into deep space — or even directly to Earth — would be much more efficient than delivering information through radio waves.

Jigsaw
2004-Sep-08, 06:03 PM
That's assuming the Aliens are interested in efficiency. But, what if they're the Martha Stewart of alien-dom? What if they're more interested in doing it "cute" than in doing it efficiently?

Sending radio signals is much cuter than writing letters, because it involves more cool equipment from Hobby Lobby, plus you can really be creative, you can vary the signal to spell out different things, like your wedding anniversary, or your dog's name.

Demigrog
2004-Sep-08, 06:15 PM
This is nothing new, really; we've got messages on many of our deep space probes, and sci-fi is full of this sort of idea (the Monolith in 2001 being the obvious example).

The "message in a bottle" approach has huge advantages if you're not in a hurry (and nobody can say aliens die as quickly as we do, nor have such short attention spans). I can see an alien civilization sending thousands of message probes to likely planets. If you make the probe "obvious" enough (a la the "gravitational anomaly" of the Monolith in 2001), an intelligent species is likely enough to notice it eventually. Radio, on the other hand, is a one-shot deal, and may be something other species never even discover. (Or even consider a weapon; anybody else read Timothy Zahn's Conquerors trilogy?)

One of the key features of a “message” probe would be something to make it stand out and be noticed. It would be an interesting exercise to come up with some ways aliens might make their probes stand out, then search for them on Earth and in our solar system. Not that I’d expect results, but it is not really so different a concept than SETI.

Normandy6644
2004-Sep-08, 06:38 PM
So what would it say?

"This asteroid is brought to you by the planet Earth. Planet Earth: hurling asteroids into the cosmos and hoping you see them but they don't hit your planet and kill you."

:wink:

Demigrog
2004-Sep-08, 06:47 PM
So what would it say?

"This asteroid is brought to you by the planet Earth. Planet Earth: hurling asteroids into the cosmos and hoping you see them but they don't hit your planet and kill you."

:wink:

How about "This is a chain-asteroid. Pass it on or have 10 million years of bad luck!".

cyswxman
2004-Sep-08, 07:00 PM
Maybe there are some other craft like the Voyagers out there. :-k

George
2004-Sep-08, 07:01 PM
There's still something about info at the speed of light that has some appeal to me. :wink:

Sending a couple of DVD's can be done using light as a carrier wave. Why "slow boat" it? Is one of the messages..."By the time you read this, we may not be a living species. We would have liked to have known you sooner but we felt this bottle would be the most effective method of communicating. BTW, if it was your teenagers that were gone longer than normal, attached are some crop circle pictures of their possible activity."

:roll:

Swift
2004-Sep-08, 07:04 PM
So what would it say?

"This asteroid is brought to you by the planet Earth. Planet Earth: hurling asteroids into the cosmos and hoping you see them but they don't hit your planet and kill you."

:wink:

How about "This is a chain-asteroid. Pass it on or have 10 million years of bad luck!".
Of great, spam-asteroids. With our luck all the asteroids we get will be messages about how to make your planet bigger or it's the brother-in-law of the former Vulcan Minister of Banking and he needs your bank account number to help transfer 10 million in latinum. :D

Jorge
2004-Sep-08, 08:44 PM
I like the idea of probes,
If we would send a probo for a 'Message in a bottle' mission we would make it flashy noticable and try to imporess them.

It would be way cooler that some alian race finds a probe with some pictures on it, some voice sample and looks cool. than a simple message via radio

George
2004-Sep-08, 08:54 PM
So what would it say?

"This asteroid is brought to you by the planet Earth. Planet Earth: hurling asteroids into the cosmos and hoping you see them but they don't hit your planet and kill you."

:wink:

Or, conversely, "This is asteroid no. 945,022 sent to you planet Earth. Planet Z: hurling asteroids to you hoping you see them when you get out past Mars." :)

CJSF
2004-Sep-08, 09:21 PM
This method, of course, biases the discovery of ET intelligence toward those that are actively seeking communication with others.

CJSF

George
2004-Sep-08, 09:56 PM
This method, of course, biases the discovery of ET intelligence toward those that are actively seeking communication with others.

CJSF

True, but this earns them the right to visit with our scientists first as opposed to our telemarketers. :)

eburacum45
2004-Sep-09, 06:04 AM
Okay; how is this supposed to work in practice?
Imagine a civilisation with several widely separated colonies; if these colonies want to send messages to one another they can either fire powerful lasers at one another, and if the lasers were powerful enough and the detecting telecopes sensitive enough these lasers would allow a bit rate of several bits per second;

or they could fire tiny pellets full of memory at each other-
thse pellets could contain terabytes of compressed memory, the equivalent of hundreds of years of laser transmission...

not a bad idea.

But how do you aim these pellets, and how do you recover them?

It would be more difficult to aim a pellet stream than a laser, and if you sent millions, perhaps only one or two would get through-

then you have to detect the pellet, and catch it as it passes through at interstellar speeds.

Maybe a beacon on the pellet could announce its location;
perhaps the pellet could be gathered by some sort of magnetic scoop

not too sure about the magnetic scoop, though;

if it is strong enough to capture a pellet, it would probably denature the information contained in that pellet.

George
2004-Sep-09, 03:26 PM
if these colonies want to send messages to one another they can either fire powerful lasers at one another, and if the lasers were powerful enough and the detecting telecopes sensitive enough these lasers would allow a bit rate of several bits per second;

Huh? Are you suggesting Morse code limitation? Lasers can currently handle about 100 billion bps. You can even combine the two by using packett transmission.

Demigrog
2004-Sep-09, 03:58 PM
or they could fire tiny pellets full of memory at each other-
thse pellets could contain terabytes of compressed memory, the equivalent of hundreds of years of laser transmission...


A pellet sized message might be ok if the recipient was expecting it and has the technology to detect and capture something that small. For sending "Hello, Universe!" messages to ET, you'd want something a lot bigger and more obvious. Some sort of inflatable structure coated with something highly reflective (preferably with a really obviously unnatural spectrum) might work.

So long as our first interstellar DVD isn't advertising "1000 free hours"-- some galactic Anti-Spam filter might decide Earth is a zombie server and shut us down. :o

Andreas
2004-Sep-09, 04:44 PM
Huh? Are you suggesting Morse code limitation? Lasers can currently handle about 100 billion bps.
Probably not at interstellar distances. First there is the question on which frequency you transmit in order to cover some distance. That frequency limits the data frequency. Second there is the question of noise and multiple paths through reflection which degrade your signal. 100 billion bps is attainable with glass fiber cable over short distances, not through interstellar space.

eburacum45
2004-Sep-09, 07:18 PM
That's right; the beam of a laser or other narrow beam collimated signal spreads out over interstellar distances until you are only receiving a limited number of photons per second;

this number can be increased if you use high-frequency light and large receiver telescopes.

Oh I am sure most interstellar data transfer will be communicated via narrowcasting of some sort;

but if you wanted to send a large data packet, such as a DNA library or an uploaded human mind, you might be better off sending it by snail mail.

Roving Philosopher
2004-Sep-09, 07:46 PM
So what would it say?

"This asteroid is brought to you by the planet Earth. Planet Earth: hurling asteroids into the cosmos and hoping you see them but they don't hit your planet and kill you."

:wink:

How about "This is a chain-asteroid. Pass it on or have 10 million years of bad luck!".

Don't go knocking the chain-asteroid. The dinosaurs broke the chain, and look what happened to them! :o

George
2004-Sep-09, 10:27 PM
That's right; the beam of a laser or other narrow beam collimated signal spreads out over interstellar distances until you are only receiving a limited number of photons per second;...
Just a quick run here....

Say a red laser of about 1ev/photon with a beam divergence of 1 arc sec. A 500ft receiver 20 lyrs. out should get about 5e^10 photons per sec. out of a terrawatt laser. This laser exists today (albeit, pulses only). Stick some large lenses out near Pluto for gain, as well as, multiple lasers and modulate away.

My confidence is low as I found nothing by googling to support this so I might be off by as much as 19 or so light years. #-o

Swift
2004-Sep-09, 11:08 PM
I wonder if the issue is whether you are communicating directly to a known receiver or whether you are just taking pot shots at unknown, possible receivers.

For example, lets say Earth had a colony at Alpha Centauri. I would guess the laser would work best. You can aim it exactly at the spot you want and I'll guess that George's calculations are ok. Plus, it only takes four years for them to get the message. Unless you had FTL (in which case, who cares) sending them a message rock has to take more time.

But if you are on Earth running a SETI program, want to send ET a message, and don't know where the receiver is it might be more of a toss-up. Keep aimming your laser at every different star in the sky, or send out a few thousand message rocks in different directions.

One idea from science fiction is self replicating probes. Create a robot probe and send it to the nearest star. It has to find materials in that system, make a couple of copies of itself, and send those probes to the nearest stars to that system. That way you slowly hop-scotch across the galaxy.