If I may quote Iron Maiden, but "Run to the hills, run for your life". That's how first contact should be handled.

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Fields of Space

LOGIC, n.
The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.

In the Year 2525.

"One small step for (a) man. One giant leap for mankind".

If an astronaut doesn't need good grammar, niether does you.

Host of Seraphim

Hmm.
Upon recieving a highly directional laser signal from another star system and exchanging a few pleasantries - try sending them this:

"On behalf of the people of Earth, errr ... Mars, the Jovian moons, Alpha C, and a few hundred minor members, we'd like to extend an invitation to join our empire! We regret not being able to spare the resources (cough cough) to send a formal delegation at the moment, but membership in our empire is simple - you only have to agree to a complete exchange of cultural information. Just start sending us your history, technology, cultural acheivements, anything of value, and as a gesture of good faith we will start doing the same thing. We look forward to working with you."

Cue highly redacted doctored broadcast of trivial information. By the time we run through the preliminaries, fake technology, and trivia, and finally send our "haha! you've been had" post-fix message, hopefully they'll have already sent all their good stuff - and all their technology, history, cultural acheivements, disposition, ect will already be under-way.

(evil laugh)

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http://amssolarempire.blogspot.com

Unless, of course, they pull the same trick on us.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Why would aliens trick us? They just travelled light years across space. Do have any idea how much of a pain in the behind it is to interstellar travel? Just to build the ship, their economy was in ruins, their ecology is in wastes and millions died, just so a few of them can travel to another star system and say, "Hello".

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Fields of Space

LOGIC, n.
The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.

In the Year 2525.

"One small step for (a) man. One giant leap for mankind".

If an astronaut doesn't need good grammar, niether does you.

Host of Seraphim

Why not? Can't assume either possibility.

I have absolutely no idea. I know it's a pain in the a-s-s for us, now, but I can't speak for anyone else of alien origin.

Where do you get this stuff??? I'll admit it's not easy keeping track of a long, meandering thread like this, but did you just make this up?

Try keeping track of what is being talked about, this particular sub-thread is about the receipt of a laser communication not of a ship.

Also while building an interstellar ship with current levels of technology would be extremely hard and break the planetary economy there is no reason to assume that aliens would be limited to that (and good reasons to not do so). With tech not much above current through it becomes a hell of a lot easier, self-replicating machinery alone will change the whole economic game making things much more practical for mega-projects like interstellar travel and Dyson swarms (which would also make interstellar travel easy thanks to the superabundance of avalible energy).

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Girl: Mister Darwin! The stupid people are breeding and taking over the planet!
Charles Darwin: Tut tut, little girl, don't worry! I'll take care of them with my CHAINSAW OF NATURAL SELECTION! Ahahahahahhaha!!!!!!
-QUeen of Wands 12/08/2003

You're assuming they'd travel? I thought the question was about them replying by radio to our radio signals.

And why would their economy be in ruins, anyway? If they have the industrial and technological capacity to build a starship, they have the capacity to bounce back from a recession without blinking. "Ecology in wastes"; you honestly believe they'd still be limited to a one-planet ecology, let alone using the bottom of a planetary gravity well as a buildsite?

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Noclevername, what is your correlation between a society building starships and bouncing back from a recession? It was a leap of logic worthy of Occam's Ghost in my opinion. Could you care to explain?

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Speaking of which, I wonder if sending a signal to another star system is as trivial as many people assume?

Let's try the following thought experiment:

Given an antenna with an aperture of 10m radius, and a megawatt of power at the source, broadcasting a microwave signal at 1E6 nm.

What is the signal irradiance assuming it's aimed at Alpha Centauri?

Alpha Centauri is 4.5 LY away, that's 42570000000000000 m

divergence = 3.18E-5 rad

radius at range = 1.3E12 m

irradiance at range = 1.73E-16 milliwatts/m^2

I don't know much about signal detection, but this seems absurdly small to me. You'd have to be staring at Earth pretty hard with a dedicated instrument to pick it up, and to broadcast such a signal would have to be intentional.

Upping the power to gigawatts or even terawatts won't help you very much - what you need is a smaller divergence angle, which you can get by using a shorter wavelength (such as a visible laser), or a larger aperture.

If your microwave antenna was 100m in radius, now your megawatt antenna is down to 1.73E-14 mW/m^2 at Alpha C.

If it was the size of a decent airport (1 km in radius), and was drawing a Gigawatt of power, your signal strength at Alpha C would be up to 1.73E-09 mW/m^2

Talking to ET may not be a trivial undertaking.

And another thing - interstellar communications (ala SETI) probably shouldn't be going on in the radio region at all given the divergences you can expect for such long wavelengths at any reasonable aperture! I wouldn't be surprised if, to send stuff interstellar distances, you'd have to use UV or X-ray - or perhaps not even use wave-based communications at all, but have to use some sort of modulated particle beam that won't diverge over the long lightyears between the stars.

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http://amssolarempire.blogspot.com

It looks like one of SETI's observatories can find fluxes as small as 1E-25 W/m^2, or 1E-22 mW/m^2. So maybe these signals have decent strength, despite the divergence.

Still, that's a highly directional emitter - it would have to be aimed at the general neighborhood of a single planet to get that sort of irradiance. Omnidirectional emmitters would peter out so fast, it's hard to imagine their signals making it to Alpha C.

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http://amssolarempire.blogspot.com

You would be well advised to use a highly directional transmitter to talk to anyone in another solar system. I'd recomment a laser beam of the shortest wavelength available to cut down on diffraction.

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

Lasers now? This is a huge thread...

Lasers you want?

Think, "Death Star" or "Supernova gamma ray burst".

That's an alien language even we can understand.

__________________
Fields of Space

LOGIC, n.
The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.

In the Year 2525.

"One small step for (a) man. One giant leap for mankind".

If an astronaut doesn't need good grammar, niether does you.

Host of Seraphim

Doesn't sound like very effective communication.
For all the speculation on this thread, the main, primary answer remains- We do not know aliens and we do not know what they are like.

We can make our best guesses according to what we do know from life here...

However it could be debated, in the end, we are going to answer. Most likely, public opinion is going to have little influence to exactly how we answer.
We will take the risk. We will respond. And the odds are highly unlikely that aliens are some destructive force.

What do you base that on? True we only have ourselves and the life on this planet to base our suppositions on, but we should look at what data is a available. Life expands when it can, that seems to be a fairly universal truth. And that expansion can be a destructive force.

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What could aliens gain by destroying a species so far away that our life or death would have little effect on their existence? In something the size of the Universe, room to expand is not a rare resource. If life existed only by killing other life, there'd be only one species on Earth; instead, most lifeforms ignore any other living things not a danger to them. We're not a danger to anything light-years away and advanced enough to make radio contact, let alone come here themselves.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

I base it on the odds of the Unknown to put it simply...

When in doubt err toward what you feel is most likely


What it comes down to is for the volume of space and distances involved, compared to the amount of likely intelligent life within it that can reach and communicate at the same time that they are technologically able to- it seems that the odds favor non destructiveness.

These papers discuss optical band communcation between stars using lasers, and suggest that it could be most effective.
http://seti.harvard.edu/oseti/tech.pdf
http://seti.harvard.edu/oseti/bioast99_paper.pdf

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

On the contrary. It is very effective.

The aliens want us dead. They kill us. Communication received.

__________________
Fields of Space

LOGIC, n.
The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.

In the Year 2525.

"One small step for (a) man. One giant leap for mankind".

If an astronaut doesn't need good grammar, niether does you.

Host of Seraphim