There are only two conceivable scenarios where it is safe to initiate communication with an alien race:

1. The aliens have directed a signal at us. The content of the message (or the transmission method itself) confirms that they are aware of our presence and are speaking to us directly. Since they already know we are here, we risk nothing by responding.

2. We have observed (through telescope or by overhearing their communications) that they are at a technological level that is inferior to our own, and therefore do not pose a threat. This however is not entirely without risk, because:

a) in the years that it took light to reach your telescope, they may have already developed technologies vastly superior to your own
b) Supposing that their technological development was halted, it's still conceivable that by exposing your position you may enable future generations to find and destroy you.

Personally I don't think it's worth it to initiate contact until we have a colony elsewhere that can bridge the gap. At least if our visitors are hostile they will only end up obliterating a colony and not the entire human race.

How close are they, and what are they aware of? If you are going to be paranoid, I think one could argue that we should not provide any additional data. A directed response in itself would give ET more information.


By "colony" do you mean an interstellar colony? So, am I right that you think we should never send out any signals until and unless we expand to at least one other star? In short, no SETI transmissions, within, optimistically, several centuries?

By the way, notice that if ET follows the same rules, we're only going to hear from interstellar civilizations, assuming, of course, that they exist and that they even care about such things.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

I'll give you my telescope when you take it from my cold, dead hands!

[Insert photoshop of Charlton Heston hoisting an antique telescope over his head]

I hate to chime in here on the side that's unpopular (actually, it seems lately I do that all too much), but I think there is a point here.

Deliberately sending a message... well, what messages we do send don't really get far if they aren't exactly focused, and they are very energy-expensive. I'm all for keeping our ears open, but sending out powerful energy-expensive messages at this point don't really seem efficient. I don't see the harm in waiting a few decades to centuries until we've at least partially mastered our own solar system before we start broadcasting to others.

That's just my $0.02, unmodified for the inflation rate.

And, just before people start making assumptions, no, I'm not paranoid. I can see why some people would be cautious in broadcasting to other races, but the way I see it, if they can expend the resources to get to Earth, they have the resources to get whatever resources they need from other methods that don't involve such long journeys.

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"A long habit of not thinking a thing wrong gives it a superficial appearance of being right." -- Thomas Paine

Being intelligent is not a felony. But most societies evaluate it as at least a misdemeanor. -- Heinlein

Creationists make it sound as though a "theory" is something you dreamt up after being drunk all night. -- Isaac Asimov

I still do not know if this has been pointed
out but it is all a non-problem..or not.
The powerful beamed signals to interplanetary
probes were directed to fixed points on the
celestial sphere. They were not deliberate
"here we are" stuff, just complex fast
changing electromagnetic energy. And completely
artificial. Detectable for 100's of lightyears
I suppose. And they will continue. So it is
no use worrying.

Our missile radar is quite obvious, and covers a large chunk of the sky. And, an advanced ET woudn't even need that. Gathering photons is much easier than building starships, so an ET species that could hurt us would have been aware of life here for a long time. From a paranoid species' point of view, it would make sense to hit any planet with complex species, to keep them from ever becoming a problem.

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

For light years and light years? Or for an infinite distance?

What range, and what stars could it get to, and not find it hard to filter it from background radiation?

Plus, if alien races from hundreds of near stars could spot us by our missile radar... what's the point in purposefully sending signals, then?

Sure, that's perfectly logical; we could also wipe out all the weaker nations like Africa to make sure they never become a problem, too. We could also wipe out, say, all the small countries before they develop a significant military. There are some that have no significant military in any way, shape, or form; logically, we should bomb the crap out of them or invade them. Just to make sure, you understand.

For your perusal, I propose we wipe out these countries that have no armed forces.

I guess I just don't see the logic -- and don't see how any species at all could arrive at this as a logical conclusion -- in going out of our way (or for any alien species to go out of their way) to attack another planet. The primary reason war and fatal competition has ever occurred here on Earth (and I'm not going to think that natural selection would work any differently on an alien planet), is because of competition for resources. However, there are far more resources in space than could successfully be harnessed by us today; and unless there's an alien race every other solar system, a species could expand and expand without ever bumping into another, and even if they did bump into each other, it just makes more sense to share what is otherwise an overly large amount of resources.

You'd have to be paranoid to the point of extremes to want to attack that small rock many hundreds of light years away "just in case" they happen to take you over for your limited amount of resources.

And a race that extremely paranoid would be too busy knifing each other in the back "just in case" the other guy thought of doing the same thing.

__________________
"A long habit of not thinking a thing wrong gives it a superficial appearance of being right." -- Thomas Paine

Being intelligent is not a felony. But most societies evaluate it as at least a misdemeanor. -- Heinlein

Creationists make it sound as though a "theory" is something you dreamt up after being drunk all night. -- Isaac Asimov

It's been discussed earlier in this thread and others - powerful radars have been painting a good chunk of the sky since the middle of the previous century. Detection range would be dozens of light years at least, depending on how big a receiving antenna is used.


To say something more interesting than "blip!"

Well, that's been the argument against active SETI - that a paranoid ET would destroy us if we said "hi!" If you're arguing against the paranoid ET position, then what other reason would there be to avoid sending out signals?

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

You are right on here WL. Think of all the really big decisions both in science and other walks of life, how are they made? By popular consensus? No way. Certain people realize that they are in positions of authority/power, and decide to do things within their group. Their attitude is, we'll just go ahead and do this, what is the population going to do about it? And therein lies the attitude behind all the significant events in history, and certainly will continue within our lifetimes. I truly wish this wasn't the way the world works, but it is.

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"fifty is nifty" , unknown poet

Mainly, the cost of resources, energy, funding, etc.

12 light years is a good distance, at least. That would hit 26 solar systems, going by this link. Although it would take quite a while for them to get there...

I'm having trouble finding out the cost of SETI's operation through funding. Can anyone come up with any figures, or at least point me in the right direction?

__________________
"A long habit of not thinking a thing wrong gives it a superficial appearance of being right." -- Thomas Paine

Being intelligent is not a felony. But most societies evaluate it as at least a misdemeanor. -- Heinlein

Creationists make it sound as though a "theory" is something you dreamt up after being drunk all night. -- Isaac Asimov

It might be quite high because for some reason NASA seems to have dropped SETI and made private people like the Planetary Society and Paul Allen fund it. This seems ridiculous to me, because what more important could NASA be funding?

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"fifty is nifty" , unknown poet

Pretty much everything else that NASA is doing.

agreed. we are learning about our universe. That gets first priority. Searching for space aliens is secondary.

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"I will do my best to understand and explain the universe from big to small without invoking miracles, unrepeatable events, or divine intervention. In place of those things I will use observations, mathematics, and science."


-Cross
My travel blog

Some of my Astrophotography


Those that lack education have a hard time understanding its value. - Cross

The SETI Institute's pretty cheap, as space exploaration programs go.

Space.com: With NASA Budget Cuts Looming, SETI Eyes Private Funding (October 2006)

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But we've been broadcasting our likely existence for millions of years using a transmitter the size of earth powered by the sun's energy. If an alien civ cared to examine the light, they'd find plenty of clues we were here anyway. If they are close enough, they could even see signs of our recent industrialization without ever leaving their home.

I'm not really a fan of active SETI but to be fair, if they are actively searching (and anywhere near us and biologically like us), they suspect this place already.

What you have said is true to a certain extent... but to say that 'we are detectable' and "they suspect this place already' is not the same thing as 'I am going to deliberately send a high power signal focused as much as possible directly to you.'

Just at this minute we don't know very much... but we may find that life is endemic... so the signals you referred to earth broadcasting over millions of years might not be all that significant. Maybe there are a billion such planets.

Lets assume that we are not special and that life on earth is not either... Lets say that you were looking for intelligent life in amongst 200 billion systems... of which maybe as much as one in a hundred have signs of life. That would give you 2 billion places 'broadcasting' in the way that you mentioned. And given that we are a very ordinary stellar type... it may be a much higher number...

Contrary to popular belief the TV signals that we broadcast wont be detectable out very far. The military radars much more so... but they are not broadcasting in every direction.... since we orbit in a plane and they are mostly in the northern hemisphere there is a large area of southern sky that doesn't often get shouted at by radars. Even in the north there are periodicities to take into effect and limits to the amount of activity over a certain latitude... *yes I know that the 'wobble' of precession and seasonal variation comes into it too...

The point is, that just at this particular decade we haven't got much info about the basic parameters in the Drake Equation, though the floodgates are soon to open with a number of new earth and space based scopes coming online soonish.

So what is the hurry about shouting out? How can they say 'I must do this now!'... when they know that an answer is going to take at least decades, and more likely, centuries, to come back.

What's the hurry?? Why not wait until some more facts are in... just in case the baby crying in the woods scenario is correct. Its not likely... but it _IS_ certainly possible. (it does at least offer an explanation of the Fermi paradox)

Yeah, if life is somewhat common then we are hidden better. Otherwise we stick out in the sky.

I'm certainly no fan of active SETI and if there is to be any caution about it it's likely something astronomers and scientists will need to decide informally. I can't imagine any lawmakers or the UN addressing it. Not that I think the signals sent to date constitute much of a risk.