Musings on life outside our planet

An aside: in discussions of extraterrestrial life, we often say "intelligent" where we mean "technological," and mainly technological to the point where electromagnetism is used for communications. Yes, a species can be intelligent and not technological (humans until recently, perhaps dolphins) but such species are unlikely to figure into the search for extraterrestrial civilizations.

As for scanning the skies for radio waves, there are a few reasons we might never get a successful detection:

1. Technological aliens use radio waves for communications, but they do the efficient thing and make them HIGHLY directional. After all, any energy carried off on a ray not extending from the transmitter to receiver is wasted. If they did send directional signals, we might not receive enough energy from them to detect unless we were near/on the transmission path.

2. Technological aliens use optical frequencies--i.e., lasers--for communications, in which case virtually none of the energy of the transmission will come to us unless we're on the transmission path.

3. Technological aliens have other means of communicating over long distances, like some entangled quantum mechanical system. Such a system WOULD HAVE NO SIGNAL between the transmitter and receiver. We could be between two communicating alien worlds and never detect the signals being passed between them.

4. Technological aliens do not send signals into space.

5. Technological aliens are aware of our existence and avoid "contaminating" us with their communications.

6. Technological aliens are not close enough to us to allow for the possibility of detecting their communications.

7. Technological aliens do not exist.

I know how radio transmissions work. To simplify, let's say our alien nations are transmitting on FM (Frequency Modulation) where the data (information) varies by frequency variations, with a steady amplitude. If we are monitoring on AM (Amplitude Modulation) we will never hear the varied frequency (FM) that carries the data.
These are but two types of radios that we developed. Who knows what type of transmissions another planet might develop- even assuming they are not that much different than us.
Why would anybody assume that aliens have developed technologies even close to what we have developed? Our way is not the only way.

As for not sending signals in 360 degrees we have had for many years the ability to steer signals only in the direction of receivers flying a pre-coordinated azimuth.
This technology is so old it's obsolete.

My point is we may be just now discovering communications that were long abandoned by other civilizations and are no longer monitored.
It would be like Indians sending smoke signals - unless Indians are on the receiving end what's the point?

We'd need to know what modulation scheme they were using in order to receive the signal properly, but we're just looking for any RF energy above the background noise. Any complex signal isn't likely to be spectrally pure (a single frequency, with no bleed, harmonics, etc. into nearby frequencies), so if we check lots of closely-spaced frequencies, and there were a signal somewhere among them, we would probably see something.

The guys who put SETI together have a little knowledge about these things.

No, and this could be a problem. They may do things very differently. It's even possible that aliens could communicate in ways INTENDED to be not-so-easily detected.

It's not obsolete; we do it all the time. It's a waste of power to do anything else. Even local TV and radio transmitters have radiation patterns that put more signal in certain directions.

To use your analogy, we might be able to see the smoke, even if we don't know what it means.

I may have fallen into that trap. But I maintain that a technological civilisation will be extremely unlikely not to use the EM spectrum in a way that is detectable.

I couldn't disagree more. There are an infinite number of ways for technology to evolve.

Well, in a sense, NO ONE uses the EM spectrum in an undetectable way for communication because communication requires detection! But I know what you mean and I pretty much agree.

Here's the rub...

Because of the distances--and therefore the transmission times--involved in interstellar communication, it may be that an interstellar species doesn't do it regularly. Think about it: if you have colonies that are, say, 20-50 light years apart, communication is pretty much one-way. You can't send urgent news because it will take years to get there and you can't send questions because the answers will be very long in coming.

If aliens have faster-than-light travel, perhaps they simply don't communicate via EM waves between their settlements. Of if aliens have faster-than-light communications, these may not be detectable by us (or, perhaps, by anyone other than the parties to the communication). If they have neither, then interactions between their settlements may be very, very rare.

Or, maybe the homeworld sends out a continuous feed of sitcoms and reality TV programming. Who knows?

I think one thing is pretty certain: if they do send out radio signals, they're not intended for us. They're intended to communicate with their own kind, who inhabit known star systems. As such, their signals are apt to be highly directional and unlikely to be seen by us unless we happen to be near the transmission path.

Technology is constrained by physical laws. It can only develop in ways that those laws allow.

So you think that the ways humans have developed so far are the limits of what physical laws allow?
In other words intelligent beings on other planets may have developed completely different forms of communication that
don't break the laws of physics, but are just so different (not better, just different) that we have no way of interacting with them.
I'm talking if these methods/technologies were revealed to us we would say "Damn! That's so simple! Why didn't we think of that?"
I think it would be great if at the exact same time humans evolved, another planet (virtually identical to Earth) had it's version of "top of the food chain" intelligent beings evolve just to see how different (or similar) technologies would evolve. My money would be on a completely different toolbox by the time we get to the present time.

Nope, never said nor implied that. You can speculate about alternative mediums of communication but these are unlikely to be simple (or we'd have discovered them).

They may not even bother communicating between colonies, we would because of how we are, another intelligence may see long term survival by diaspora combined with isolation. Each colony dedicated to seeding another X number of colonies and then getting on with things, erasing all knowledge of their origin world and colonies, so if any other species did come along they'd have no knowledge to give them of their other worlds.