One of the limits which most impressed me was a drawing of the diameter of travel of our communication signals. Almost two hundred years since it got to, "dot dot dash"? That energy has radiated most of 200 light years in every direction. Our galaxy is 100,000 light years across. Probability of life needs to be pretty high to expect an answer within this century!

If our fancy receivers pick up something from a few hundred light years away, how you gonna get there?

I'm such a wet blanket about interstellar contact!

 

One of the factors that make me wonder the most is the sheer number of stars out there. Over 400 billion in the Milky Way alone. That makes me think that confirming there's more intelligent life than just us is only a matter of time.

But there's another fact that I've just learned that throws a different light on the problem: the age of analog communications in our civilisation has practically come to an end, and it lasted only a little more than a 100 years. If the same applies to extraterrestrial civilisations then it's going to be extremely hard to identify them.

All of our communication is now performed digitally. And also practically all of it is encrypted. The reason for that is not only privacy, but also for efficiency's sake. We encrypt most of our communication because we use compression algorithms to make it faster and more efficient.
And I read somewhere that that sort of signal could be indistinguishable from noise to the outside observer.

There might be evidence aplenty out there of intelligent communication, and yet maybe we're incapable of identifying it.

No other area of scientific research requires a more perfect balance of skepticism and enthusiasm.

 

Plenty of wet blankets to go around.

 

Plenty of wet blankets to go around.

I'm afraid you lost me there... that's slang that I don't understand. Mind elaborating?

 

And I read somewhere that that sort of signal could be indistinguishable from noise to the outside observer.

I meant to bring that up. Only counting the high power broadcasters, thousands of megahertz speed transmissions per hour will surely look like noise a hundred light years away. Maybe the sheer noisiness of our planet would be a clue to a highly focused observer, but any particular message is unintelligible, for sure. I wonder how far a megawatt transmitter signal would have to travel to diminish to the background noise level. I'm sure that can be calculated.

 

I'm afraid you lost me there... that's slang that I don't understand. Mind elaborating?

Wet blanket: useless pile of discouragement. I am one. There are plenty more like me.

 

I wonder how far a megawatt transmitter signal would have to travel to diminish to the background noise level. I'm sure that can be calculated.

Yes, I saw exactly that calculation somewhere on this forum, and it's not that far. I remember it because I had never heard it before and it's one of those things that's "obvious" once you learn it.

It's yet another wet blanket. It means we can only see enormous - solar system sized - transmitters, or transmitters that are quite close to us. If intelligent life is not nearby, we'll never detect them unless/until they come calling.

I think a wet blanket gets its excitement-dashing allusion from being such a good way to put out a fire. You throw a wet blanket over it. Similar to a lead balloon, or my favorite, the turd in the punchbowl.

 

Just use the standard distance to signal strength calculations to find where the artificially generated signals strength drops below that of the average background noise of space.

I don't recall the exact numbers but I think that for the most part the biggest radio transmissions we have ever made likely become indistinguishable from typical cosmic background noise at less than 20 - 40 light years.

 

the turd in the punchbowl

That, I got

 

... I think that for the most part the biggest radio transmissions we have ever made likely become indistinguishable from typical cosmic background noise at less than 20 - 40 light years.

I suppose our nuclear blasts would show up quite a bit farther away, but would be brief and hard to explain as evidence of intelligence.

 

That's the biggest problem. As the distance gets further the ability to discern anything of value from our signals gets lower and lower.

At some point even our nuclear blasts would be hard to differentiate from the noises that our sun makes.
The biggest nuclear blasts we have ever made when compared to the noise our sun produces is like single mouse farting on the back of an elephant with stomach issues.

 

Just use the standard distance to signal strength calculations to find where the artificially generated signals strength drops below that of the average background noise of space.

I don't recall the exact numbers but I think that for the most part the biggest radio transmissions we have ever made likely become indistinguishable from typical cosmic background noise at less than 20 - 40 light years.

If you can identify a signal up to 20 light years, then this mesoplanet can be within communication reach...
...definitely within out 200 light years of coverage.

https://en.m.wikipedia.org/wiki/Gliese_667C_c

 

If you can identify a signal up to 20 light years, then this mesoplanet can be within communication reach...
...definitely within out 200 light years of coverage.

https://en.m.wikipedia.org/wiki/Gliese_667C_c

And here is a list of other options...

https://en.m.wikipedia.org/wiki/List_of_nearest_terrestrial_exoplanet_candidates

 

Road trip!

 

Aliens are natives somewhere.

 

Aliens are natives somewhere.

And, now that you framed the reference, all of our spaceships are their UFOs.

 

Neil Armstrong is rumored to have reached an agreement with the Lunan president and military to trade technological secrets for the right to abduct a limited number of natives for study purposes.

 

If you can identify a signal up to 20 light years, then this mesoplanet can be within communication reach...
...definitely within out 200 light years of coverage.

I think that with very good directional antenna and strong enough focused signals that communication over 200 light years distances could be theoretically possible without too much difficulty with today's technology.

Personally I would be looking to use ultra high powered modulated laser signaling not RF based methods though.

 

Rough for a passing bird.

 

Rough for a passing bird.

You don't have to go that high tech. I saw a YouTube video of a bird which got in the way of a baseball. Fortunately, the video stopped at the cloud of feathers...not the wet corpse.