In 500 years we've gone from signalling towers to lasers, fiber and RF. If someone got a 10,000 year jump on us and has a technological improvement rate close to us, we don't know the scale, frequency, or means of communication. There's a lot of physics we know, but there's also more we don't know.

Also, I can't use language bi directionally with a plant no matter how hard I try. Maybe we're the plants. Maybe they don't have language.

The universe is about 14bn years old. Earth is about 4.5bn years old. Humans are about 100k years old. Writing is about 5k years old. Radio communication is about 150 years old. The laser is about 50 years old.

So that window holding our current level of communication abilities is 0.15% to 0.05% of our species' age, and our species is in a similarly tiny window.

Problem is, if they're at our level, their signals aren't going to be detectable.

Most people don't seem to realize this. Even if the nearest star had an earth level civilization, we wouldn't be able to detect its signals[1].

[1] https://www.seti.org/faq#obs12

I ain't no astrologist either, but there's also an assumption other beings would have similar biology to us, it seems.

To the side now with assumption they might communicate chemically only between themselves... WHAT IF their clock rate is way slower than ours? Like snails, or plants. Their bitrate of communication would be undetectable to us, if they're way slower. I suspect it would be detectable if their rate is higher though.

The age of the Sun is ~4.6 billion years, but it's rather young as most other stars in our galaxy are 10 billion years old or older.

That would mean most civilizations in our galaxy could be very much older than ours.

Radio only came about 100 years ago for us. Some new form of communication could be 100 or 1000 years out, which is no time at all on these scales.

Not an expert, so someone who is (I'm sure we have several on HN, hopefully one will reach this point), please jump in...

But life as we know it requires small but essential smatterings of "heavier" elements like potassium, iron, calcium, etc. Seems like we may need one or more cycles of stars forming and dispersing these elements into the interstellar medium to then form a solar system with enough of these elements to have life "as we know it." (Not to mention having a rocky planet for the life to live on.)

Stars that can produce elements up to iron and spread it through a supernova are massive and have relatively short lifespans of 10-30 million years. Since the Universe is 14 billion years old, we have had already more than a hundred generations of such stars before a 10-billion years-old planet has formed, so the necessary elements are probably there.

Yet another reason I love HN. Thank you. ;-)

There's a great short story by Harry Turtledove called "The Road Not Taken" that tries to jostle that view. If you can find a copy of it, worth a read.