[TheOtherHobbes]

Problem - humans have been doing all of the above for decades, occasionally as a deliberate attempt to communicate, but mostly by accident.

So I can't see how your comment has any basis in fact.

You're only going to compress a data channel if you're in a hurry. When a message is going to take decades or centuries to get somewhere, you're more likely to keep the encoding as simple as possible to increase the chances of reception.

Besides that, I can't imagine radio being used for interstellar communication at all. It's fine for "Is anyone there?" but unless your aliens live at geological rather than biological rates, it's far too slow for almost anything else.

[jerf]

Compressing increases bandwidth, which is forever going to be at a premium. If you want to improve reception reliability, you put error correction on top of that. This is all off-the-shelf tech here on Earth, to say nothing of what aliens can come up with.

"Besides that, I can't imagine radio being used for interstellar communication at all. It's fine for "Is anyone there?" but unless your aliens live at geological rather than biological rates, it's far too slow for almost anything else."

Well, it's the fastest thing available unless you're basically willing to hypothesize magic. Anyone willing to do so is welcome to do so, and I'm serious about that; I just advocate that you be aware that you've switched to advocating magic. There's a difference between reasonable speculations based on real physics and arbitrarily advanced engineering, vs. new physics that despite all our research we still have little more than a whiff of, if that, and keeps crawling into ever more exotic energy domains to even peek at.

[rz2k]

I think we are talking about overhearing communication between aliens speaking the same "language", where compression makes even more sense over a difficult channel. Consider data transmitted from spacecraft in our own solar system. The signal is quiet, and the bitrate is very slow. They could send uncompressed data if it is were easier to receive, but instead they recognize the bitrate as a physical constraint and optimize for information per bit. Uncompressed data could provide an advantage in terms of redundancies making errors more apparent and often recoverable, but error correction algorithms are both more robust and more efficient.

The point is that compressed transmission actually is simpler, and a formalized error correction scheme is much more reliable than relying on redundancies that arise by chance.

What about the parent comment belies anything factual? There is no data on alien transmissions, and the efficiency of compression and formalized redundancies just is, as a result of the math, not as a finding of collected data, even if real world data confirms what is mathematically understood.