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One thing I seldom see mentioned, too, is why would a K3 civilization use easily detected communications like radio or broadly focused light sources? If we laun

One thing I seldom see mentioned, too, is why would a K3 civilization use easily detected communications like radio or broadly focused light sources? If we launched Voyager 3 (for lack of a better name) next decade, would we use primarily always-on, omnidirectional radio? Would we use a laser? Maybe we'd use a tightly focused, burstable digital radio system. What about next century? Are we simply looking largely for the wrong things?

grishka 5y ago
The tightly focused radio beam would still leak into surroundings and scatter off of things, and would thus still be detectable. Thing is, we still don't know yet what matter and energy actually are. We still don't understand the nature of spacetime. We have a lot of physics to discover. Those other civilizations might have discovered physics in different order. They might be communicating using phenomena we have no idea exist. It's not right to assume that advanced alien civilizations will be using any technology similar to ours.
- giantrobot 5y ago
  A radio observatory on Earth might be using a fiber optic connection to connect to the rest of the world but it's still looking at natural radio phenomena. It doesn't matter at all what a civilization might use as a backhaul, their Space iPhones could use SubspaceWifi, but their radio observatories will be looking at natural molecular hydrogen emissions. For an interstellar beacon signal radio is pretty good. Lots of natural phenomena are radio sources, CMB is radio, and a lot of things opaque to visible and near visible light are transparent to radio. So a radio beacon has a good chance of being detected just because any civilization that discovers radio astronomy can stumble across it. The idea that SETI would ever detect I Love Lqwynngh'tch reruns from an ETI has always been ludicrous. Even our most powerful radio telescopes (by sensitivity) wouldn't be able to detect television or radio broadcasts even a lightyear out from Earth. The only interstellar signal we (or another civilization) will ever detect are very intentional directed signals. If you had an omnidirectional radio source detectable from interstellar distances you could use it once as it would fry itself and anything around it pretty quickly.

grishka 5y ago

The tightly focused radio beam would still leak into surroundings and scatter off of things, and would thus still be detectable. Thing is, we still don't know yet what matter and energy actually are. We still don't understand the nature of spacetime. We have a lot of physics to discover. Those other civilizations might have discovered physics in different order. They might be communicating using phenomena we have no idea exist. It's not right to assume that advanced alien civilizations will be using any technology similar to ours.

giantrobot 5y ago
A radio observatory on Earth might be using a fiber optic connection to connect to the rest of the world but it's still looking at natural radio phenomena. It doesn't matter at all what a civilization might use as a backhaul, their Space iPhones could use SubspaceWifi, but their radio observatories will be looking at natural molecular hydrogen emissions. For an interstellar beacon signal radio is pretty good. Lots of natural phenomena are radio sources, CMB is radio, and a lot of things opaque to visible and near visible light are transparent to radio. So a radio beacon has a good chance of being detected just because any civilization that discovers radio astronomy can stumble across it. The idea that SETI would ever detect I Love Lqwynngh'tch reruns from an ETI has always been ludicrous. Even our most powerful radio telescopes (by sensitivity) wouldn't be able to detect television or radio broadcasts even a lightyear out from Earth. The only interstellar signal we (or another civilization) will ever detect are very intentional directed signals. If you had an omnidirectional radio source detectable from interstellar distances you could use it once as it would fry itself and anything around it pretty quickly.