I put it to you that any civilization advanced enough to construct a Dyson sphere is also advanced enough not to leave mid-infrared signatures of their having done it for the rest of the Universe to observe.
@mcfate I would argue any civilization advanced enough to do this likely has never had any reason to fear others externally or internally. Advances like this can really only be made by civilizations with a strong sense of working together and agreement on common goals and ideas.
The concept of intentionally hiding one's presence out of fear of being found is evolutionarily a prey instinct, as well as a very human one. So, we would be projecting our own values and fears on said civilization.
Where will the advanced civilizations get the resources they need to expand their civilization?
@mcfate it's kinda why I hate movies like Independence Day from the perspective of the military tactics. The resources they needed exist in abundance in our galaxy, there really was zero reason for them to invade Earth, except for it would make a good movie. Lol. Tactically it's risking potentially massive losses and travel expenditures for relatively net zero gain.
If your species needs more "lebensraum", as it's inevitably going to, you're not going to be interested in uninhabitable worlds.
An alien species that makes megastructures is not going to get into a ground war with a less advanced species. They'll just wipe out the indigenous autochthons from a perfectly safe distance.
Subjecting the entire planet to a solid month of high-decibel infrasonic sound would clear away things pretty well.
Not to mention that losing one ship on a scouting mission for a civilization building ships bigger than the moon doesn't constitute a "massive loss".
I continue to have no idea at all what the upside of announcing our presence to more advanced civilizations is supposed to be.
If a bunch of Sentinel Islanders had somehow gotten to England in a canoe in the 17th Century and managed to find Isaac Newton, how would they benefit from this encounter?
@mcfate why Isaac Newton specifically?
I'd imagine our own encounter with intelligent life far beyond our own understanding would result in us being studied and the Earth or solar system similarly made illegal for entry until such a time that we can reach them. What resources do we really offer that makes us so lucrative to wipe out and risk the nuclear counter attacks?
A rocky planet in the Goldilocks zone is a pretty rare commodity.
What makes you think "nuclear counter attacks" would be a deterrent to a civilization that's taking apart entire planetary systems to build gigantic artifacts?
And Isaac Newton because there's nothing a Sentinel Islander could learn from him without undertaking a few generations of "getting up to speed".
Also interesting that you don't seem to view being forcibly turned into research subjects in a zoo as "hostile". What happens if we don't want to be "studied"?