Are we surrounded by an ancient advanced Civilisation, but not understanding what we are looking at?
I joined the sub today, so apologies if this is old ground. One of the possibilities that has fascinated me since I thought about it is that our ability to detect the evidence of other civs is hampered by being in an incredibly unlucky starting position.
Imagine if you will, an incredibly advanced civ with the sort of technology we have considered in the wildest extremes of what we could do; literally consuming stars and solar systems for raw materials or using stars for solar engines to move planet scale populations around. A civilisation right on the cusp of being Kardashev type III where individual stars are being used as fuel but they are not quite masters of the energy of the entire galaxy.
Then imagine that this incredible civilisation meets its end. warfare, some techno self-destruction.. who knows, maybe they even sublimed in some form (nod to the Culture...)
What would the remnants look like?
Well, one thing that might be a telltale sign would be a dramatically reduced density of stars in the area. particularly a shortage of hotter, brighter younger stars and a higher than expected ratio of colder, redder stars with less energy to be harvested...
So, what if a new civilisation developed from a species evolved on a younger star within this space... they would encounter a space around them with nothing more than a void where they should have seen many, many closer stars..
We know what this could look like on a much grander scale - the Bootes Void could be explained as the end result of a voracious Type III civ...
But we have our own local version - the Milky way has a lower than expected Stellar Density. our own local area seems to be in a particularly star deprived region.
What if the reason we don't see the evidence of a civilisation that has gone before is that we are looking for something to be there, rather than looking for something which is missing?