I read some where or was watching a fantasy show about aliens. Maybe both.
It got me to thinking about advanced civilizations and our on going search for Earth II. It occurred to me that early man lived in hospitable areas on earth. Places that naturally provided food and shelter with little or no input by man. This is kind of what we have and what we are looking for in Earth II.
It is also the root of our fears of nasty aliens taking over our planet. This makes me think that say, a bear might be worried that we would turn him out of his lair, while we were thinking his lair is a nasty hole in the ground. In other words, a civilization that has mastered interstellar travel, would have also mastered the art of building planets and putting them into orbit around stars. Those civilizations would be no more interested in this planet than we would be interested taking over the trees of an ape colony.
Hurmp
Qazulight (All the Star Wars shows make no sense now)
Whoever designed or built the universe was (is?) a pretty smart cookie. If life elsewhere is like life on Gaia then the first thing they (we) do is go to war with the neighbours. If not war, at least hunt them down for food.
That is the reason for the limit on the speed of light and intergalactic distances. Who ever did it, wanted a peaceful universe.
I’d say they would travel just to see what is “out there”. They would know it is impractical to move massive volumes of items long distances in space.
Not sure if building a planet is a good idea. Contact Slartibartfarst and listen to what he and his co-builders would say. The mice used them to build their experiment, after all.
A Dyson sphere would be interesting, but too many ways for it to fail (from either internal or external issues/problems).
I would think a giant ring around a star might work. Massive land area with a circle 185-million miles (2 AU) across–by how many miles up/down? Do the math… Far more land area than any planet.