Type II Kardashev civilizations eventually completely enclose their planetary system in a Dyson sphere because space is way too big to look at all the time.

"Occulting Telescope", by Randall Munroe, licensed under Creative Commons Attribution-NonCommercial 2.5 License

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Type II Kardashev civilizations eventually completely enclose their planetary system in a Dyson sphere because space is way too big to look at all the time.