like a void without minds? without humans?"mindless" means without a mind or brain.
Here "mindless void" means the empty space outside the Earth where there is no life - there isn't a mind there which can think - so it is "mindless":
Adjective. 1. mindless - lacking the thinking capacity characteristic of a conscious being; "the shrieking of the mindless wind..."
thefreedictionary.com - mindless
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