“If I ask whether two events – one on Earth and the other on Proxima b – are happening “at the same moment,” the correct answer would be: “It’s a question that doesn’t make sense, because there is no such thing as ‘the same moment’ definable in the universe.” The “present of the universe” is meaningless.”

“If I ask whether two events – one on Earth and the other on Proxima b – are happening “at the same moment,” the correct answer would be: “It’s a question that doesn’t make sense, because there is no such thing as ‘the same moment’ definable in the universe.” The “present of the universe” is meaningless.”

— Carlo Rovelli