Was the Universe “timeless” before the Big Bang?

Imagine a clock ticking away at the bottom of the ocean, in orbit, or near a black hole. Surprisingly, it would keep perfect time, just like on Earth. This consistency of time's passage, one second per second for all observers, is a fundamental feature of our Universe, explains astrophysicist Ethan Siegel.

But before the Big Bang? That's another story. In those primordial moments, time as we know it didn't exist. Our familiar rules of physics break down in the extreme conditions of the early Universe.

This quirk of time's constancy, despite the mind-bending effects of relativity, offers a fascinating glimpse into the nature of our cosmos. It's a reminder that even in the most extreme environments, some fundamental laws remain unchanged, anchoring our understanding of the Universe's grand design.