When you look up, you're not seeing the universe as it is. You're seeing it as it was.
Light takes time to travel, so every star is a snapshot from the past. Sirius reaches us 8.6 years late.
Some stars visible tonight may already be gone. Their light is still arriving. You're watching ghosts.
Look farther into space and you look farther back in time.
The universe hides its past in plain sight.