Light has a finite speed. So whatever our eyes see happened in the past. If what you’re seeing is near you, light will take just a few nanoseconds to bounce off the object and into your eyes (but it’s not instantaneous). If you’re looking at the stars in the sky, you may be looking as far as millions of years into the past. We never see the “present”.
Someone with a better understanding of physics might be able to explain this better, but as far as i understand it, according to the theory of relativity, changes in the universe are propagated at the speed of light. So there is no definitive “present” without a frame of reference.
Let’s say you observe two death stars equidistant from you, that are also moving at the same speed as you, blow up at the same time. From your frame of reference, they blew up at the same time. But from the frame of reference of each one of them, the other one blew up later. And this isn’t just a matter of perception. The change in gravity because of them blowing up would also only travel at the speed of light. This speed limit is a fundamental property of the universe.
Not only that, but electricity travels through nerves at a finite speed (that is less than light speed), and brain spends non-zero amount of time to piece together the reality you perceive from all of your senses. So yeah, there’s always a delay in your perception and IIRC there even are experiments that prove that
No such thing as the present or ‘now’. There will be the future and there is the past. And the line between those two is the ‘now’. Except that line has no thickness.
Everything we perceive is a memory is something that has already happened.