The speed of light
The speed of light
It’s deeper than that as we have instruments to measure things we can’t personally perceive.
From everything we know it’s quite literally the limit the universe can update. For the photon moving at light speed time quite literally doesn’t exist. When you look up at the stars, for the photons hitting your eye balls their experience is that creation to reception is instantaneous. The millions or billions of years we perceive it traveled doesn’t exist at that speed.
I just think that’s neat.