According to the History Channel’s program “The Universe – Light Speed” ….
Laura Danly, Griffith Park Observatory Curator in LA:
Because it takes time to travel, we’re able to look back in time, the further out we look in distance, the further back in time we look. We would have no idea what our cosmic history was if the speed of light travelled instantaneously.
What a concept! To look in the sky and see the stars, knowing that what we see is not what exists at this moment!
if you did not know that it takes years and years for what happens in the sky to be visible to us, and if you did not know that you did not know that, you would think you are watching the comet racing through the sky in real-time. It’s your perception. And your perception is your reality.
It’s not what you saw, it’s what you think you saw.