If it takes 8 minutes for light from the Sun to reach us, then why is it that when I open my eyes… by Richard Muller
Answer by Richard Muller:
You are seeing the way the sun was 8 minutes ago. When you open your eyes and see something “instantanteously” you are not seeing it the way it is now, but the way it was then.
If the sun exploded into a supernova 7 minutes ago (by the way… we don’t think this is possible) you wouldn’t know yet. Not a hint.
When you open your eyes and look at your computer screen, you are (instantly?) seeing the way it looked about 1 to 2 nanoseconds ago — since light travels about 1 foot per nanosecond. (For a modern computer, that nanosecond represents 3 computer cycles; for modern electronics, it is not a long time.)
When you instantaneously hear thunder from a flash of lightning that you saw 5 seconds earlier, you are hearing the sound that was emitted almost 5 seconds earlier.