“Due to the amount of time required for light traveling through the cosmos to reach the Earth, astronomic observers are always viewing the past—an effect known as ‘look-back time. The Sun has a look-back time of eight minutes, while the Andromeda galaxy’s is two million years.”
From Lapham’s Quarterly.
Of course, look-back time also occurs in our day to day experience; i.e., the amount of time it takes light from a building to hit my eye, and then perception-time, the amount of time it takes the cells to process that photon into some sort of image. Human beings don’t see the present, ever, we perceive only what has already occured perhaps 1/60th of a second ago.