@astro_rottier
Light from distant stars and galaxies takes so long to reach us that we are actually seeing these objects as they appeared in the past. As we look up at the sky, we are really looking back in time. For example, the Sun’s light takes almost 8.5 minutes to travel to Earth, so we see the Sun as it looked 8.5 minutes ago. The nearest star to us, Proxima Centauri, is 4.2 light-years away, so it appears as it was 4.2 years ago. The nearest galaxy is 2.5 million light-years away, and it looks as it did when our australopithecus hominid ancestors walked the planet.The farther away something is, the further back in time it appears.���� ||