When we think of the past we do not think about the actual minutes and seconds spent but more of a memory. In space, what we see through a telescope is that exact object’s look just minutes ago. For example, the distance of the moon and the travel of light from us to the moon, that is the moon’s exact look about 1.3 seconds ago. Starts are measured in “light years” which is the distance traveled by light in one year. In general, looking into the night sky is just like looking into the past.

Key Takeaways:

  • When we see lightning, we are seeing the past in milliseconds ago, but when we peer through a telescope, we are seeing the past in great magnitudes.
  • Because light takes 1.3 seconds to travel from the moon to the earth, when we see the moon, we are looking at something that existed 1.3 seconds ago.
  • Because the sun is 150 kilometers away, light takes eight minutes to travel from the sun to the earth.

“Our senses are stuck in the past. There’s a flash of lightning, and then seconds pass until we hear the rumble of distant thunder. We hear the past.”

Read more: https://theconversation.com/when-you-look-up-how-far-back-in-time-do-you-see-101176