When we look into the night sky we are actually looking into the past. how do you explain this?

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Physics

Guest

4 September, 10:02

When we look into the night sky we are actually looking into the past. how do you explain this?

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Answers (2)

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Efrain · Answer 1

Light takes time to cover a distance.

ANY light you see left its source some time ago.

The time depends on how far away the source is.

Whatever the distance is, you see the source as it was

when the light left it, not as it is "now".

- - When you look at Alpha Centauri, you see light that left it 4 years ago.

- - When you look at the sun, you see light that left it 8 minutes ago.

- - When you look at the moon, you see light that left it 1.28 seconds ago.

- - When you look at the refrigerator on the other side of your kitchen,

you see light that left it 0.0000000133 second ago.

German Short · Answer 2

Because you are watching the light that is coming from the stars and those stars are extremely far away from us. The time that light need to arrive to the Earth is "the past" that you are watching in that moment.