• Question: in space, is it likie behind 1000 years so they can see the people that was here 1000 years ago?

    Asked by 07yousafj to Hywel on 25 Jun 2010 in Categories: .
    • Photo: Hywel Vaughan

      Hywel Vaughan answered on 25 Jun 2010:

      Not far off in the concept Yousaf!
      The distance between our planet and the next closest solar system (Alpha Centauri) is 4.22 light years. A light year is the distance that light travels (at the speed of light of course!) in one year – about the same as 5,878,630,000,000 miles.

      If we are talking only 4.22 light years, it means that the light leaving our solar system doesn’t reach theirs until 4.22 years later, so what they are seeing is 4.22 years old!

      If we are talking further and greater distances, then yes, the light they see could be 1000years old, and vice versa. A lot of the stars we see in the night sky were there millions of years ago, and the light is only just reaching us – we are essentially looking back in time.
      It is the same when you look at our sun – it takes the light about 8 minutes to reach the Earth after leaving the sun, so what we see is actually 8 minutes ago…