• Question: because there is a speed of light is there a speed of dark, if so how fast?

    Asked by anon-174833 to Alex, Carl, Hayley, Melanie, Tim, Yewande on 18 Jun 2018.
    • Photo: Alex Seeney

      Alex Seeney answered on 18 Jun 2018:

      Darkness is the absence of light, so in theory, darkness travels at the speed of light.

    • Photo: Carl Barford

      Carl Barford answered on 18 Jun 2018:

      Think you need to read Terry Pratchet discworld books, there is definitely an answer there

    • Photo: Tim Craig

      Tim Craig answered on 18 Jun 2018:

      Darkness is the lack of light. So I guess it has no speed in and of itself, but can propagate as fast as light can disappear (so at the speed of light).

    • Photo: Hayley Wragg

      Hayley Wragg answered on 19 Jun 2018:

      The speed of light is the speed of light waves traveling through a vacuum. What we see is our eyes receiving light waves, when things are dark this is due to an absence of light but we are still receiving waves in order to know it’s dark.
      So like Alex said, darkness travels at the same speed.
      Think of it this way, it would take the same time to know if the thing you were looking at was dark as if it was light, since you would have to wait to see if the light ray reached you.

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