Why is Space Black? Can it be Explained?

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Discussion Overview

The discussion revolves around the question of why space appears black, exploring concepts related to color perception, light scattering, and implications of Olbers' Paradox. Participants examine the absence of color in the context of the universe's structure and light behavior.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions why space isn't any other color, prompting exploration of color perception.
  • Another participant states that black is defined as the absence of color.
  • A participant explains that the blue sky is due to light scattering by air molecules, contrasting this with the lack of scattering in space, leading to the perception of black.
  • Reference to Olbers' Paradox is made, suggesting that the universe's structure influences the visibility of light and color in space.
  • It is noted that seeing black indicates no visible light is scattering towards the observer from that region.
  • A participant asserts that Olbers' Paradox implies there are not enough galaxies and stars to fill the gaps, leading to the conclusion that the universe cannot be both spatially and temporally infinite.

Areas of Agreement / Disagreement

Participants present multiple viewpoints regarding the nature of space's color and the implications of Olbers' Paradox, indicating that the discussion remains unresolved with competing interpretations.

Contextual Notes

Some assumptions about light scattering and the structure of the universe are not fully explored, and the implications of Olbers' Paradox are referenced without detailed resolution.

kramer733
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Why isn't it any other color? Can it be explained?
 
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The sky is blue because the air molecules scatter light so that you see not only light coming directly from the sun and stars but also all of the scattered light that eventually gets to your eye.

In space there is (almost) nothing to scatter light so if you are looking directly at a start you will see light from it- but no light beteen stars. No light means no color and, as Russ Watters said, no color means black.
 
More specifically, if you're seeing black, it means no visible light is scattering towards you from the region you're seeing black.
 
Olber's paradox, not enough galaxies and stars to fill in the gaps. Olber deduced our universe cannot be both spatially and temporally infinite.
 

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