3 ms·

Because it is daytime. (If the camera exposure was set for the faint stars, then the sun-lit scene would be hugely overexposed.)

JPLeRouzic 9y ago
I am not sure this is the complete explanation. On Earth we do not see stars because of light scattering (Rayleight and Mie) [0]. In the outer space there is no scattering and the light from each star represents a tiny point in the picture, but this point is bright. After all it comes from a sun. But the original image [1] has a dark background as well. Maybe it is due to the fact that jpeg compression losses small artifacts or something else. On some pictures it is possible to see tiny white points such as in [2] [0] https://en.wikipedia.org/wiki/Diffuse_sky_radiation https://en.wikipedia.org/wiki/Diffuse_sky_radiation [1] https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-14-2383HR.jpg https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-14-... [2] https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-15-2561HR.jpg https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-15-... (some non important edits, including changing link 2 which was a thumb view)
- gcthomas 9y ago
  We see stars during solar eclipses, so it is the scattering of the light of the sun that obscures them. It really _is_ the exposure issue, since the surface brightness of the Earth is that of full daylight and so full daytime exposures were needed. Stars will never show up unless longer exposures are used. Here is an over exposed photo of Earth by Apollo 16 from the lunar surface, with stars visible: https://en.wikipedia.org/wiki/File:Apollo_16_UV_photo_of_Earth_rotated.jpg https://en.wikipedia.org/wiki/File:Apollo_16_UV_photo_of_Ear...
  - JPLeRouzic 9y ago
    I may not have been so clear (English is not my native tongue, etc), but you repeat what I wrote: * it is the scattering of the light of the sun that obscures them * On some pictures, stars are visible (I even provided a link) However having said that you also say "It really _is_ the exposure issue" but it has nothing to do with light scattering?
    - moioci 9y ago
      I think light scattering is an atmospheric phenomenon.
- deleted 9y ago
  [deleted]

JPLeRouzic 9y ago

I am not sure this is the complete explanation. On Earth we do not see stars because of light scattering (Rayleight and Mie) [0]. In the outer space there is no scattering and the light from each star represents a tiny point in the picture, but this point is bright. After all it comes from a sun. But the original image [1] has a dark background as well. Maybe it is due to the fact that jpeg compression losses small artifacts or something else. On some pictures it is possible to see tiny white points such as in [2] [0] https://en.wikipedia.org/wiki/Diffuse_sky_radiation https://en.wikipedia.org/wiki/Diffuse_sky_radiation [1] https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-14-2383HR.jpg https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-14-... [2] https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-15-2561HR.jpg https://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-15-... (some non important edits, including changing link 2 which was a thumb view)

gcthomas 9y ago
We see stars during solar eclipses, so it is the scattering of the light of the sun that obscures them. It really _is_ the exposure issue, since the surface brightness of the Earth is that of full daylight and so full daytime exposures were needed. Stars will never show up unless longer exposures are used. Here is an over exposed photo of Earth by Apollo 16 from the lunar surface, with stars visible: https://en.wikipedia.org/wiki/File:Apollo_16_UV_photo_of_Earth_rotated.jpg https://en.wikipedia.org/wiki/File:Apollo_16_UV_photo_of_Ear...
- JPLeRouzic 9y ago
  I may not have been so clear (English is not my native tongue, etc), but you repeat what I wrote: * it is the scattering of the light of the sun that obscures them * On some pictures, stars are visible (I even provided a link) However having said that you also say "It really _is_ the exposure issue" but it has nothing to do with light scattering?
  - moioci 9y ago
    I think light scattering is an atmospheric phenomenon.
deleted 9y ago
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