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Suppose there is complete darkness and there are no dust or water particles in the air. A laser beam passing in front of a man would not be visible to him because there is nothing in the air to reflect light to his eyes.

When the sun has completely set, there will still be some light. Please have a look on the attached picture. The blue triangle represents the area which still has some light, therefore a person standing in that area can still see the birds in the sky. But theoretically there should be no light in the blue area because light rays aren't reaching there. I believe there is some light because of dust particles and water molecules in the air. Perhaps diffraction of light rays through the air also play some role.

Questions:
Please edit the above text.

In the first paragraph I have used present tense in the sense where it is used to tell a story. Would it be called fake present tense?

In the second paragraph I have used the combination of present and future tenses. I am asking the reader to imagine a situation. Is the used combination of tenses correct one?
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Suppose there is complete darkness and there are no dust or water particles in the air. A laser beam passing in front of a man would not be visible to him because there is nothing in the air to reflect light to his eyes.

When the sun has completely set, there will still be some light. Please have a look at on the attached picture. The blue triangle represents the area which still has some light, therefore a person standing in that area can still see the birds in the sky. But theoretically there should be no light in the blue area because light rays aren't reaching there. I believe there is some light because of dust particles and water molecules in the air. Perhaps diffraction of light rays through the air also plays some role.
Comments  
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Thank you for the corrections. By the way, why couldn't on be used?
Jackson6612Thank you for the corrections. By the way, why couldn't on be used?

We look at a picture. Hopefully we can see something in the picture. This photo is damaged, there is a scratch on it.
Thanks for the clarification.

Best wishes,
Jackson
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Jackson6612there is nothing in the air to reflect light to his eyes.
I would say "there is nothing in the air to deflect light into his eyes".
Jackson6612theoretically there should be no light in the blue area because light rays aren't reaching there. I believe there is some light because of dust particles and water molecules in the air.
Twilight is caused by Rayleigh scatter in the upper atmosphere illuminating the lower atmosphere. This scattering is caused by the air molecules themselves not by dust, which would have more of an effect at lower frequencies.
Huevos
Jackson6612there is nothing in the air to reflect light to his eyes.
I would say "there is nothing in the air to deflect light into his eyes".
Jackson6612theoretically there should be no light in the blue area because light rays aren't reaching there. I believe there is some light because of dust particles and water molecules in the air.
Twilight is caused by Rayleigh scatter in the upper atmosphere illuminating the lower atmosphere. This scattering is caused by the air molecules themselves not by dust, which would have more of an effect at lower frequencies

Hi Huevos,

You are correct and only a person having scientific knowledge can give such an answer. Thank you for the correction and the explanation.

Best wishes,
Jackson