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B Why does light travels in all directions?

  1. Jul 31, 2015 #1
    My understanding of time, gravity and speed of light:

    Earth revolves around the Sun. Sun revolves around Milky Way centre. Milky Way also keeps moving. All these movements are caused by gravity. Thus, all that what is formed by fermions (particles causing mass) has been affected by gravity. But photons (particles of light) are not affected by gravity. Because unlike fermions, photons are not mass particles. Thus, actually it's we who move away from photons making us feel light travels away from us. (Please correct me if am wrong anywhere in my understanding)


    Now I have this question. Let's assume we are in space(vacuum) with a source of light with us. At any given time t1 when our source of light emits a photon, it should remain at same position (unaffected by gravity). And at the time t2 (say a second after t1) we'll move away (because of the gravity) from that photon, with the light source still with us emitting photons.

    Thus, we should see trail of light only from t1 to t2 (and this should be 299,792,458 meters long as that much is "speed of light" means we've came away that much distance from first photon in a second after t1)

    However, in reality this doesn't happen and we see photons emitted at t1 goes in all directions when we reach to t2. Can someone please explain this?
  2. jcsd
  3. Jul 31, 2015 #2


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    No, movement is not necessarily caused by gravity. It may be effected by it, but gravity is not necessary for movement.

    Fermions do not cause mass. Also, there are massive particles which are not fermions. Do not confuse mass with matter.

    This is not correct. Photons are affected by gravity.

    This is a personal philosophy which has very little to do with actual physics. Please note that posting personal theories is not allowed at PF.

    The rest of your post is based on the above misconception and therefore moot. Thread closed.
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