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B Do Photons from one star affect other stars?

  1. May 29, 2016 #1
    I am not a physicist but have heard that photons from the sun effect the flight path of asteroids? I was just wondering if these same photons would ever be able to effect nearby star systems? Therefore could there be a slight push between star-systems pushing them further apart? (Does this come into effect when calculating dark matter/energy?) Probably a stupid question but just interested. Thanks.
  2. jcsd
  3. May 29, 2016 #2


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    Not to the extent that they modify the other star's orbit, to be sure

    No. Stars contain only matter; dark energy is a property of space. Dark matter and dark energy only come into play on very large scales that vastly dwarf the distance between nearby stars.
  4. May 29, 2016 #3


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    I believe so. But since the intenity of the light from one star falling on another star is usually extremely low, the radiation pressure is also extremely small. That combined with the fact that stars are very massive means that the effect is negligible to the point of being immeasurable in almost all cases.
  5. May 29, 2016 #4
    I remember Susskind, in one of his lectures on youtube, discussing the effects of radiation pressure on cosmological expansion. The effect was significant in the very early universe, but ceased to be so long before the formation of stars. I'll try to go back and find the specific lecture and post a link to it.
  6. May 29, 2016 #5


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    Indeed, and this was during the radiation era. But the photons that drove the expansion were from the cosmic microwave background, not stars.
  7. May 29, 2016 #6
    Thanks for your reply guys - might have to go and watch Susskinds youtube lecture now :)
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