Likelihood of light being absorbed/re-emitted in 50 light years

AI Thread Summary
The discussion centers on the likelihood of light being absorbed and re-emitted by interstellar gas over a distance of 50 light years, questioning how much of this re-emitted light is what we actually observe. It highlights that absorption is wavelength-dependent, resulting in spectral dark bands that indicate not all light is absorbed. The conversation also touches on the behavior of high-energy x-rays, suggesting they are less likely to be disturbed by the interstellar medium and potentially unaffected by the heliosphere. Clarifications are sought regarding why the 1977 paper views the heliosphere's effects differently compared to Earth's atmosphere on hard x-rays. Overall, the complexities of light propagation and absorption in space are emphasized, indicating that light's journey is not simply "second hand."
epicurean
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What's the likelihood of light striking some interstellar gas and being absorbed, then re-emitted, and the re-emitted light actually being the light we see rather than the original light from the source? Also, what about the likelihood of reemission after passing through the heliosphere? Anyone care to make a rough guess at the percentage of light that reaches us that is not filtered this way? Are there any particular wavelengths of light that might be more likely to make it through because they aren't likely to be absorbed by the interstellar medium or the heliosphere?
 
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Hmm, apparently this paper http://www.ekkehard-friebe.de/Brecher-K-1977.pdf answers that question. It says high energy x-rays are less likely to be disturbed... any thoughts? Would high energy x-rays be able to pass through the heliosphere unaffected?
 
When light is absorbed and then re-emitted it is so in random directions isn't it?
 
Apparently hard x rays are absorbed rather well by the Earth's atmosphere, so I'm not sure why the 1977 paper does not think the heliosphere would have a similar effect. Can someone help clarify?
 
epicurean said:
What's the likelihood of light striking some interstellar gas and being absorbed, then re-emitted, and the re-emitted light actually being the light we see rather than the original light from the source? Also, what about the likelihood of reemission after passing through the heliosphere? Anyone care to make a rough guess at the percentage of light that reaches us that is not filtered this way? Are there any particular wavelengths of light that might be more likely to make it through because they aren't likely to be absorbed by the interstellar medium or the heliosphere?

Pretty likely, we can see the adsorption bands in spectorgraphs of distant objects. Since such adsorpton is usually wavelenght depentent not all of the light is adsorbed. That which does leaves dark bands in the spectrum.
 
You can think of light propagation as vacuum absorbing and re-emitting it. If something else gets in the way and does the same thing, all it's going to change is index of refraction. The light isn't any more "second hand" because of it.
 
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