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catloaf
2016-Jun-11, 04:16 PM
Hi, long time no post (not that it really matters)

My question regards the character of our sun's light in the outer reaches of the solar system. Does the light tend to be bluer further from the light source than in the inner solar system?

I would presume the redder wavelengths would be much weaker further out, inverse square law and all that, making the blue wavelengths more prominent. I do not think the sun's light would make any outside observer mistake it for a O or B class star, just a little less in the red area of the spectrum.

swampyankee
2016-Jun-11, 05:02 PM
There will be a slight red shift (see hyperphysics.phy-astr.gsu.edu/hbase/Relacativ/gratim.html), but it would be small. 21595

Hornblower
2016-Jun-11, 07:41 PM
Hi, long time no post (not that it really matters)

My question regards the character of our sun's light in the outer reaches of the solar system. Does the light tend to be bluer further from the light source than in the inner solar system?

I would presume the redder wavelengths would be much weaker further out, inverse square law and all that, making the blue wavelengths more prominent. I do not think the sun's light would make any outside observer mistake it for a O or B class star, just a little less in the red area of the spectrum.

My bold. Why would you presume that?

catloaf
2016-Jun-11, 09:19 PM
Because I don't know and I'm asking a question. I would believe context would help people provide an answer rather than answering a question with yet another question.

Pardon me for being a casual who doesn't keep a nose in astronomy books 24/7 and isn't pursuing astronomy for a PhD or avocation. Merely laity here.

What an unfriendly and unwelcoming forum.

Hornblower
2016-Jun-11, 10:21 PM
Because I don't know and I'm asking a question. I would believe context would help people provide an answer rather than answering a question with yet another question.

Pardon me for being a casual who doesn't keep a nose in astronomy books 24/7 and isn't pursuing astronomy for a PhD or avocation. Merely laity here.

What an unfriendly and unwelcoming forum.

I'm sorry my blunt, simplistic response was annoying. I should have said something like, "The inverse square relation affects all wavelengths by the same amount. Your presumption suggests that you may have encountered some bad writing on the topic online or in the popular media. It could happen to anyone. We are here to help clear up such misunderstandings and misinformation."

George
2016-Jun-11, 11:51 PM
Pardon me for being a casual who doesn't keep a nose in astronomy books 24/7 and isn't pursuing astronomy for a PhD or avocation. Merely laity here. Glad you're here. I too have not had academic astronomy but have learned much from many astronomers, like Hornblower, to which I am grateful. Their help has inspired me to purchase astronomy books and learn much on my own, augmented by their assistance.

You were explicit with your blue color shift result, implying you had a reason to pick that certain color, which would be as much fun to address as the true question -- a more general one -- you were asking.

Another reason, though also slight, for reddening comes from scattering. Gas and small particles will scatter more blue light than red, which is why the sky is blue. The gas and dust encountered by sunlight heading out of the solar system will cause a small portion of blue light to scatter in other directions, thus more red is seen. The greens and yellows, in between the blues and reds, will scatter more than the reds, but less than the blues.

There are roughly 10 million trillion photons that enter the eye from direct sunlight as seen from Earth. So it would take a fair amount of gas and dust to make a noticeable shift in scattering, and I doubt the scattering effect would be noticeable. Our atmosphere, however, is quite a culprit. Astronomers have a way of making all the adjustments for scattering when they look at the spectrums of celestial objects.

01101001
2016-Jun-12, 12:04 AM
If you just want an answer and do not care to have your presumptions questioned: no.

(But you must realize curious presumptions make curious people ask why. I understand why they asked.)