The Light From a Star: Comparing Photons & Travel Distance

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Discussion Overview

The discussion centers on the characteristics of photons emitted by stars compared to those from man-made sources, particularly focusing on their ability to travel vast distances. Participants explore concepts related to photon stability, dilution, and brightness as it relates to distance.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that there is no intrinsic difference between photons from stars and those from man-made sources, asserting that both types of photons are stable and travel at the same speed.
  • Others argue that the brightness of a star is due to the sheer number of photons emitted, rather than any difference in the photons themselves.
  • A participant questions whether photons decay, suggesting that if they did, all photons should decay at the same rate, which would imply that light from stars should not be visible.
  • Another participant clarifies that photons do not decay but rather become lost in the universe, referencing the inverse-square law to explain how light intensity diminishes with distance.
  • There is a discussion about the concept of a "dilution rate," with some participants questioning its definition and its implications for the range of light from different sources.
  • One participant notes that the dilution of light is simply a result of photons spreading over a larger area as they travel away from the source.
  • Some participants emphasize that all photons, regardless of their source, behave the same way in terms of stability and travel until they interact with matter.

Areas of Agreement / Disagreement

Participants generally agree that there is no fundamental difference between photons from stars and those from artificial sources. However, there is ongoing debate regarding the concepts of photon decay, dilution, and the implications for light visibility over distance.

Contextual Notes

Limitations in the discussion include varying definitions of terms like "dilution rate" and assumptions about the behavior of photons over distance, which remain unresolved.

dizam
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What is different about the photons from a star compared to something man-made which allows it to travel so far?
 
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dizam said:
What is different about the photons from a star compared to something man-made which allows it to travel so far?

The star's bright!

Garth
 
In other words, there is nothing different about the photons themselves, it is just the sheer number of them emitted by the star.
 
Janus said:
In other words, there is nothing different about the photons themselves, it is just the sheer number of them emitted by the star.

But then doesn't that imply that photons decay? If so then, shouldn't all photons decay at the same rate? Which means that the light from stars shouldn't be visible. Sorry, I'm a noob. I googled a lot of info but it's hard for me to find accurate and very specific answers to very specific questions. I appreciate any and all replies.
 
But then doesn't that imply that photons decay?
No, they merely get http://en.wikipedia.org/wiki/Inverse-square_law" , lost in the universe.
 
Last edited by a moderator:
Ich said:
No, they merely get http://en.wikipedia.org/wiki/Inverse-square_law" , lost in the universe.

Is the dillution rate constant?

If not, then, would light from a flashlight have limited range because the photon dillution rate is much higher than the rate of the light from stars?
 
Last edited by a moderator:
I don't know how a "dilution rate" should be defined. If you take a look at the link in my last post, you see that the photons simply spread over an increasingly large area as they gain distance from the star.
 
dizam said:
Is the dillution rate constant?

If not, then, would light from a flashlight have limited range because the photon dillution rate is much higher than the rate of the light from stars?

"dilution rate" is simply a way of saying that something further away appears less bright, because there are fewer photons per unit area (or per eyeball) as the light spreads out over a larger area.

There's no difference between man made photons and natural photons. They are all just photons.

A Sun-like star appears no more and no less bright than a 3.8 x 1026 Watt light bulb.
 
To answer your initial question nothing. There is no difference between sun made photons and flashlight made photons. They are both stable (do not decay). They both travel at the same speed c. They both just keep going until they hit something. Then they may be absorbed or scattered.
 
  • #11
Photons must be stable, else the Electromagnetic force would be limited in range...(IIRC)
 
  • #12
Photons disperse and scatter, they do not become 'diluted' over time.
 

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