Why Doesn't the Night Sky Shine as Bright as the Sun Despite Infinite Stars?

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The discussion centers on Olbers' paradox, which questions why the night sky is dark if the universe is infinite and filled with stars. Stephen Hawking's assertion that every line of sight should end on a star is challenged by the finite lifespan of stars and the decreasing brightness of light with distance. Participants argue that while the density of stars is limited, the paradox holds under the assumption of a homogeneous distribution of stars in space and time. The redshift of distant stars, due to the universe's expansion, further complicates the paradox by diminishing the light's detectability. Ultimately, the conversation highlights the complexities of cosmic observations and the assumptions underlying Olbers' paradox.
  • #31
On the subject of star lifetimes:

No, a star does not have to be infinitely long-lived. Suppose it exists for a long time then dies - what then?

Well, since your line of sight extends infinitely far in this model, the probability that there will be an active star somewhere behind the space the first star used to fill will tend towards 1.

In fact, if your line of sight is truly infinite and the universe is homogenous, your line of sight will always extent through an infinite number of active stars.

Even more damning evidence against this model, I'd say.
 
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  • #32
Fascinating, PL. It appears you are asserting 'math' is irrelevant in your odel of the universe.
 
  • #33
Sojourner01 said:
On the subject of star lifetimes:

No, a star does not have to be infinitely long-lived. Suppose it exists for a long time then dies - what then?

Well, since your line of sight extends infinitely far in this model, the probability that there will be an active star somewhere behind the space the first star used to fill will tend towards 1.

In fact, if your line of sight is truly infinite and the universe is homogenous, your line of sight will always extent through an infinite number of active stars.

Even more damning evidence against this model, I'd say.

well.. I´m not going to say that this model should be proven correct. I´m just trying to understand why its wrong... :)

Suppose the life time of a star is 1 year. But star density is the same as it is now. Stars keep popping up and dying out all the time, natural process I guess.

Intuitively, I feel like the average life span of a star in this model determines how bright the nigh sky lights up (also star density is a factor I guess). Now, I know intuition is not always your best friend in science, but sometimes it's all you have,. :)

I don't see how the star's light/radiation continues to move for ever. Perhaps mathematically it does, but a at a certain point it's not practical anymore.

Has there never been done any calculation on the relation between star density, average star life span and the brightness of the night sky? (in an infinite universe, or even in "our" finite big bang universe)
 

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