Is There an Infinite Number of Galaxies in an Infinite Universe?

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SUMMARY

The discussion centers on the implications of an infinite universe on the number of galaxies and stars. It establishes that if the universe is infinite, then it contains an infinite number of galaxies and stars, despite our limited observational capacity. The age of the universe is estimated at 13.7 billion years based on the temperature of the cosmic microwave background and the universe's expansion rate. The Cosmological Principle is highlighted as a foundational assumption that supports the homogeneity and isotropy of the universe, allowing astronomers to make meaningful observations despite the limitations of our observable slice.

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  • Understanding of the Big Bang theory
  • Familiarity with the concept of the cosmic microwave background
  • Knowledge of the Cosmological Principle
  • Basic grasp of astronomical measurements and distances
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  • Research the implications of the Big Bang theory on cosmic structure
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  • Explore the Cosmological Principle and its applications in cosmology
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Astronomers, cosmologists, astrophysics students, and anyone interested in the fundamental nature of the universe and its structure.

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If the universe is infinite (and BB theory can work with infinite and finite space equally well), then does that mean that there is an infinite number of galaxies with an infinite number of stars?

I know we can only observe our slice of the universe that the light had time to reach us and that the universe is estimated to be 13.5 billion (or 150 billion which i saw somewhere else) years old but let's assume that the universe is finite with no boundary and it's expanding, then isn't the best thing we can do is give an ESTIMATE of how many stars and galaxies there are in the universe and how old it is based on our observable slice and keep updating the data as our instruments get stronger?

Does that make claims such as "the universe has x amount of stars and x amount of galaxies" and "the universe is x years old" vacuous? How can we put limits on our observable piece of the universe without mentioning that perhaps on the unobservable plane there is an infinity of the same matter or at the very least, an infinity of black space with no galaxies?
 
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The age of the universe is not based on how far we can look. The temperature of the microwave background as well as the universe expansion rate lead to the 13.7 billion year age.
 
In order for observations to have meaning, astronomers have adopted the Cosmological principle which states that, when taken on a large enough scale, the universe is homogenous and isotropic. This means that we assume that the universe looks basically the same to all viewers regardless of position. So someone sitting 46.5 billion light years away at the edge of the observable universe should see (at this exact moment) an observable universe that appears 13.7 billion years old and 93 billion light years across.
 

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