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

In summary, the conversation discusses the concept of an infinite universe and how it affects our understanding of the number of galaxies and stars in the universe. It also raises questions about the accuracy and limitations of our current understanding of the age and size of the universe. The idea of the Cosmological principle is mentioned as a way to account for these factors in our observations.
  • #1
alexsok
123
0
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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  • #2
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.
 
  • #3
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.
 

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

1. What is meant by an "infinite universe"?

An infinite universe refers to a universe that has no defined or measurable boundaries, and therefore has no end. It is constantly expanding and has no limit to its size.

2. How do we know if the universe is truly infinite?

It is currently impossible for us to know for certain if the universe is truly infinite. However, scientists use various methods, such as studying the curvature of space-time, to estimate the size and nature of the universe.

3. If the universe is infinite, does that mean it is also eternal?

Not necessarily. While an infinite universe may not have an end, it does not necessarily mean it has existed for eternity. The universe could have had a beginning, but still be infinite in size.

4. If the universe is infinite, does that mean there are infinite versions of ourselves?

There is no scientific evidence to suggest that an infinite universe would result in infinite versions of ourselves. However, with an infinite amount of space, it is possible that there could be other planets with similar conditions to Earth, and therefore potentially other forms of life.

5. Does an infinite universe mean there are an infinite number of stars and galaxies?

Yes, an infinite universe would mean an infinite number of stars and galaxies. However, due to the vastness of the universe, we are only able to observe a small fraction of it, and therefore cannot confirm the exact number of stars and galaxies in the universe.

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