The Breadth of the Universe...

[Luminal]

Hi.

 

When estimates are made concerning the number of galaxies in the Universe, such as 100 billion, are these estimates of the total number using some sort of calculations (that are beyond me) which take into account expansion rates, density, age, shape, and so on.... or are these estimates only regarding the number of galaxies in the observable Universe?

 

In other words, have scientists essentially ruled out the possibility that the Universe has an infinite number of galaxies at this point in time?

[Klaynos]

I've always assumed they mean observable Universe.

[Zephir]

...have scientists essentially ruled out the possibility that the Universe has an infinite number of galaxies at this point in time...

Of course not, but here's a practical limit in our ability to see them due the limited speed of light spreading. If we consider, the distribution of galaxies density is uniform, this effectively rules out the possibility, we can ever see an infinite number of galaxies at the same moment.

[Luminal]

Of course not, but here's a practical limit in our ability to see them due the limited speed of light spreading. If we consider, the distribution of galaxies density is uniform, this effectively rules out the possibility, we can ever see an infinite number of galaxies at the same moment.

 

I understand that it would be impossible to see an infinite number of galaxies at the same time, however are there not means of estimating the the total number of galaxies using the approximation of the age of the Universe coupled with both the acceleration rate and the current distribution of matter?

[Klaynos]

I understand that it would be impossible to see an infinite number of galaxies at the same time, however are there not means of estimating the the total number of galaxies using the approximation of the age of the Universe coupled with both the acceleration rate and the current distribution of matter?

 

Not without an estimated size which we don't have. The visible galaxy we know quite well how big it is.