# Different kinds of infinity in physics?

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• supernova1054
In summary, the conversation discussed the topic of infinity, particularly how it relates to the multiverse and different types of infinities. The conversation also touched on the concept of multiple universes and the potential for an infinite number of galaxies and selves within them. The speaker also mentioned their interest in gravitational waves and a book they recently received on the subject.
supernova1054
TL;DR Summary
Do different versions of infinity matter in physics?
I am reading several books on infinity as first developed by Georg Cantor.
Some physicists claim that the multiverse might be infinite. But they don’t seem to mention two of the kinds of infinity which might (exist?). It makes an infinite difference to make a bad pun. The integers define countable infinities but the real numbers are a larger infinity. I have read statements that if there are an infinite number of galaxies then there are an infinite number of myself in some infinite subset of this infinite multiverse. But that is not the case if this infinite number of galaxies is a countable infinity!
Don’t worry, I am not a mystic. I just find careless use of concepts unfortunate in scientific papers. Then again, many concepts are rather vague.

I just received the book “Beyond Spacetime” Ed. by Huggett, Matsubara and. Wuthrich.
Look very interesting.
I am also reading books and papers about gravitational waves — at last an experimental
field.

Thread is in Moderation until we can figure out what to do with the thread title or if it needs to be moved between forums...

## 1. What is the concept of infinity in physics?

The concept of infinity in physics refers to the idea that there are infinitely many values or states that a physical quantity can take on. This concept is often used in theoretical physics to describe phenomena that cannot be measured or observed directly.

## 2. How is infinity related to the size of the universe?

Infinity is often used to describe the size of the universe because it is believed to be infinite in size. This means that there is no limit to how large the universe can be, and it continues to expand infinitely.

## 3. What are the different kinds of infinity in physics?

There are two main kinds of infinity in physics: mathematical infinity and physical infinity. Mathematical infinity refers to the concept of a number being infinitely large, while physical infinity refers to the idea of a physical quantity having an infinite value.

## 4. How is infinity used in theories such as string theory and black holes?

In theories such as string theory and black holes, infinity is used to describe the behavior of matter and energy at extremely small or dense scales. For example, in string theory, the concept of infinity is used to describe the infinite number of dimensions that make up the fabric of the universe.

## 5. Can infinity be measured or observed in physics?

No, infinity cannot be measured or observed in physics. It is a theoretical concept used to describe the behavior of physical systems and is often used in mathematical equations to simplify complex phenomena. However, it is not something that can be directly observed or measured in the physical world.

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