Can the space (or else measurable) be actually infinite?

In summary, the flat model of the universe is believed to be infinite in space. However, there is no way to directly measure the infinity of space. The diameter of the universe can be inferred from the model's measurable parameters, but this is based on assumptions about homogeneity and topology. While the simplest assumptions result in an infinite universe with zero curvature, it is possible for the universe to be finite if different regions have different laws of physics or if the topology is not standard. The latest measurements of curvature use CMBR and can be found in the PLANCK mission's 2015 results papers.
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Dmitri Martila
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The (most popular) flat model of Universe is space-infinite. How the infinity is measured? Can you give me references to the papers about the actual infinity of space?
 
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I don't think it's measured as such, but is the inevitable inference of zero curvature.
It's not certain from measurements that curvature of the Universe as a whole actually is zero, but if it is present it's very small.
 
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  • #3
rootone said:
I don't think it's measured as such, but is the inevitable inference of zero curvature.
It's not certain from measurements that curvature of the Universe as a whole actually is zero, but if it is present it's very small.
It is the measurement of local curvature. I am talking about the measurement of the diameter of the Universe by the ruler.
 
  • #4
Hi Dimitri, welcome to PF.
This is a question about cosmology, and should be put in the relevant subforum if you want the best answers.
I'll ask mods for the thread to be moved.

Dmitri Martila said:
The (most popular) flat model of Universe is space-infinite. How the infinity is measured? Can you give me references to the papers about the actual infinity of space?
There aren't any, because the spatial extent of the universe as a whole is not part of the model, nor can you ever measure anything from beyond the cosmic event horizon.
As rootone said, the extent of the whole can be inferred from the model, depending on its measurable parameters, and as long as you make some assumptions about homogeneity and topology. Infinity is what you get with the simplest assumptions (cosmological principle holds everywhere, and topology is not exotic) and zero curvature.
This is hardly the same as stating that the universe IS infinite. After all, laws of physics may be different in other regions of the universe, and even a flat universe can be finite if it's shaped like e.g. a 4D torus.

Dmitri Martila said:
It is the measurement of local curvature. I am talking about the measurement of the diameter of the Universe by the ruler.
As long as by 'local' you mean whole of the observable universe. Curvature measurements use CMBR, so it's the longest ruler you can get. The most recent such measurements can be found in PLANCK mission's 2015 results papers.
 

Related to Can the space (or else measurable) be actually infinite?

1. Can the concept of infinity be applied to physical space?

The concept of infinity is a mathematical concept that describes something that is unbounded and endless. While it can be applied to abstract ideas and numbers, it is not clear if it can be applied to the physical world. There is ongoing debate and research among scientists about whether space can truly be infinite, or if there is a limit to its size.

2. How do we measure the size of space?

Measuring the size of space is a complex and ongoing process. Currently, scientists use various methods such as triangulation, parallax, and redshift to measure distances between celestial objects and estimate the size of the observable universe. However, these methods have limitations and may not accurately reflect the true size of space.

3. Is the universe infinite or just expanding?

The current scientific consensus is that the universe is expanding, but whether it is infinite or not is still unknown. The expansion of the universe suggests that it has no boundary, but it could still have a finite size. Ongoing research and advancements in technology may one day provide a definitive answer to this question.

4. Can we ever reach the edge of space?

If the universe is infinite, then there is no edge to reach. However, if the universe is finite, it may be possible to reach its edge. However, due to the vast distances and limitations of our technology, it is currently not possible to reach the edge of space.

5. How does the concept of infinity impact our understanding of the universe?

The concept of infinity has a significant impact on our understanding of the universe. It challenges our perceptions of space and time and raises questions about the nature of reality. The possibility of an infinite universe also has implications for the existence of other intelligent life forms and the potential for multiple universes. It continues to be a topic of exploration and debate among scientists.

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