The discussion centers on the concept of whether space, particularly in the context of the universe, can be considered actually infinite. Participants explore the implications of the flat model of the universe, measurements of curvature, and the challenges in defining and measuring infinity in cosmology.
Participants express differing views on the nature of infinity in the universe, with no consensus reached on whether the universe is actually infinite or how it can be measured.
Limitations include the dependence on assumptions about homogeneity and topology, as well as the unresolved nature of the curvature of the universe as a whole.
It is the measurement of local curvature. I am talking about the measurement of the diameter of the Universe by the ruler.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.
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.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?
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.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.