B The distance to the nearest identical Hubble volume in light years?

B
Thread starter Cerenkov
Start date Sep 9, 2023
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Light years

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The discussion centers on converting a vast distance, estimated by Tegmark to be about 10^10^115 meters, into light years for better comprehension. It is clarified that this distance translates to a figure with approximately 10^115 - 16 zeroes after it in light years, making it incomprehensibly larger than the observable universe, which is about 10^11 light years across. Participants express confusion about the distinction between the Hubble volume and the observable universe, with references to relevant literature for further understanding. The conversation highlights the complexities of cosmological distances and the challenges in grasping their scale. Ultimately, the vastness of these distances emphasizes the limitations of human observation and comprehension in cosmology.

Sep 22, 2023

PeterDonis

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PeroK said:

How can we say with any certainty that the universe has a radius at least ##10^{10^{115}}## times larger than that of the observable universe?

We can't, of course. This is one of those cases where it's not even clear how to estimate a probability. At our current state of knowledge, we can only treat Tegmark's statement as a consequence of certain assumptions whose probability we can't estimate. (The other key assumption, in addition to the one you state here, is that our intuitive picture, from what knowledge of quantum field theory and quantum gravity we have, that there are only a finite number of possible states of a finite Hubble volume, is correct.)