On Friday, April 11, 2025 at 2:14:37 PM UTC-6 Brent Meeker wrote:
On 4/10/2025 9:42 PM, Alan Grayson wrote: On Thursday, April 10, 2025 at 9:43:20 PM UTC-6 Brent Meeker wrote: On 4/10/2025 8:34 PM, Alan Grayson wrote: *The boundary condition for the universe is its present state and it's not finite. * Brent How do you* know *that? ISTM, you're speculating and misrepresenting your speculation for knowledge. Data from the Planck spacecraft isn't conclusive. AG Read any text, or Vic's "Comprehensible Universe". It you're going to choose a boundary condition for the universe what would you pick besides the one state you know? Brent We don't KNOW that the universe is infinite in spatial extent! This is true regardless of what one chooses as its boundary condition. AG Did you miss the word "choose"? Do you have an alternative in mind? Do you know what the equation is? Brent What's an equation? I have no idea what it means or is. Look up FLRW cosmology or read Vic's Comprehensible Cosmos chapter on cosmology. Please stop you're BS. You claimed the universe is infinite in spatial extent. *YOUR WORDS! *You don't know what the fuck you are claiming. AG And you don't know what the fuck you're talking about. I notice you write "YOUR WORDS!" but you didn't actually quote me. *I certainly did quote you. You need to scroll down a bit to see it. AG * The FLRW equation for the universe only has a scale factor which is set to 1 at the present so depending on the other parameters it describes a universe that expands indefinitely or that collapses in the future. The scale factor going to zero in the past (or future) means that the part of the universe we know was then infinitely dense. All the stuff we can see was packed into a zero size. Whether the universe is spatially infinite is a slightly different question. It's an extrapolation from the part we can see to assume it's homogeneous and isotropic on a large scale. The CMB is at 2.73degK and varies by only 0.0001degK across the sky. If we make that extrapolation, as is commonly done, the universe is infinite. Without some such extrapolation beyond what we can see we can't write down any solution of Einstein's equations and we can't do cosmology. Brent *The boundary condition for the universe is its present state and it's not finite. **Brent* -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/2a8acc74-485e-430a-9f78-813874a88140n%40googlegroups.com.
