Timeline for Are there other proofs of the expanding universe apart from the redshift?
Current License: CC BY-SA 4.0
7 events
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| Jan 9, 2019 at 14:16 | comment | added | Alchimista | The point wasn't if expansion is reasonable. It was if it is observed at work with methods not involving shift. But ok. I am not arguing but it seems to me that everything here is rooted in seen z. The cmbr at first. Looking at cmbr is looking at z anyway. This is my point. What is not clear is that the lower T is right a red shift. | |
| Jan 8, 2019 at 22:21 | comment | added | pela | Sure, the size of our Universe wasn't really my point, though there's no evidence against it being infinite either (that's why I wrote "seems"). Anyway, I definitely agree on the hot beginning part. | |
| Jan 8, 2019 at 22:09 | comment | added | Mark Olson | @peta: There's no evidence that the universe is infinity large -- that's pure speculation. All we can say from observation is that it's at least ~10x what we observe. Regardless, we can say that what we see makes it very hard for the universe to have always existed. And whether or not you assume that red shifts reflect a universal expansion, what we observe looks a lot like a universe which was a very, very hot, very, very dense plasma which cooled and diluted and started to form stars and galaxies ~10 billion years ago. | |
| Jan 8, 2019 at 21:54 | comment | added | pela | But even an expanding universe can be born infinitely large (in fact ours seems to have been), so I don't readily see a reason that a static universe couldn't also be born infinitely large, and then start forming structure. But of course, forming structure in a universe as dilute as our current Universe is difficult, so you would need a mechanism for that. Anyway, +1. | |
| Jan 8, 2019 at 16:21 | comment | added | Mark Olson | The only way the universe can look younger as we look out into space (back in time) is if it was younger then. In which case it is evolving from younger to older and must have had a beginning. Beginnings are very awkward in a static universe without even a singularity to sweep difficult questions under. | |
| Jan 8, 2019 at 15:56 | comment | added | pela | Doesn't the fact that we see younger galaxies farther away merely say that light travels at a finite speed? A (somehow) static universe would exhibit the same feature. | |
| Jan 8, 2019 at 15:30 | history | answered | Mark Olson | CC BY-SA 4.0 |