- Quasars in the past: yes, but not that the universe was (necessarily) more dynamic. Instead, I think, implying the universe was smaller and galaxy-galaxy interactions were more common (with the implications that galaxy-galaxy interactions drive the activity in the central regions of the galaxes, that is, feeding the supermassive black hole).
Agreed. "Dynamic" isn't the best word to use. It is the no. of small gallaxies forming large ones, as you note, that needs the focus. I'll polish this bullet so it riffles better.
- Distant supernova: I'm assuming these are the observations leading to "dark energy". It's not "dilation" but rather that some supernova (around 1 billion light years away/ 1 billion years ago) are more distant than a uniform expansion rate implies. Hence dark energy, that is causing the expansion rate to accelerate.
That aspect might make for a new bullet I hadn't considered since it fits within the BBT.
However, the time dilation arguement is different. The time dilation of SN some say is the best of all the arguments for expansion. I failed to convey the crux of the argument as it is a little more involved than average.
[for general consumption...] When we compare a nearby SN Type 1a to a very distant SN Type 1a, and if we were to assume they were identical in every respect, not only would we see greater redshift for the more distant SN but we would expect to see the peak light (also diminished due to reduced photon flux) take more time to decay. This "time dilation" is attributable to the much greater recessional speed from us. So, after a given no. of months, the distant SN will be much farther away taking the bright light longer to reach us, thus lasting longer than the closer SN.
This is important because redshift alone has been debateable from the start. Time dilation, however, seems very substantial in arguing expansion, including its rate. [Hubble never argued that redshift was due to expansion, contrary to a ton of claims otherwise. I suspect his personal time with deSitter at the
Solvay conference (1928 IAU meeting in Holland) influenced him. DeSitter produced a solution to GR that demonstrated redshift for a Static Universe, but his model included no mass in the universe.
Einstein's solution had mass but no redshift. Lemaitre was the first to offer both as a physics model (Friedman had presented a math model earlier, unknown to Lemaitre). Hubble did say, IIRC, that he wanted to leave theory to theorists, hence keeping his worthy claim as a great astronmer in tact. Recall some astronomers ventured into theory with some regrets.
]
- Olber's paradox: I don't know if I would include this as support for the BBT. What it does support is that the universe is not infinitely big (and old)
Yes, but I think it negates some of the major counter theories (e.g. Steady State) that do argue infinite age and size, thus it still is an arugment that at least favors BBT. It isn't as strong as other bullets, admittedly, just worth mentioning, I think.
Note that some of these items will be tweaked as new observations are made. Some that come to mind are big spiral galaxies very early in the universe (the lack of which you take as evidence for the BBT) and very large black holes in the same period (bigger than we think possible in that period). Some examples:
https://www.space.com/old-galaxy-in-early-universe-aless0731 https://www.space.com/oldest-spiral-galaxy-in-universe.
Any surprises, of course, will be welcome as this will add to the excitement inherent in astronomy.
Giant early galaxies, IMO, will still be seen as more oxymoronic than not. If their distribution is anything close to that of today then we certainly will have a problem. Is this a fair statement?
If these observations hold (and the Webb Telescope will help here), it is telling us that we need to learn more about the early universe, but probably not, necessarily, that the BBT is wrong.
Yes, Webb's unique access to those regions of the early universe should have a lot to say about BBT. Perhaps something will be seen that will help qualify some of the Inflation theories, as well.
Thanks for your comments!
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