> Not possible. Redshift is not the only observation we have. The totality of all the observations we have cannot be explained in any other way than an expanding universe.
Well..? What are those other observations that point to expansion?
Well..? What are those other observations that point to expansion?
The apparent brightness and apparent angular size of distant galaxies, and more importantly, the relationship between the three observables of redshift, apparent brightness, and apparent angular size. No known model other than the expanding universe predicts the actually measured relationship between those three observations.
No, it isn't. I explicitly described two other direct observations that are not redshift.
> when people say redshift evidence they mean the relationship between redshift and brightness of a standard candle.
No, they don't. Redshifts of distant objects are directly observed. We don't need a "standard candle" to measure them.
Observations of apparent brightness are used to estimate distances to objects by comparing apparent brightness to the absolute brightness of a "standard candle" that is the same kind of object. However, such distance estimates are model-dependent; before they can even be made, the model parameters first have to be estimated using the observed relationship between redshift, apparent brightness, and apparent angular size.
> And regardless of whether you call it redshift or the relationship between redshift and something else, it would be impacted by a change to redshift.
I have no idea what you mean here.
How do you know the object is distant? (notion being challenged “more redshift -> more distance”)
Please answer. Thanks for the patience.
https://en.wikipedia.org/wiki/Angular_diameter_distance
You know how distant objects appear smaller, well in an expanding universe that isn't completely true, very distant objects start looking bigger again. Roughly speaking this happens because the distance between paths different photons take to get to us gets stretched by the expansion.
Theres also the very obvious observation of the cosmic microwave background, which isn't explained by any non-expanding universe model.
The problem with that is that, if the Universe had remained the same size and has the finite age it appears to have, there would not have been time for information from the "north" side of our observable Universe to reach the "south" side. After all, the "north" side's light is only just now reaching us, at the center of our observable Universe, and would have to travel a very long way again to reach the south side. In cosmological/relativity terms, we say they're not causally connected.
The obvious explanation for this is that the early Universe expanded from a very small region that was causally connected for long enough to reach thermal equilibrium, and then expanded. So while the "north" side of the observable Universe and the "south" side of the observable Universe cannot communicate from their current positions (and in an expanding Universe will never be able to do so again), they were able to communicate in the past for long enough to establish equilibrium.
Without expansion, you need a way for two patches of sky that have never been able to communicate with one another to somehow "agree" to be the same temperature. And that's pretty hard to do.
I wanted to address this in a few ways: 1. The speed of light is absolutely invariant,
however the space it travels through, can not only be varient, but it can be varient in ways that we are failing to understand In two ways, one way is that we are reaching to understand it, and the other is that we may never understand it.
Is the speed of atoms invarient? I.e.is the temperature invarient?
Occams razor is one of the most powerful tools along with the belief in the both the elegance of the universe, and it's nature to make things very tricky to uncover that elegance.
There are some very deep thinkers here.
No.
“universe appeared everywhere at once at exactly same temperature” Same level of obviousness, if not more.
For some reason a disclaimer is mandatory these days: I am not saying I know more than cosmologists, just that inflation is nowhere near the “obvious explanation” territory.
> Because the universe is expanding, a pair of distant objects that are now distant from each other were closer to each other at earlier times. Because the speed of light is finite, the light reaching us from this pair of objects must have left them long ago when they were nearer to one another and spanned a larger angle on the sky.