There's also a recent theory, that suggests, that the space expanding is accelerating due to a very distant merger of gigantic (on the scale of mass of the entire visible universe) black holes, caused by long gravitational wave pressure (as I understood it), emitted by that merger. The theory is interesting for it drops the need for cosmological constant.
> Here's the possibly unsettling news: The new numbers remain at odds with independent measurements of the early universe's expansion, which could mean that there is something unknown about the makeup of the universe.
Unsettling?! This is the stuff that makes science exciting.
"Unsettling?! This is the stuff that makes science exciting. "
There are a ton of researchers who are only waiting to see data that's not consistent with the current models. From what I have read it's disappointing for many how well the standard model and relativity are holding up.
If the Hubble observations end up fitting old boring theories, I fear those scientists might release a new Universe.js framework on their own. A modern, beautiful and almost as performant universe than the native one,
Given the flexibility of it, I've seen some people claim that this is essentially String Theory, and that's why it's not a suitable model. While the math works out, it also has so many tune-ables that you can make any kind of universe you want, and take any observations and make any number of universes that fit those observations.
And since these tune-ables aren't inherit properties of any kind, just numbers (or other kinds of values) you can plug in, there's very little predictive power in the theory. You can just always re-tune the whole thing to any observation, and make a nearly infinite number of predictions from it still. There's no way to try to select for anything that looks like a fundamental property of the universe.
That's because string theory is not a model, it is a framework for model-building; just like the Standard Model is only one possible quantum field theory. String theory is fully compatible with quantum field theory, so the current state of theoretical research is seeing them come to live side by side as two tools within a single discipline.
The problem really is that string theory provides a language for discussing phenomena we can't probe directly (due to the extreme energies involved), and so theoreticians are stuck conducting thought experiments until new experimental options are developed/discovered for testing particular models making use of string theory. Until then, there's no real path forward for applying that framework to expand or amend the Standard Model, because of how successful quantum field theories have been at explaining the phenomena we have access to currently.
Because we will never be able to build a galactic-scale particle accelerator required for doing scattering experiments at planckian energies, astronomical observations offer one of the best hopes for getting access to contradictory data. The study of holographic duality offers another possibility, if we can devise lower energy systems within our experimental grasp that are dual to high energy systems that aren't.
Since the universe is 13.8 billion years old, we are able to see objects which are 13.8 billion light years away. How are the physicists able to say that the diameter is 93 billion light years? Shouldn't it be closer to 27.6 billion light years in diameter?
So as you've set things up, the radius of the sphere we can see is 13.8 billion light years. That means that the diameter of that sphere is 27.6 billion light years. But here's the rub, the visible parts are all moving away from us, so while we see them as being 13.8 billion light years away, they've been traveling for 13.8 billion years away from us. Along with that, the rate that they're traveling has been increasing the further away (in time and space) they are.
Now since we've found ways to correlate the distance and velocity that things are traveling on large scales in the universe, we can actually figure out about how far away the objects we can see should be from us, after traveling 13.8 billion years. This is where the 93 billion light year figure comes from, how far away those "edges" have traveled since they emitted the light we see today.
The usual image is to picture light traveling through the universe as being like an ant crawling along an expanding balloon. The distance from where the ant is to the point that it started at is longer than the distance that it crawled. Because you have to add in how much the path expanded after the ant crawled past.
In 13.8 billion years, light crawled 13.8 billion light years. However the point where it started is now roughly 45.5 billion light years away. Making the diameter of the visible universe 93 billion years.
(In general relativity there are complications about what "now" means between distant points. But suffice it to say that there is a reasonable way that sensible people can agree on to make sense of it, and those are the answers that we arrive at.)
They don't. Light from distant stars has red shift, similar to Doppler shift.
IF this red shift is interpreted as Doppler shift, then we can calculate corresponding velocity and then calculate position of a star at today date, and we will see that visible Universe is expanding. However, we need to point to source of energy for that expanding (with acceleration!). Nobody able to find that source yet.
IF this red shift is interpreted as something else (e.g. loses due to friction), then visible Universe is still.
IMHO, you don't need that. If you will accept that our Universe is «digital» in nature (i.e. you cannot have 1/2 of black hole or 1/2 of star, of 1/2 atom, etc.), then you will see that each photon can be represented by large _integer_ number. This means that photon will lose 2*1/2 of it smallest digit at each revolution at average. Exceeding energy will make vacuum «hot». It's all.
Because they just fudge the math to match the old theory. They're frauds that are uncomfortable with change. Changing the theory to match new data so many times over the last century and acting like the theory hasn't failed or really had to change at it's core (and when other theories have predicted CMB and other measurements more closely) is the definition of fraud in science.
I'm not arguing for that since anyone who is steeped in the topic can determine a general "change history." I didn't claim it was someone in their backyard, did I? No it is job stability. No one who doesn't believe in string theory will get a specialized degree in it, for example. HN seems open to criticizing generalities like, "science publications are often fabricated" or "academia is too closed," but you start getting too specific and the folks who have most of the academic budget for a mainstream paradigm will come out of the woodwork to discredit skeptics using straw man arguments, ad hominem attacks, and various disingenuous methods of thwarting reasonable opposition. For example, just look at the percentage of worldwide physics funding goes toward big bang based fields vs the rest.
https://don-beaver.livejournal.com/196412.html
Mix of Russian explanation + paper in English published in MNRAS (closer to the end of post).
The theory's main premise is that "gravitational waves don't have gravitational mass", and spewed quite a lot of debate.
I wish I'd know physics better to check their math.