
Improved Hubble data provide fresh evidence for new physics - rbanffy
https://hub.jhu.edu/2018/03/02/adam-riess-cosmic-ladder-universe-expansion/
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lostmsu
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.

[https://don-beaver.livejournal.com/196412.html](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.

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hartror
> 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.

~~~
maxxxxx
"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.

~~~
ASalazarMX
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,

~~~
simcop2387
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.

~~~
philipov
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.

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hi41
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?

~~~
simcop2387
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.

~~~
petermora
How could they travel that far? Isn't that faster than speed of light?

~~~
IceyEC
Stuff can't move faster than light, but space is bound by no such law!

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keyle
Hubble, that outdated expired project that keeps on giving. Most of the global
good news I read came from Hubble these days. <3

~~~
sametmax
That's a good point. I keep hearing from it since I was a kid. And it doged
retirement many times already. The builders can be proud.

~~~
rbanffy
Congress should tell NASA to prepare a servicing mission. It can be competed
out to Boeing and SpaceX, at least.

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xelxebar
Not quite sure, but I think this is the main paper in question:

[https://arxiv.org/abs/1801.02711](https://arxiv.org/abs/1801.02711)

Just reading the titles of Riess' other papers on arXiv gives an interesting
peek at the clever work that went into getting this H0 measurement.

Thanks for sharing!

~~~
acqq
I think it's this one:

[https://arxiv.org/abs/1801.01120](https://arxiv.org/abs/1801.01120)

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montrose
This is copied from another site. The original is at:
[https://hub.jhu.edu/2018/03/02/adam-riess-cosmic-ladder-
univ...](https://hub.jhu.edu/2018/03/02/adam-riess-cosmic-ladder-universe-
expansion/)

~~~
dang
Thanks! Changed to that from [https://www.astromart.com/news/show/an-improved-
hubble-yards...](https://www.astromart.com/news/show/an-improved-hubble-
yardstick-gives-fresh-evidence-for-new-physics-in-the-universe).

