
Mystery of the Universe’s Expansion Rate Widens with New Hubble Data - daegloe
https://www.nasa.gov/feature/goddard/2019/mystery-of-the-universe-s-expansion-rate-widens-with-new-hubble-data
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ncmncm
So there are three numbers: the expected expansion based on Planck
measurements of a historical value based on cosmic microwave background, red
shift of distant supernovas calibrated to nearby Cepheids, and an independent
value obtained from LIGO based purely on gravitational waves, which still has
uncertainty that encompasses both of the others, but will sharpen in coming
years.

The LIGO measurement is not subject to vagaries of electromagnetic effects
that could be introducing anomalous redshift, or to possible systematic
changes in supernova brightness, such as might be caused by metal
concentration of stars decreasing with distance/age.

So, if we just wait, LIGO will give an answer. Possibly, a third answer. If
so, we will then have two problems, or maybe three: explaing why the Planck
prediction is off, explaining why supernova brightness and/or redshift is off,
and maybe even why LIGO is off.

~~~
chopin
Do you have a citation for the LIGO based derived Hubble constant? I didn't
find it mentioned in the article (just CMB and Cepheid derived values).

~~~
ncmncm
No, it wasn't in the article, because it wasn't relevant, except as
independent confirmation that both are in the ballpark.

I just gurgled LIGO and Hubble relation, and up popped
[https://arxiv.org/pdf/1710.05835.pdf](https://arxiv.org/pdf/1710.05835.pdf)
and 'Dr Stephen Feeney of the Center for Computational Astrophysics at the
Flatiron Institute in New York City, “We should be able to detect enough
mergers to answer this question within 5-10 years.”'

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danielbigham
I wonder if spacetime, in addition to being curvable by mass, is also
inherently curved at the scale of the universe.

~~~
scotty79
Maybe it's not inherently curved. Maybe it's just curved by a mass that is
further from us than tens of billions of light-years.

We can't know if whole universe looks as smooth as observable universe.

~~~
ben_w
I sometimes ask a similar question about matter/antimatter symmetry, if the
“tiny asymmetry” that gets used as an explanation for why any baryonic matter
exist at all, could be explained by the antiparticles we should’ve annihilated
with being on the other side of our cosmic event horizon.

~~~
DebtDeflation
I've often wondered the same thing. What if the entire universe is finite, but
something like 1^(enormously large number) times larger than the observable
universe? We could be this tiny speck of a backwater that's completely
unrepresentative of the overall universe. The Big Bang itself could have been
a minuscule local disturbance that took place in some small part of the
overall universe which is trillions of times older.

~~~
jvanderbot
Surely you mean 10^(enormously large number)

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stillbourne
Missed opportunity for title alliteration: Hubble Hobbles Hubble Constant.

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ccvannorman
We are an ant on a leaf in a bathtub with a fancy tiny telescope. These
observations aren't going to make sense until we get far outside of our mono
perspective from Earth (eg travel to Andromeda and take more data).

Yes, I realize this requires FTL. :-]

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v_lisivka
The mystery is why only one theory is accepted, while all other are left
behind.

For me, it's clear that Universe has no bounds, so objects after Visible
Universe is invisible because of geometry - we just cannot see objects which
are sending less than 1 photon per hour per square meter, so there was no Big
Bang less than nanosecond ago at Universe scale, it's just aging of light, so
background microwaves is just aged light from distant objects.

~~~
magicalhippo
> The mystery is why only one theory is accepted, while all other are left
> behind.

Because the other theories we leave behind do not make predictions compatible
with our measurements of the universe.

> so there was no Big Bang less than nanosecond ago at Universe scale

What is this supposed to mean?

> it's just aging of light

You mean red-shifting or something else here?

> so background microwaves is just aged light from distant objects

How do you account for the CMB angular power spectrum[1][2] with your "tired
light"?

[1]:
[http://background.uchicago.edu/~whu/intermediate/summary.htm...](http://background.uchicago.edu/~whu/intermediate/summary.html)

[2]:
[http://folk.uio.no/hke/AST5220/v11/AST5220_2_2011.pdf](http://folk.uio.no/hke/AST5220/v11/AST5220_2_2011.pdf)
(slide 23 and onwards)

~~~
v_lisivka
> Because the other theories we leave behind do not make predictions
> compatible with our measurements of the universe.

It's temporary. With more data, we will have more and more exceptions, which
cannot be explained by patches to mainstream theory.

>> so there was no Big Bang less than nanosecond ago at Universe scale

> What is this supposed to mean?

Lifetime of larger objects usually is much larger than lifetime of smaller
objects, so, as we increase scale of x,y,z, t axis should be increased
proportionally.

> You mean red-shifting or something else here?

Modern version of tired light. A kind of resistance for light, which causes
loss of energy proportional to light frequency. See below.

> How do you account for the CMB angular power spectrum[1][2] with your "tired
> light"?

I see just aged spectrum. IMHO, it's helium. :-/

~~~
magicalhippo
> It's temporary.

Yes, it's called science.

> With more data, we will have more and more exceptions, which cannot be
> explained by patches to mainstream theory.

At which point we hopefully come up with a new theory which fits the
observations, and leave the current mainstream theory behind. This happened
for example when General Relativity was introduced.

Until we find a new theory which fits all the observations, we have a
transition period where things are a bit confusing. See for example particle
physics before the QCD model tied it back together. Now we're starting to see
cracks in the the current standard model of particle physics, so something new
is likely needed soon. This is science.

> I see just aged spectrum. IMHO, it's helium. :-/

The power spectrum I linked to is the _angular_ power spectrum of the CMB.
It's _not_ the spectral density. The horizontal scale is (in essence) angular
separation, not frequency.

How does helium explain the peaks in the _angular_ power spectrum? Link to
some calculations please.

~~~
v_lisivka
> _angular_ power spectrum of the CMB

My bad. I'm not familiar with this.

(Beware, my English is weak).

I had year long discussion about similar topic by email, so I see nothing
exceptional there. If you have sum(sin(x_nat _scale)), and you will start to
play with scale, you will see sinusoidal graphic, freq=a_ sin(scale). Object
formations in space usually have round shape, so it's will be same in 3D. :-/

Why? Because our formation exists for very long time. Let's play simple
example: we need a 1d function f(x), such as sum(f(x_nat*scale)) newer
produces infinite sum or singularity. Physical meaning: Our Universe exists
for infinite time, but all matter is not attracted into one single point of
infinite mass, so it's not possible.

The simplest such function is sin(x) or cos(x). If we will try to play with
scale, we newer be able to make infinite sum, because Pi is irrational number.
The closer our scale will be to Pi, the larger peaks of sum we will have.

In real life, this influence diminishes after some point, so, for example,
size of nuclei has influence at frequency (distribution) of chemical elements,
but it has no influence at macro objects, so function becomes flat and sum
must rise (e.g. collapse into a black hole), then next level begins.

So, it looks like at some point, these formations cannot be bigger, or we
cannot see light from them, e.g. because they are so massive, so light cannot
escape them. If so, we have lower limit of formation size we can see at this
distance, dictated by geometry (angular size) and luminosity, and upper limit
dictated by nature, e.g. upper mass of formation of such size (upper density).

It's like in our galaxy: we can see stars, but cannot see black holes (too
heavy), lone planets and smaller objects (too cold), and far away objects
after certain distance (too small luminosity). IMHO, angular power spectrum of
visible stars must show distribution similar to CMB or distribution of
chemical elements.

~~~
magicalhippo
> I had year long discussion about similar topic by email, so I see nothing
> exceptional there.

But the point is we have models which predict quite specific values for the
angular power spectrum, and when compared matches observations very well.

This is highly non-trivial. And for any new model to take over, it must do
better.

It's not enough that it has potential to have some sinusoidal-like features.
Lacking matching model predictions, you'd need to have a plausible explanation
for why the features are missing from your model predictions. For example you
used some first-order approximation for some term and due to <insert
convincing argument here> a higher-order approximation should produce the
missing features.

~~~
v_lisivka
I saw math paper about systems, which can remain stable for unlimited time. As
far as I remember, infinity number of solutions exist for 1D, and 2D worlds.
Only 3 solutions found for 3D world (named 1, 2, and 42). None found for 4D
world, so, if infinite time given, 4D world will collapse into 3D world.

I can't find this paper again yet. (I'm quite busy: revolution, ongoing war,
problems with health, my father died, politics, delivery for 1+y long project
in less than 2 weeks, etc.)

This paper complimented view I already had in my head (everything is particle,
surrounded by spherical wave, and propelled by vibrations/noise), because now
I know that Universe is very simple thing in general. Nothing complex can
survive in infinite time. This mean that on lower level only extremely stable
(simple) systems can survive, because time is very fast on level below. On our
level, we can find temporary complex systems (we live at one of them, and we
itself are another example). On level above, it unlikely that we will find a
complex system, chances are very low, thus what is see around us should
continue for very long time and space.

