Mystery of the Universe’s Expansion Rate Widens with New Hubble Data

https://www.nasa.gov/feature/goddard/2019/mystery-of-the-universe-s-expansion-rate-widens-with-new-hubble-data

by daegloe • 7 years ago

80 27 7 years ago

v_lisivka5• 7 years ago

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.

magicalhippo3• 7 years ago

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...

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

andrekandre• 7 years ago

> it's just aging of light
You mean red-shifting or something else here?

I think they are probably talking about tired light[1]

[1] https://en.wikipedia.org/wiki/Tired_light

[edit] spacing

v_lisivka5• 7 years ago

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. :-/

danielbigham• 7 years ago

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

scotty792• 7 years ago

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• 7 years ago

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.

pixl97• 7 years ago

A mass that happens to be around us in all directions?

firethief• 7 years ago

Is it possible that we are observing effects of mass that is outside the observable universe?

781• 7 years ago

It's an open question.

https://en.wikipedia.org/wiki/Shape_of_the_universe#Curvatur...

caprese• 7 years ago

could there be an adjacent sphere of expanding matter? a "parallel universe" or universes, not in the sci-fi alternate dimension sense, but in the "physically adjacent big bangs in space" sense where the light has simply never reached us yet, but could one day

lazulicurio• 7 years ago

My personal (lay) theory is that the global curvature of the universe is flat, but that there are local distortions due to the energy of the big bang/rip.

Two (probably completely inaccurate) thought experiments:

Imagine a sheet of aluminum foil. Crumple it up really tightly into a ball then stretch it back out again. The sheet won't be perfectly flat anymore: it will have ridges and valleys introduced when compressing the sheet. Place objects with mass onto the sheet and those will cause further distortions, but there will be areas without mass that are also distorted.

Imagine a sheet of fabric. Place an object with mass on the sheet, then pull on the sheet (like trying to remove a tablecloth without displacing the tableware). Depending on the velocity of the pull, the mass of the object, and a bunch of other factors, you might introduce ripples into the sheet around the object. Again, distortions in areas without mass. (From my very lay understanding, this would be related to, but independent from, gravitational waves, which are caused by motion of mass in space-time rather than the expansion of space-time itself. But then again, motion is all dependent on the frame of reference, so what do I know?)

ccvannorman• 7 years ago

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. :-]

ncmncm2• 7 years ago

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• 7 years ago

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).

ncmncm2• 7 years ago

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 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.”'

stillbourne• 7 years ago

Missed opportunity for title alliteration: Hubble Hobbles Hubble Constant.

Mystery of the Universe’s Expansion Rate Widens with New Hubble Data

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