A riddle for our time

A Riddle for Our Time
A schematic of cosmic history. Astronomers have called attention to a neglected riddle of the expansion: although the outward flaring seen in the graphic (representing cosmic acceleration) might have started at any time, curiously it has happened in our own time. Credit: NASA/WMAP

One of the most remarkable successes of astrophysics in the last century was its discovery that the age of the universe as measured by its oldest stars was about the same as the age estimated in an entirely different way, from the recession of galaxies. Both came up with surprisingly long times—billions of years—providing reassuring confirmation that both were probably on the right track. But the two values were not identical and scientists very quickly realized a major discrepancy: the oldest stars were older than the universe itself. Refinements to the measurements and the models to resolve this contradiction were underway until 1998 when cosmic acceleration was discovered. It proved, in a single sweep, that the universe was actually much older than had been thought, and in particular was older than the oldest stars.

But there was a riddle in the discovery: The motion of the universe is governed by matter, whose gravity tends to slow the expansion down, and by acceleration which speeds it up. Since the average density of matter in the universe steadily drops as the universe swells, in time it has a smaller and smaller value. Curiously, today it just happens to have almost exactly the same value (when expressed in the same units) as the acceleration parameter. Why? There was a second riddle too: The theoretical size of the acceleration parameter could be almost anything; indeed, basic suggest it should be vastly larger than it is. Why it is as small as we measure is a mystery.

CfA astronomers Arturo Avelino and Bob Kirshner have just published a paper calling attention to yet another riddle. The universe did not expand at a constant rate that was just the blend of these two factors. For the first nine billion years of cosmic evolution, contraction dominated and the universe gradually slowed its expansion. Since the relative importance of grows with time, however, for the past 5 billion years acceleration has dominated and the universe has sped up its expansion. Curiously, though, today the looks the same way it would have if it had always been expanding steadily at a constant rate (the rate required to prevent ultimate re-collapse).

Although it sounds slightly similar to the original riddle, the authors describe why this new puzzle is actually different: We are living (apparently) in a privileged epoch; the other puzzles do not have this implication. The explanation(s) for these riddles is not yet known. If some specific new kinds of elementary particles exist, the scientists suggest, they could provide the answer, but for now the only thing that is certain is that more observational research is needed.


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Study finds 'lumpy' universe cannot explain cosmic acceleration

More information: "The Dimensionless Age of the Universe: a Riddle for Our Time," A. Avelino and R. Kirshner, ApJ 828, 35, 2016. adsabs.harvard.edu.ezp-prod1.h … /2016ApJ...828...35A
Citation: A riddle for our time (2016, September 12) retrieved 18 August 2019 from https://phys.org/news/2016-09-riddle.html
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Sep 12, 2016
Let's look at the actual evidence.

The galaxies nearest the Milky Way are and slowest galaxies (have the the speed +100, +200, +600, or minus 100, -200, etc.). If galaxies are closer, then are more in the present of more distant, galaxies. Distant galaxies (5, 10 or 13 billion ly) have the speed 100,000 km / sec, 200,000 km / sec and 270,000 km / sec (they are also the most distant in the past 13.7 or 13.8 ly).

On the basis on which evidence "the Harvard-Smithsonian Center for Astrophysics" perform its claims about accelerating matter in the universe?

Sep 12, 2016
The galaxies nearest the Milky Way are and slowest galaxies (have the the speed +100, +200, +600, or minus 100, -200, etc.).

This is not an english sentence. What are you trying to say?

If galaxies are closer, then are more in the present of more distant, galaxies.

This is not an english sentence. What are you trying to say?

Distant galaxies (5, 10 or 13 billion ly) have the speed 100,000 km / sec, 200,000 km / sec and 270,000 km / sec (they are also the most distant in the past 13.7 or 13.8 ly).

Where do you get these numbers from?

On the basis on which evidence "the Harvard-Smithsonian Center for Astrophysics" perform its claims about accelerating matter in the universe?

They are not talking about accelerating matter. They are talking about accelerating expansion of space.


Sep 12, 2016
The explanation(s) for these riddles is not yet known.

Come on. Every good fantasy needs a good riddle to keep it alive. And the Huge Bang Fantasy has an endless supply. Enough to keep many, many riddlers employed for a long, long time!

RNP
Sep 12, 2016
@wduckss
antialias_physorg summed it up. You do not understand the physics that you are critisizing.

@Tuxford
I am fully aware that this is a pointless exercise, but for the benefit of all I am going to say it again:

If you want your stance to have any credibility you must give an alternative explanation of the data that is reported in these papers, or at least give a clear explanation of why you think the conclusions drawn from it are wrong. As far as I can see, you have never even tried to do this. Why not?

Sep 12, 2016
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Sep 12, 2016
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Sep 12, 2016
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Sep 12, 2016
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RNP
Sep 12, 2016
@tinitus
As long as you continue making statements like:
The Friedmann model really handle the Universe like the massive cloud, which started to expand from its center of mass.


you will NOT be taken seriously. Friedmann made NO such claim. Indeed, the idea is in almost the antithesis of the (hypothetical) universe he modeled.

For as long as you misunderstand and misrepresent the cosmological models you will continue not to be taken seriously by anyone that actually does.

Sep 12, 2016
To follow on with RNP, there IS NO CENTER OF MASS in the FLRW model (that you simply call Friedmann, incorrectly). The FLRW assumes a volume of space without boundaries that is uniformly filled with matter and radiation. There are several ways space can be without boundaries, but the simplest involve either wrapping back around on itself, or being infinite in size. We have data strongly suggestive of the latter possibility. In either case, a center is defined as the point equidistant from some edge or border. If there are no edges or borders, then there can be no center.

Why all this pedantry is important is because the popular picture of space 'exploding out from a point' is totally inaccurate, and maybe why you think that it should re-collapse. (that there's some common center of mass point they'd all fall back to)

Sep 12, 2016
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Sep 12, 2016
@RNP, antialias_physorg & the jury

Or are you blind or fanatic believers who do not see beyond the nose (of the so-called authority).
For first graders.
Closer galaxies have a lower speed (lower red shift) or have negative the speed (instead of distancing those approaches).
Their speed is (Wiki, etc.) a negative or a few hundred km / sec as opposed to the galaxy at a distance of 13.7 billion ly, which have estimated the speed 270,000 km / sec.
Connect the two, and two (please remove the dark glasses with a brain).
The increase in space (expansion) is directly related to the redshift (observation we are working with the Earth not from "singularity").

Sep 12, 2016
which are subject of so-called Tolmann paradox. According to this paradox the surface brightness or distant objects should way lower


The Tolmann paradox has to to with causality and time travel, not cosmology. It's the Tolmann test and it is consistent with an expanding universe. It can be used to test any cosmology predicts simple observable like angular size distance and luminosity distance. The complication is that in order for it to give you the exact expected (1+z)^4 you have to assume galaxies don't evolve and that your k corrections are prefect. Neither of these things are expected in standard cosmology. However the Tolmann test is pretty much dead, it relied on many assumptions about galaxy evolution, we now have baryon acoustic oscillation data which tests the angular size distance and radial coming distance to percent accuracy. Steady state models have yet to explain even the existence of the BAO peak, standard cosmology on the other hand predicted it.


Sep 12, 2016
Instead of it the recent analysis revealed, that the distant galaxies appear relatively larger, not smaller. They look blurred and expanded like the distant lights observed through scattering fog.


LambdaCDM predicts a fixed angular scale starts to look larger above redshift ~2. And no, there is no evidence for any blurring. There is still no mechanism of scattering that can explain the Independence of redshift with wavelength, even after a hundred years of searching.

Sep 12, 2016
The answer to this so-called "riddle" and all the others is blatantly obvious: X did it.
where X= my favorite Sky Daddy.

So let's just stop trying to confuse people with facts and concentrate on the only thing that matters: Do you really think your Sky Daddy can beat up my Sky Daddy?*

*if you answered "yes" you are obviously evil and/or willfully blind.

Sep 12, 2016
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Sep 12, 2016
Why all this pedantry is important is because the popular picture of space 'exploding out from a point' is totally inaccurate, and maybe why you think that it should re-collapse. (that there's some common center of mass point they'd all fall back to)
............so if you really believe this, then why are you not making fun of the diagram at the top of the page that makes the Universe look as if it blown out of a cannon?

I just love these cannon shot portrayals these kinds of discussions open up with, entertaining stuff.

It's also just so entertaining to read as Asstro-physicists go through mind bending postulates how the space between galaxies can change faster than galaxies are actually moving when it is the galaxies themselves which define the space between them, the space between them can change no faster than the defining boundaries between them change, Maybe Keplerians need to go back to the celestial mechanics drawing boards?


Sep 12, 2016
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Sep 12, 2016
Maybe Keplerians need to go back to the celestial mechanics drawing boards?



Astronomers need to spend less time gazing at the stars and more time gazing into their Pasta.

All they need to do is open their hearts to the Flying Spaghetti Monster (peace be upon It) and all will be revealed.

Sep 12, 2016
Are you sure?
Trends in Cosmology: Beyond the Big Bang


There's no reference to any such study in your link. They're even trying to explain away the lack of blurring in tired light cosmologies. Read what you post.

You should read a bit more about metamaterial models of vacuum. The red shift is not quite independent on wavelength anyway due to GZK limit


The first link has nothing to do with tired light. The GZK limit is for cosmic rays, not light and it has nothing to do with redshift.

Nevermind, I get from your random links that you are in fact yet another Zephr sock account. I won't waste my time. Spamming unrelated nonsense is what you do.

Sep 12, 2016
why are you not making fun of the diagram

Because there's literally nothing I can do to change the fact that popular science articles will always include such incorrect pictures. The picture at the top of the page is, in fact, incorrect. That being said.... How would YOU draw an infinite 3d volume expanding over time? I can't say that I know an easy way to do that.

go back to the celestial mechanics drawing boards

Well it's funny. I guess we didn't know as much in the 17th century as we do now. I'm sure that's quite a shocker. But it turns out Newton's approximation of gravity is just that. An approximation. It's a useful fiction in a variety of circumstances, but insufficient to describe all astrophysical phenomena we see. Thus we have to rely on more precise approximations (those we find in GR) to describe those phenomena. And we know there are still observations yet to be explained by GR, but we don't know what that next level of precision is yet.

Sep 12, 2016
Privileged ..indeed..you should watch the Privileged Planet Full
to see.

Sep 12, 2016
How would YOU draw an infinite 3d volume expanding over time? I can't say that I know an easy way to do that


Part III: Considerations on the Universe as a Whole
Albert Einstein 97
If we are to have in the universe an average density of matter which differs from zero, however small may be that difference, then the universe cannot be quasi-Euclidean. On the contrary, the results of calculation indicate that if matter be distributed uniformly, the universe would necessarily be spherical (or elliptical). Since in reality the detailed distribution of matter is not uniform, the real universe will deviate in individual parts from the spherical, i.e. the universe will be quasi-spherical. But it will be necessarily finite. In fact, the theory supplies us with a simple connection between the space-expanse of the universe and the average density of matter in it.

Well Shavo, Einstein did it, I just copied the actual text of it from a page in his GR.

Sep 13, 2016
The point of the article is not to suggest anything else than our known cosmology, but to present an analysis of a seeming coincidence in it.

The early expansion of a universe after inflation will pass through matter dominance and hence slow down. Later the expansion will make the universe leave matter dominance and the expansion will speed up.

That series of events happened early, and life can emerge early, but nothing suggests a connection. As the paper itself notes: "it might be a meaningless coincidence or [...]".

Though I like the paper's expression of the "cosmic jerk" [3d time derivative of distance] that we had to suffer.

Sep 13, 2016
@Benni: "why are you not making fun of the diagram at the top of the page that makes the Universe look as if it blown out of a cannon?"

The diagram has all sorts of problems (that is neither here nor there). But it is essentially correct as a standard depiction of how the scale factor changes which you can see in every cosmological course.

The scale factor is non-dimensional [see the paper, say] and describes the expansion amount at any given time. You are just misreading it as distance, likely since you haven't studied basic cosmology, helped along by the placing of illustrative content of the universe at any given time.

Re Einstein, the sphere he was talking about was based on a curvature not close to zero as we now know it is. The question for you was how to draw the latter, over time.

Sep 13, 2016
Curiously, though, today the universe looks the same way it would have if it had always been expanding steadily at a constant rate (the rate required to prevent ultimate re-collapse).

Now, there's a surprise!

Sep 13, 2016
Einstein did it

Even discounting the fact that our perception of the universe has changed (the evidence doesn't seem to support a 'quasi-spherical' universe), how do you DRAW that? Because even his 'quasi-spherical' (which we would now call a hypersphere) is a volume with no center that wraps back around on itself.

For an example: where is the center of the *surface* of the Earth? Ie, what point **on the Earth's surface, and not its interior** is the 'center'? Einstein's 'quasi-spherical' volume is the same way, just in 3-dimensions. It wraps back around on itself, but nowhere within any constant time slice of spatial volume is a 'center'.

Sep 13, 2016
Re Einstein, the sphere he was talking about was based on a curvature not close to zero as we now know it is. The question for you was how to draw the latter, over time.


our perception of the universe has changed (the evidence doesn't seem to support a 'quasi-spherical' universe


Here we are, two Asstro-physicists bragging they are smarter than Einstein based on a self-proclaimed superior "perception"? As I always expect, it is never surprising how Asstro-physicists take somebody else's words (Einstein's in this case), turn them upside down in an attempt to make them sound like he REALLY meant the opposite of what he actually stated.

Unlike you two, Einstein actually had an excellent comprehension of the 2nd Law of Thermodynamics, that the distribution of energy results in random scattering of particles inside the closed boundary in which the energy is distributed, and the pattern of scattering is spherical, in the physical sciences we call this ENTROPY.


Sep 14, 2016
It must be narcissism. Navel staring. Never getting out of the village.
And of course total ignorance is another ingredient.
...........I gather the potato chip crumbs around your armchair are becoming deeper to the point you can only see far enough above them to view the computer screen on one of your many laptops.

Authority in these matters does not rest on simiesque copy/paste agility.
Right you are, but quoting from Einstein's GR suits me just fine.......you are the one who has problems with it.

Sep 14, 2016
@Benni
Quoting Einstein may be chique and sophisticated, but it does not lift your status of ignoramissimus. It is just snobbery in your case.


@Benni
Quoting Einstein may seem chique and sophisticated, but it does not lift your status of ignoramissimus. It is just snobbery in your case.


........bespeaking the name calling that you pile on others, what is the difficulty your're having with simply keeping a simple keyboard under control so that you can avoid double posting the same submittal ? By the way, try this for assistance in enunciation & spelling: ig·no·ra·mus............we know, you were in a hurry to get to the next bag of potato chips & your greasy fingers were slipping & sliding all over the keyboard causing you to...........

Sep 16, 2016
@Benni
I see you are jousting with FizzWun, so I am seeing his twaddle when you quote it despite him being on my ignore list. Jousting with him is a bit like playing hide and seek with a dead sheep, he ignores your clinical thrusts and has no talent for producing a meaningful response. Put him on your ignore list, and stop wasting your time (and mine) reading his crap.

Sep 16, 2016
@Benni
I see you are jousting with FizzWun, so I am seeing his twaddle when you quote it despite him being on my ignore list. Jousting with him is a bit like playing hide and seek with a dead sheep, he ignores your clinical thrusts and has no talent for producing a meaningful response. Put him on your ignore list, and stop wasting your time (and mine) reading his crap.


I understand what you mean Reg. But sometimes ir is just so entertaining watching him & Shavo go absolutely berserk when I point out to them why they are not smarter than Einstein & why their most treasured Asstro-physicists icons (Zwicky & Schwarzschild) could never hold a sensible conversation with him, of course it is for the same reason I can't have a sensible conversation with the two of them, it's all about the depth of comprehension of Nuclear Physics.

Sep 17, 2016
@Benni
Well, I respect your point of view. I used to feel the same about Cap'n Grumpy, but in the end his sheer stupidity and predictability became so boring I had to switch him off. In your case, you still have delusions that Fizz does understand some Nuclear Physics so you can converse with him, but in fact he just reacts to your words rather like a Pavlov-trained dog, spouting meaningless dogma given the right stimuli. Still, if it amuses you, I suppose you will carry on, although it is like poking a drunken sailor to hear him swear. For myself, I tend to feel it is wicked to mock the afflicted, but to each his own.

Sep 17, 2016
I believe that those riddles are caused by the following scenario.
Stars begin as very low entropy hydrogen, and end up as extremely low entropy heavier elements while releasing still relatively low entropy photons, which are then captured by other gravity sinks, like black holes. Once the structure of the universe shift towards the domination of black holes, we get a different picture. Black holes start as very low entropy, but produce high entropy hawking radiation, dark matter, or whatever they evaporate into, which is not recycled as efficiently as lower entropy photons, resulting in expansion. At this point the universe undergoes the same transition as a red giant star, with the core unable to attract its expanding rare mantle.
Nothing in the evolution of life, the universe, and everything, makes sense, unless in light of thermodynamics (LD)

Sep 17, 2016
I understand what you mean Reg. But sometimes ir is just so entertaining watching him & Shavo go absolutely berserk when I point out to them why they are not smarter than Einstein & why their most treasured Asstro-physicists icons (Zwicky & Schwarzschild) could never hold a sensible conversation with him, of course it is for the same reason I can't have a sensible conversation with the two of them, it's all about the depth of comprehension of Nuclear Physics.

No, actually it is because you are an idiot and a liar. An idiot because you think you can profess to be something you are not on a science site without getting found out, and a liar because you tried to do it in the first place.

Reg is just an incoherent, stark raving, loon. Of course the two of you would have a bromance.

Sep 17, 2016
actually it is because you are an idiot and a liar. An idiot because you think you can profess to be something you are not on a science site without getting found out, and a liar because you tried to do it in the first place.


Phys1, why do you allow Maggie to talk about you like this? Prove to him the reverse that, "you can profess to be something you are not on a science site without getting found out, and a liar because you tried to do it in the first place".

Hey there 1st semester physics guy? Take up the challenge & prove it, post your resume, Maggie won't do it to prove he's not a "liar", but we know how different YOU are don't we?

Sep 20, 2016
@Maggnut
Reg is just an incoherent, stark raving, loon. Of course the two of you would have a bromance.

Nice to hear from you again, although your invective has deteriorated over the years. Senility kicking in? The falling potency of your vituperation indicates yet further decline in your scant mental capacity, and I think you should retire before you become a laughing stock (although its probably too late for that....).

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