Expansion different in different directions

[Bmpbmp1975]

3 minutes ago, Mordred said:

Correct the range in this paper is 3.026 Gly or if you prefer 926 Mpc. Assuming my calculations is correct. This gives a range to z=0.3 in cosmological redshift value.

 The universe has a radius of roughly 46.5 Billion light years. 46.5 Gly. Z= 1096 roughly

We are examining only a miniscule portion of the observable universe.

3.026 Gly out of 46.5 Gly.

Local group only... And only a small sample of the observable universe.

 

So the universe is not expanding 30% quicker in certain areas, and this is not something for us to worry about in our lifetimes then

[pzkpfw]

  

2 minutes ago, Bmpbmp1975 said:

So the universe is not expanding 30% quicker in certain areas, and this is not something for us to worry about in our lifetimes then

 

 

Even if it were expanding 30% quicker in some areas, why would that be a concern in our lifetimes?

Why is that always a conclusion you jump to?

Edited April 9, 2020 by pzkpfw

[Bmpbmp1975]

5 minutes ago, pzkpfw said:

  

 

 

Even if it were expanding 30% quicker in some areas, why would that be a concern in our lifetimes?

Why is that always a conclusion you jump to?

if it expands quicker it ends quicker 

 

Just trying to understand since this is local galaxy cluster 

Edited April 9, 2020 by Bmpbmp1975

[Mordred]

12 minutes ago, Bmpbmp1975 said:

So the universe is not expanding 30% quicker in certain areas, and this is not something for us to worry about in our lifetimes then

The paper isn't a wide range of area study. It has only examined the nearby 313 galaxy clusters out of billions of galaxies.

 It cannot state anything beyond its examination range which I have given.

It also explains dipole anistropy in its opening paragraphs.

CMB shows a remarkable isotropy at small angular scales (high multipoles), whilst some anisotropies are still present in lower multipoles. The most prominent one is the so-called CMB dipole which, if one assumes its purely kinematic origin, is caused by the Doppler shift due to the motion of our Solar System with respect to the CMB rest frame.

Edited April 9, 2020 by Mordred

[Bmpbmp1975]

5 minutes ago, Mordred said:

The paper isn't a wide range of area study. It has only examined the nearby 313 galaxy clusters out of billions of galaxies.

 It cannot state anything beyond its examination range which I have given.

It also explains dipole anistropy in its opening paragraphs.

 

 

So as I stated nothing to fear in our lifetimes?

[Mordred]

In other words it is studying the local effects our motion and the local mass density has on our measurements. This is examined by the mass to luminosity relations.

Ie brightness

2 minutes ago, Bmpbmp1975 said:

So as I stated nothing to fear in our lifetimes?

Of course not. Your lifetime is insignificant compared to cosmological time.

It would be like comparing the lifetime of a flea to a rock.

Edited April 9, 2020 by Mordred

[Strange]

5 hours ago, Bmpbmp1975 said:

So as I stated nothing to fear in our lifetimes?

When the subject is cosmology, the answer to that question is always NO.

Have you ever considered getting help with your anxiety problems?

[Airbrush]

Has there been any mention of "dark flow" or the "great attractor" in any of this?

Suppose that some kind of dark flow is really happening, could that point to an irregular shape for the early universe?  Instead of expanding from a "point" it expanded from an irregular shape like a lightning strike?  I was thinking of string theory and the idea of branes colliding, like sheets hanging on a clothesline.  When the wind blows they make contact, but not in one point, but over a vast irregular region.

Edited April 9, 2020 by Airbrush

[MigL]

The term 'dark' in Cosmology just means we don't know.
The 'flow' is an apparent motion in a specific direction.
This could be cause by a gravitational forcing in that direction, i.e. Great Attractor.
But there is a small possibility that this apparent anisotropy is due to other reasons ( Cosmological Constant, or Dark Energy anisotropy ? ).
Since we are not sure, it is called 'dark' flow, or motion.

[Bmpbmp1975]

1 hour ago, MigL said:

But there is a small possibility that this apparent anisotropy is due to other reasons ( Cosmological Constant, or Dark Energy anisotropy ? ).
Since we are not sure, it is called 'dark' flow, or motion.

Can someone explain this better to me

does this tie in what mordrez explained to me or is it different 

Edited April 9, 2020 by Bmpbmp1975

[zapatos]

18 minutes ago, Bmpbmp1975 said:

Can someone explain this better to me

 

I suspect the answer to your question is "no". I'm afraid it may be time for you to recognize that the conversations on this site are simply above your comprehension level.

[Bmpbmp1975]

8 minutes ago, zapatos said:

I suspect the answer to your question is "no". I'm afraid it may be time for you to recognize that the conversations on this site are simply above your comprehension level.

You don’t have to if you don’t want to but a few people have been helping me learn already on this post 

[Strange]

The always-excellent Ethan Siegel has written about this. He is sceptical of the result Nicely, he has highlighted as a problem one of the things I mentioned. Also the small sample size and the data quality.

Quote

It is eminently possible — and tremendously interesting and even revolutionary if true — that our assumptions about the magnitude and scale of anisotropies in the Universe are flawed. If so, it will be data about the large-scale structure of the Universe, going well beyond our local corner of space, that demonstrates it. X-ray clusters, such as the ones discussed and analyzed here, might be the first robust test that discovers it, if so. But this new study is only a clue in that direction, one with many reasonable objections. The sample size is small. The correlation used is new and its universality is dubious. Foreground effects are not sufficiently modeled. And the data itself could be a lot better.

https://www.forbes.com/sites/startswithabang/2020/04/10/new-study-challenging-the-universes-expansion-deserves-lots-of-skepticism/#5083c674441c

[michel123456]

19 minutes ago, Strange said:

The always-excellent Ethan Siegel has written about this. He is sceptical of the result Nicely, he has highlighted as a problem one of the things I mentioned. Also the small sample size and the data quality.

https://www.forbes.com/sites/startswithabang/2020/04/10/new-study-challenging-the-universes-expansion-deserves-lots-of-skepticism/#5083c674441c

I'd like to come back (again) on this kind of statement:( from the link above):

"On the largest scales, the Universe really does appear to be the same everywhere."

How is that compatible with the fact that the Universe is evolving from a dense state into a dissipated state? Because the farther you look, the more closer to the BB are the galaxies you look at. Doesn't the existing theory states that the Universe must be denser for the far away galaxy clusters? Which means that an alien living in the past inside of some of this far away galaxy would have observed a denser Universe than we do today?

If the Universe is the same everywhere then doesn't that mean that in the past the Universe looked the same as today? IOW that wherever you are, and whenever you are, the Universe around you will look the same?

Or the statement "the Universe really does appear to be the same everywhere" means in fact "the universe as it appears to us was denser in the past and any observer living in our "today" is currently observing the same as we do now, no matter his position in the Universe"? And consequently one has to consider the concept of a kind of "today" applying everywhere in the Universe?

[Strange]

12 minutes ago, michel123456 said:

How is that compatible with the fact that the Universe is evolving from a dense state into a dissipated state? Because the farther you look, the more closer to the BB are the galaxies you look at. Doesn't the existing theory states that the Universe must be denser for the far away galaxy clusters? Which means that an alien living in the past inside of some of this far away galaxy would have observed a denser Universe than we do today?

Yes, and because of the, when we look at very distant areas of the universe, they are not the same as the local area (denser, different stars and galaxies, etc). However, everywhere we look at that time (ie. at that distance) is homogeneous. And, when we take into account the changes over time, we can see that on a large scale the universe is homogeneous.

And yes, someone in that past would have seen a homogeneous universe around them, but one that is denser than the one we see (eg. galaxies would have been closer together).

Quote

If the Universe is the same everywhere then doesn't that mean that in the past the Universe looked the same as today? IOW that wherever you are, and whenever you are, the Universe around you will look the same?

Obviously not. As has been explained to you many times, the universe is evolving from a hot dense state. It looked different in the past.

Quote

Or the statement "the Universe really does appear to be the same everywhere" means in fact "the universe as it appears to us was denser in the past and any observer living in our "today" is currently observing the same as we do now, no matter his position in the Universe"?

Yes, that is a good way of putting it. Wherever you are in the universe, it will appear the same (on large enough scales).

Quote

And consequently one has to consider the concept of a kind of "today" applying everywhere in the Universe?

Can I suggest that if you want to relate this to your bizarre personal understanding of what 'now' means, that you do it in one of your existing threads or start a new one.

Please do not hijack yet another thread with your inability to understand that light travels at a finite speed. Thank you.

[michel123456]

On 4/10/2020 at 11:43 AM, Strange said:

Please do not hijack yet another thread with your inability to understand that light travels at a finite speed. Thank you.

You're welcome. Please also stop to underestimate my IQ, I am not underestimating yours.

[Strange]

2 minutes ago, michel123456 said:

You're welcome. Please also stop to underestimate my IQ, I am not underestimating yours.

I am not commenting on your IQ. Just your inability to understand one thing. There are lots of things I am unable to understand. I don't think that makes me stupid. (Others may disagree.)

[dimreepr]

3 hours ago, michel123456 said:

You're welcome. Please also stop to underestimate my IQ,

Apparently, my IQ is quite high; but I still say stupid stuff...

[MigL]

Haha
Apparently it's so high, nobody else knows what you're talking about, half the time.

[dimreepr]

16 hours ago, MigL said:

Haha
Apparently it's so high, nobody else knows what you're talking about, half the time.

Only a visionary (when stoned) can understand everything I say. 😉

[taeto]

2 hours ago, dimreepr said:

Only a visionary (when stoned) can understand 

Judging from your avatar you might well have come across a few visionaries who got stoned 🙄.

[Airbrush]

On 4/9/2020 at 2:59 PM, zapatos said:

I suspect the answer to your question is "no". I'm afraid it may be time for you to recognize that the conversations on this site are simply above your comprehension level.

The best scientists can explain what they do to someone who is not an expert.  I'm not an expert and yet I learned a lot from the folks around here. 😃

[dimreepr]

12 minutes ago, taeto said:

Judging from your avatar you might well have come across a few visionaries who got stoned 🙄.

Ye, and they all understood me... 🙃

[zapatos]

1 hour ago, Airbrush said:

The best scientists can explain what they do to someone who is not an expert.  I'm not an expert and yet I learned a lot from the folks around here. 😃

Absolutely! Me too. Of course, them being able to explain it is not the same as me being able to understand it.

[Phi for All]

2 hours ago, Airbrush said:

The best scientists can explain what they do to someone who is not an expert.

I wouldn't word it quite this way. I think there are absolutely amazing scientists who have trouble dumbing complex knowledge down so the laymen understands. It's a special talent when one can relate knowledge that way, but I don't think science/scientists have any obligation to do so. Does a master carpenter have to be able to explain to a laymen what they're doing in order to build a magnificent home?