Questions on Redshift, Hubble’s Law, spacetime expansion and the standard model

[johnmartin]

The current state of NASA’s version of cosmology is amazing to watch –

The Sun orbits the center of the Milky Way at about 250 km/second and it takes about 220 million years to complete an orbit.
The Milky Way is part of a group of galaxies known as the Local Group. All of these are moving relative to each other due to their gravitational interaction with speeds of around 100 km/s or less. Calculating the velocities of the galaxies in the Local Group is difficult because there are probably members that have not yet been discovered because they are too dim or are obscured by the plane of the Milky Way. The radial velocities relative to the Milky Way are found by measuring Doppler shifts in the spectra of stars in the galaxies. You will find more information at http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970821a.html
The Local Group is also moving at about 600 km/second relative to the cosmic microwave background. There's a nice picture of this at http://antwrp.gsfc.nasa.gov/apod/ap960205.html

According to modern cosmology, which NASA endorses, the Milky Way is moving through space at 600km/s and the Earth is moving through space at 30km/s and the sun is moving through space at 250km/s. So if we total up these velocities we have 880km/s for the velocity of the Earth through space, relative to the CBR. Conservatively according to NASA, the earth’s motion through space is 600km/s.
What is the cause of galaxy redshift? According to NASA, redshift is caused by the motion of the galaxy away from the observer or the expansion of spacetime itself.

cosmological redshift
An effect where light emitted from a distant source appears redshifted because of the expansion of spacetime itself. Compare Doppler effect.
Doppler effect (C.J. Doppler)
The apparent change in wavelength of sound or light caused by the motion of the source, observer or both. Waves emitted by a moving object as received by an observer will be blueshifted (compressed) if approaching, redshifted (elongated) if receding. It occurs both in sound and light. How much the frequency changes depends on how fast the object is moving toward or away from the receiver. Compare cosmological redshift.

1. If the redshift of galaxies means the universe is expanding is the correct interpretation of redshift, then the following questions apply -
2. If the universe is expanding in all directions, then are the distances between the galaxies observed to be getting larger over the years? If so, what is the evidence?
   
3. If the universe is expanding in all directions and the galaxies are moving away from Earth at large velocities, are the galaxies observed to have light dimmed over the years? If so, where is the evidence? If not, how does science explain the large velocities without the need for galaxy light dimming as seen from the earth?
   
4. According to modern cosmological theory as stated by NASA, the galaxies are moving away from the Earth due to the universe’s expansion and along with this, the space time continuum is also expanding between the galaxies and the earth. As spacetime is merely a version of Cartesian coordinates, (x,y,z,t), which is merely a mathematical model, how then does light redshift, when a mathematical model of (x,y,z,t) is said to expand?
   
5. In another way, x,y,z,t is not a physical thing or physical cause or physical anything at all, so how can x,y,z,t exist in the real, let alone expand in the real and then be a cause of redshift in the real?
   
6. As spacetime is said to expand between the galaxies and the earth, because of the big bang, when then is the cause of the expansion of x,y,z,t? What experimental evidence is there that x,y,z,t exists and can even expand?
   
7. What experimental evidence is there that an expanding x,y,z,t acts on light to make light redshift?
   
8. If x,y,z,t expands, that means it has a change in distance over time, meaning an expanding x,y,z,t has a velocity and possibly an acceleration as well. As such, how is the velocity of expansion calculated?
   
9. What is the x,y,z,t expansion referred to as the zero velocity benchmark? Is it space, which is to be self referencing? Or is it the earth?
   
10. If the x,y,z,t expansion is referred to the Earth as the zero velocity benchmark, doesn’t this mean the theory is merely an Earth based theory, which assumes the Earth is stationary relative to the moving galaxies and expanding spacetime? Explain.
    
11. If x,y,z,t is expanding, does relativity also apply the Lorentz contraction to this expansion? If so, what then is the proper distance used and how do relativists know experimentally?
    
12. If x,y,z,t is expanding spacetime, how is this applicable to Hubble’s law that does not use spacetime in its model, but derived his law from empirical observation?
    
13. If a proper distance is used in Hubble’s law, doesn’t that mean the distance is relative to a motionless observer at the Earth and therefore Hubble’s law is then evidence for a stationary earth?
    
14. If Hubble’s law uses proper distance, but the Earth is not stationary, what then is the proper distance relative to?
    
15. If Hubble’s law uses proper distance relative to the CBR then, are the velocities of say 600km/s, 100km/s and 30km/s used in the calcs to remove the Earth's various velocities to then determine the proper distance relative to a stationary earth?
    
16. Assuming the Hubble constant of 65km/s per Mpc is correct, are the velocities of say 600km/s, 100km/s and 30km/s used in the calcs to remove the Earth's various velocities to then determine the proper distance relative to a stationary earth? If so, how is it that there have been studies that show galaxies are uniformly quantized around the earth, even though the Earth is supposedly moving through space at such a large velocity?
    Put in another way, if the Earth is moving through space at say 600km/s, then this velocity must be accounted for in the redshift calculations. As such, the earth’s velocity of 600km/s must be removed from galaxies to which the Earth is moving towards, not removed from galaxies which it moving against and added to galaxies it is moving away from. Then the uniform distribution of galaxies around the Earth is a simply fantastic fluke of nature, meaning, if the 600km/s is correctly used in the redshift calcs to really have the redshift as a Doppler shift, then the galaxies in front of the Earth's motion are moving along with the Earth and the galaxies behind the earth’s motion at the same velocity.
    
    If the galaxies in front and to the rear of the Earth's 600km/s motion, move along with the earth, then -
    Galaxy in front of earth’s motion is 12km/s + 600km/s = 612km/s relative to 600km/s earth.
    Galaxy at the rear of the earth’s motion is 12km/s – 600km/s = 582km/s relative to 600km/s earth.
    This of course means galaxies in front of and behind the earth’s motion are some how attached to the Earth's motion. What an amazing phenomena the big bang theory produces when its concepts are consistently applied! Yet again, what a huge problem for the big bang theory when the concepts are consistently applied! The problem probably hasn’t even been noticed, let alone discussed and dismissed by relativists.
    
17. What is the physical cause of the spacetime expansion, which is really only an expansion of the quantities x,y,z,t?
    
18. As the universe is expanding in all directions, what is the physical cause of expansion of spacetime between the galaxies?
    
19. Let us assume the bending of spacetime around matter is the cause of gravity as relativity says it is. If then science posits the physical cause of expanding spacetime continuum is dark matter and dark energy, and matter is said to have a bending of space time around it, then how does more matter in the universe cause space time to expand? After all, if more matter exists, then shouldn’t that mean that spacetime curves more, causing the universe to contract, rather than expand.
    
20. Alternatively, if more dark matter causes to flatten and therefore expand, how can a flattening of the spacetime cause the universe to expand, when almost all the universe already has a flat spacetime curvature?
    
21. If dark energy causes the expansion of spacetime, what are the properties of this dark energy which can expand merely a mathematical concept?
    
22. If dark energy causes the expansion of spacetime, what are the properties of this dark energy which cause spacetime to expand? Does the dark energy heat up the spacetime and cause it to expand like a hot iron rod? Or does it somehow bend of flatten spacetime?
    
23. If dark energy affects space-time curvature, what is the experimental relationship between dark energy and change in space-time curvature? How do we know experimentally or mathematically?
    
24. If there is expansion of space-time between galaxies that are closer and further away from the earth, what has been observed in regard to the light that travels from further galaxies, through the expanding space-time continuum of closer galaxies. Shouldn’t the light traveling between the closer galaxies actually make the light expand?
    
25. Does the cause of expansion of spacetime between galaxies act at a constant rate, or at a different rate? Evidence?
    
26. When redshifts are observed, how are the velocities of the galaxies calculated? Do the velocities incorporate the velocity of the Earth at 600km/s though space? If so, please show the calcs.
    
27. If the redshift observations are considered to be observations of real velocities, then doesn’t that mean if say a redshift which produces a velocity of say 12km/s or 72km/s, really means the galaxy is moving 612km/s and 672km/s, because the observations are being made from earth, which is traveling through space at 600km/s?
    
28. If the earth’s velocity is taken into account when making the redshift observation, doesn’t this place into question Hubble’s law of distance, whereby redshift is proportionate to distance, simply because the Hubble’s law is related to a mythical non moving point in the universe?
    
29. The Hubble telescope is used to take pictures of the universe. The satellite travels in an orbit with a velocity of 17,500 mph. The lenses used are shaped according to a very accurate design. If the lens is out on only a fraction of a mm, then the telescope will not be able to take good quality pictures.
    
    

    Hubble's mirrors are very smooth and have precisely shaped reflecting surfaces. They were ground (shaped by removing glass with abrasives) so that their surfaces do not deviate from a perfect curve by more than 1/800,000ths of an inch. If Hubble's primary mirror were scaled up to the diameter of the Earth, the biggest bump would be only six inches tall. http://hubblesite.org/the_telescope/nuts_.and._bolts/optics/

    According to relativity, when a body moves with velocity, it shrinks in the direction in which it moves. As the lens was created on Earth and is now used on a telescope that moves at 17,500 mph, then according to relativity, the lens must shrink by a Lorentz contraction of 0.94%. Was the lens designed at the earth’s surface assuming the lens would contract, or not? If so, then the lens must distort a length of 0.94% in space, so the lens must have been made over sized on Earth by 101.07% in the direction which the satellite was to move, thereby allowing the lens to contract in space and thereby allow the lens to take good quality pictures.
30. When we inspect some of the literature on the lens design here - http://www.pgccphy.net/ref/hst-optics.pdf, there is no discussion whatsoever on the Lorentz contraction used in the design. The reason of course is the lens doesn’t need the Lorentz contraction and the Ritchey–Chrétien telescope criteria used in the telescope does not require the use of relativity theory - http://en.wikipedia.org/wiki/Ritchey–Chrétien_telescope#Mirror_parameters. Evidently the Hubble telescope lens design overturns relativity theory. This is not unexpected as the Lorentz contraction is merely science hodgepodgery, which is routinely ignored by NASA herself when building her satellites.
31. If the earth’s velocity is not taken into account when making the redshift observation, doesn’t this place into question Hubble’s law of distance, whereby redshift is proportionate to distance, simply because the law is not observationally related to a stationary object?
    
32. Quasars with greater redshifts have been found in front of galaxies with lesser redshifts. How is this observed phenomena accounted for in modern cosmology according to redshift indicating distance? It seems redshift does not indicate distance as observed, but does indicate distance according to Hubble’s law. How is this contradiction resolved?
    
33. If the Earth orbits the sun in an ellipse, this means over a year, the Earth moves closer and further away from the sun. Has the sun been observed to become redshifted and blueshifted due to the Earth's motion away and towards the sun?
    
34. If the sun is moving through space at 600km/s, does light from the sun aberrate?
    
35. If black holes exist, then they suck in all matter around them, including light. Does a black hole then suck in dark matter and dark energy and if so, doesn’t that mean if black holes exist, then the amount of dark matter and dark energy should decrease over time, causing the universe to contract, rather than expand?
    
36. If black holes exist, then they suck in all matter around them, including light. If the universe is then expanding, which is caused by dark matter and dark energy, then this dark matter and dark energy must have been much greater than it was billions of years ago and the universe must have expanded at far greater velocities than it currently does. However modern science says the universe is expanding at greater velocities, meaning dark matter and energy must be increasing. How does modern science explain the loss and gain of dark matter and energy to account for black holes in an expanding universe?
    
37. If there is some other explanation for the existence of black holes and the expanding universe through dark matter and dark energy, what is the science explanation?
    
38. If the universe is expanding in all directions and this expansion is caused by a massive force that permeates the entire universe, what is the cause of this force that can expand spacetime, but doesn’t prohibit the curving of spacetime around collapsing stars? It seems this mysterious force can cause a massive expansion when needed, but cannot counteract a relatively small contraction of matter when it is observed. Please comment on the apparently contradictory properties of this mysterious cause acting throughout the universe.
    
39. If black holes exist, then they suck in all matter around them, including light, how then do black holes not expand, when they are surrounded by dark matter and dark energy that causes expansion?
    
40. If black holes exist, why do they remain stable in size and not expand along at the same rate as the surrounding galaxy movement and cosmological expansion rate, with dark matter and dark energy?
    
    The final and most important question –
41. As x,y,z,t is merely a mathematical concept and not related to anything physical in the real, why then do so many scientists take cosmological redshift to mean the expansion of a quantity as a real expansion of a distance between galaxies and the earth?

 

[zhermes]

Maybe you should get a textbook on modern cosmology.

 

[johnmartin]

Maybe you should get a textbook on modern cosmology.

Choose any three questions and let's have some fun. I think the standard model is in a lot of trouble. We shall see.

JM

 

[Chalnoth]

Choose any three questions and let's have some fun. I think the standard model is in a lot of trouble. We shall see.

JM

tl;dr

 

[Dotini]

The current state of NASA’s version of cosmology is amazing to watch –

I certainly agree with this!

NASA is a large government organization with many semi-autonomous sites, programs, missions, and other "centers of excellence". There are even maverick NASA scientists who occasionally go off the reservation and publish audacious papers. So NASA speaks with many tongues, some of which seem contradictory. Which NASA observations are to be taken seriously, the ones which echo previously published textbooks, or the ones which report surprising new discoveries? Is NASA to be accorded respect and credibility, or not?

I would like to know in particular if it's safe to dismiss and ridicule the Voyager, IBEX and THEMIS missions? In this era of debt and deficit, should the budgetary plug be pulled on all or parts of the organization if it issues observations in conflict with the standard model?

Respectfully submitted,
Steve

 

[Lost in Space]

I find the redshift question rather confusing. Not all the galaxies are moving away from each other. Galaxies collide. The Milky Way and Andromeda galaxies are said to be heading toward each other, so how can the light from Andromeda be redshifted? I can appreciate that very distant galaxies are redshifted due to the expansion of space but I have difficulty understanding how galaxies that are headed toward each other locally can be redshifted. If it's true that all galaxies appear redshifted to each other, wouldn't this mean that space was expanding so fast that they could never collide?

 

[Chalnoth]

I find the redshift question rather confusing. Not all the galaxies are moving away from each other. Galaxies collide. The Milky Way and Andromeda galaxies are said to be heading toward each other, so how can the light from Andromeda be redshifted? I can appreciate that very distant galaxies are redshifted due to the expansion of space but I have difficulty understanding how galaxies that are headed toward each other locally can be redshifted. If it's true that all galaxies appear redshifted to each other, wouldn't this mean that space was expanding so fast that they could never collide?

Yes, galaxies are redshifted on average. Local velocities are frequently hundreds to a thousand or so km/s with respect to the average motion. Since the expansion rate is 70km/s/Mpc, that means you have to go out as far as about 14Mpc (46 million light years) or so before nearly all of the galaxies are redshifted.

 

[Shenstar]

I found some of your questions very interesting and would like to know the answers to them.

With regards to your last question (41) - then aren't the 4 dimensions real and not just abstract mathematical concepts?

I was more interested in knowing the answer to the questions relating to redshift and the Earth's motion, galaxy motion, solar system motion etc.

I think I know what the answer is to some parts of your questions relating to expansion. They say the expansion is happening beyond the local galaxy group level. So beyond the area where gravitational forces have an effect, although I struggle to believe that. Why would something which is allegedly building up speed or accelerating as a force not be able to counter gravitational forces, which are said to be the weakest of the four fundamental forces?

 

[marcus]

According to modern cosmology, which NASA endorses, the Milky Way is moving through space at 600km/s and the Earth is moving through space at 30km/s and the sun is moving through space at 250km/s. So if we total up these velocities we have 880km/s for the velocity of the Earth through space, relative to the CBR.

Lots of fun questions! But you went off track right at the start. You can not simply add velocities without regard for direction.

The solar system motion around the Milky center is roughly partly BACKWARDS from the overall motion of Milky relative to Background. So it partly CANCELS. So the net effect is that the solar system (i.e. the sun et al.) is moving at around 370 km/s.

You cannot just add 600+250+30 because these velocities are in all different directions and partly cancel. The sun's speed of 250 is an orbital velocity and its direction will eventually change as it comes around to the other side of Milky. Then it will tend to reinforce the Milky speed of 600 and the solar system will be traveling much faster relative to Background.

But that change in direction happens very slowly (over tens, even hundreds of millions of years)

On the other hand the direction of the Earth's motion, going 30, constantly changes direction over the course of one year and sometimes it slightly adds and sometimes it slightly cancels the effect of the larger overall motions of solar system. So the Earth as an observation platform has a slightly more complicated motion (relative to Background) than the overall solar system motion (relative to Background).

Earth orbit plane is tilted at angle about 60 degrees from solar system motion and from galactic plane IIRC (if I recall correctly). and so you would not just add or subtract the 30 from the 250. It would involve sines and cosines and the season of the year.

To avoid headaches and have a simple picture, think of a point on the edge of a whirling Frisbee as the Frisbee flies through the air. Sometimes the point is on the retro side and its whirl motion cancels----as the solar system orbital is now canceling part of the Milky 600.
And then the point comes around to the other side, the forwards side, and its whirl motion adds with the overall speed of Frisbee flight. As the solar system orbital 250 will some day millions of years from now add (in some degree) to the Milky 600.

We are now on the retro side of the galaxy. The angles in the picture are not exact but it give the rough idea.

 

[zhermes]

Many of these are excellent questions. You clearly have a sharp mind.
Many of your questions are based on false assumptions to the answers of previous questions, it would be better to just start with the first questions next time.

*Edit - Marcus has made an excellent, concise response that cuts to the core of the issues at hand; if nothing else, understand his response.

If the universe is expanding in all directions, then are the distances between the galaxies observed to be getting larger over the years? If so, what is the evidence?

The change in distance is too small to observe.

If the universe is expanding in all directions and the galaxies are moving away from Earth at large velocities, are the galaxies observed to have light dimmed over the years?...

Again, the change in distance over human life-times is incredibly negligible.

As spacetime is merely a version of Cartesian coordinates, (x,y,z,t), which is merely a mathematical model, how then does light redshift, when a mathematical model of (x,y,z,t) is said to expand?

* - See endnote.
Spacetime is not a 'version of [any] coordinates'. The coordinates are a metric for describing the spacetime. http://en.wikipedia.org/wiki/Cosmological_redshift" .

In another way, x,y,z,t is not a physical thing or physical cause or physical anything at all, so how can x,y,z,t exist in the real, let alone expand in the real and then be a cause of redshift in the real?

See above.
The next few questions on "x,y,z,t" are answered in the same way, see also endnote '*'.

What is the x,y,z,t expansion referred to as the zero velocity benchmark? Is it space, which is to be self referencing? Or is it the earth?

It is not the earth. See endnote '*'. There are a few reference points which can be used, generally any local region of space can be used as a reference frame. In more complex situations, you can use the cosmic microwave background, or even statistical methods with nearby galaxies, clusters, etc.

If x,y,z,t is expanding, does relativity also apply the Lorentz contraction to this expansion? If so, what then is the proper distance used and how do relativists know experimentally?

*; its not that simple, the effects are accounted for in full general relativity. There are numerous ways of measuring proper-distance vs. distance, its complicated and requires the coordination of lots of different measurements together to bring down the error-bars. I don't know the details.

Assuming the Hubble constant of 65km/s per Mpc is correct, are the velocities of say 600km/s, 100km/s and 30km/s used in the calcs to remove the Earth's various velocities to then determine the proper distance relative to a stationary earth? If so, how is it that there have been studies that show galaxies are uniformly quantized around the earth, even though the Earth is supposedly moving through space at such a large velocity?

I don't understand this one. You can take into account whatever velocities to want to find velocities relative to whatever object you want. Usually the velocity is measured with respect to the sun, or even the milky-way as a whole (for cosmological objects). Those velocities aren't very large, usually in cosmological contexts.
What does 'galaxies are uniformly quantized' mean?
The velocities of the Earth are an incredibly small detail of the calculations. One of the most trivial aspects. Measurements are made over the course of decades, requiring Earth's orbit to always be taken into account, and measurements averaged and weighted properly.
In the types of immense statistical samples that are used for Hubble's law measurements, mean motions are always subtracted and residuals considered.

This of course means galaxies in front of and behind the earth’s motion are some how attached to the Earth's motion. What an amazing phenomena the big bang theory produces when its concepts are consistently applied! Yet again, what a huge problem for the big bang theory when the concepts are consistently applied! The problem probably hasn’t even been noticed, let alone discussed and dismissed by relativists.

Do you really think that you understand each facet of general relativity, celestial dynamics, and cosmology to provide original, unique, novel insight to problems and concepts which the greatest minds have spend their lifetimes on for a hundred years? Aren't we humble.

There are thousands of amateur and professional scientists out there, far more intelligent and better learned than you or I, who would love nothing more than finding a problem with the standard model. People devote their lives to finding those problems, to changing the accepted paradigm. Nothing too strong has turned up yet. When I don't understand some of these complex concepts (which happens very often), I try to learn about them, instead of making wild assumptions and trying to disprove them.

You are missing the most basic understanding of these concepts---there's absolutely nothing wrong with that, and I applaud your interest and passion in the topics. The problem: you're not trying to learn the concepts, you're just trying to disprove them out of some political, sociocultural, or religious predisposition.

What is the physical cause of the spacetime expansion, which is really only an expansion of the quantities x,y,z,t?

Again, that is a false interpretation. We believe the expansion to be continuing from the big bang, and the acceleration of that expansion from dark energy / the cosmological constant.

As the universe is expanding in all directions, what is the physical cause of expansion of spacetime between the galaxies?

Same question, same answer.

Let us assume the bending of spacetime around matter is the cause of gravity as relativity says it is.

Poor wording. GR says gravity and 'the bending' are one and the same.

If then science posits the physical cause of expanding spacetime continuum is dark matter and dark energy, and matter is said to have a bending of space time around it, then how does more matter in the universe cause space time to expand?

False.

After all, if more matter exists, then shouldn’t that mean that spacetime curves more, causing the universe to contract, rather than expand.

True.

Alternatively, if more dark matter causes to flatten and therefore expand, ...

This is completely jumbled. http://en.wikipedia.org/wiki/Dark_matter" . The flatness of space also does not lead to or mean expansion!

If dark energy causes the expansion of spacetime, what are the properties of this dark energy which cause spacetime to expand? Does the dark energy heat up the spacetime and cause it to expand like a hot iron rod? Or does it somehow bend of flatten spacetime?

Dark energy causes the rate of expansion to increase (a very different thing). We don't know 'why' this happens. 'Dark energy' is what we call whatever it is that causes this effect, it's 'dark' because its a mystery. It could simply be a property of spacetime and the universe itself.

If dark energy affects space-time curvature, what is the experimental relationship between dark energy and change in space-time curvature? How do we know experimentally or mathematically?

Unfortunately we can't do experiments on the scale of the universe as a whole. See endnote *, and the previous answer for 'how do we know'.

Shouldn’t the light traveling between the closer galaxies actually make the light expand?

What?

When redshifts are observed, how are the velocities of the galaxies calculated? Do the velocities incorporate the velocity of the Earth at 600km/s though space? If so, please show the calcs.

Please show the calculations? Why don't you look up the thousands of papers on the subject, or the textbooks who present the ideas?

If the redshift observations are considered to be observations of real velocities, then doesn’t that mean if say a redshift which produces a velocity of say 12km/s or 72km/s, really means the galaxy is moving 612km/s and 672km/s, because the observations are being made from earth, which is traveling through space at 600km/s?

It depends on what you're talking about---obviously. If you're asking about the velocity relative to pluto, it will be completely different; or the velocity relative to the milky way, or to a race car, or to a rainbow in africa.

The Hubble telescope is used to take pictures of the universe. The satellite travels in an orbit with a velocity of 17,500 mph...According to relativity, when a body moves with velocity, it shrinks in the direction in which it moves.

These effects are entirely negligible as you must consider the telescope's velocity with respect to what its looking at. Additionally, these effects are accounted for in the image processing and the statistical nature of the imaging and processing processes.

The reason of course is the lens doesn’t need the Lorentz contraction ... Evidently the Hubble telescope lens design overturns relativity theory.

'Of course' eh? From your extensive career in optics and relativity? Why are you making wild unfounded accusations when you have virtually zero understanding of the underlying concepts?

Quasars with greater redshifts have been found in front of galaxies with lesser redshifts.

Source? Citation?

If the Earth orbits the sun in an ellipse, this means over a year, the Earth moves closer and further away from the sun. Has the sun been observed to become redshifted and blueshifted due to the Earth's motion away and towards the sun?

Yes. Of course.

If black holes exist, then they suck in all matter around them, including light. Does a black hole then suck in dark matter and dark energy and if so, doesn’t that mean if black holes exist, then the amount of dark matter and dark energy should decrease over time, causing the universe to contract, rather than expand?

By god! You're right. Without a single equation, and likely without a single course or publication in any of these fields, you've discovered the underlying flaws in all of physics! This must mean that in 2012 the universe is going to contract upon itself, killing us all, except for elvis who is still alive now and always.

If the universe is expanding in all directions and this expansion is caused by a massive force that permeates the entire universe, what is the cause of this force that can expand spacetime, but doesn’t prohibit the curving of spacetime around collapsing stars?

From even the most rudimentary, high school level calculation, it is clear that the force causing the accelerating expansion is incredibly small on as small spatial-scales as stars or even galaxies. It is only on scales as large as the universe as a whole that it becomes significant. The expansion, per se (i.e. not the acceleration), is not a force---per se. And is again, entirely negligible on the scale of stars.

Please comment on the apparently contradictory properties of this mysterious cause acting throughout the universe.

Occam's razor would suggest that the apparent contradiction is in your understanding. Not in that of everyone else, or of actuality.

If black holes exist, why do they remain stable in size and not expand along at the same rate as the surrounding galaxy movement and cosmological expansion rate, with dark matter and dark energy?

They would expand as such.

As x,y,z,t is merely a mathematical concept and not related to anything physical in the real, why then do so many scientists take cosmological redshift to mean the expansion of a quantity as a real expansion of a distance between galaxies and the earth?

As 'johnmartin' is merely a linguistic concept, based on concepts related to sociocultural practices, neither with any connection to the physical world, why then do so many questions get asked by him? As 'learning' and 'knowledge' is merely a philosophical concept and not related to 'anything physical in the real', why then do so many people strive for it---unlike, said johnmartin?

* - Get a textbook on differential geometry, general relativity, or cosmology. There is too much to explain all of it to you on a forum.

I am very happy to help you better understand any of the above concepts that are very apparently unclear. If any of my responses are unclear, I will be happy to expand or direct you to better sources---as my understanding itself is only rudimentary. Again, I truly applaud your interest and passion in the topics you raised, and encourage you to continue pursing them from an unbiased and authentically curious perspective.

 

[marcus]

The answer is YES. The known motion of the solar system (which is the net effect of the various motions you mention) IS USED TO ADJUST the observations. And it only after we allow for that motion that we see the uniformity of expansion as perfectly as we do.

The net motion is actually about 370 km/s in a direction which is marked by a certain constellation (Leo) which has been visible in the evening sky for the last few months. It is a springtime constellation.

[*] Assuming the Hubble constant of 65km/s per Mpc is correct, are the velocities of say 600km/s, 100km/s and 30km/s used in the calcs to remove the Earth's various velocities to then determine the proper distance relative to a stationary earth? If so, how is it that there have been studies that show galaxies are uniformly quantized around the earth, even though the Earth is supposedly moving through space at such a large velocity?
Put in another way, if the Earth is moving through space at say 600km/s, then this velocity must be accounted for in the redshift calculations. As such, the earth’s velocity of 600km/s must be removed from galaxies to which the Earth is moving towards, not removed from galaxies which it moving against and added to galaxies it is moving away from. Then the uniform distribution of galaxies around the Earth is a simply fantastic fluke of nature, meaning, if the 600km/s is correctly used in the redshift calcs to really have the redshift as a Doppler shift, then the galaxies in front of the Earth's motion are moving along with the Earth and the galaxies behind the earth’s motion at the same velocity.

If the galaxies in front and to the rear of the Earth's 600km/s motion, move along with the earth, then -
Galaxy in front of earth’s motion is 12km/s + 600km/s = 612km/s relative to 600km/s earth.
Galaxy at the rear of the earth’s motion is 12km/s – 600km/s = 582km/s relative to 600km/s earth.
This of course means galaxies in front of and behind the earth’s motion are some how attached to the Earth's motion. What an amazing phenomena the big bang theory produces when its concepts are consistently applied! Yet again, what a huge problem for the big bang theory when the concepts are consistently applied! The problem probably hasn’t even been noticed, let alone discussed and dismissed by relativists.

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The problem was noticed and dealt with long ago. The need to adjust observation for the net Earth motion was already noticed. I don't know by whom. I think even before the CMB was observed.

The adjustment is not especially great. 370 km/s is only around 1/1000 of the speed of light. So that would correspond to a redshift of 0.001.

As long as one is not trying for exquisitely accurate measurements of redshift or of Background temperature, 0.001 is not a big deal. One usually states redshifts with only one or two significant digits, so 0.001 is negligible.

 

[Shenstar]

Thanks for that clarification. I didn't know all the other motions had been taken into account

 

[marcus]

Actually the analysis is done in what might seem to you at first sight to be reverse order.

The NET motion of the solar system relative to the ancient light background (CMB) is the easiest thing to determine.

The instruments that do that typically orbit the sun independently, farther out than the earth, so it is not the Earth's speed that enters but the instrument's own orbital velocity. But adjusting for that is trivial. The main thing is to MAP THE CMB TEMPERATURE from the standpoint of the center of mass of the solar system.

And then one finds that the temperature is about ONE TENTH OF A PERCENT WARMER in the direction of constellation Leo. Showing that the solar system is moving in that direction at one tenth percent of speed of light, relative to CMB rest.

More precisely that turns out to be 370 km/s. (what I mean by very roughly a tenth percent of c.)

That is the real speed that matters. The other speeds are inferred starting from that. Because we can tell approximately what our speed is around the center of the galaxy. It can be estimated by observing how stars nearer the galactic center catch up with us and how we catch up and pass stars farther out (which orbit more slowly). It is also estimated by using radiotelescopes to gauge the speeds of large clouds of neutral hydrogen, which are also orbiting the center of the galaxy. All that is rather technical. The upshot is we can estimate the orbital speed and direction of the solar system relative to galactic center.

THAT IS WHAT LETS US TELL THE SPEED AND DIRECTION OF THE GALACTIC CENTER relative to CMB rest.

you see how "backwards" it is? We first measure our own S.S. velocity relative CMB. And then we measure how S.S. is moving relative to Milky Center. But that says how Milky Center is moving relative to S.S.! So since we know the velocity vector of S.S. we can determine the velocity vector for Milky Center.

And from that we can figure out the center of mass velocity of the Local Group of galaxies, relative to CMB.

All our Local Group is flying like a squadron of airplanes in a direction marked by Southern constellations Hydra and Centaurus----more precisely a small constellation near them named the Drinking Cup (in Latin: "Crater").

But the main information, the basis for the other estimates, is the Solar System motion relative to CMB, which we know from the temperature dipole----the Leo hotspot in the microwave sky.

 

[johnmartin]

I found some of your questions very interesting and would like to know the answers to them.

With regards to your last question (41) - then aren't the 4 dimensions real and not just abstract mathematical concepts?

I was more interested in knowing the answer to the questions relating to redshift and the Earth's motion, galaxy motion, solar system motion etc.

I think I know what the answer is to some parts of your questions relating to expansion. They say the expansion is happening beyond the local galaxy group level. So beyond the area where gravitational forces have an effect, although I struggle to believe that. Why would something which is allegedly building up speed or accelerating as a force not be able to counter gravitational forces, which are said to be the weakest of the four fundamental forces?

Good question and I think there is probably no real answer as far as i can tell because dark matter and dark energy are unknowns. I really believe the standard model is in trouble on many fronts and expansion of space-time is one such problem area.

 

[johnmartin]

We are now on the retro side of the galaxy. The angles in the picture are not exact but it give the rough idea.

Gotcha, the spinning disk thing is happening.

 

[Chalnoth]

Good question and I think there is probably no real answer as far as i can tell because dark matter and dark energy are unknowns. I really believe the standard model is in trouble on many fronts and expansion of space-time is one such problem area.

The data say otherwise.

 

[Shenstar]

I thought dark matter was the place holder for whatever it is that gives parts of space more mass that should exist but it unseen.

And dark energy was to do with expansion and was the 'force' that was behind the acceleration of this expansion?

 

[Lost in Space]

Yes, galaxies are redshifted on average. Local velocities are frequently hundreds to a thousand or so km/s with respect to the average motion. Since the expansion rate is 70km/s/Mpc, that means you have to go out as far as about 14Mpc (46 million light years) or so before nearly all of the galaxies are redshifted.

So as galaxies approach each other they are in fact blueshifted?

 

[Chalnoth]

I thought dark matter was the place holder for whatever it is that gives parts of space more mass that should exist but it unseen.

There's a bit more to it than that, as it behaves like a weakly-interacting massive particle created in the early universe. In other words, like a neutrino but more massive (neutrinos travel at too high of velocities to explain structure formation in the early universe). Many other potential explanations for dark matter have been ruled out. We still don't know precisely what that particle is, but the evidence is pretty good that it must be such a particle.

And dark energy was to do with expansion and was the 'force' that was behind the acceleration of this expansion?

Sorta kinda. The expansion is still governed by General Relativity, so there is no other force acting here but gravity. It's just that when you have a nonzero energy density in empty space, you get an accelerated expansion.

But the thing I was really objecting to was your last statement: that the expansion of space-time is a problem area. This is manifestly not the case, as the spatial expansion is strongly supported by a wide variety of extremely different sorts of data.

 

[Chalnoth]

So as galaxies approach each other they are in fact blueshifted?

Yes, absolutely. They are blueshifted relative to one another. Andromeda is blue-shifted, for example, which is how we know that it will collide with our galaxy in a few billion years.

 

[Lost in Space]

Yes, absolutely. They are blueshifted relative to one another. Andromeda is blue-shifted, for example, which is how we know that it will collide with our galaxy in a few billion years.

Thanks for clearing that one up. I just find it annoying when people say that all galaxies are redshifted and moving away from each other due to the expansion of space, when in fact only very distant galaxies can be observed to be doing this. In point of fact even galactic clusters are moving towards each other. Our local group is said to be being pulled towards the Virgo Supercluster. Gravity may be considered the weakest of the forces but it's got an incredibly long range!

 

[Chalnoth]

Thanks for clearing that one up. I just find it annoying when people say that all galaxies are redshifted and moving away from each other due to the expansion of space, when in fact only very distant galaxies can be observed to be doing this. In point of fact even galactic clusters are moving towards each other. Our local group is said to be being pulled towards the Virgo Supercluster. Gravity may be considered the weakest of the forces but it's got an incredibly long range!

Well, you can say that all galaxies beyond an average redshift of about 0.01 to 0.02 or so are redshifted (by average redshift I mean the average redshift of galaxies at that distance). So it is an accurate statement, provided it is qualified by the fact that nearby galaxies can be moving towards or away. But all of the further away galaxies are redshifted.