Substitute to Dark Matter?

[TeleMad]

Freethinker: Dark is the ABSENCE of light. It is NOT the opposite of light. It is strictly a relative relationship. What would be considered DARK in one relationship would be LIGHT in another. A cloudless full moon night would be dark compared to the day, but light compared to bottom of the ocean.

 

TeleMad: Seems you've contradicted yourself. If dark is the ABSENCE of light, as you so strongly emphasize, then if there is any light, then light isn't absent and it isn't dark. Therefore, what you go on to call a dark night is not a dark night since there IS light...moonlight.

 

FreeThinker: 1) contrary to your claim, there is NOT always moonlight at night.

 

Now you’ve stooped to being dishonest!

 

Look again at what I said and what you said I was replying to.

 

 

TeleMad: Therefore, what you go on to call a dark night is not a dark night since there IS light...moonlight.

 

In response to..

 

FreeThinker: A cloudless full moon night would be dark…

 

Tsk tsk. You can't do this the mature, honest way.

 

FreeThinker: need to Google this if you are not yet aware of it.

 

No, I am quite aware of your underhanded tricks, like the one you somehow THINK you’ve managed to pull off here.

 

FreeThinker: 2) try reading more than one sentence in a post.

 

ROTFLMAO! You’re the one with a reading problem. See above for proof.

 

FreeThinker: You will find I very specifically established "dark" to be "strictly a relative relationship" in the 3rd sentence.

 

Too bad you will find that you very specifically – and with strong emphasis – established dark to be the ABSENCE of light, in your first sentence.

 

That you contradicted yourself can’t be used to show that you didn’t contradict yourself.

 

FreeThinker: Again you may need to use Google or WWWebster if you are not familiar with the word "relative".

 

LOL! Backwards again FT.

 

Again, YOU may need to use Google or WWWebster if you are not familiar with the word ABSENCE.

 

FreeThinker: But please do it in front so I do not have to correct you and direct your activities later.

 

Dream on dude!

[Freethinker]

Originally posted by: Tormod

Distant Spacecraft Seem To Be Showing No Respect For The Laws Of Physics

Careful. Next thing you know Bush will have UN sanctions against them and spend hundreds of billions trying to attack them.

[BlameTheEx]

Tormod.

 

I had another look at that article:

 

Distant Spacecraft Seem To Be Showing No Respect For The Laws Of Physics

http://www.mufor.org/antigrav4.html

 

I can only agree that the unexplained deceleration will probably not be a new force, still it is interesting to speculate on the possibility that it is.

 

I did a bit of maths which I hope somebody will check. Assuming that this unexplained drag is a universal constant and not velocity dependant (both assumptions could easily be wrong) it will decelerate an object travelling at the speed of light to zero in 12 billion years. It is remarkably close in terms of magnitude to the hubble constant!

 

It is just possible that this is the force that is also responsible for the red shift. If the red shift is in some way a property of space, or of a force, and those distant galaxies are not actually travelling away from us, then we should expect something like this. This force/property would have to decelerate moving objects as well as red shifting light waves. It would be necessary to conserve mass/energy.

 

Still there are questions to be answered here. The pioneer spacecraft are NOT travelling at the speed of light. At least not relative to us. It is possible to argue, with justification, that all objects are travelling at the speed of light in some direction, if only in the direction of time. Will spacecraft travelling at different velocities decelerate in proportion? What happens to a craft that is at rest? If this deceleration is dependent on velocity, then velocity relative to what?

[Tormod]

Blame - this gets too heavy for my lacking mathematical insight. I hope Bo or someone else are able to discuss this.

[Freethinker]

Originally posted by: BlameTheEx

It is just possible that this is the force that is also responsible for the red shift.

You have a real fixation on inventing some exlanation for red shift other than the most obvious and well supported one.

If the red shift is in some way a property of space,

Red shift IS a property of time/ space. It is completely explainable based on the observation of objects moving relative to each other.

or of a force,

this would add an agent and thus violate Ockham's Razor.

and those distant galaxies are not actually travelling away from us,

Again, this is a real hangup for you. I am not aware of anything that would suggest non-expansion of the universe. To the contrary, everything we observe supports expansion.

then we should expect something like this. This force/property would have to decelerate moving objects as well as red shifting light waves.

We KNOW that red shift happens because of doppler. We can measure it locally. While there is nothing to support that red shift is caused by anything else.

Still there are questions to be answered here. The pioneer spacecraft are NOT travelling at the speed of light. At least not relative to us. It is possible to argue, with justification, that all objects are travelling at the speed of light in some direction, if only in the direction of time. Will spacecraft travelling at different velocities decelerate in proportion? What happens to a craft that is at rest? If this deceleration is dependent on velocity, then velocity relative to what?

1) there is no such thing as a craft at rest.

 

2) and since velocity is dependant upon specific references, to suggest that something woould adjust it's velocity in proportion to only one such reference is to ignore the universal (literally) reference of everything to everything else. i.e. to say that object "A" would decelerate proportionately to object "B" relative to both's relative velocity to "C", which could be completely opposite to the relative velocity of both to "D".

[Tormod]

Hey FT, give Blame a break. I think his questions here are valid. His hangup on red shift (yeah, I know I've commented on that, too) is a valid POV and I think it's fair to discuss his ideas.

 

But Blame, I do agree with FT that everything we currently observe support the stance that the universe is expanding. Red shift is (as we have discussed before) a result of light travelling through expanding space-time, which stretches it and create a doppler effect. The farther light has to travel, the more red-shifted it becomes.

 

I am curious about your question of whether Pioneer travels at the speed of light relative to something, and thus is at rest (I know this is not exactly what you state but bear with me for the sake of argument). I distinctly remember having this discussion a while ago here at Hypography (long ago, I think) where I argued that the only possible way to have something at rest would be for an object to move against the expansion of the universe at the exact rate of expansion.

 

However, that idea fails because it assumes that the expansion moves from a center (as inside a balloon) and not on a flat surface (as on the outside surface of the balloon). The latter is a representation of the 4D space-time we currently use to describe the universe and as such it is not possible to stay at rest, because the expansion works in all directions. It's like a boat on the ocean - it cannot ever be at rest because there will always be waves on the surface of the water.

[Freethinker]

Originally posted by: Tormod

Hey FT, give Blame a break. I think his questions here are valid. His hangup on red shift (yeah, I know I've commented on that, too) is a valid POV and I think it's fair to discuss his ideas.

I never said his ideas where not fair game for discussion or not a valid *personal* POV. I was merely making an observation. That he always goes back to that POV. That he brings it into his propositions regularly without ever providing proof to allow for it's acceptance.

Red shift is (as we have discussed before) a result of light travelling through expanding space-time, which stretches it and create a doppler effect. The farther light has to travel, the more red-shifted it becomes.

I do not agree. Red shift is the name given to a specific type of doppler shift. One involving photons with molecular level generated markers for specific elements and their relative measured frequency when the source and destination are moving away from each other. But doppler is valid even in relatively localized source destinations. It does not REQUIRE any significant travel thru extensive expanding time/space

 

I am not aware of ANYTHING that attributes red shift specifically to the expansion of the Universe rather than the relative velocities experienced by the expansion. i.e. not BECAUSE of expansion directly, but the RESULT of expansion causing relative motion between objects in the universe.

 

e.g. let's see if I can explain this better. Source A is generating photons with specific molecular markers at the given frequency for that type element. It is some distance from our solar system and thus is "moving away" from us based on expansion. At some distance from earth we have a stationary (relative to earth) satelite. It is capable of detecting photons and measuring for said molecular markers. We also have launched a rocket which is travelling directly towards this stationary satelite at the same speed but opposite direction as the source of the photons. Just as the rocket is parrallel to the satelite relative to the photon source (the same distance from the source) photons are detected and red shift measured.

 

Yes we would detect the expected red shift at the stationary location. But as the rocket is moving at the same relative speed as the source, there would not be any red shift detected in photons it recieved.

 

This would prove that red shift is NOT encoded into the photon at creation nor emparted into the photon's matrix during transit thru space/ time. It is EXCLUSIVELY a result of RELATIVE MOTION between source and destination. NOT a function of space/ time expansion in and of itself or of distance travelled.

I am curious about your question of whether Pioneer travels at the speed of light relative to something, and thus is at rest

Boy, and I get accused of twisting people's posts! :-)

the only possible way to have something at rest would be for an object to move against the expansion of the universe at the exact rate of expansion.

It would seem that EVERYTHING is "at rest" relative to the universe' expansion, until measured against some other location.

[BlameTheEx]

Tormod

 

First thanks for your support. Yes, I do have a hang-up with the expanding universe. And yes, it probably is expanding, but you never know. The trick to progress is that there are an awful lot of people out there with there own particular hang-ups. They each take a little bit of reality, and dig. Out of that multitude of cranks just occasionally, one strikes gold. A lot of discoveries happen that way.

 

Everything we observe CAN be viewed as supporting the expanding universe theory. Much is the result of starting with the assumption that expansion occurs, and then figuring out an explanation for the observations that fits. You can do the same with any theory. The actual evidence that supports expansion is thinner. It boils down to the red shift, background microwave radiation, and some pretty conclusive evidence that stars started forming about 14 billion years ago. Good evidence, but against that you come across some big problems. Why did the Big Bang not produce an equal quantity of ant-matter? Why didn't the original mass form a black hole?

 

I agree that there can be no universal zero velocity, however there might be a local zero velocity for each point in space. You argued as much for an expanding universe. It can also work for a non-expanding universe. If space is curved, the direction (in 4 dimensions) of local zero velocity could define that point in space. I suggested such a model on 09/09/2004 10:14am here: http://www.hypography.com/forums/messageview.cfm?catid=14&threadid=689&STARTPAGE=1&FTVAR_FORUMVIEWTMP=Linear

 

Sadly that thread died after Freethinkers tirade buried on-topic posts, as usual.

[Tormod]

Originally posted by: Freethinker

Originally posted by: Tormod

I am curious about your question of whether Pioneer travels at the speed of light relative to something, and thus is at rest

 

Boy, and I get accused of twisting people's posts! :-)

 

Huh? Wasn't that the essence of the final part of Blame's post? What am I twisting?

 

It would seem that EVERYTHING is "at rest" relative to the universe' expansion, until measured against some other location.

 

And? My point is that nothing *is* at rest. It might appear to be for all it's worth, but that is not what I was saying.

[Freethinker]

Originally posted by: BlameTheEx

Sadly that thread died after Freethinkers tirade buried on-topic posts, as usual.

OK. let's get one thing straight, You started that thread to keep from having to answer questions you were asked on an earlier thread. Your first post even set up a series of conditions (as if you are in a position to do so) you intended to use against me and my trying to get you to stand up to those earlier claims. Both Tormod and Unc called you on the carpet for it.

Originally posted by: Tormod

I was about to reply but got put off by your final list of points

...

Since the list of points is directed at FreeThinker you are violating our FAQ.

 

There. I brought your discussion off topic. See, the entire essence of your post is an attack at one of my moderators and I do not tolerate that.

Originally posted by: Uncle Martin

C'mon Blame'.....

Answer his question and be done with it. Then we can continue to read what you have in mind.

And now you want to do the same here? If you answered questions asked of you there would not be these issues.

 

Don't blame ME for YOUR dragging this battle into this thread. I had done nothing here for you to start this line of attack.

[Tormod]

Okay, let's not make this thread go off topic, too. I want to discuss this local-rest-issue but am struggling to find any scientific evidence to back it up.

[Freethinker]

Originally posted by: Tormod

I am curious about your question of whether Pioneer travels at the speed of light relative to something, and thus is at rest (I know this is not exactly what you state but bear with me for the sake of argument). I distinctly remember having this discussion a while ago here at Hypography (long ago, I think) where I argued that the only possible way to have something at rest would be for an object to move against the expansion of the universe at the exact rate of expansion.

 

However, that idea fails because it assumes that the expansion moves from a center (as inside a balloon) and not on a flat surface (as on the outside surface of the balloon). The latter is a representation of the 4D space-time we currently use to describe the universe and as such it is not possible to stay at rest, because the expansion works in all directions. It's like a boat on the ocean - it cannot ever be at rest because there will always be waves on the surface of the water.

I don't buy the boat analogy. Not enough similarity for it to be valid.

 

And the rest goes back to something I have questioned many times before. The concept of a static location in space based on GR space/time. But this is not even important related to an individual mass and it's location in an expanding space/time.

 

I am not sure of what you meant with "move against the expansion of the universe". Did you actually mean "move (WITH) the expansion of the universe"? I am not sure how you could move AGAINST it. As you say, it is not like the universe is moving "away" from a center point. Does direction even make sense in discussing the universe' expansion? Can a single point be said to be moving in a specific direction? And this is what it seems to come down to. Actually perhaps two questions.

 

1) is there such a thing as a singular point in the universe?

 

2) if there is, does it move in and of itself or only in relation to another point?

 

To make things even more complicated, what if we look at the rtelationship between 3 points. Let's say we arbitrarily pick one (A) as the fixed POR with no motion other than that imparted by the expansion of the universe. And point C is also fixed in space/time, has no motion other than that imparted by the expansion of the universe. Thus we would assert that the two points have a relative (to each other) velocity based on expansion of the universe. Yet each is in and of themselves, stationary.

 

Now the 3rd point, B, is locked at a given distance from A, on the line segment A-C, with no angular momentum relative to C (and thus none to A either). B would seem to be the only one considered to be "moving" in and of itself. That by NOT moving AWAY from A, B is in motion, against the expansion of the universe (EofU). And that while A and C are not moving relative to the EofU, they have no momentum of their own, they are moving away from each other. Yet B, which is NOT moving relative to A is the only one that IS "moving", has momentum of it's own.

 

Er.... did I say that right?

[Freethinker]

Originally posted by: Tormod

Okay, let's not make this thread go off topic, too.

Nor do I, but I did not appreciate the arbitrary inclusion of the comment. Hopefully not a continuing issue.

I want to discuss this local-rest-issue but am struggling to find any scientific evidence to back it up.

I have tried to find info RE my problem with space travel from the stand point of what happens to a specific point in "space" after the lapse of some given period of "time". If we were able to "freeze time" locally, would "space" move away from it? e.g. in time travel movies, some machine travels in time, but keeps it's physical location on earth. But with GR it would seem that any ability to provide control over local time, would also have an inherent locational change in space.

 

And I am curious about your reaction to the red shift issue. Whether you agree that red shift is NOT imparted by a photon's travel thru expanding space because we would not see a red shift no matter how far thru an expanding universe it travelled if the destination had the same relative velocity as the source. That red shift is exclusively a phenom of relative velocity between the source and destination.

[Tormod]

Originally posted by: Freethinker

And I am curious about your reaction to the red shift issue. Whether you agree that red shift is NOT imparted by a photon's travel thru expanding space because we would not see a red shift no matter how far thru an expanding universe it travelled if the destination had the same relative velocity as the source. That red shift is exclusively a phenom of relative velocity between the source and destination.

 

Ok, this one first: I think that the red-shift is caused by stretching time-space. This can be interpreted as seeing a doppler effect, too. Because as the universe expands, objects move (or are pushed, depending on the cosmological model) which causes a doppler effect. As light travels through expanding space-time over vast distances, there is a stretching of the light waves which makes it more red. So the doppler effect and the cosmic expansion are both causes for red-shift.

 

I'm a bit confused by the term "relative velocity". If two objects are far enough apart, light moving between them would be red-shifted due to spacetime expansion no matter how they moved relative to each other.

 

Here is one article which supports this view:

 

What Causes the Hubble Redshift?

http://math.ucr.edu/home/baez/physics/Relativity/GR/hubble.html

[Tormod]

Originally posted by: Freethinker

Originally posted by: Tormod

It's like a boat on the ocean - it cannot ever be at rest because there will always be waves on the surface of the water.

 

I don't buy the boat analogy. Not enough similarity for it to be valid.

 

That's fine. I use it for simplicity. The boat analogy uses a 2D surface with 3D ripples to explain a 4D problem.

 

I am not sure of what you meant with "move against the expansion of the universe". Did you actually mean "move (WITH) the expansion of the universe"? I am not sure how you could move AGAINST it.

 

Like I said, I had used the "move against the expansion" analogy and saw myself that it would fail because of the reasons I provided above. Since space is not moving away from a center point but expands in all directions there is no way to move against the expansion. It is a misconception which I admitted to having used a long time ago.

 

1) is there such a thing as a singular point in the universe?

 

My immediate response is, "yes". I don't see this as an issue. It would depend on the semantic definition of what a "point" is, of course, and I'm sure that it is possible to argue that in higher dimensions no point is where we think it is etc, but frankly I imagine that points can be defined as fields.

 

2) if there is, does it move in and of itself or only in relation to another point?

 

Nothing moves of itself according to Newton and Einstein. It needs to be affected by some force, like magnetism, gravity, pressure, etc. But since I've already claimed that "nothing can be at rest in the universe" I think that even an object/particle which appears to be at rest is still in motion relative to something. It can possibly be at rest relative to something, too. Like when IBM used those incredible microscopes to write "IBM" with single atoms (or some similar experiment) - it would be impossible if the atoms in question did not stay put. A far fetched example, perhaps...

 

(shortened) That by NOT moving AWAY from A, B is in motion, against the expansion of the universe (EofU).

 

Pardon my ignorance but I think we just agreed that it is impossible to move against the expansion of the universe. I think the same logic implies that it is impossible to be at rest relative to the expansion. So your example does not make sense to me.

[Freethinker]

Originally posted by: Tormod

Ok, this one first: I think that the red-shift is caused by stretching time-space. This can be interpreted as seeing a doppler effect, too. Because as the universe expands, objects move (or are pushed, depending on the cosmological model) which causes a doppler effect. As light travels through expanding space-time over vast distances, there is a stretching of the light waves which makes it more red. So the doppler effect and the cosmic expansion are both causes for red-shift.

I think you are missing the point. The assertion I am refuting is that somehow the photon itself contains in it's information matrix, red shift. That if a particular photon is evaluated independant of relative velocties of the source/ destination, a red shift would still be found. That some photons emitted by a particular element a some specific location would have markers at one freq while others would have markers are another which is red shifted. The red shifted freq of the marker is encoded into the photon's information matrix. Not just the known standard, non-shifted marker's freq.

 

This as opposed to every photon generated by a specific element no matter where it is located in the universe would have the same markers at the same freqs. And that any red shift detected woould be the results of the source and destination moving away from each other.

 

Yes I agree that expansion of the universe causes the red shift. The expansion of the universe creates a relative velocity difference between the source and the destination. The two are moving apart and thus a photon from one point as the source would have it's wave stretched due to the relative movement of the source from the destination. But this red shift is NOT encoded into the photon. The photon's information matrix refelcts the established markers freq, not a red shifted value.

I'm a bit confused by the term "relative velocity". If two objects are far enough apart, light moving between them would be red-shifted due to spacetime expansion no matter how they moved relative to each other.

OK. Let's say because of the distance of the source away from the destination the relative velocity of the movement of the two away from each other is 100 km/sec. Again we have a stationary (relative to it's space/time expansion) photon/ red shift detector which when it recieves a photon from the source, shows an appropriate red shift. as caused by the relative speed at which the two are moving away from each other.

 

However from some distance further away from the source, in a straight path with the "line of sight" from source to destination, another photon/ red shift detector is flying towards the source also at 100 km/sec.

 

When this flying detector is at a point the same distance from the source to the stationary detector a photons from the source hits both detectors.

 

The marker freq measured at the stationary detector would reflect the red shift as would be expected because of the increasing distance between, the relative velocity of, the source and destination.

 

However, the flying detector and the source are NOT moving away from each other. They are moving in the same direction at the same speed, just a distance away from each other. The photons hitting the flying detector would have been emitted by the source at the same time as those hitting the stationary detector. They would have travelled across the same space/time for the same length of time. But since there is no difference in relative velocity between the source and the flying detector, there would not be a red shift in the marker freq.

Here is one article which supports this view:

 

What Causes the Hubble Redshift?

 

And it agrees in theory with what I am saying.

 

"What Causes the Hubble Redshift? Are the Light-Waves "Stretched" as the Universe Expands, or is the Light D

[BlameTheEx]

Tormod

 

Assuming that the universe is expanding, according to the "surface of a 4 dimensional balloon" model, it is difficult to escape the concept of local zero velocity.

 

Clearly velocities of matter in general ARE ordered. The position of any particular galaxy (with a few exceptions) can be roughly defined by its direction and velocity. That includes ours. We can prove that we are more or less at rest by measuring the microwave background radiation, that is assumed to be left over from the BB. It is remarkably even in all directions. There is no detectable red shift from one side of the sky to the other so we are close to our local zero velocity, at least in relativistic terms. Whether or not a particular piece of space can be defined by its "Zero Velocity" clearly mass/energy in the universe gives it one.

 

There is good argument that if the contents of the universe defines local "Zero Velocity" then so does space itself. Ether the universe is expanding, and dragging its contents with it, or the other way round. In some way one is telling the other where to go.

 

I may add that similar arguments hold for a non-expanding universe. In that case the red shift would be caused by something more akin to gravity than velocity. Time dilation without motion. Still, gravitational potential is equivalent to velocity, and this would lead to a need for an equivalent to "Zero velocity".