Moving at light speed

[Buffy]

Now if this were to be true and the fact that we are moving against this background radiation (the background radiation would not 'bounce' off the external event horizon now would it. The external EH would sending out it's own electromagnetic waves as the gravitation of the black holes, planets and stars have been found to do). The external EH would need to be stationary as would the EH at the centre of the universe. Now here we have movement against the radiation. The universe would no longer be expanding as such but moving away from the centre.

Well, that's definitely an interesting theory! A kinda natural, intergalactic Dyson Sphere! Unfortunately, the Hubble Limit has a very natural definition, and it is a limit that is defined from the point of view of the observer with the colloquial definition of "past that point its just too far for the photons to go to ever reach us." But as I said we can see things happening in other places in the universe that have Hubble Limits that go far beyond our own and they don't behave differently, so there's no evidence that our "sphere of visibility" is special in any way. (and see my previous post on the anisotropy you noted).

The galaxies themselves would not, as I have already stated, be experiencing the effects of such movement because space would be moving with it (not against it). The galaxy itself would appear to be not moving at all due to everything moving with it. Remember SR if you are moving at the speed of light then all other bodies moving relative to you will appear to be stationary.

To clarify, its that they are "not moving within their local frame of reference": everything has to be tied to the reference frame or its really meaningless, because...there's no absolute reference or center of the unverse...

I was upset when we began this discussion because I felt that what you were saying didn't conclusively proved me wrong. I however feel that my universe model could exist with all the necessary observations that your universe does (relative to each observer).

Well, keep at it, you may yet prove us wrong, but you've got several thousand man years of theory to overturn...

Another point is I'm not really male, I chose the name Damien because I have found that people take you more seriously when they think you are male.

Hopefully seeing that a blonde vamp slayer who regularly sounds like a valley girl (which I actually am...well, except for the slayer part is reserved for anti-science nuts), can and does get some pretty siginificant respect on this nerds forum (and they know I am too and read that endearingly). Be yourself. If other people don't like it, that's their problem. But try to be nice to everyone you meet... Read more of Turtle's posts to get a better feel for that, as I can rant if you get me going. Good luck Josephine!

 

Cheers,

Buffy

[Damo2600]

Hi Buffy,

 

So you are not overly excited by my model.

 

I don't know why exactly you think my model wouldn't experience the exact same isomorphism as yours does (I've asked you this many times I know)? I mean your theory makes less sense to me now than when you explained it to me (I almost accepted it by the way). This is because your explanation states that the universe expanded from within a point. That means it is simultaneously expanding in every direction from every point within the universe. So think about it. That would have to mean that earth is not really moving. The space between the galaxies is expanding in all directions. If our galaxy were moving against the radiation then it would have to be going somewhere. Your model suggests that if I travel in a straight line then I will hit earth. This would be proof that the galaxy is not going anywhere. Furthermore if I travel in a straight line and the universe is expanding and I still hit earth. That means a straight line, from anywhere within the universe, is a direct route back to the same unmoveable point you started at. The only way I can see, that your model would make sense is, that if the whole universe is moving in the same direction, for e.g. I could say east. However there is nothing east of the universe. East is merely the same direction of where you are. (So how could we possibly be moving against the radiation)

 

I have a feeling that you are going to suggest to me that you would not come back to the exact same spot by travelling in a single line. However this would not fit your theory because I can direct you back to the top of the page. If the universe is expanding equally in all directions (from EVERY point within the universe) it is not therefore travelling in any one direction.

 

Consider it Buffy (edit: consider what I am saying very carefully before you respond please)

 

Josephine

[Tormod]

Thank you

Josephine

 

I see. Do you happen to be the same Josephine that was posting as liliangrn?

 

For the record: We take anyone as seriously as we can. Boys *and* girls. Any violation of THAT rule would be not taken lightly.

[ldsoftwaresteve]

I am in awe of the complexities that this thread attempts to illuminate.

 

I am also in awe of the intellectual depth and apparent visualization skills possessed by those taking part in this thread.

 

But even the smartest folks can end up in left field - and being that I have spent an inordinate amount of time in that area myself, I know all about it. And right now, were I there, you guys would be standing right next to me.

 

Sometimes ones strengths tend to dictate what kinds of things one has an affinity for. I'm sure somebody has defined this strange sort of bias and given it a name and if they haven't, they should.

 

I have no such skills. But I do recognize that I need to have things kept simple. So allow me to try and get this back to simple.

 

Buffy, you are one of my heroes. You said,

We all know that an object cannot travel at the speed of light because it would take infinite energy to do so, which does not exist in the universe. No mass can travel at the speed of light.

This only holds true if light is not a particle. If it is a particle, then assuming it has mass how could it travel at ... its own speed?

[BlameTheEx]

ldsoftwaresteve.

 

That quote from Buffy is using a valid definition of mass but to be free of ambiguity it should read:

 

"We all know that an object cannot travel at the speed of light because it would take infinite energy to do so, which does not exist in the universe. Nothing with rest mass can travel at the speed of light."

 

I would say that a photon has mass but not rest mass. However for others mass IS rest mass. They would claim that the mass like properties of photons are something else.

[Damo2600]

Are you still there Buffy?

[Buffy]

Yes, but you asked me to think about it. I must admit I'm still trying to understand what you are proposing other than what I've described above. To clarify: you are stating that the universe is shaped as a sphere, it has an "event horizon" that corresponds to the hubble limit and there is nothing beyond it or it is beyond the hubble limit. This event horizon is a hard surface and waves and particles bounce off it. It is expanding along with the rest of the universe.

 

Does it reflect waves but attract particles? It would have to if we can see the CMB but we don't see anything bouncing off of it unless you're claiming that we just can't see them yet.

 

Given that known movement within the local group of galaxies explains the CMB blue shift that you referred to, shouldn't we see some other evidence of the fact that we are not at the center of the universe (e.g. fewer galaxies on the side of us facing away from the center of the universe), or are you claiming that we are at the exact center of the universe?

 

If there is an event horizon that attracts particles, what is it made of and why does it persist post big bang? If it is the reason that the universe is accellerating its expansion, its surface area would be dissipating at the cube of the radius of the universe, and thus any gravitational pull would be dissipating as well. Also, if it is beyond the hubble limit, we know from General Relativity that gravitation propagates at the speed of light, and since it must be receding at at least that speed due to having to keep up with the expansion of the universe, its effects on objects close to the "center" of the universe would be weakening. Why do experiments show that the accelleration of the expansion of the universe is uniform for all objects within our hubble limit?

 

Cheers,

Buffy

[Damo2600]

Hi Buffy,

 

I actually asked you to consider how, if our universe is expanding in all directions i.e. there is no centre of the universe i.e. anywhere you describe is the centre of the universe, yet earth is moving in one direction.

 

My theory is mostly conjecture at this stage. How ever I think it has some merit.

 

Damien

[Buffy]

I actually asked you to consider how, if our universe is expanding in all directions i.e. there is no centre of the universe i.e. anywhere you describe is the centre of the universe, yet earth is moving in one direction.

Josephine,

All objects have a vector representing their movement. Its been shown that the universe is expanding, but with isomorphism, there is no center, everything is just moving away from whereever you are. Our vector of movement that we can measure is within our local frame of reference and various galaxies and objects move in different directions (that's why there's that blue shift in the page you referenced). For example, we are going to collide with M31 (Andromeda galaxy) in a few billion years. If everything were expanding from a center, nothing would collide with anything else! In fact however galaxies can orbit each other just as planets orbit stars.

 

So, I guess I don't understand what you're asking...

 

Cheers,

Buffy

[Damo2600]

Its been shown that the universe is expanding, but with isomorphism, there is no center, everything is just moving away from whereever you are.

 

You said it correctly here. If this is true how can Earth be moving. We are the centre of the universe then. Galaxy a, galaxy b and galaxy c are all the centre of the universe as well so they are not moving either. The space between the galaxies is expanding. In your model there is no edge to the universe. So there is nothing to compare your movement to. We are the centre of the universe therefore we are stationary. Galaxy a is the centre of the universe therefore they are stationary as well. I am the centre of the universe therefore I am not moving. You travelling in an aeroplane are the centre of the universe so you are stationary aswell. Your statement makes no sense. That is if the Earth is moving.

 

Josephine :circle:

[Buffy]

You're completely skipping over the notion of motion relative to various different frames of reference. With respect to the universe as a whole, yes, everything seems to be moving away from us, within the "Local Group" of galaxies, we are in fact moving toward Andromeda and away from several others. Within the Milky Way, we are moving in an orbital direction with respect to the center of the galaxy, within our solar system, we are orbiting the sun, on earth we are revolving around the earth's core. There's *all kinds* of motion going on. By over simplifying it you find contradiction, but the situation is complex and all factors have to be taken into account.

 

Cheers,

Buffy

[Damo2600]

You forgot one detail. The edge of the universe doesn't exist. So we are not moving relative to the universe. No edge of the universe: nothing to compare our movement to on a cosmological scale. Cosmological* we cannot be moving. Just like the ballon you explained to me. None of the dots are moving remember. If we describe Earth to be one of the dots on the ballon then cosmological* and logically there is absolutely no way we can be moving unless there is some stationary point on the balloon (the cosmological balloon), you describe, to compare it to.

 

Absolutely Buffy (think about it - seriously)

 

Josephine

 

This is a MAJOR MAJOR MAJOR detail you are forgeting here.

 

*(edit: that should be Cosmologically)

[Buffy]

I didn't mention an edge of the universe except in my earlier post #126 where I was trying to describe what I thought you were saying. Nothing in #130 mentions an edge. There is no edge according to modern cosmology. Why are you saying I'm overlooking it? It again appears that you do not understand the notion that we can indeed compare our motion to other local objects, and these show we are moving along an extremely complex moving vector is our local space with respect to our local location. At the same time we know that the universe as a whole is expanding, and if we correct for what we know about our motion within a reference frame defined by the Local Group of galaxies--which provides a "large enough scale" to be within the Cosmological Principle of "isomorphism and homogeneity on large scales"--then the blue shift in that particular picture is *exactly* cancelled out, proving the CP... The missing concept in both the threads were posting in has *everything* to do with local reference frames, and I'd suggest you investigate that concept in more detail.

 

Cheers,

Buffy

[Damo2600]

Forget it Buffy

 

I found an absurdity to your model and you can't even see it.

 

Cosmologicallly we are not moving. Cosmologically Galaxy A is not moving. So what do you do you talk about local reference frames. In *your* own theory the first two sentences in this paragraph are absolutely true and you are not willing to stick to your own theory. Full stop.

 

Damien

[Damo2600]

The Earth and moon are in orbit around each other. Which one is actually moving?

 

If I define the sun as the local reference frame then the Earth is stationary.

 

However is the Sun travelling around the Earth? If we describe the galaxy as the local reference frame then the Sun is stationary.

 

Is the Sun travelling around the centre of the galaxy? Well according to other galaxies (local reference frames) it is.

 

Is the galaxy moving away from other galaxies? This case has no reference frame. There is no edge to the universe so are they moving? Well there is nothing to compare it to.

 

So if there is nothing to compare the movement of the galaxy then on the grand scheme of things there is nothing to compare the movement we see according to the earth and the moon. If I travel in a straight line from the moon I will hit the moon. It hasn't gone anywhere you see.

 

According to one frame one event is happening and from the opposite POV something else is happening. With no Absolutes who is correct?

 

You cannot eradicate an absolute reference frame outside the universe and maintain local reference frames. We can say this distance is getting further or this distance is getting shorter.

 

But by getting rid of absolute reference frames you are simultaneous making individual reference frames absolute.

 

If I experience the universe to be revolving around me, and I am stationary, then I am absolutely correct.

 

If you are on the moon and experience the universe revolving around you then you are absolutely correct. Local reference frames no longer have any meaning whatsoever.

 

Absolutes they are a funny breed aren't they?

 

Josephine

[paultrr]

 

Is the galaxy moving away from other galaxies? This case has no reference frame. There is no edge to the universe so are they moving? Well there is nothing to compare it to.

 

 

I do not know where you get you're data, but, its well known that there is a general movement of different galatic groups and even in the local group we have our galaxy and Andromeda moving towards each other. See:

 

http://www.cita.utoronto.ca/~dubinski/tflops/

 

http://curious.astro.cornell.edu/question.php?number=96

 

Our Galaxy and the local group has a velocity that is known also. See:

 

http://hypertextbook.com/facts/1999/PatriciaKong.shtml

[Damo2600]

Yes Paul, you can measure the distances between the galaxies. But how do you know which one is moving? If the Sun, Earth and moon existed and nothing else how would you know which one was moving. If you saw the Sun and Earth and moon a million light years away from where you are on earth expanding away from you would this help?

 

If there were a billion^billion galaxies within the hubble limit would this help?

 

How can you tell which one is moving?

 

Like I said absolutes are a funny thing.

 

Josephine