what if (on colliding galaxies)

"Greg Neill" wrote in message...
m...
Painius wrote:
"Greg Neill" wrote...
in message m...

. . .
The redshift values give us the radial velocities. It's
comparison of the radial velocities for different distances
that give us the acceleration.

Why is this seen as an acceleration? E.g., a galaxy seen
at, say, 8 billion light years away has a higher redshift
than a galaxy that's 4 billion light years away. So the
farther galaxy 8 billion years ago was going faster than
the closer galaxy 4 billion years ago. If galaxies were
going slower 4 billion years ago than they were 8 billion
years ago, wouldn't this indicate that things are slowing
down?

The analysis is complicated slightly by the light transit
time. It has to be disentangled from the scenario in order
see the result.

It might help to see it in the following way. In another
four billion years the galaxy that we currently see as
4 billion light years distant will have moved further
away from us. Without acceleration we would suppose that
it would add a distance of 4 billion years multiplied by
the velocity obtained by the measured redshift value.
Instead what we find is that it will have moved an additional
distance above and beyond what it would be if it were to
keep a constant recession pace. Thus an acceleration is
ocurring. . . .

It is found that in 4 billion years the galaxy will have
moved an additional distance above and beyond what
it would be if it were to keep a constant recession pace.
And you say that you find this result by "disentangling"
the light-transit time from the scenario? If i read this
correctly, you are deducing this from the redshift
magnitudes that you measure for the galaxies that are
8 billion light years away? That these redshift values
are higher than would be expected if these galaxies
had kept a constant recession pace? From a time when
these galaxies were 4 billion light years away 4 billion
years ago?

So you deduce from this that the galaxies that appear
to be 4 billion light years away to us *now* are actually
more than 8 billion light years away, and those galaxies
that *presently* appear to us to be 8 billion light years
away are in reality more than 16 billion light years away?

So the galaxies that appear to be 4 billion light years
away are traveling at an accelerated pace that would
average out to be over 1 billion light years per billion
years, or 1 light year per year or about 6 trillion miles
per year... or over c? So space is not only expanding
faster than light velocity, but is actually accelerating
well beyond light velocity?

First, i really don't follow how cosmologists can just,
with a sweep of the mathematician's pencil, ignore the
"disentangled" light-transit time. Because it seems to
me that the light-transit time is a very real and crucial
factor in this. How do you know that by disentangling
the light-transit time from the scenario that you aren't
introducing an unconscionable amount of error?

Secondly, it seems to me that when you *allow* the
light-transit time back into the scenario, you have to
deal with the fact that galaxies that can be seen near
to us in the past are going slower than galaxies that
we can see from farther back in the past. The farther
the galaxy appears to us, the farther back in time we
are looking, and the faster is the galaxy's velocity.
And the nearer to us in the past the galaxy appears to
us, the later in time we are looking, the closer to us
in time we are seeing, and the slower is the galaxy's
velocity.

Can you see how this is very, very difficult for people
who are not scientists to understand?

And it is especially frustrating that everytime i have
seen this seeming paradox brought up, scientists say
something about "relativistic effects" and disappear.
Very frustrating.

happy days and...
starry starry nights!

--
Indelibly yours,
Paine Ellsworth

P.S.: Thank *YOU* for reading!

P.P.S.: http://yummycake.secretsgolden.com

"G=EMC^2 Glazier" wrote...
in message ...

Painius I get very flustered when I read light has slowed down or
accelerated. bert

I know the feeling, Bert. On one hand you read
that nothing can exceed light speed, "c". And you
might somehow get the idea that light itself will
always travel at "c". Then you read that light can
and does sometimes go slower depending upon
the medium it is going through, that "c" is only the
*maximum* speed of light.

Then maybe you read about how one of the first
and best tests for relativity theory was the bending
of a star's light as it traveled past the Sun during a
full eclipse. And you know that anything, including
light, that travels a curved path is "accelerated".
Maybe you read a little more and find that when a
scientist says "accelerated", this could mean either
a speeding up *or* a slowing down. So what did
the star's light do? It couldn't have sped up. It was
already going "c", as fast as it could go. So, did it
slow down? Was it a "negative" acceleration? (Or
what i would call a "deceleration"?)

Apparently neither. The star's light is treated as a
"velocity", which means that it can be represented
by a vector. And a vector has both magnitude (or
"speed" in this case) and *direction*. So when the
light from the star is bent as it passes the Sun, it
goes in a different direction. And when the direction
changes, even if the speed stays constant, then the
light ray is "accelerated".

So light can be accelerated even if it doesn't change
speed, even if all that changes is the direction it is
going. Such things can be very flustering.

Then, on top of everything else, you read that space
is expanding at an accelerated rate of speed. And
that space's expansion rate does not have to stick to
the "nothing can exceed the speed of light" rule. It
(space) can expand at speeds well beyond the speed
of light. More sources to fluster a person.

And it's sometimes very hard to understand how so
many cosmologists can appear to remain unflustered
by all this.

Maybe it's like the holy man who, by day, preaches
devoutly to glassy-eyed followers from a holy book
written long ago, and then by night he sits alone in
his room knowing somewhere deep down inside that
he doesn't really have a clue that he's right about all
that. I guess some people will believe just about
anything if it is told to them by someone they trust.

Belief is an important feeling, but is it ever enough?
Evidence is a very important basis for belief, but this
can also not be enough if the evidence is subject to
interpretation, possibly false interpretation. It always
makes me secretly wonder if truth -- i mean real and
factual and TRUE truth -- is ever possible to attain in
the more flustering science disciplines.

/rant g

happy days and...
starry starry nights!

--
Indelibly yours,
Paine Ellsworth

P.S.: Thank *YOU* for reading!

P.P.S.: http://yummycake.secretsgolden.com

"G=EMC^2 Glazier" wrote...
in message ...

Painius How many stars would it take clustered in one area of space to
be given the term galaxy. If they had no BH core would the term galaxy
fit? If all the stars were white dwarfs would galaxy fit? Can a galaxy
be a galaxy if it only had 150 thousand stars? What if our solar system
only had one object rotating around the Sun(like say Mercury) We could
not call that a solar system. Terminology Hmmmmm bert

Here ya go, Bert...

http://en.wikipedia.org/wiki/Galaxy

The low-end number of stars appears to be now set at
10 million. Any number of stars less than that would not
be considered a galaxy. You'll see at this next link...

http://en.wikipedia.org/wiki/Local_group

....that there are some clusters of stars that used to be
classified as galaxies that have been reclassified as
globular clusters.

It's believed that many galaxies, "perhaps most or all"
galaxies have BH cores. But maybe not. A BH core is
not a necessity for a cluster to be called a galaxy.

And i suppose if we came across a white-dwarf cluster
that contained at least 10 million white dwarfs, then it
would be classified as a galaxy.

If a cluster had only 150 thousand stars, it would be a
cluster and not called a galaxy.

"Solar system", while sometimes used with other star
systems, is technically supposed to apply just to our
system of star, planets and other objects in orbit
around the Sun. It comes from "Sol", the name our
Sun is sometimes called. Other systems are called
"stellar systems" or "star systems". Even if it's just
a binary system, it could still be called a stellar/star
system. Or even a "solar system" nowadays. As long
as there are two or more objects of any kind, the
relationship can be called a "system" of some sort.
Like the "binary planet" system of Earth and Selene,
for example. g

happy days and...
starry starry nights!

--
Indelibly yours,
Paine Ellsworth

P.S.: Thank *YOU* for reading!

P.P.S.: http://yummycake.secretsgolden.com

"BradGuth" wrote in message...
...
On Sep 8, 8:02 am, "Painius" wrote:
"Saul Levy" wrote in message...
...
On Sun, 07 Sep 2008 18:32:43 GMT, "Painius"
wrote:

When i say "rogue", i'm just talking about the galaxies
that are out on their own and not satellites of the bigger
galaxies...

http://www.atlasoftheuniverse.com/localgr.html

In that picture, there are some rogues in the upper left.
Sextans A and B, NGC 3109, and so on.

That's a misleading term then, Paine! lmao!

Galaxies are NOT rogues.

Not according to my lexicon, Saul. When used as an
adjective describing a noun, the term "rogue" means...

"Operating outside normal or desirable controls."

As i said, these are small galaxies that, while bound
gravitationally to the Local Group, are not satellites
of any of the large spiral galaxies. They can be seen
as galaxies that operate outside normal controls...

"r o g u e g a l a x i e s"

You're speaking to a certified Zionist/Nazi rabbi of the denial and
evidence excluding kind. Why bother?

~ BG

You probably won't like this answer, but for me and
for all those who i am privileged to be read by, "the
Sun shines down on us all".

happy days and...
starry starry nights!

--
Indelibly yours,
Paine Ellsworth

P.S.: Thank *YOU* for reading!

P.P.S.: http://yummycake.secretsgolden.com

"Saul Levy" wrote in message...
...
On Mon, 08 Sep 2008 15:02:29 GMT, "Painius"
wrote:

Not according to my lexicon, Saul. When used as an
adjective describing a noun, the term "rogue" means...

"Operating outside normal or desirable controls."

As i said, these are small galaxies that, while bound
gravitationally to the Local Group, are not satellites
of any of the large spiral galaxies. They can be seen
as galaxies that operate outside normal controls...

"r o g u e g a l a x i e s"

How about in astronomy, Paine?

I've never heard that term used for galaxies.

I think i remember it being used by astronomers who
theorize that gravity will eventually take over and lead
to a contracting Universe and a "big crunch". The term
was used to describe a galaxy that would "appear" at
the farthest distance as red shifts cease and blue shifts
begin.

As for my usage, i probably heard this used somewhere
as it relates to non-satellite galaxies in the Local Group.
Or maybe i made it up. I honestly don't know.

I get more than a couple thousand hits on Google for

"rogue galaxy" astronomy

but even many of those refer to the PlayStation game.

You're *such* a rogue. g

happy days and...
starry starry nights!

--
Indelibly yours,
Paine Ellsworth

P.S.: Thank *YOU* for reading!

P.P.S.: http://yummycake.secretsgolden.com

Painius wrote:
"Greg Neill" wrote in message...
m...
Painius wrote:
"Greg Neill" wrote...
in message m...

. . .
The redshift values give us the radial velocities. It's
comparison of the radial velocities for different distances
that give us the acceleration.

Why is this seen as an acceleration? E.g., a galaxy seen
at, say, 8 billion light years away has a higher redshift
than a galaxy that's 4 billion light years away. So the
farther galaxy 8 billion years ago was going faster than
the closer galaxy 4 billion years ago. If galaxies were
going slower 4 billion years ago than they were 8 billion
years ago, wouldn't this indicate that things are slowing
down?

The analysis is complicated slightly by the light transit
time. It has to be disentangled from the scenario in order
see the result.

It might help to see it in the following way. In another
four billion years the galaxy that we currently see as
4 billion light years distant will have moved further
away from us. Without acceleration we would suppose that
it would add a distance of 4 billion years multiplied by
the velocity obtained by the measured redshift value.
Instead what we find is that it will have moved an additional
distance above and beyond what it would be if it were to
keep a constant recession pace. Thus an acceleration is
ocurring. . . .

It is found that in 4 billion years the galaxy will have
moved an additional distance above and beyond what
it would be if it were to keep a constant recession pace.
And you say that you find this result by "disentangling"
the light-transit time from the scenario? If i read this
correctly, you are deducing this from the redshift
magnitudes that you measure for the galaxies that are
8 billion light years away? That these redshift values
are higher than would be expected if these galaxies
had kept a constant recession pace? From a time when
these galaxies were 4 billion light years away 4 billion
years ago?

Accounting for the light transit times removes a layer of
complication, but it's not the whole story (as you point
out). In order to come to the conclusion that space is
not only expanding but accelerating in that expansion,
we need to have a model of space and some measurements
to fit to that model. What we can measure are distances
and (radial) velocities, and in certain circumstances,
the ages of things.

If your model of space is a simple expansion with a fixed
Hubble constant, you expect things at a given distance to
have a given redshift in accord with that model. If the
expansion rate changes over time, then things are more tricky
because what we "see" is the result of the accumulation of
any changes that occurred up to the instant in time that
the light from a given object was emitted, plus whatever
happened to all the regions of space that the light travelled
through during its transit to us. The light from things
further away have less pre-emission history and more post-
emission history, if you follow.


So you deduce from this that the galaxies that appear
to be 4 billion light years away to us *now* are actually
more than 8 billion light years away, and those galaxies
that *presently* appear to us to be 8 billion light years
away are in reality more than 16 billion light years away?

Not quite. If you go strictly by the currently observed
distance we use our model to tell us how long ago the
light was emitted. Given that space has been expanding
while the light travelled to us, we can project backwards
to tell us what the distance actually was when the light
was emitted. During that same interval of time that the
light was travelling to us, the object has continued to
move away, too. So "now", it should be much further away
than what we directly perceive. How much further away it
is depends upon the Hubble "constant" and whether it really
is constant over time and distance.


So the galaxies that appear to be 4 billion light years
away are traveling at an accelerated pace that would
average out to be over 1 billion light years per billion
years, or 1 light year per year or about 6 trillion miles
per year... or over c? So space is not only expanding
faster than light velocity, but is actually accelerating
well beyond light velocity?

The specific figures for expansion rate depend upon the
model. But it is true that for *any* given positive
expansion there must be a distance at which the recession
velocity will equal the speed of light, and beyond that
it will exceed the speed of light.

What that means for us as observers is that there is a
cosmic horizon beyond which we cannot see. Light from
the events taking place at the horizon is redshifted to
nil energy, and light from beyond it can never reach us;
we are effectively cut off from the rest of the universe
that lies outside that horizon.


First, i really don't follow how cosmologists can just,
with a sweep of the mathematician's pencil, ignore the
"disentangled" light-transit time. Because it seems to
me that the light-transit time is a very real and crucial
factor in this. How do you know that by disentangling
the light-transit time from the scenario that you aren't
introducing an unconscionable amount of error?

One has to rely on the model, which must meet the burden
of agreeing with the current physics (Equations of
General Relativity for permissible shape and evolution
of space) and empirical observation.

Cosmology is attempting to discover and refine a model that
meets these burdens. It is an ongoing process, and I don't
think the game is over. It's not like the Science taught in
highschool where the results are hard and fast and based
upon a very well supported, "tried and true" model (Newtonian
Mechanics). This is the ragged edge of physics where not
everything is settled.


Secondly, it seems to me that when you *allow* the
light-transit time back into the scenario, you have to
deal with the fact that galaxies that can be seen near
to us in the past are going slower than galaxies that
we can see from farther back in the past. The farther
the galaxy appears to us, the farther back in time we
are looking, and the faster is the galaxy's velocity.
And the nearer to us in the past the galaxy appears to
us, the later in time we are looking, the closer to us
in time we are seeing, and the slower is the galaxy's
velocity.

Can you see how this is very, very difficult for people
who are not scientists to understand?

Yes. We mere humans are used to dealing with a local
environment where "now" is the same for all of it and
lightspeed appears to be infinite. Our working mental
model of the world does not include light transit time
effects for what we see around us.


And it is especially frustrating that everytime i have
seen this seeming paradox brought up, scientists say
something about "relativistic effects" and disappear.
Very frustrating.

Things do get complicated very quickly when you are dealing
with things on the scale of the Universe, since you need to
turn immediately to solutions of the equations of General
Relativity to formulate your models. Without plowing right
into the mathematics, all you can do is pick and choose and
describe some of the observed effects.

Saul I knew about the Doppler shifts before you were born. Know how
Hubble used this information to show the universe was
expanding.(spectral lines toward the red end of the spectrum) . Hubble
showed the more distant the galaxy was from us the greater the red shift
thus the faster it was moving away from us. Reality is this fit well
with Einstein predictions in his theory of general relativity. You see
Saul I know how all stuff works,and can incorporate this knowledge in
how the universe works This makes the mysteries of the universe easier
for me to figure out. I have a theory on every thing,and all are based
on good science thinking bert

That would be your brain and your insanity, BradBoi! lmfjao!

It runs your life!

Saul Levy


On Mon, 8 Sep 2008 18:55:47 -0700 (PDT), BradGuth
wrote:

It's all about word games, on behalf of whatever keeps us snookered
and dumbfounded past the point of no return.

~ Brad Guth Brad_Guth Brad.Guth BradGuth

On Sep 8, 11:06*pm, "Painius" wrote:
"G=EMC^2 Glazier" wrote...

Painius *I get very flustered when I read light has slowed down or
accelerated. *bert

I know the feeling, Bert. *On one hand you read
that nothing can exceed light speed, "c". *And you
might somehow get the idea that light itself will
always travel at "c". *Then you read that light can
and does sometimes go slower depending upon
the medium it is going through, that "c" is only the
*maximum* speed of light.

Then maybe you read about how one of the first
and best tests for relativity theory was the bending
of a star's light as it traveled past the Sun during a
full eclipse. *And you know that anything, including
light, that travels a curved path is "accelerated".
Maybe you read a little more and find that when a
scientist says "accelerated", this could mean either
a speeding up *or* a slowing down. *So what did
the star's light do? It couldn't have sped up. It was
already going "c", as fast as it could go. *So, did it
slow down? *Was it a "negative" acceleration? *(Or
what i would call a "deceleration"?)

Apparently neither. *

Well sure it slowed down. This is precisely what sets General
Relativity apart from Special Relativity.. or rather what *expands
upon* SR and its mandate of universal c-invariance. Traversing a
gravity well, a ray of star light deflects twice as much as it
'should' under the Newtonian model of gravity and the prediction of
SR. Why is this so? Obviously it spent more time in traversing the
gravity well than it 'should'. To wit, it slowed down. Then sped up
again upon exiting the gravity well. This prompted Einstein's seminal
statement:

"According to the (radically new) General Theory of Relativity, the
law of the constancy of the velocity of light in vacuo, which
constitutes one of the two fundamental assumptions in the Special
Theory of Relativity.. cannot claim unlimited validity. A curvature of
rays of light can only take place when the *velocity of propagation*
varies with position (in traversing a gravity well)."

With that observation, SR and lightspeed-invariance became a wholly
owned subsidiary of GR. GR became the natural extension/expansion of
SR. But it only *described* the observation. It did not _explain_ it.

The next extension/expansion of Relativity itself is to _explain the
mechanism_ of why lightspeed varies as it does.

And that mechanism is the changing density (or PDT value) of the very
real spatial medium itself. The deeper you descend in a gravity well,
the less dense the spatial medium becomes, hence the slower
propagation speed of light therein.

Conversely, looking back closer and closer toward the Big Bang
("playing the tape backwards"), the more dense the spatial medium
becomes, and the higher the speed of light therein. This is the
*cosmological density gradient* and what Wolter called 'c-dilation'.
But the speed of light is always constant *locally* at any point
across the gradient. The constancy of the speed of light is never
violated *locally*, the Lorentz invariance is never violated, nor is
any other constant for that matter. The prime variable is the density
(PDT value) of the spatial medium itself climbing exponentially back
toward the BB. And as you pointed out previously, space itself
contracts concomitantly with the climbing PDT value.

Then, on top of everything else, you read that space
is expanding at an accelerated rate of speed. *

That's the grand illusion of the Void-Space Paradigm which deems space
a universally-isotropic 'Nothing' all the way back to the BB, having
no concept of the cosmological density gradient.

And it's sometimes very hard to understand how so
many cosmologists can appear to remain unflustered
by all this.

Maybe it's like the holy man who, by day, preaches
devoutly to glassy-eyed followers from a holy book
written long ago, and then by night he sits alone in
his room knowing somewhere deep down inside that
he doesn't really have a clue that he's right about all
that. *I guess some people will believe just about
anything if it is told to them by someone they trust.

Belief is an important feeling, but is it ever enough?
Evidence is a very important basis for belief, but this
can also not be enough if the evidence is subject to
interpretation, possibly false interpretation. It always
makes me secretly wonder if truth -- i mean real and
factual and TRUE truth -- is ever possible to attain in
the more flustering science disciplines.

One simple adjustment to the sitting paradigm is all it would take to
set it straight -- replace the 'void' of space with the Plenum of
space, recognizing it for what it demonstrates itself to be - the
dynamic, highly mobile Fluid that's compressible/expansible and
amenable to density (PDT) gradients.
And recognize its property of 'hyperfluidity', that
being itself inertia-less and frictionless, confers upon matter the
properties of of inertia and momentum.. which is directly responsible
for gravity-acceleration equivalence, the key to the mechanism of
gravity itself : gravity is the effect upon matter of
**accelerating**, flowing space.

Painius My theory is light can never slow down,but can go a greater
distance. Its crazy even to talk a photon is pushed back or gets
friction to make it go slower. Or visa versa Slowed by a
medium begs this question When it leaves this medium what energy is
used to bring it back up to light speed? That can not be answered
because like I just said It has to answer crazy talk. Light takes
200,000 years to go from core of Sun to its surface. The theory on this
is a good one,and at no time does this theory ever mention the photons
slowing down,and that is why its a good theory. Best to make the
distance a photon has to travel than ever think about it changing speed.
bert