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| Sandcastle... |
 Posted: Tue Oct 13, 2009 8:48 am |
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Guest
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I like to think outside the box, proving again that a little knowledge
is a dangerous thing. But I would love someone to run the numbers and
show that this thought has no merit.
Current thinking:
1. The universe is expanding
2. The rate of expansion was decreasing, but has been increasing since
about 5 Billion years ago
How do we know it is expanding? The primary source of this knowledge is
a combination of stars as standard candles and red shift. We use the
standard candle stars to estimate the stars distance.We use the red
shift to determine how fast a star is moving away from us. Careful
analysis of these two factors not only tell us the rate of expansion,
but since it takes a long time for the light to get to us, the data from
distant stars tells us how fast it was expanding in the past.
But, to date, we have assumed the red shift was due entirely to the
Doppler shift . the same effect as the decrease in tone of a train
whistle as it passes us. But there is another mechanism that can cause a
red shift.
Back in 1923, Arthur Compton ran an experiment where he fired X-rays at
a piece of carbon and looked at the scattered radiation. He found that
radiation was red shifted. The amount of red shift increased with the
scattering angle.
This experiment provides a compelling argument for the existence of the
photon. It is believed that some of the momentum of the photon is given
up to the electrons that the photon collides with. It has been shown
experimentally that the red shift is proportional to the amount of
energy that would be transferred in such an elastic collision.
The universe is very big. There is a lot of material between those
distant stars and us. It is highly unlikely that any light from those
far distant stars do not experience a number of grazing collisions.
Light from further stars will experience a larger number of collisions.
I am proposing that some portion of the red shift is due to these
collisions. The rate of expansion needs to be adjusted to account for
this effect.
If the effect is significant, the number of super nova and other
powerful events may be increasing the density of free particles and
could, conceivably, make us think that the rate of expansion is
increasing. If the effect is great enough, we might be able to drop the
idea of dark energy.
It is doubtful that the effect is great enough to threaten the Big Bang
theory itself. But I believe the effect should be looked at and may
cause us to adjust our time scale numbers for the formation of the
universe.
Gary Derman |
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| Phillip Helbig---remove CLOTHES to reply... |
| Posted: Tue Oct 13, 2009 10:59 am |
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In article <har5gp$47k$1 at (no spam) adenine.netfront.net>, "Sandcastle"
<gary at (no spam) vipilot.com> writes:
[quote:f4e9a89b0c]I like to think outside the box, proving again that a little knowledge
is a dangerous thing. But I would love someone to run the numbers and
show that this thought has no merit.
Current thinking:
1. The universe is expanding
2. The rate of expansion was decreasing, but has been increasing since
about 5 Billion years ago
[/quote:f4e9a89b0c]
OK.
[quote:f4e9a89b0c]How do we know it is expanding? The primary source of this knowledge is
a combination of stars as standard candles and red shift. We use the
standard candle stars to estimate the stars distance.We use the red
shift to determine how fast a star is moving away from us. Careful
analysis of these two factors not only tell us the rate of expansion,
but since it takes a long time for the light to get to us, the data from
distant stars tells us how fast it was expanding in the past.
[/quote:f4e9a89b0c]
More or less.
[quote:f4e9a89b0c]But, to date, we have assumed the red shift was due entirely to the
Doppler shift .
[/quote:f4e9a89b0c]
Yes, with the proviso that you need to be clear, in cosmology, what you
mean by "Doppler shift". Replace it with "cosmological redshift" and
there is no confusion.
[quote:f4e9a89b0c]Back in 1923, Arthur Compton ran an experiment where he fired X-rays at
a piece of carbon and looked at the scattered radiation. He found that
radiation was red shifted. The amount of red shift increased with the
scattering angle.
The universe is very big. There is a lot of material between those
distant stars and us. It is highly unlikely that any light from those
far distant stars do not experience a number of grazing collisions.
Light from further stars will experience a larger number of collisions.
I am proposing that some portion of the red shift is due to these
collisions. The rate of expansion needs to be adjusted to account for
this effect.
[/quote:f4e9a89b0c]
Others have thought of similar mechanisms. Your mechanism needs to give
a redshift which is independent of wavelength. Does it? Also, is the
amount of scattering required consistent with the lack of blurring of
distant objects? |
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| Jonathan Thornburg [remove -animal to reply]... |
| Posted: Tue Oct 13, 2009 10:59 am |
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Guest
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Sandcastle <gary at (no spam) vipilot.com> wrote:
[quote:c6d5d133cd]The universe is very big. There is a lot of material between those
distant stars and us. It is highly unlikely that any light from those
far distant stars do not experience a number of grazing collisions.
Light from further stars will experience a larger number of collisions.
I am proposing that some portion of the red shift is due to these
collisions.
[/quote:c6d5d133cd]
If Compton scattering were significant for photons which we observe
from distant objects, then we'd expect those collisions to also change
the direction-of-travel of those photons (Compton in fact derived a
precise equation connecting the changes in photon direction-of-travel
and photon energy), so we'd see such distant objects to all be a bit
blurred.
But what (for example) the Hubble Space Telescope actually sees is
that images of distant galaxies look just as sharp as images of nearby
galaxies. So do radio VLBI images. So, this blurring must be very
small.
Your mission, should you choose to accept it, is to come up with a
QUANTITATIVE theory in which Compton scattering can simultaneously
(a) remove over 80% of photons' energies (for redshifts > 5), AND
(b) remove exactly the same fraction of the energy even for photons
with very different initial energies (so that the measured
wavelengths of different spectral lines stay in the correct
proportions, i.e., so that the calculated "redshift" doesn't
vary significantly from one spectral line to another within
the same object), AND
(c) not introduce any photon momentum in the direction transverse to
the line-of-sight which is more than 0.000001 times the original
line-of-sight momentum (approximate constraint from sharpness of
Hubble Space Telescope images), or even 0.000000001 times the
original line-of-sight momentum (approximate constraint from
sharpness of radio VLBI images).
--
-- "Jonathan Thornburg [remove -animal to reply]" <jthorn at (no spam) astro.indiana-zebra.edu>
Dept of Astronomy, Indiana University, Bloomington, Indiana, USA
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam |
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| Lester Welch... |
| Posted: Tue Oct 13, 2009 11:21 pm |
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On Oct 13, 2:48 pm, "Sandcastle" <g... at (no spam) vipilot.com> wrote:
The amount of red shift increased with the
[quote:52d2451286]scattering angle.
Is it not true that if a particular photon from afar is scattered its[/quote:52d2451286]
trajectory will not remain colinear with the others and thus will not
be "seen" by the observer?
Is it not true that the electrons in otherwise "empty" space have a
spectrum of energies, and thus any Compton scattering (an inelastic
process) would result in a spectrum of light instead of the sharp
(albeit red-shifted) lines seen? |
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| Sandcastle... |
| Posted: Tue Oct 13, 2009 11:37 pm |
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Guest
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Thank you for your thoughtful response. Here is my thinking on your three
main points:
===== replace with "cosmological redshift" =====
Actually, to be complete I should include relativistic Doppler, cosmological
red shift, and gravitational redshift. They generally exclude scattering and
optical effects.
===== independent of wavelength. Does it? =====
That is hard to say until someone runs the numbers. The red shift at
different scattering angles will be different, but most of the scattered
light never makes it to us.
Scattering does disperse the image. Gravitational lensing is usually looked
at as having to deal with huge masses such as black holes, galaxies, and
even clusters of galaxies. However, gravitational lensing will also apply to
very small particles when at close distances.
It should be noted that scattering changes light trajectory away from
particles while also decreasing frequency. The slight gravity associated
with the particle will change light trajectory back toward the original
path. There may very will be a balance point where there is an ever so
slight redshift while the scattered particle resumes close to it's original
path. That balance point, if it exists through such a long distance with so
many grazing collisions might very will produce a redshift which would be a
function of distance and particle density.
I do not, currently, have sufficient mathematical expertise to properly run
the numbers to determine where the balance point exists or if it is
significant. But it is not outside of our current knowledge and should be
calculated before we dismiss it. At that balance point, the combined effects
would allow us to generate a specular image.
My guess is that there is very small angular range of scatter that balances
the lensing correction. Since the red shift only depends on the angle of
scatter, not the color, my guess is that we will find it applies to all
colors. Until we run the numbers, we do not really know.
===== lack of blurring of distant object =====
I think that is covered in the above section.
Gary
"Phillip Helbig---remove CLOTHES to reply" <helbig at (no spam) astro.multiCLOTHESvax.de>
wrote in message news:hb2i8m$2qg$1 at (no spam) online.de...
[quote:b44ed27e3b]In article <har5gp$47k$1 at (no spam) adenine.netfront.net>, "Sandcastle"
gary at (no spam) vipilot.com> writes:
I like to think outside the box, proving again that a little knowledge
is a dangerous thing. But I would love someone to run the numbers and
show that this thought has no merit.
Current thinking:
1. The universe is expanding
2. The rate of expansion was decreasing, but has been increasing since
about 5 Billion years ago
OK.
How do we know it is expanding? The primary source of this knowledge is
a combination of stars as standard candles and red shift. We use the
standard candle stars to estimate the stars distance.We use the red
shift to determine how fast a star is moving away from us. Careful
analysis of these two factors not only tell us the rate of expansion,
but since it takes a long time for the light to get to us, the data from
distant stars tells us how fast it was expanding in the past.
More or less.
But, to date, we have assumed the red shift was due entirely to the
Doppler shift .
Yes, with the proviso that you need to be clear, in cosmology, what you
mean by "Doppler shift". Replace it with "cosmological redshift" and
there is no confusion.
Back in 1923, Arthur Compton ran an experiment where he fired X-rays at
a piece of carbon and looked at the scattered radiation. He found that
radiation was red shifted. The amount of red shift increased with the
scattering angle.
The universe is very big. There is a lot of material between those
distant stars and us. It is highly unlikely that any light from those
far distant stars do not experience a number of grazing collisions.
Light from further stars will experience a larger number of collisions.
I am proposing that some portion of the red shift is due to these
collisions. The rate of expansion needs to be adjusted to account for
this effect.
Others have thought of similar mechanisms. Your mechanism needs to give
a redshift which is independent of wavelength. Does it? Also, is the
amount of scattering required consistent with the lack of blurring of
distant objects?
[/quote:b44ed27e3b] |
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| Lester Welch... |
| Posted: Wed Oct 14, 2009 8:07 am |
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Guest
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On Oct 14, 5:37 am, "Sandcastle" <g... at (no spam) vipilot.com> wrote:
[quote:f62bfb2291]However, gravitational lensing will also apply to
very small particles when at close distances.
[/quote:f62bfb2291]
When the bending of light by gravitation was first investigated
experimentally, the planet of Jupiter was used as the source of
gravity - did the apparent position of the stars change as their light
grazed Jupiter? The result was "not detectably." Jupiter was not near
massive enough to see any effect - hence the use of the sun during an
eclipse. A small particle has no possibility of bending the light
sufficient to compensate for the Compton scattering angle.
To clarify an earlier remark - many (most?) electrons in space are a
part of a atom and thus the Compton scattering must "lose" energy to
overcome the binding energy of the electron, thus the collision is
inelastic. |
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| Sandcastle... |
| Posted: Wed Oct 14, 2009 8:47 am |
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Guest
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Hi Jonathan,
Your comments are much appreciated.
Your first paragraph is answered in my post in response to Phillip Helbig.
Thank you for the mission statement. Unfortunately I have to add to it.
(d) show that there is enough matter between the source and us to assure
that most photons will engage in a statistically significant number of
collisions before they reach us. This is probably the show stopper. If there
is enough matter, our brightness is significantly reduced and current
distance calculation due to brightness are probably in error. If there
isn't, then the best we can hope for is a dim sub-spectrum due to this
effect.
The calculation for the balance point between the scattering angle and the
microscopic-lensing (as differentiated from micro-lensing) will only provide
a specular image for photons scattered by a very small angle range as is
needed to meet your item (c). The remainder are lost (another possible
problem).
If there is enough matter, your item (a) is not a problem since the redshift
is cumulative. If I understand the Compton effect correctly, the red shift
(change in wavelength) is a function of geometry (see
http://en.wikipedia.org/wiki/Compton_scattering ), not initial energy. So
your item (b) should not be a problem. The microscopic-lensing which brings
the photon back on track is a warp in space-time and is independent of
frequency.
Note that the Compton scattering assumes the mass of an electron. This is
likely to be different for Dark Matter.
Gary
"Jonathan Thornburg [remove -animal to reply]"
<jthorn at (no spam) astro.indiana-zebra.edu> wrote in message
news:alpine.BSO.1.10.0910131610590.5600 at (no spam) nitrogen.astro.indiana.edu...
[quote:15fafa105e]Sandcastle <gary at (no spam) vipilot.com> wrote:
The universe is very big. There is a lot of material between those
distant stars and us. It is highly unlikely that any light from those
far distant stars do not experience a number of grazing collisions.
Light from further stars will experience a larger number of collisions.
I am proposing that some portion of the red shift is due to these
collisions.
If Compton scattering were significant for photons which we observe
from distant objects, then we'd expect those collisions to also change
the direction-of-travel of those photons (Compton in fact derived a
precise equation connecting the changes in photon direction-of-travel
and photon energy), so we'd see such distant objects to all be a bit
blurred.
But what (for example) the Hubble Space Telescope actually sees is
that images of distant galaxies look just as sharp as images of nearby
galaxies. So do radio VLBI images. So, this blurring must be very
small.
Your mission, should you choose to accept it, is to come up with a
QUANTITATIVE theory in which Compton scattering can simultaneously
(a) remove over 80% of photons' energies (for redshifts > 5), AND
(b) remove exactly the same fraction of the energy even for photons
with very different initial energies (so that the measured
wavelengths of different spectral lines stay in the correct
proportions, i.e., so that the calculated "redshift" doesn't
vary significantly from one spectral line to another within
the same object), AND
(c) not introduce any photon momentum in the direction transverse to
the line-of-sight which is more than 0.000001 times the original
line-of-sight momentum (approximate constraint from sharpness of
Hubble Space Telescope images), or even 0.000000001 times the
original line-of-sight momentum (approximate constraint from
sharpness of radio VLBI images).
--
-- "Jonathan Thornburg [remove -animal to reply]"
jthorn at (no spam) astro.indiana-zebra.edu
Dept of Astronomy, Indiana University, Bloomington, Indiana, USA
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam
[/quote:15fafa105e] |
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