Map reveals strange cosmos.

There are two ways to image the CMB radiation: As two circles or combined as an ellipse. M Tagmark in 2003 used the circle appoarch in the BBC article.
In order to show the CMB radiation as a rotating sphere I wrote a small program in Visual Basic. To get a copy select:
http://users.telenet.be/nicvroom/M.%...-%20Cosmos.htm
The .exe file is almost at the end of the url.

My current activity is to calculate the Power Spectrum only by using the data (Temperature fluctuations) of this image. The range shown is between -100 micro Kelvin and 100 micro Kelvin.

Nicolaas Vroom

Le 02/02/13 23:26, Nicolaas Vroom a écrit :
M Tagmark in 2003 used the circle appoarch in the BBC article.

Any reference a bit more specific than that?

Thanks

In article , Nicolaas Vroom
writes:

There are two ways to image the CMB radiation: As two circles or
combined as an ellipse. M Tagmark in 2003 used the circle appoarch in
the BBC article.

It might not be clear to all readers: I think what you are discussing
are different projections. The "two circles" would be views of a sphere
from opposite sides (where, of course, we are outside the sphere while
we are inside the sphere of the CMB---in this case, it is like a
celestial globe with stars) while "combined in an ellipse" would be a
projection which shows the whole sky in one image, such as also exist
for maps of the Earth. Of course, there are other projections, but
these two are the only common ones in discussing the CMB (and the
ellipse is much more common).

My current activity is to calculate the Power Spectrum only by using the
data (Temperature fluctuations) of this image. The range shown is
between -100 micro Kelvin and 100 micro Kelvin.

Is this just an exercise in order to understand how it is done or do you
hope to do something new?

On Sat, 02 Feb, Nicolaas Vroom wrote:
In order to show the CMB radiation as a rotating sphere I wrote a small program in Visual Basic.

I had a look and it is pretty, but rotating spheres do not
traditionally present the same lateral motion on the limb as at the
centre.

On 2/3/2013 10:19 AM, Phillip Helbig---undress to reply wrote:
In article , Nicolaas Vroom
writes:

There are two ways to image the CMB radiation: As two circles or
combined as an ellipse. M Tagmark in 2003 used the circle appoarch in
the BBC article.

It might not be clear to all readers: I think what you are discussing
are different projections. The "two circles" would be views of a sphere
from opposite sides (where, of course, we are outside the sphere while
we are inside the sphere of the CMB---in this case, it is like a
celestial globe with stars) while "combined in an ellipse" would be a
projection which shows the whole sky in one image, such as also exist
for maps of the Earth. Of course, there are other projections, but
these two are the only common ones in discussing the CMB (and the
ellipse is much more common).

But if it comes to programming a visualization, then
the sphere with control by mouse (or by giving Euler
angles or something similar) would probably be a good
choice. In the example here, however, control is missing.

My current activity is to calculate the Power Spectrum only by using the
data (Temperature fluctuations) of this image. The range shown is
between -100 micro Kelvin and 100 micro Kelvin.

Is this just an exercise in order to understand how it is done or do you
hope to do something new?

And, for others who might want to play with it, is
there a link to the raw data? (The ASCII file with
the numbers that give rise to these images?)

--
Jos

Op zondag 3 februari 2013 10:19:35 UTC+1 schreef Phillip Helbig-het volgende:
In article , Nicolaas Vroom

writes:

My current activity is to calculate the Power Spectrum only by using the
data (Temperature fluctuations) of this image. The range shown is
between -100 micro Kelvin and 100 micro Kelvin.

Is this just an exercise in order to understand how it is done or do you
hope to do something new?

It is mainly an exercise to understand and the best way is IMO to do it yourself.

Please go to the document:
http://www.ualberta.ca/~pogosyan/tea...lecture31.html
And goto the section: "Why are the Boomerang and WMAP Data Important"
Near the left image is written:
"If the universe is closed, light rays from opposite sides of a hot spot
bend toward each other and as a result the hot spot appears to us to be
larger than it actually is."
IMO the following sentence should be added:
" and the cold spots appears to us SMALLER than it actually is "
Question: Why this preference of hot spots while what we are are discusing
here are photon intensities.

This whole issue is tricky because bending towards hotspots for a closed universe implies bending away for coldspots. Does this mean that the universe can be both closed and open?

The deeper issue is: How is image "a" calculated. Does image a, b and c represent the same section of the Universe.

Nicolaas Vroom

In article , Nicolaas Vroom
writes:

"If the universe is closed, light rays from opposite sides of a hot spot
bend toward each other and as a result the hot spot appears to us to be
larger than it actually is."
IMO the following sentence should be added:
" and the cold spots appears to us SMALLER than it actually is "

No. The hot spot is simply some observable feature. One could just as
well consider a cold spot. This is not unique to the CMB; it applies to
all angular-size distances in cosmology.

Question: Why this preference of hot spots while what we are are discusing
here are photon intensities.

The map of the CMB is a map of temperature.

This whole issue is tricky because bending towards hotspots for a
closed universe implies bending away for coldspots.

No, it doesn't.

Op zondag 3 februari 2013 20:07:55 UTC+1 schreef Jos Bergervoet het volgende:
On 2/3/2013 10:19 AM, Phillip Helbig---undress to reply wrote:
In article , Nicolaas Vroom
writes:

But if it comes to programming a visualization, then
the sphere with control by mouse (or by giving Euler
angles or something similar) would probably be a good
choice. In the example here, however, control is missing.

Be my guest. But I do not think this is of much scientific value.

My current activity is to calculate the Power Spectrum only by using
the data (Temperature fluctuations) of this image. The range shown
is between -100 micro Kelvin and 100 micro Kelvin.

The range is from -200mK to 200 mK.
In reality the coldest (delta) temperatures are lower than -200 mK
and the highest (delta) temperatures are higher than 200 mK

What is worthwhile is to calculate the Power Spectrum from
the surface of the Sun and from the surface of our Earth.

And, for others who might want to play with it, is
there a link to the raw data? (The ASCII file with
the numbers that give rise to these images?)

For raw data goto: http://map.gsfc.nasa.gov/media/121238/index.html
Each value is a combination of 4 parameters:
alpha (=255), red, green and blue.
However for some reason NASA used tricky colors.
When you go to: http://space.mit.edu/home/tegmark/saskmap.html
they use for the color scheme from -100 mK to 100 mK the following scheme:
Red --- X 0 0 0 X X
Green - 0 0 X X X 0
Blue -- X X X 0 0 0

X stands for the value 255.
The colors are from left to right: magenta, blue, cyan, green, yellow, and red.
In between magenta and blue there are 254 colors:
(255,0,255) next (254,0,255) next (253,0,255) finally (1,0,255) and (0,0,255)
In between all blue and cyan there are also 254 colors etc.
This scheme is simple and allows you to calculate the Temperature
in a straight forward manner.

The Nasa scheme is much more complicated:
The scheme is from -200 mK to 200 mK .
The color code starting with the coldest is:
(33,6 98) (32,7,96) (32,9,95) (32,9,91) (32,10,86) (32,11,77) (32,12,75) (27,20,65) etc
Maybe there are more intermediate values used.
The color code ending with the higest temperature is:
(243,52,17) (241,43,16) (236,34,17) (227,25,18) and (213,19,19)
When you consider the value green: The lowest value is 6, slowly
increases to 255 and than decreases back to 19.
It is more complicated to calculate the temperature using this scheme (?)
IMO what NASA should have done is to use the following scheme:
Red --- 0 X 0 0 0 X X X
Green - 0 0 0 X X X 0 X
Blue -- 0 X X X 0 0 0 X
0,0,0 stands for black and X,X,X stands for white with X = 255.

Nicolaas Vroom

In article , Nicolaas Vroom
writes:

What is worthwhile is to calculate the Power Spectrum from
the surface of the Sun and from the surface of our Earth.

Can you explain why? Consider also that the data were taken while the
satellite revolved (with the Earth) around the Sun.

Op maandag 4 februari 2013 08:39:56 UTC+1 schreef Phillip Helbig---undress to reply het volgende:
In article , Nicolaas Vroom

writes:

"If the universe is closed, light rays from opposite sides of a hot spot
bend toward each other and as a result the hot spot appears to us to be
larger than it actually is."
IMO the following sentence should be added:
" and the cold spots appears to us SMALLER than it actually is "

No. The hot spot is simply some observable feature. One could just as
well consider a cold spot. This is not unique to the CMB; it applies to
all angular-size distances in cosmology.

This whole issue is discussed in more detail he
http://users.telenet.be/nicvroom/M.%...s.htm#hotspots

Question: Why this preference of hot spots while what we are are discusing
here are photon intensities.

The map of the CMB is a map of temperature.
Maybe it is a matter of both.
When you study the following you can see that the "equator" consists
of 4096 pixels. The question is what is measured.
I do not know the details but I expect that the number of photons
for each pixel is counted for a fixed time period. However that is not
enough you have to do that for each pixel for different frequencies
or wavelengths. The (raw) value for each pixel is than set
with the frequency with the highest count.
However I expect that that is not the end.
I expect that a certain smoothing is taken into account. That means
that the final frequency is calculated based on a couple of surrounding
pixels.
Based on the final frequency you can calculate a color and the temperature
for each picture.

Nicolaas Vroom