APOD: Microwave Milky Way (2010 Jul 09)

[APOD Robot]

Microwave Milky Way

Explanation: Seen from our edge-on perspective, the Milky Way Galaxy sprawls across the middle of this false-color, all sky view. The expansive microwave map is based on 1 year's worth of data from instruments onboard the sky-surveying Planck spacecraft. Remarkably, the bright stripe of gas and dust clouds along the galactic plane and the galaxy's enormous arcing structures seen at microwave energies are hundreds or thousands of light-years away, while the mottled regions at the top and bottom represent the Cosmic Microwave Background (CMB) radiation, some 13.7 billion light-years distant. Left over from the Big Bang, fluctuations in the CMB reflect the origins of structure in the evolving universe. Analyzing the microwave data, Planck scientists plan to separate the contributions of the Milky Way and CMB radiation. The work will ferret out the characteristics of the CMB across the entire sky and glean information about the make up of our Milky Way Galaxy.

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[owlice]

I suppose it's too late for me to add this image to a "Bystander's Finds" poll, isn't it?

[neufer]

Microwave Milky Way

---------------------------------

<<Planck is a space observatory designed to observe the anisotropies of the cosmic microwave background (CMB) over the entire sky, using high sensitivity and angular resolution. Planck was launched into orbit in 2009, reaching the Earth/Sun's L2 Lagrangian point in July, and had successfully completed a second all-sky survey by February 2010. The mission will complement and improve upon observations made by the NASA Wilkinson Microwave Anisotropy Probe, which has measured the anisotropies at larger angular scales and lower sensitivity than Planck.>>

Low Frequency Instrument (LFI) 30–70 GHz receivers
High Frequency Instrument (HFI) 100–857 GHz receivers

[The cosmic microwave background radiation corresponds to
a temperature of 2.725 K with an emission peak at 160.2 GHz.]

---------------------------------

<<The WMAP observes in five frequencies (23–91 GHz), permitting the measurement and subtraction of foreground contamination (from the Milky Way and extra-galactic sources) of the CMB. The main emission mechanisms are synchrotron radiation and free-free emission (dominating the lower frequencies), and astrophysical dust emissions (dominating the higher frequencies). The spectral properties of these emissions contribute different amounts to the five frequencies, thus permitting their identification and subtraction.

Foreground contamination is removed in several ways. First, subtract extant emission maps from the WMAP's measurements; second, use the components' known, spectral values to identify them; third, simultaneously fit the position and spectra data of the foreground emission, using extra data sets. Foreground contamination also is reduced by using only the full-sky map portions with the least foreground contamination, whilst masking the remaining map portions.

23 GHZ:


41 GHZ:


91 GHZ:


The five-year models of foreground emission, at different frequencies.
Red = Synchrotron; Green = free-free; Blue = thermal dust.

---------------------------------

[Guest]

so much time in so little space

[orin stepanek]

False color: but it is quite pretty!

[nybiomedtutor@gmail.com]

Is it possible to 3D the microwave image?

[moonstruck]

What Neufer said

[León]

For Popper the growth of science is in terms of conjectures and refutations. Moreover, a condition that is considered a scientific theory is that its content is refutable.The success of science is measured by its ability to expose and repudiate the doctrines misleading inconsistent theories

That said, I feel rushed considering the origin of the Cosmic Microwave Background (CMB) radiation, which as seen is not uniform.

It's time to find a simpler explanation to the phenomenon, the analysis of causes stripping fantasy.

Scientists want to study this grainy signature across the entire sky, which means seeing through the "fog" of our Milky Way. The Planck teams are busy now removing this foreground fog, a meticulous process akin to identifying and removing all the hay in a haystack to reveal the needle within. The process will take about two more years, with the first processed data being released to the scientific community toward the end of 2012.

http://www.chromoscope.net/?w=m

[neufer]

Click to view full size image

Click to view full size image

[owlice]

This is one of my favorite APODs ever, simply for the sheer beauty and excitement of it; it's just a piece of the image neufer posted above but deserves to be seen in all its glory!

Click to view full size image

APOD: The Nearby Milky Way in Cold Dust (2010 Mar 22)
ESA: Planck sees tapestry of cold dust

[neufer]

This is one of my favorite APODs ever, simply for the sheer beauty and excitement of it;
it's just a piece of the image neufer posted above but deserves to be seen in all its glory!

Click to view full size image

The Seahorse of the Large Magellanic Cloud

http://asterisk.apod.com/vie ... 77#p102577

[NoelC]

False color: but it is quite pretty!

Uh oh, you realize that begs the question of what is a TRUE color microwave image... One you could cook with?

-Noel

[Chris Peterson]

False color: but it is quite pretty! 8-)

Uh oh, you realize that begs the question of what is a TRUE color microwave image... One you could cook with? :D

Well, you could try putting your head in a microwave oven, and maybe that would stimulate a color response. <g>

It's kind of like those recordings you hear of bat or dolphin sonar, where they mathematically lower the frequency so we can use our ears to get some sense of what these animals are hearing. Is that "false sound"? Is it somehow unsatisfying, or intellectually dishonest? I don't think so. But I do get the sense that some people (none in this discussion!) have that concern with false color scientific images- even in cases like this where there is no alternative.

[jman]

Many recent discussions have surrounded the human sense of "sight" and the physiological perception of "colour". Because our eyesight is so imporant we put a very heavy emphasis on it's value. What if for a moment - we consider the eye just another sensor (stimulus-response), something akin to smell or taste or sound. In all reality, it's possible that sight is no less subjective than the sense of sound or taste or smell, and trying to describe what we "see" could be just as subjective (and futile) as trying to describe a smell. Look at how many words we have to describe the range of colours we can perceive - and compare this to the spectrum of sounds we can hear. There's really no difference technically.

[Chris Peterson]

Many recent discussions have surrounded the human sense of "sight" and the physiological perception of "colour". Because our eyesight is so imporant we put a very heavy emphasis on it's value. What if for a moment - we consider the eye just another sensor (stimulus-response), something akin to smell or taste or sound. In all reality, it's possible that sight is no less subjective than the sense of sound or taste or smell, and trying to describe what we "see" could be just as subjective (and futile) as trying to describe a smell. Look at how many words we have to describe the range of colours we can perceive - and compare this to the spectrum of sounds we can hear. There's really no difference technically.

I think our sense of sight is somewhat different from our other senses. It is the only one where we can accurately map our perception into a form easily shared with others. To a lesser extent that is possible with sound, and it is almost impossible with the other senses.

Yes, we've discussed in great technical detail subtleties of vision, but it is important to remember that these things really are subtle. In reality, we talk about color and brightness and shape and texture all the time with very little ambiguity. This is much more difficult when trying to express in words the impression of other senses.

[orin stepanek]

False color: but it is quite pretty!

Uh oh, you realize that begs the question of what is a TRUE color microwave image... One you could cook with?

Well, you could try putting your head in a microwave oven, and maybe that would stimulate a color response. <g>

It's kind of like those recordings you hear of bat or dolphin sonar, where they mathematically lower the frequency so we can use our ears to get some sense of what these animals are hearing. Is that "false sound"? Is it somehow unsatisfying, or intellectually dishonest? I don't think so. But I do get the sense that some people (none in this discussion!) have that concern with false color scientific images- even in cases like this where there is no alternative.

I don't recommend putting your head in one; So I'll tell you; mine is black. I don't recall seeing any colors inside when it is running though. Actually I don't have any trouble with color enhancement on these pictures. How drab APOD would be if all the Photos were black and white and grey. So keep splashing the color; I love it.
I've heard that dogs don't have any sense of color; and that's sad if that's true. My dog sure gets excited when she sees a blue uniform though. Just ask my mail man.

[DavidLeodis]

What a fascinating 'image'. It's like a painting but a bit spooky.

I wonder if other Universes ever heard the Big Bang of ours? It would have been an amazing sight if they saw it! My mind is wandering so apologies if my thoughts are considered ridiculous (it's the inner child in me that thinks of such things! )

[Henning Makholm]

Is it somehow unsatisfying, or intellectually dishonest? I don't think so. But I do get the sense that some people (none in this discussion!) have that concern with false color scientific images- even in cases like this where there is no alternative.

I don't think intellectual dishonesty enters the picture. But it does raise an interesting question of whether what we admire in the picture is a product of inherent natural beauty, or rather the artistic skill somebody applied in selecting a pleasing color representation for his data set.

[geckzilla]

I think a lot of people feel betrayed to the point of animosity when they realize that space doesn't actually look like any of the cool photos on APOD most of the time. And by that I mean as seen with the naked eye. I can remember feeling that way a little but I learned fairly young and got over it quickly. It's just nice to have this fantasy vision of how it would be to fly around in a space ship through glowing nebulas and reality robs one of that fantasy unless you just completely ignore the facts. It's very enlightening to realize how limited human vision really is, though. I guess not everyone sees it that way.

[neufer]

I think a lot of people feel betrayed to the point of animosity when they realize that space doesn't actually look like any of the cool photos on APOD most of the time. And by that I mean as seen with the naked eye. I can remember feeling that way a little but I learned fairly young and got over it quickly. It's just nice to have this fantasy vision of how it would be to fly around in a space ship through glowing nebulas and reality robs one of that fantasy unless you just completely ignore the facts. It's very enlightening to realize how limited human vision really is, though. I guess not everyone sees it that way.

Simple solution: Send instruments into space NOT people!

• ________ Scientific American JUNE 1960
  
  "Putting a man in space is a stunt: the man can do no more
  than an instrument, in fact can do less." So said Vannevar Bush,
  chairman of the Board of Governors of the Massachusetts Institute of
  Technology, in a statement to the House Committee on Science and
  Astronautics. "ŒThere are far more serious things to do than to indulge
  in stunts. As yet the American people do not understand the
  distinctions, and we in this country are prone to rush, for a time, at
  any new thing. I do not discard completely the value of demonstrating
  to the world our skills. Nor do I undervalue the effect on morale of
  the spectacular. But the present hullabaloo on the propaganda aspects
  of the program leaves me entirely cool."

P.S., You need 2 more posts to get into the 1,000 post club, Judy;
Owlice needs 6 more... but she could beat you

• -------------------------------
  ____ Up in the Air (2009)
  
  Natalie Keener (Anna Kendrick): So, what are you saving up for? Hawaii? South of France?
  
  Ryan Bingham (George Clooney): It's not like that. The miles are the goal.
  
  Natalie Keener: That's it? You're saving just to save?
  
  Ryan Bingham: Let's just say that I have a number in mind and I haven't hit it yet.
  
  Natalie Keener: That's a little abstract. What's the target?
  
  Ryan Bingham: I'd rather not...
  
  Natalie Keener: Is it a secret target?
  
  Ryan Bingham: It's ten million miles.
  
  Natalie Keener: Okay. Isn't ten million just a number?
  
  Ryan Bingham: Pi's just a number.
  
  Natalie Keener: Well, we all need a hobby.
  ____ No, I- I- I don't mean to belittle your collection. I get it. It sounds cool.
  
  Ryan Bingham: I'd be the seventh person to do it. More people have walked on the moon.
  
  Natalie Keener: Do they throw you a parade?
  
  Ryan Bingham: You get lifetime executive status. You get to meet the chief pilot, Maynard Finch.
  
  Natalie Keener: Wow.
  
  Ryan Bingham: And they put your name on the side of a plane.
  
  Natalie Keener: Men get such hardons from putting their names on things.
  ____ You guys don't grow up. It's like you need to pee on everything.
  -------------------------------

[Chuck Drinnan]

I have what is probably a simple question. Why is this image elliptical? What do the individual images look like that are mosaicked into this combined image?
Thanks
http://asterisk.apod.com/pos ... 9a9d00199d#

[Chris Peterson]

I have what is probably a simple question. Why is this image elliptical? What do the individual images look like that are mosaicked into this combined image?

The image shape is a consequence of the mapping used to display the celestial sphere on a flat screen. This is just like many mappings (e.g. Mercator) used to display the spherical Earth on a flat page. I don't think the image is actually a mosaic at all. The WMAP instrument basically looks at just one point of the sky. It is scanned to build up data covering the entire sky at a time. The raw dataset is probably just a big array of values associated with celestial coordinates. That data could be plotted many different ways- this is just one example.

[bystander]

The WMAP instrument basically looks at just one point of the sky.

Yes, and obviously, Planck does the same.

[neufer]

I have what is probably a simple question. Why is this image elliptical?
What do the individual images look like that are mosaicked into this combined image?

The image shape is a consequence of the mapping used to display the celestial sphere on a flat screen. This is just like many mappings (e.g. Mercator) used to display the spherical Earth on a flat page. I don't think the image is actually a mosaic at all. The WMAP instrument basically looks at just one point of the sky. It is scanned to build up data covering the entire sky at a time. The raw dataset is probably just a big array of values associated with celestial coordinates. That data could be plotted many different ways- this is just one example.

The Mollweide is a pseudocylindrical projection in which the equator is represented as a straight horizontal line perpendicular to a central meridian one-half its length. The other parallels compress near the poles, while the other meridians are equally spaced at the equator. The meridians at 90 degrees east and west form a perfect circle, and the whole earth is depicted in a proportional 2:1 ellipse. The proportion of the area of the ellipse between any given parallel and the equator is the same as the proportion of the area on the globe between that parallel and the equator, but at the expense of shape distortion, which is significant at the corners.

A Mollweide projection of the Earth

Click to view full size image

Also known as the Babinet projection, homolographic projection, or elliptical projection. As its more explicit name Mollweide equal area projection indicates, it sacrifices fidelity to angle and shape in favor of accurate depiction of area. It is used primarily where accurate representation of area takes precedence over shape, for instance small maps depicting global distributions.

• moll : minor (German)
  weide: meadow (German)

The projection was first published by mathematician and astronomer Karl Brandan Mollweide (1774 – 1825) of Leipzig in 1805 as an improvement upon the Mercator projection. It was popularized by Jacques Babinet in 1857, giving it the name homalographic projection.

[ronw12]

Actually, the Microwave Background Radiation is NOT 13.7 billion light years distant. The radiation was captured by the Planck telescope. That means it is here. The radiation originated 13.7 billion years ago, but it can't be 13.7 billion years distant. We wouldn't be able to see it. This is kind of like saying when you take an image of the Andromeda Galaxy, M31, the light is 2.2 million light years distant. The galaxy is 2.2 million light years distant, but the light has to be in your telescope and in the CCD camera in order to see it.