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August 22, 2019

CATEGORY: Blog [back]
TOPIC: Old Light, New Tricks [refresh]
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Blogger Mark Wyman wrote on Jul. 14, 2010 @ 16:06 GMT
One of the fastest moving fields in contemporary astronomy involves getting some new tricks out of the oldest light in the Universe. The cosmic microwave background radiation, or CMB for short, is the light left over from the hot plasma that filled the Universe after the Big Bang. This glow fills all of space and encodes the state of the Universe at the early time when it was released. This information has been and is still being mined by space telescopes, the now long-in-the-tooth Wilkinson Microwave Anisotropy Probe and the newer Planck satellite. The data that we have gained from these experiments already have revolutionized our understanding of early-Universe cosmology.

In addition to teaching us about the Universe’s earliest moments, it turns out the CMB can be used for other purposes. One of these is the finding and counting up of galaxy clusters that live between our observers and the distant screen it establishes on the boundaries of the sky. As a background, the CMB acts as a backlight to every object that formed or exists in the time since its creation. These CMB photons can thus be affected by the objects through and by which they pass.

Galaxy clusters are a perfect example of this. Galaxy clusters are the largest collections of matter in the Universe -- the gathering place of dozens to hundreds of galaxies and huge amounts of hot gas. There are actually two ways that clusters affect CMB photons. The more subtle is a phenomenon known as the Integrated Sachs-Wolfe (ISW) effect. As photons pass through a galaxy cluster, they are blue shifted as the “drop” into the well of the cluster’s gravitational attraction, then red shifted as they climb out to escape. In a static or matter-dominated Universe, these shifts exactly cancel. But in our Universe, which has been accelerating in its expansion for the past few billion years, the red and blue shifts don’t cancel out, leaving a characteristic effect on photons that flow through clusters. This effect has been detected and provides striking independent evidence for the Universe’s accelerating expansion.

As nifty as the ISW effect is, the Sunyaev-Zeldovich effect may prove to be an even richer vein for observers to mine. This effect comes about from the direct interaction of the hot gas that lives in clusters with the CMB photons. Essentially, the CMB is “heated up” by interacting with the hot gas in a way that telescopes on Earth can detect. Because this effect is acting on CMB photons, it is one of very few observations that doesn’t discriminate against clusters that are very distant from us -- a cluster so distant that its stars can’t be seen directly can still be found by searching for this effect in the CMB light.

This is why the SZ effect has astronomers and cosmologists heated up themselves. For a start, clusters are extremely interesting objects on their own, but they are difficult to search for directly using either optical or X-ray methods, which are the traditional tools. In the optical, it’s a lot of work to definitively prove that a grouping of galaxies are truly bound together by gravity, since galaxies that sit next to each other on the sky can be millions of light-years apart in the direction along our line of sight. The hot gas in cluster centers is a smoking gun for clusters, but X-ray telescopes can’t easily scan the sky searching for clusters we haven’t found through other means. Hence the ability for CMB observations to catalog cluster locations could make individual cluster finding a much more straightforward process.

In addition, cosmologists have long known that the number and sizes of clusters are an independent source of information about the Universe’s laws and initial conditions. As the largest objects in the Universe, clusters probe the tail of the probability distribution for density fluctuations -- regions with so much extra stuff relative to the background are very rare events. Hence, an exhaustive catalog of these rarest events can tell us a lot about the nature of the probability distribution for cluster formation, much as super-tall NBA centers give us a notion of what nations and racial backgrounds have a genetic propensity for tallness. This, in turn, gives us a handle on what kind of physics was at play when that probability distribution was formed in the very first moments of the Universe’s existence.

Right now, two major experiments to hunt for SZ clusters are underway: the South Pole Telescope (SPT), located, surprisingly enough, at the South Pole; and the Atacama Cosmology Telescope (ACT), located in Chile’s high, dry Atacama desert, where it almost never rains, keeping the sky crystal clear for observing most of the year. Unlike the all-sky space telescopes used to look at the CMB before, these telescopes are designed for high-resolution work. This is because the primordial fluctuations in the CMB are from so early on in the Universe’s history that they have been spread out by the Universe’s expansion into large and easy to resolve shapes, even using the a small telescopes that can be carried into space. Clusters, however, are diminutive in comparison, requiring the larger collecting areas that ground-based telescopes can provide. These telescopes have already gathered and released their first data, confirming the promise of SZ observing by finding at least a few clusters that had never before been seen in any other way. However, there has also been a disappointing surprise: the telescopes have seen far fewer clusters than expected. This is still something of a mystery, but the most likely explanation is that the computer models used to calculate the size of the effect have, hitherto, inadvertently overestimated it. In any event, though, this field is expanding quickly, and will be teaching us a lot about clusters and many other things in the coming months and years.

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Anonymous wrote on Jul. 14, 2010 @ 16:44 GMT
A four dimensional space really can only be 3 dimensional. It is understood as stretched and compacted. in fact, this flattened space can be understood as subdivided in 6 dimensions, 2 dimensions, and 4 dimensions -- all at the same time -- with the average being 4.

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Lawrence B. Crowell wrote on Jul. 14, 2010 @ 23:34 GMT
I read last year an article on the history of the Sunyaev-Zeldovich effect, and the troubles Zeldovich had in promoting the idea. It was a huge problem, for the SZ effect appears at first blush to violate the laws of thermodynamics. Zeldovich was clever enough to see there might be local gravity pockets, similar to the physics of the ISW, where there is this heating up effect. Zeldovich faced formidable opposition, again in the Soviet Union which was good at making life Kafka-esque, from the Landau school of thought

This image is the first release from the Planck spacecraft. One of the hopes is to detect B-modes in the CMB. Detecting B-modes is crucial. This will tell us much about inflationary cosmology and anisotropy. Further, these B-modes are CMB detection of an analogue of the CMB that involved gravitons. Prior to the inflationary period the universe was quantum gravity dominated. The decoupling of gravitons from the other fields and its transition to classical behavior is the source of these gravity waves. These B-modes are induced by huge gravity waves that were produced in a sort of black body radiation of gravitons. The gravitons were stretched into classical gravity waves which are now stretched to nearly the length of the cosmological horizon. These should have a footprint in the CMB. It is interesting to think that the CMB is a sort of gravity wave detector, and we are now trying to detect the reading of that detector.

Cheers LC

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Eckard Blumschein wrote on Jul. 15, 2010 @ 05:05 GMT
To me, Mark Wyman's blog provides a lot of serious results. However, I am missing a clear distinction between used methods, reached results and related problems on one side and more or less speculative hypotheses like temporal and spatial finiteness of the object under study on the other side. Aren't Big Bang and accelerated expansion still hypotheses to be confirmed by means of as diverse as possible observations including CMB? Well, the FQXi community seems to predominantly include pure theorists like LC rather than leading experts of microwave measurement.

The picture of measured CMB reminds me of the difficulty to correctly interpret ground penetrating radar pictures where the indications of buried land mines to be found are superimposed by numerous artifacts.

Eckard

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Steve Dufourny wrote on Jul. 15, 2010 @ 17:11 GMT
In perpetual search of our origins, we watch and analyze our environment.

We want to know everything as impatients.

We can imagine and extrapolate, indeed, to these universal truths.

But we are young biological masses moving,evoluing in this physicality towards a harmony.Can we see all ? Can we understand all ? ....it's always this wall, or Should I say the walls around us,in us, suround us....which are so far of us.

Like this hypothetic BB, the CMB is an approximation so difficult to perceive correctly......indeed the rays are so weaks 0.3mm to 1.....we must insert the point of reference with a kind of lagrangian indeed but the center seems a problem if we insert the evolutive rotations more the increase of mass and the relations of volumes between spheres.

In my line of reasoning, the distribution of energy is correlated with the black body in an isotropic system.....if the spatial fluctuations and rotations more the different centers, that becomes very difficult,and still I forget the parameters of superimposings implying problems.

That said the distribution is like the law of Black Body, it's logic in a thermodynamical point of vue.

I insist about the real distribution of energy via the rotating spheers,quantics or cosmologics........there we can correlate for the main center, thus the main central volume, this ultim coded sphere.....now of course we must insert the correct serie of evolution around the main center,in the 2 senses, if not ....

Furthermore with age of the universe it's also possible to see the real distribution of energy , matter.The law of Hubble interpreted like a Doppler Fizeau effect with all these rotations with the age can give us the correct topology.And thus we shall know where we are and where we go....The density decreases logically towards the center thus this Hypothetical BB.

iF WE KNOW THAT? WE CAN SORT THE SYSTEM OF WAVES AND THEIR AGES .

The expansion is just a step and has its specif osillation of evolution.We can made generalities abbout this expansion.The space in dilatation is just a step of evolution and when the number is ok, the densityn and mass makes the rest towards the main center...the oscillation becomes a contraction , of course the line time constant in its locality must be respected, thus we can see where we are and how we turn around this center,also this BB.

Regards

Steve

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Lawrence B. Crowell wrote on Jul. 15, 2010 @ 19:45 GMT
Eckard,

The SZ effect is an inverse Compton scattering with photons in the CMB and KeV energy electrons. This can happen before or after the onset of the matter dominated period of the universe. So a distant galaxy may have jets and the like which interact with CMB photons and increase their energy. This will introduce local non-blackbody distributions in the microwave radiation detected.

Cheers LC

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Eckard Blumschein wrote on Jul. 15, 2010 @ 21:20 GMT
Lawrence, As a layman I would like to learn whether the path of earth around the sun has already been used like a huge phased array.

The main reason for me to distrust is the tacit denial of any possible alternative to some putative facts like creation of universe. When I was five years old and far from my relatives for health reasons in Binz at Baltic sea, a nurse told to me and many older children a poem: Stalin, you are the light of the world.

Incidentally, I appreciate your hint to the word naturalized units. I was already aware that physicists prefer c=h_bar=1. However, I considered this a sloppy disregard of the metric system SI just for convenience. Your hint caused me to search for "naturalized units". Yahoo returned almost nothing matching. Why? Our basic units meter and second are arbitrarily chosen ones like the year of Christ's birth. Shouldn't we look for a natural system of units instead of arbitrary ones? My suggestion to accept the very moment as the natural zero of time is perhaps even more uncommon. What quantity is the most basic one? Time? Or Energy? Or length? Or what else?

Eckard

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Lawrence B. Crowell replied on Jul. 15, 2010 @ 23:40 GMT
Units are fairly arbitrary, and one can reset the scaling arbitrarily. There are some cut-offs, such as the Planck units. There are also pure numbers such as the fine structure constant.

Cheers LC

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Eckard Blumschein replied on Jul. 16, 2010 @ 05:46 GMT
Isn't CMB alone a shaky ground? While it yields just one picture of reality that may of may not confirm theories the more reliably the more obviously redundant features will be found in combination with other methods, redundancy due to arbitrarily chosen units should be eliminated. One does not need Siemens because it is just the reciprocal of Ohm. One does not need Ohm because it equals Volt divided by Ampere, etc. Natural cut-offs and zeros may help to further naturalize physics. I do not see conclusive evidence for limitation of time and space in CMB.

Let me reiterate and specify my so far implicit question concerning interpretation: What causes the bright horizontal line in the middle? Is it an artifact? Don't the "poles" look red-shifted? Why? Is the distance of the blue-shifted structures available?

Eckard

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Georgina Parry replied on Jul. 19, 2010 @ 11:54 GMT
Eckard,

Energy. IMO change in spatial position. It is something natural that happens. Whether any measurement using distance and time are made.

Length and time are scales used to make comparisons. Within the space-time construct they are not fixed scales but are flexible, as there can be time dilation and length contraction. Also as Lawrence says "Units are fairly arbitrary, and one can reset the scaling arbitrarily."

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Don Limuti (zenophysics.com) wrote on Jul. 16, 2010 @ 02:17 GMT
Care should be used in interpreting the Integrated Sachs-Wolfe (ISW) effect. It may be due to the acceleration of the expanding universe as postulated OR it may be due to light traveling at slightly different speeds at different wavelengths as indicated by results from the Magic Gamma Ray Telescope.

"A very special possibility was offered by observation of a short outburst of the blazar Markarian 501. which seems to show some energy dependence of gamma arrival times" From: http://magic.mpp.mpg.de/

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Lawrence B. Crowell replied on Jul. 16, 2010 @ 03:02 GMT
The Fermi spacecraft (GLAST) discounted speed deoendency with frequency.

Cheers LC

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Don Limuti (zenophysics.com) replied on Jul. 16, 2010 @ 06:28 GMT
Lawrence,

That is true. But the Magic gamma ray people are standing by their results, for now.

The future will tell.

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Lawrence B. Crowell replied on Jul. 16, 2010 @ 13:25 GMT
I suspect something is wrong here. The system is also based on the ground, which makes me ponder whether there is some media effect due to the atmosphere. The universe makes less sense if there is a frequency dependency with the speed of light. In fact you could parametrically amplify photons in a way which permits a temporal communication of information.

Cheers LC

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Jason Mark Wolfe wrote on Jul. 18, 2010 @ 19:37 GMT
Lawrence,

Would there have been time ordered ambiguities withing the jet stream that was belched forth out of the super-massive black hole at the center of Messier 87? The jet stream was clocked at 4 to 6 times the speed of light. If this is somehow a trick if light or of angles, then why don't we see this sporadically for low energy cosmological events, as well.

When a super-massive black hole spits out of jet stream that is 5000 light years long, when it appears to violate the laws of physics, a reasonable person has to suspect that stability conditions for the laws of physics have been exceeded.

What ever time order of events you are talking about, there is a super-massive black hole out there that seems to disagree with you.

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Lawrence B. Crowell replied on Jul. 19, 2010 @ 01:05 GMT
Jason,

These apparent superluminal velocities of jets are similar to shining a light on a wall an moving the spot faster than light.

LC

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Eckard Blumschein replied on Jul. 19, 2010 @ 05:37 GMT
Yes LC, I uttered this argument in a discussion with Peter Jackson and did not face any compelling refutation. I do not yet see a reason to either question the method of MAGIC or further boost speculative theories. Even if the twin paradox seems to demand the admission of the opposite of time dilation too, I see the limit to the velocity of speed anchored in electromagnetic properties.

Incidentally in Magdeburg and with my grandson, I visited again a nice but ten years old exhibition on the history of science and found mentioned that there are a few galaxies, if I recall correctly less than ten. The recent discovery of much more does not suggest the world being a closed system as claimed by monotheists, Hilbert, Hawking, Schulman, etc. At least, I cannot see an ultimate border while on the other hand, constant c and MP3 go on proving very reasonable.

Eckard

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Jason Wolfe replied on Jul. 20, 2010 @ 02:20 GMT
Lawrence,

So a supermassive black hole can belch forth a jet of energy and create a light on a wall effect? I don't see how that seems likely.

As for trying to beat relativity using angles and shadows, I don't think you can because that is considered "signaling" or tranmitting information. But if a supermassive black hole appears to spit out energy that is clocked at 4 to 6c, and I've looked at the pictures, I just don't see how a trick of light can explain that.

Eckard,

Do you know anything about this "trick of light" that only super massive black holes can accomplish?

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SteveDufourny wrote on Jul. 19, 2010 @ 16:20 GMT
Why so many violations of our constants, of our equivalence principle......

why to search these roads of violations ....that has no sense......

We must differenciate the perceptions and the reality, it's that the relativity,

It doesn't exist any road of violation which explains the quantum gravity .....

An illusionary causality do not explain nothing.......

Never the fluctuations can be used in these roads of confusions where the foundamentals aren't respected.

Best Regards

Steve

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Steve Dufourny wrote on Jul. 20, 2010 @ 16:42 GMT
All that seems just an optical perception due to superimposings of evolution and parameters.

The special relativity is essential for all locality and its intrinsic parameters of evolution, thus why these perceptions.

The radioastronomy must be realistic and objective respecting our referential.

When we correlate the quazars for example, we see the links with NGAs.

These nuclei , actives are in a specific dance of evolution where the superimposings of time are numerous.

The distribution of energy is specific also and the special relativity is necessary for all good correlations.

The spectral cosmologic displacable seems a cause of confusions.

In conclusion, the BH is at the center and is the cause, gravitational of the galaxy dynamic, the rule is not to eject these superluminal things,on the other if that exists, few probable, the decrease towards the respect of special rerlativity ,thus c will be.....

A jet of quazars is due to photons of the cosmological scale boosted by relativistic electron if my memmory is good,we know thus the intensity of this cosmological effect and thje energy of the BH.....for PROOF, see the CHANDRA results of ejections of this BH, the X rays of course.

OR THE IDEA OF THE DAY,the special relativity is only for a perception of a star system ....there the DFM from Peter seems very relevant about the informations and the evolution......that seems relevant there also about the velocities linears and spinals and orbitals of all spheres the sense implying the difference between mass and light, the time makes the rest.

Best Regards

Steve

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Spiridon Dumitru wrote on Jan. 10, 2011 @ 16:38 GMT
For

BOARD OF EDITORS

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INSTITUTE (FQXi)

PO Box 3022

New York, NY 10163

mail@fqxi.org

Dear Editors ,

With this letter I am sending you, as attached files) twoo copies of a short text

(2 pages and 876 words), in Word and LaTex 2e formats, entitled:

Will the Uncertainty Relations Survive

as Fundamental Pieces in the Future of Physics?

I ask you to be so kind as to put my text to an adequate examination

in order to be agreed for a publication among the Blogs of FQXi COMMUNITY.

I inform you that I have joined to the FQXi Mailing List.

Anticipating an early and positive answer from you I thank you in advance.

Sincerely yours

Spiridon Dumitru

= = = = =

PS.Will you be so kind as to confirm the reception of this e-mail and attached files.

Prof. Dr. Spiridon DUMITRU,

Department of Physics (retired)

"TRANSILVANIA" University of Brasov

B-dul Eroilor 29,

500036 Brasov ,

ROMANIA

e-mail: s.dumitru42@yahoo.com

attachments: 2_Will_the__Uncertainty__Relations_Survive_as_Fundamental_Pieces_in_the__Future_of__Physics..tex, 2_Will_the_Uncertainty_Relations_Survive_as_Fundamental_Pieces__in_the_Future_of_Physics.doc

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songjoong sdfsd df wrote on Dec. 27, 2017 @ 07:20 GMT
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