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Fraser
2005-Mar-11, 08:32 PM
SUMMARY: Thanks to data collected by NASA's WMAP probe in 2001 and 2002, plus the hard work of astrophysicists, we now know that the Universe is 13.7 billion years of age - give or take a few hundred million years. And thanks to the way distant galaxy clusters interacted with the cosmic microwave background radiation (CMBR) some 7 billion years ago, we may soon be able to peel away layers of time and better understand irregularities in the shape of the universe as it is today.

View full article (http://www.universetoday.com/am/publish/probing_structures_universe.html)

What do you think about this story? Post your comments below.

Guest
2005-Mar-11, 08:58 PM
great info :)

SunPin
2005-Mar-11, 10:41 PM
Damn fine piece. Now the researchers have a clear explanation in the media about their project. That should help funding somewhere along the line.

The Near-Sighted Astronomer
2005-Mar-11, 10:52 PM
There's a lot more to this. What WMAP points at can not be emphasized enough. The original thinking associated with scale invariance (brought into the WMAP project) may not cut it for very large scale structures. Immediate bottom line: On the very largest scales the Universe may be more uniform in the distribution of matter than once thought. What falls out of this? I'df just be guessing but an analogy goes like this. Imagine that you lived on a tiny sprig of a christmas tree. Wow how diverse everything around you looks but if you could step back from the tree you'd see something as a whole that looked - well like a christmas tree - not the sprigs.

Mind boggling eh?

Another thing: I learned that my concept of CMBR is all wrong. We aren't seeing "virgin photons" here these are photons that have been banged around the Universe by free electrons. The virgin ones are probably long gone after the time of transparency - they are "pathfinder photons irradiating a space time continuum that we have no way to see since we are inside the material universe and they aren't!

Holy Shmolly Batman!

vet
2005-Mar-12, 01:15 AM
my dear mr. fraser---it is only correct to say 'THIS' bit of the infinite multiverse is that old---if you apprise yourself of current cosmology, you will see 'NEW' ones 'bubble-forth' from the infinite former---'given-enough-time'. a new topic?
let's see---cheers

vet
2005-Mar-12, 01:21 AM
i attempted to start 'new-topic' as 'multiverse', was denied---how is this done? or is my idiosyncratic nature got me in trouble? if so, i do know how to gracefully exit.

The Near-Sighted Astronomer
2005-Mar-12, 04:36 AM
Hi Vet,

In fact I do have an article discussing alternatives to the Big Bang in the offing entitled "Is There An Alternative To the Big Bang?" But we shall see if and when it sees the light of day. Thanks for the note of encouragement along these lines,

jeff

antoniseb
2005-Mar-12, 08:47 AM
Originally posted by vet22@Mar 12 2005, 01:21 AM
i attempted to start 'new-topic' as 'multiverse', was denied---how is this done? or is my idiosyncratic nature got me in trouble?
If you were in trouble, you'd have been informed. You are not in trouble. No one but Fraser should start a thread in the Story Comments section. If you want to discuss "Multiverse" try opening a thread in the "Everything Else in the Universe" section.

antoniseb
2005-Mar-12, 08:50 AM
Originally posted by The Near-Sighted Astronomer@Mar 11 2005, 10:52 PM
There's a lot more to this. What WMAP points at can not be emphasized enough.
Very nice article. I can hardly wait till the second and third year (as well as the polarization) data from WMAP becomes available. Most people just don't understand how much this probe is telling us about the nature of our universe.

In two years the ESA will launch Planck, which will tell us even more, but as this article pointed out, even that will not be enough detail.

imported_Thomas
2005-Mar-12, 05:16 PM
In my opinion the WMAP data are very suspect and suffer from crucial errors in the design of the telescope and the data analysis (see my webpage http://www.physicsmyths.org.uk/wmap.htm ).

antoniseb
2005-Mar-12, 08:01 PM
Originally posted by Thomas@Mar 12 2005, 05:16 PM
the WMAP data are very suspect and suffer from crucial errors in the design
Interesting. Have you taken a look at the design for the Planck probe that will be launched in a few years. Does it have the same flaw?

Greg
2005-Mar-13, 08:49 AM
Even if there is a design flaw, it would seem to me just a coincidence that the peak occured in the range of uncertainty. This simply means that we cannot be sure that the peak exists, but does not disprove its existance either. THere is good reason via big bang theory to expect that a peak should occur there, so I think it is not likely to be an random artifact.

imported_Thomas
2005-Mar-13, 11:34 AM
Originally posted by antoniseb+Mar 12 2005, 08:01 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (antoniseb @ Mar 12 2005, 08:01 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Thomas@Mar 12 2005, 05:16 PM
the WMAP data are very suspect and suffer from crucial errors in the design
Interesting. Have you taken a look at the design for the Planck probe that will be launched in a few years. Does it have the same flaw? [/b][/quote]
As far as I am aware, the design of the Planck probe is different and does not use the two-telescope differential design, so in this sense the criticism that I addressed on my page http://www.physicsmyths.org.uk/wmap.htm does not directly apply. However, previous missions to measure the cosmic microwave background also used only one telescope but then applied a differential method by using data from two frequency channels, which could have led to the same problem. Unfortunately most resources on the web do not go into much detail regarding the data analysis, so it is difficult for me to say whether such an effect should have occurred there as well. However, the previous experiments were anyway much less accurate than WMAP and the spectrum did not extend far enough to show the second peak clearly (which is the one that this effect would produce).
As mentioned on my page, I consider it however also possible if not likely that the primary peak is an artifact of the data analysis as well (although due to different circumstances). The point is that in my opinion one should always be suspicious about features that are rather close to the resolution threshold of the telescope (which is the case even for WMAP).

imported_Thomas
2005-Mar-13, 11:38 AM
Originally posted by Greg@Mar 13 2005, 08:49 AM
Even if there is a design flaw, it would seem to me just a coincidence that the peak occured in the range of uncertainty. This simply means that we cannot be sure that the peak exists, but does not disprove its existance either. THere is good reason via big bang theory to expect that a peak should occur there, so I think it is not likely to be an random artifact.
Well, in order not to disprove anything, you would actually not need to do an observation, but could just afford to do nothing at all.
The point is that, as far as I am aware, cosmologists did actually not exactly know what these spectra should look like either. If you take some theoretical publications pre-dating the corresponding observations, the spectra shown there look indeed quite different to the WMAP one. The latter is only reproduced if certain free parameters in the Big-Bang theory are tweaked accordingly. On the other hand, as shown on my page http://www.physicsmyths.org.uk/wmap.htm , one should expect at least the second peak necessarily as an artefact of the data analysis (assuming that the microwave background is indeed only a completely random signal), and there are also clear indications from other experiments that the first peak may be just an artefact of the data analysis as well.
The situation could simply be resolved by analysing a corresponding random artificial signal or by re-running the data analysis by changing the assumptions for the differential width of the telescope beams accordingly (as far as I am aware, neither has been done yet, although I informed some of the WMAP researchers already about this soon after the first result were published 2 years ago).

antoniseb
2005-Mar-13, 11:48 AM
Originally posted by Thomas@Mar 13 2005, 11:34 AM
one should always be suspicious about features that are rather close to the resolution threshold of the telescope (which is the case even for WMAP).
I agree with this.

In a world with more resources, we could build and launch a probe capable of assembling its dish after launch, with perhaps a 30 meter instead of the 1.5 meter for WMAP and Planck observatories.

Such a mission will not launch for at least 20 years, and perhaps much more.

VanderL
2005-Mar-13, 01:35 PM
Hi Thomas,

I quickly scanned your website, and if your analysis of the errors in the WMAP data is anything to go by, physics in general is in worse shape than even I thought. Is it correct to conclude from your analysis that the excellent agreement of WMAP data to the BBT is based on "confirmatory bias" (seeing what one wants to see)?

Cheers.

madman
2005-Mar-13, 10:44 PM
here&#39;s a contrast enhanced black and white version of the wmap data....the projection method is hammer-aitoff.

http://hometown.aol.com.au/Profnim/cmb.jpg

does anyone know if it&#39;s possible to retrieve a plate caree version from the wmap site?

The Near-Sighted Astronomer
2005-Mar-14, 02:10 AM
This is all very fascinating and I wonder what the upshot would be. But lets start with this exploration. Galaileo&#39;s view of Saturn (at some 40mm in aperture and 30x) was unable to resolve the ring system separate from the planets disk. (In effect the planet had "ears". Imagine any theory of Saturn&#39;s nature based on the inability to fully resolve the ring system from the globe itself?

Now of course, Galileo did not carry a presumption of "all planets are spheres" into his observation so the anomaly likely didn&#39;t upset him too much nor (presumably) did he make an effort to "explain away" the empirical data.

But with the CMBR Gamou-Alpher predicted it, Wilson-Penzias detected it, COBE first resolved it (to some limited degree) and WMAP reinforced COBE&#39;s resolution with finer detail.

So let&#39;s say there was a theory of planet formation that preceded Galileo&#39;s observation "All planets are round because they spun during formation". Galileo buys into this, sees the rings and says. "Yep, Saturn must spin very fast."

Later Cassini resolves the rings with a more powerful telescope and lo and behold Saturn is a sphere (more or less) too. But now you still have to account for the Rings&#33;

Ah well, that&#39;s how science works, observation, speculation, test, validation, theorization, anomally, do over.

What does all this have to WMAP? The observation fit expectations well enough ("the CMBR just spins faster") but it will only be with "more rersolution - especially in terms of the polarity of the radiation - that any anamolies will be revealed.

What then? Will we junk the Big Bang?

Not likely - we will arrive at the same conclusion that the article "Are We Alone" comes to in terms of intelligent life in the Universe "If it can happen once..."

Cheers,

jeff

wstevenbrown
2005-Mar-14, 01:41 PM
one should always be suspicious about features that are rather close to the resolution threshold of the telescope (which is the case even for WMAP).

I heartily agree. Researchers may be in essential conflict with their own inner selves here (Cognitive Dissonance = "This has cost so much, it has to be worth it"), and projecting career-based hopes onto the data set. It is like &#39;finding&#39; Waldo too early.

As a number of researchers have commented, the motion-correction effects are larger than the signal. An incorrect guess on any of several spacecraft motions will swamp the data with either systematic or periodic error. Tweaking the motions for &#39;best fit&#39; is the usual course of action. While any single error source can be tuned out, I wonder at the cumulative effect on the data of several such sources of error. The calculations are hairy, at best.


The situation could simply be resolved by analysing a corresponding random artificial signal or by re-running the data analysis by changing the assumptions for the differential width of the telescope beams accordingly (as far as I am aware, neither has been done yet, although I informed some of the WMAP researchers already about this soon after the first result were published 2 years ago).

I have seen several null-hypothesis calculations of the power spectrum, but they did not contain any assumptions about the aperture used in the observation-- they were idealized.

Your approach is skeptical without being cynical. I like that. Best regards-- Steve

Guest_david
2005-Mar-15, 09:59 PM
....we now know that the Universe is 13.7 billion years of age - give or take a few hundred million years.

As far as I&#39;m aware this is just theoretical and that we don&#39;t really know how old the universe is. Also, as we observe the universe from our own location in it, can we be absolutely sure where we are in relationship to the centre and to the &#39;skin of the bubble&#39;.

These are coodinates that determine measurements and time, so without that data we are merely guessing. Take these next first sentences of another discovery report.:-

&#39;Some 13 billion years ago in a distant cluster of stars, a planet formed. Remarkably it&#39;s still there, according to astronomers using the Hubble Space Telescope. The confirmation of this ancient world means planets formed very early in the history of our universe--&#39;

Now, assuming, as some say, that we are located closer to the centre of the universe than we are from the outside edge, we have to be possibly well over 7 billion light years away from that cluster; and that, even if the star cluster, ourselves, and the centre of the universe were in a straight line.

So, surely we are looking at a cluster that is over 7 billion years older than the 13 billion years it is said to be.

Clearly, the cluster is not where it now appears to be but has moved on with the expansion of the bubble by at least half the believed age of the universe.

If by chance we are looking at this cluster from the other side of the centre, or anywhere in between, how old is the universe then?

To put the point another way:- The planet in this cluster formed 13 billion years ago. Are we to believe that the universe had expanded out to where we see it now in a mere 0.7 billion years and that expansion had suddenly stopped around 7 billion years ago?

Without knowing the Big Bang boundaries as they are right now and the relevant coordinates, the age of the universe is surely still a questionmark.

David

Numbers can be quite confusing
If they’re the wrong ones that we’re using
And one that wasn’t born in Heaven
Is that little beastie, thirteen point seven (DCH)

The Near-Sighted Astronomer
2005-Mar-15, 11:43 PM
Good point but doesn&#39;t really apply to the "age of the universe" based on background radiation...

The age of the universe is now anchored to four "factors":

1. That we can theoretically predict the time at which transparency occurred (380,000 years after the Big Bang)

2 The average blackbody temperature of the Universe at the time of transparency (3000 K - the de-ionization temperature of hydrogen gas)

3. The average blackbody radiational temperature of the Universe in our current epoch (2.7 K).

4. The amount of redshift-expansion necessary to reduce the overall temperature from 3000K to 2.7K.

What I believe you are referring to is not so much the age of the Univrse but the fact that the current formula used to determine redshift distances only applies to things on the near side of the Universe - not the "Gary Larson" side. Thus a galaxy moving away from us on the far side would have twice the expansionary potential as on the near side and we would confuse the two. So basically the redshift-time equation:

t = z/(1+z) * 13.7BY

is not universally valid but only so from our current reference location in one half (roughly) of a "flat" (spherically expanding) universe. The result is that things on the "far side" of the universe have a much higher redshift than those on the same side since they expand outward in the opposite direction than our own.

(It would be neat to come up with an equation that incorporated radial angles but unfortunately we don&#39;t know where or even "if" there is a fixed location for a center from which such angles can be subtended&#33; So astronomers simply ignore this factor and say a thing has so much or another "z" - redshift and leave it up to popularizers - such as myself- to convert that into space-time" distance using the above formula - meanwhile they simply chuckle to themselves knowing that such a conversion ignores a host of probably unknowable factors.)