NS: Has Jupiter sent cosmology down a false trail?

[bystander]

Has Jupiter sent cosmology down a false trail?
New Scientist - 11 June 2010

It's supposed to be the "gold standard" of evidence supporting the standard model of cosmology – including dark matter, dark energy and the exponential expansion after the big bang known as inflation.

But could it be wrong? Might misleading measurements by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) have been leading us towards the wrong theory of cosmology? One astrophysicist thinks so, and he says the planet Jupiter is to blame – though others insist that there is nothing amiss.
...
To calibrate the microwave data, WMAP scientists use the planet Jupiter, which they assume to be a steady source of microwaves. Observations of Jupiter show how much the cosmic ripples are being blurred by the instrument's optics, allowing the WMAP team to correct for this.

Now Shanks and his PhD student Utane Sawangwit have recalibrated the data using objects such as radio galaxies observed by WMAP that also emit microwaves. The result is a spectrum that is compatible with a host of theories that the WMAP team claims to have ruled out. For example, one-dimensional cosmic strings – defects in the fabric of space-time – or modified laws of gravity might explain the clumping of matter that is currently attributed to the dark matter and dark energy of the standard model.

Durham astronomers' doubts about the 'dark side'
Royal Astronomical Society - RAS PN 10/44 - 14 June 2010

New research by astronomers in the Physics Department at Durham University suggests that the conventional wisdom about the content of the Universe may be wrong. Graduate student Utane Sawangwit and Professor Tom Shanks looked at observations from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite to study the remnant heat from the Big Bang. The two scientists find evidence that the errors in its data may be much larger than previously thought, which in turn makes the standard model of the Universe open to question. The team publish their results in a letter to the journal Monthly Notices of the Royal Astronomical Society.

Launched in 2001, WMAP measures differences in the Cosmic Microwave Background (CMB) radiation, the residual heat of the Big Bang that fills the Universe and appears over the whole of the sky. The angular size of the ripples in the CMB is thought to be connected to the composition of the Universe. The observations of WMAP showed that the ripples were about twice the size of the full Moon, or around a degree across.

With these results, scientists concluded that the cosmos is made up of 4% ‘normal’ matter, 22% ‘dark’ or invisible matter and 74% ‘dark energy’. Debate about the exact nature of the ‘dark side’ of the Universe – the dark matter and dark energy – continues to this day.

Sawangwit and Shanks used astronomical objects that appear as unresolved points in radio telescopes to test the way the WMAP telescope smoothes out its maps. They find that the smoothing is much larger than previously believed, suggesting that its measurement of the size of the CMBR ripples is not as accurate as was thought. If true this could mean that the ripples are significantly smaller, which could imply that dark matter and dark energy are not present after all.
...
In addition, Durham astronomers recently collaborated in an international team whose research suggested that the structure of the CMB may not provide the robust independent check on the presence of dark energy that it was thought to.

If dark energy does exist, then it ultimately causes the expansion of the Universe to accelerate. On their journey from the CMB to the telescopes like WMAP, photons (the basic particles of electromagnetic radiation including light and radio waves) travel through giant superclusters of galaxies. Normally a CMB photon is first blueshifted (its peak shifts towards the blue end of the spectrum) when it enters the supercluster and then redshifted as it leaves, so that the two effects cancel. However, if the supercluster galaxies are accelerating away from each other because of dark energy, the cancellation is not exact, so photons stay slightly blueshifted after their passage. Slightly higher temperatures should appear in the CMB where the photons have passed through superclusters.

However, the new results, based on the Sloan Digital Sky Survey which surveyed 1 million luminous red galaxies, suggest that no such effect is seen, again threatening the standard model of the Universe.

Beam profile sensitivity of the WMAP CMB power spectrum

• arXiv.org > astro-ph > arXiv:0912.0524 > 02 Dec 2009 (v1), 08 Jun 2010 (v2)
  to be published in Monthly Notices of the Royal Astronomical Society: Letters

[neufer]

<<It was once believed that the Roman god Jupiter was in charge of cosmic Justice, and in ancient Rome, in their courts of law people swore by Jove to witness the oath, which lead to the common expression "By Jove!".>>

<<Jupiter's powers enabled him to change into anything he wanted. He used these transformations to hide from his wife, Juno, while he was pursuing beautiful women. Jupiter may appear in paintings disguised as a swan, a bull, an eagle, a cloud or a shower of gold.>>

[Beyond]

kinda sounds like the same-old same-old, to me.

[Ann]

Sometimes I check out the Arxiv Astrophysics page, and even though I don't understand much of what they write there, I do realize that all kinds of wild theories are circulationg there. Often a theory is put forth by just one astronomer or just one group of astronomers. These theories never reach the general public, probably for two reasons: One, you can't take all cosmological speculation seriously, and two, often these wild theories can't even be expressed in a layman's terms so that the general public can understand them. But Jupiter is a well-known and beloved planet. Personally I think that this Jupiter theory isn't more interesting than most other wild hypotheses, but simply because this one can be explained by invoking Jupiter it is going to get publicity. I'm not too impressed with the theory, at least not until those who formuated it manage to convince more of their peers in the astronomical community that they are right.

Ann

[bystander]

Sometimes I check out the Arxiv Astrophysics page, and even though I don't understand much of what they write there, I do realize that all kinds of wild theories are circulationg there. Often a theory is put forth by just one astronomer or just one group of astronomers. These theories never reach the general public, probably for two reasons: One, you can't take all cosmological speculation seriously, and two, often these wild theories can't even be expressed in a layman's terms so that the general public can understand them.

For the most part, I have to agree, but the source for this was a reputable science news site and has already reached at least a part of the public.

But Jupiter is a well-known and beloved planet. Personally I think that this Jupiter theory isn't more interesting than most other wild hypotheses, but simply because this one can be explained by invoking Jupiter it is going to get publicity. I'm not too impressed with the theory, at least not until those who formulated it manage to convince more of their peers in the astronomical community that they are right.

This isn't so much a new theory as it is a questioning of the accuracy of the WMAP findings. Due to the cosmological importance of WMAP, I think these findings need to be verified or refuted. Because of this, I think this paper is of some importance and that New Scientist is justified in their reporting of it.

[Chris Peterson]

Sometimes I check out the Arxiv Astrophysics page, and even though I don't understand much of what they write there, I do realize that all kinds of wild theories are circulationg there.

Arxiv is a valuable resource for early publishing and some self publishing. But it has to be approached very carefully. I approach any paper from that source with an extra measure of skepticism. For any paper making extraordinary claims, I look at the authors, their institutions, publishing history, and other references. This paper passes muster: while the lead author is only a grad student, the other (who I might guess is his advisor) has a good publication history, this paper has been reviewed and accepted in a high quality journal, and there's little reason to doubt that it is of some value.

That said, this matter (WMAP calibration problems) has been looked at before, and in every case the conclusion has been that the data is fundamentally solid. And that data is supported by other instruments as well. I predict that the conclusion will be the same here... but nobody knows for sure.

[bystander]

Astronomers stoke cosmic debate
Science News - 16 June 2010

More heat than light from a dispute over the universe's dark side

Though dark energy and dark matter rank among the more mind-boggling concepts in astronomy, they appear to be necessary evils.

Theorists summon dark energy, the mysterious entity that transforms gravity from a cosmic pull to a cosmic push to account for the accelerating expansion of the universe. Meanwhile dark matter, the proposed invisible material theorists say makes up more than 80 percent of the universe’s mass, keeps galaxies intact and galaxy clusters from flying apart.

Now, two astronomers say they can banish the dark side of the universe to the dust heap of ill-conceived theories. But other astronomers aren’t getting too revved up about the tentative findings.

In an article in press in the Monthly Notices of the Royal Astronomical Society, astronomers Utane Sawangwit and Tom Shanks of Durham University in England argue that there are flaws in astrophysicists’ analysis of tiny temperature fluctuations in the cosmic microwave background — the whisper of radiation left over from the Big Bang.

(see first post) ...

This isn’t the only way Shanks and his colleagues are trying to put the kibosh on dark energy. In a separate paper published in the Monthly Notices of the Royal Astronomical Society, the researchers compare hot spots in the microwave background — regions of higher than average temperature — with the locations of galaxy clusters. If dark energy exists, the hot spots should match up with the cluster locations, as indicated by a survey of 1 million luminous red galaxies recorded by the Sloan Digital Sky Survey. The researchers find no such match.

Stay tuned for how it all shakes out. But chances are that Spergel and other theorists won’t easily give up on dark energy or dark matter, whose existence explains many puzzles about the universe. Any rumors of their death are likely to be greatly exaggerated.

Cross-correlating WMAP5 with 1.5 million LRGs: a new test for the ISW effect

• arXiv.org > astro-ph > arXiv:0911.1352 > 06 Nov 2009 (v1), 02 Dec 2009 (v2)
  Monthly Notices of the Royal Astronomical Society Volume 402 Issue 4
  (30 Dec 2009) doi: 10.1111/j.1365-2966.2009.16054.x