[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy is bad for Astronomy

Authors:  Simon D.M. White
Abstract:  Astronomers carry out observations to explore the diverse processes and objects which populate our Universe. High-energy physicists carry out experiments to approach the Fundamental Theory underlying space, time and matter. Dark Energy is a unique link between them, reflecting deep aspects of the Fundamental Theory, yet apparently accessible only through astronomical observation. Large sections of the two communities have therefore converged in support of astronomical projects to constrain Dark Energy. In this essay I argue that this convergence can be damaging for astronomy. The two communities have different methodologies and different scientific cultures. By uncritically adopting the values of an alien system, astronomers risk undermining the foundations of their own current success and endangering the future vitality of their field. Dark Energy is undeniably an interesting problem to attack through astronomical observation, but it is one of many and not necessarily the one where significant progress is most likely to follow a major investment of resources.
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Alessandro Melchiorri
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy

Post by Alessandro Melchiorri » April 19 2007

Hi all,

any comments about this quite provocative paper ? :-)
As a cosmologist, I quite strongly disagree with the idea of dividing people in
"fundamentalists" and "generalists".
However I do share some of the criticisms of the author concerning the real potential of future astronomical surveys (especially X-ray) in discriminating between dark energy models.

cheers
Alessandro

Pier Stefano Corasaniti
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energ

Post by Pier Stefano Corasaniti » April 19 2007

I think this interesting perspective by Simon White has not passed unnoticed by whoever has screened today arxiv. I honestly confess that spending most of my time on dark energy search my first reaction to title and abstract has been: "Wow, if the director of a world class scientific institution writes a review as such, am I ever going to get a permanent job by working on dark energy? Or is better that I start seriously considering about a career in something else like horse-race broker, car sales, running Italian restaurant in Novosibirsk, etc..?".

Nevertheless after reading the paper I have to say that I agree with most of the suggestions the author has proposed. I completely agree about the issue of large project collaborations and the issue of how assessing the work of individuals and how to preserve creativity and imagination (by the way if there is a field more creative and imaginative this is certainly that of dark energy). It is also very true that progress on dark energy can only be made through advancements and understanding of several astrophysical phenomena which are used to probe dark energy and therefore focus should be mostly on the study of these phenomena, constraints on dark energy are an important byproduct.

I also think that is a natural reaction that some astronomers may feel unease with the overwhelming pressure from cosmologists and particle theorists about testing dark energy, but this is simply because of the lack of more accurate data than those collected so far. Although my personal feeling would be unease even if I had been a pure astronomer by knowing that whatever I see at whatever wavelength is only a tiny fraction of the Universe with only a vague gravitational knowledge of how a misterious dark sector relates with the phenomena I observe with a telescope. And this is why I do not think that the quest for dark energy should be perceived as a threat, particularly from the side of the astronomers, and that's where I think I disagree with this paper. The conclusions presented seem to suggest that dark energy is a menace to the "romantic" view of Astronomy. In contrast I strongly believe that dark energy poses such a new great challenge and long term goal that lots of new astrophysics will be discovered along the way as well as fundamental physics.

The quest for dark energy may indeed provide motivations for deeper studies in a variety of fields. Let us think for instance to the physics of SN Ia. It is highly probable that the next generation of SN surveys will provide constraints less optimistic than those hoped, nevertheless these dedicated surveys (and not short time campaign on big
telescopes from time to time) by collecting a sample of SN Ia data many order of magnitudes larger will certainly lead to some new discovery in the SN Ia sector. New families of standard candles? Effects from circum-stellar environment? Dependence on progenitors composition and host galaxy metallicity?
I am just tossing words, but these are things which can make astronomers really happy, no?

Always remaining in the context of SN searches, assessing how much dust is present in the IGM is necessary for avoiding misleading conclusions about DE, but this would also require advances across several fields. I can think of those who study the IGM with Ly-alpha and those who study the metallic pollution of the IGM through simulations, those who look at X-ray halo scattering of QSO or those who look in the Far IR of the unresolved background emissions. Isn't this all honest to God Astronomy necessary for a better evaluation of dark energy measurements? Perhaps these fields would never cross each other, preventing further advances in astrophysics without the unifying motivation of understanding also what the bulk of the Universe is made of.

Next July the ESA will start collecting the next proposals for a scientific satellite mission. In the past 10 years we had successful satellites which have been looking at specific astrophysics phenomena in the IR, X-ray and Gamma domain, none dedicated to phenomena which may have also been used to study dark energy. I wonder whether such
a science-policy manifesto may put under bad lights those astronomers who are proposing missions in the direction of studies such phenomena.

From my biased perspective I really hope this not to be the case, because
search on dark energy may be easily delayed by a decade. We need more data and astronomers are the only one who can provide them.

Pier Stefano

Alessandro Melchiorri
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy

Post by Alessandro Melchiorri » April 21 2007

Hi Pier,

Let me say that more I read this paper and less I agree with it .
Let me make a practical example. Let's go back to 1993 and read this paper:

Nature 366, 429 - 433 (02 December 1993); doi:10.1038/366429a0
The baryon content of galaxy clusters: a challenge to cosmological orthodoxy
Simon D. M. White, Julio F. Navarro, August E. Evrard & Carlos S. Frenk
Baryonic matter constitutes a larger fraction of the total mass of rich galaxy clusters than is predicted by a combination of cosmic nucleosynthesis considerations (light-element formation during the Big Bang) and standard inflationary cosmology. This cannot be accounted for by gravitational and dissipative effects during cluster formation. Either the density of the Universe is less than that required for closure, or there is an error in the standard interpretation of element abundances.

it sounds like a catastrophe for cosmology and I remember at that time (I was an undergraduate) several people in many sectors of physics questioning the reliability of cosmology as a serious science (see the fractal universe debate of Pietronero for example). But only thanks to "fundamentalists" experiments we have now a much better understanding of the problem and we can make the right choice between the two hypothesis presented in the abstract. This is a clear example, in my opinion, of how much "fundamentalists" experiments are fundamental for modern astrophysics, cosmology and astronomy.

Moreover, I found the argument about astronomers being more creative with HST than WMAP as quite weak. Experiments like WMAP have stimulated the creativity of thousand of researchers. WMAP papers have more or less 10000 citations (from paper with just few authors!). Those results have been useful to an enourmous amount of researchers in the world. And, I guess, stimulated their scientific creativity.


Cheers
Alessandro

p.s. please send me more infos about the italian restaurant at Novosibirsk.

vincenzo antonuccio delog
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[arXiv:0704.2291v1] : A different question Fundamentalist p

Post by vincenzo antonuccio delog » April 25 2007

Let me pose a more "sociological" question, not touched by the mentioned astro-ph but, I think, directly connected to it. I think that today young bright physicists are attracted towards cosmology BECAUSE it deals with fundamental questions like the nature of Dark Energy. Exactly asm, when I was a phd students (more than 20 years ago) we were attracted by Large Scale structure because it dealt with a then fundamental problem (i.e. the existence of Dark Matter).

Does anybody agree with this proposition?

Paddy Leahy
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy

Post by Paddy Leahy » April 25 2007

Lowering the tone here, I'm intrigued by White's claim that:
As an extreme example, the fourth ranked astrophysicist by citations to papers published over the last decade has never written a first-author paper for a refereed journal and has gained almost all his citations through his right to sign official papers by a large collaboration in which he played a purely functional role.
Is this right? Havn't figured out how to extract such info directly from ADS, but after trying some obvious suspects this anonymous person would need more citations than Andy Fabian to qualify. (I've found about a dozen people with >10,000 citations to refereed papers in the last decade and all have plenty of first-authorships).
In response to White's substansive comment and the previous post, I find it depressing how many bright students still want to do particle physics...

Alessandro Melchiorri
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy

Post by Alessandro Melchiorri » April 25 2007

Hi,

No, I don't think this claim can be true. It would be in any case interesting to know the name of this astrophysicist, he may say something about is pure "functional" role in the collaboration !

In any case I guess that in 1975 communication between astrophycists was much more difficult than today (just phone and ordinary mail and not even fax in some countries !!!). Internet and e-mail may well explain why astrophysicists work in teams today more than in the past. I consider the fact that someone in China is now able to work remotely with other astrophysicists in USA and Russia as probably one of the most beautiful things in recent history. I personally prefer to work with collaborators from other universities and countries: it is much more fun and you ultimately have a better cross-check on the science you are doing !
If you look at fig.3. in the paper you see that the major increase starts after 1990, i.e. in the internet era. What do you think ?

Moreover, with internet and astro-ph it is now becoming impossible to do not cite properly the work done by previous papers. Your paper is on the web, everybody can read it and if you don't cite someone properly you may get an e-mail from him the same day (or, if the case is extreme, a comment on the web 2 days later). In few words, reference lists may be longer, but I could consider this as consequence of having papers now giving the right credit to the work of everyone, no matter from which university or country comes.

Finally, I still miss the connection between all this and the "dark energy"!
Anyway, probably we gave too much attention to this paper..

cheers
Alessandro

Uros Seljak
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Re: [arXiv:0704.2291v1] Fundamentalist physics: why Dark Ene

Post by Uros Seljak » April 26 2007

Paddy Leahy wrote:Lowering the tone here, I'm intrigued by White's claim that:
As an extreme example, the fourth ranked astrophysicist by citations to papers published over the last decade has never written a first-author paper for a refereed journal and has gained almost all his citations through his right to sign official papers by a large collaboration in which he played a purely functional role.
Is this right? Havn't figured out how to extract such info directly from ADS, but after trying some obvious suspects this anonymous person would need more citations than Andy Fabian to qualify. (I've found about a dozen people with >10,000 citations to refereed papers in the last decade and all have plenty of first-authorships).
In response to White's substansive comment and the previous post, I find it depressing how many bright students still want to do particle physics...
While I haven't checked explicitly his ranking, I am sure Simon is referring to J. Brinkmann (on some papers misspelled as Brinkman), who is a technician at Apache Point, and who enjoys putting his name on every single official SDSS paper. I have dozens of papers with him, sometimes with as few as three other coauthors, so you would think I know him well. But I never met him nor did I ever get a single comment about any paper from him. Just a coauthorship request, usually within minutes of posting the paper to SDSS collaboration.

Alessandro Melchiorri
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energy

Post by Alessandro Melchiorri » April 26 2007

I must admit that Simon is right...
http://in-cites.com/top/2006/sixth06-spa.html#Top

I don't trust much ISI, but still...

cheers
Alessandro

Simon White
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energ

Post by Simon White » April 26 2007

If you do not believe my contentions about the rapid evolution of citation habits in
our field, check out the site which Alessandro just mentioned. At the end of 2003
ISI believed that the 10th most cited astrophysicist had accumulated 4878 citations
to papers over the preceding 11 years. At the end of 2006 the corresponding
figure for the 10th most cited astrophysicist was 10334 citations. At the high end, the
citation rate of astrophysicists has doubled in 3 years. If you check the names, the growing
influence of large collaborations is also obvious.

Oystein Elgaroy
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[arXiv:0704.2291v1] Fundamentalist physics: why Dark Energ

Post by Oystein Elgaroy » May 04 2007

I don't think the prospect of working in a large collaboration drives talent away from a field. People I know in particle physics tell me that there is no shortage of talented young people flowing into the big experiments. If a research area is perceived as interesting, important and active, the good students will as a rule be attracted to it. After all, most of them have never even heard of scitation counts and the like when they choose topic for their thesis. This is something they will learn more than they ever wanted to know about later on.

Having said that, I think it is healthy with a bit of skepticism towards costly experiments that will "probe the nature of dark energy" and not much else. If we already had a widely accepted solution of the cosmological constant problem, then I don't think many people would have been willing to devote time and money towards measuring w=-1 more accurately. There is nothing so far to suggest that dark energy is anything more complicated or exiting than the cosmological constant. It should not be of great concern for astronomers that theoretical physicists find the cosmological constant frustrating.

Tommy Anderberg
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Re: [arXiv:0704.2291v1] Fundamentalist physics: why Dark Ene

Post by Tommy Anderberg » May 04 2007

Oystein Elgaroy wrote:People I know in particle physics tell me that there is no shortage of talented young people flowing into the big experiments.
You may want to check that their definition of talent matches yours.
Oystein Elgaroy wrote:It should not be of great concern for astronomers that theoretical physicists find the cosmological constant frustrating.
That might be a valid point of view if accelerating expansion was an unambiguous observational fact, independent of theoretical assumptions going into the data analysis. This condition is not satisfied.

Roberto Trotta
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Re: [arXiv:0704.2291v1] Fundamentalist physics: why Dark Ene

Post by Roberto Trotta » May 10 2007

Oystein Elgaroy wrote:Having said that, I think it is healthy with a bit of skepticism towards costly experiments that will "probe the nature of dark energy" and not much else.
It seems to me that many of the mid and long-term dark energy flagship projects will do plenty more than just dark energy. There is a big difference between building the LHC to look for the Higgs (say) and setting up a large imaging survey to do dark energy science: the latter will produce a gold mine of data that will be exploited for years to come for purposes totally different than dark energy (just think of the legacy of the SLOAN, for instance).

Another relevant point in my opinion is that there is plentiful of checks and tests that have not been performed yet that we need to do before conclusively jump on the conclusion that dark energy (or a cosmological constant) is out there. In this respect, basing the discussion of which future probes/observations we need to do purely on figures of merits ("my errorbars are smaller than yours!") seems to be a bit reductive.

Alessandro Melchiorri
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[arXiv:0704.2291v1]

Post by Alessandro Melchiorri » May 19 2007

Hi,

Let me come back to the discussion about citations.
I 100% agree that the career of a scientist should not be completely related to the number of his citations and papers. The case pointed out by Simon and Uros is a good example. However I think people are always hired (or fired) taking in to account several other factors like the number (and quality) of collaborators, students etc. etc.

On the other hand I see that arguments against citations and paper counting are usually used by several not so famous scientists who feel their work as vastly underappreciated. They may be right sometime but in most of the cases I believe that the reason is just bad science.
In few words, the citation criteria is definitly flawed, however I would not
blindly attack people or fields with high citations since I could become the paladin of bad scientists or of experts in now sterile fields of astronomy.

Cheers
Ale

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