PAMELA Results Mean Only One Thing: Please Trust the Scientific Process
Written by Nancy Atkinson
The PAMELA Spacecraft
Scientists from the PAMELA (Payload for Antimatter/Matter Exploration and Light-nuclei Astrophysics) orbiting spacecraft have published preliminary results, putting an end to months of speculation about the first direct detection of dark matter. The science team was, in essence, "forced" to publish before they had conclusive results because other scientists "pirated" data from the team. “We wanted to make our final results available to the scientific community once the data analysis was finalised,” PAMELA member Mirko Boezio said in an article in Physicsworld.com. “Given that our preliminary conference data are starting to be used by people, we felt this was a necessary step — not least because it provides a proper reference that correctly acknowledges the whole PAMELA collaboration and is available to the scientific community at large.” This is not the way the PAMELA team wanted to present their results, but really, they had no choice.
In a preprint on arXiv, the team says PAMELA has seen more positrons above a certain energy (10GeV) than can be explained by known physics. This excess seems to match what dark matter particles would produce if they were annihilating each other at the center of the galaxy. This excess, the authors say, “may constitute the first indirect evidence of dark-matter particle annihilations.” But they add that there could yet be other explanations, such as that positrons of this kind of energy can also be generated by nearby pulsars.
The science team will need to gather more data and do more work to be able to distinguish between the positron signature of dark matter annihilation and the positron signature of pulsars.
Two previous papers were published based on photos taken of slides of preliminary data that were shown at a science conference by the PAMELA team. See their papers here and here.
We humans are a curious and impatient lot. But we have to allow scientists to do their job, and do it the best way that science allows. Science done right does not mean secrecy or concealment. It means not speculating and waiting to announce results until proof positive. A similar event happened earlier this year with the Phoenix team and the detection of perchlorates. The Phoenix science team was forced to call a press conference to end all the speculation. Right now, the PAMELA team cannot say conclusively one way or the other whether they've made a direct detection of dark matter. Given enough time and more data, they will. Unless someone else steals the show again.
Sources: Physicsworld, arXiv, arXiv blog
Filed under: Dark Matter
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November 5th, 2008 at 5:34 pm
Well, as a scientist myself, I guess I can consider myself pseudo-informed…
I think it's an ethically gray area. In essence, no one actually stole the PAMELA results. The PAMELA team was the first to present their data at a conference. The two other papers just state "Assume PAMELA IS seeing a dark matter excess with these values, what does that mean?"No one actually published results, claiming they were somehow their own.
And if you present your material at a conference, you are presenting it. It's there for people to see. Anyone who attends can see it. To actually state that no one is allowed to use it henceforth, in essence saying "forget what you just saw here" is also wrong, I think.
Now, concerning the data themselves. Fermi recently reported a "dark pulsar" seen only in high-energy gamma rays, and inferred that there might be a LOT of these in the Milky Way. I think this should be taken into account, as it might handily explain the positron excess.
Though the Dark Matter explanation would be much more profound.
November 5th, 2008 at 8:08 pm
Agreed Don. Although I think it unfortunate that they feel they now have to prematurely release their data, they should not have presented results if they did not want them in the public domain. By definition, presenting results at a conference is releasing them to other scientists for their consideration.
Accordingly, if these results are related to the work of other scientists present at the conference, then I think they are more than welcome to discuss them, so long as they add the disclaimer that the results in question have not yet been vetted to the full satisfaction of the PAMELA scientists.
November 5th, 2008 at 8:39 pm
Hello, and thanks for the article, Nancy;
I enjoy reading you articles and the articles on UniverseToday.
However, could you please forward my request that this site be made more MOBILE friendly, or to create a separate MOBILE site?
Thanks again for your good work.
November 6th, 2008 at 12:53 am
Mr. Alexander has a very valid point. Once the genie is out of the bottle you can't put him back in again, so to speak. As long as other scientists acknowledge the PAMELA team's work as one source of their speculations on Dark Matter existence then I think they really aren't "stealing" anything.
November 6th, 2008 at 7:00 am
It proves something else: There are many out there who can't wait to leap onto the dark matter bandwagon. High energy sources in the bodies of galaxies that 'require new physics' are an exciting observation. The first explanation out-of-the-block is not always the best scientific answer.
November 6th, 2008 at 3:04 pm
Scientists have to be careful how they say things.
This is how all the nonsense about the LHC got started, because an honest yet nieve scientists said there was a very small chance that something could go wrong with the giant particle accelerator.
What he failed to add was that the odds were practically zero, but the undereducated press took his words literally and went to town. In the process they panicked an even less informed public.