Of Particular Significance

Arsenic, Dead or Alive

POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON 07/10/2012

A distant topic, yet not distant at all. Science, as a process, creates trustworthy knowledge; it has proven this over and over, and much of our economy is based upon it. But scientists? As individuals, they are just as human as anyone else: they make mistakes, harbor biases, believe things without much evidence, overstate their cases, and do all sorts of problematic things. Some are a lot more reliable than others, and often the unreliable ones are the ones who take their scientific case to the media (the reliable ones often not seeing the need to do so). Consequently, media stories on science are on average somewhat less reliable than the ones scientists produce and read.

So when a brand new science story makes the headlines — say, the possibility of faster-than-light neutrinos from the OPERA experiment at the Grand Sasso laboratory (withdrawn before publication due to discovery of a technical problem), or the bacteria substituting arsenic for phosphorus as claimed by a group of scientists who first predicted the possibility and then claimed to find it (here’s the abstract of the published paper in Science magazine, and a popular New York Times article about it) — caution is advised.  [Cold fusion, anyone? Utah’s governing institutions should perhaps have been a bit more patient…]

Multiple arguments against the arsenic-incorporating bacterium result have been made from the beginning. Now two new papers (#1, #2) have hit Science magazine, and the press. Both argue (among other things) that the bacterium in question is still dependent on phosphorous and that there is no sign of arsenic in its DNA.

Which is all to say that reproducibility lies at the core of scientific research. It is the process of confirmation and cross-checking of a result that allows a media story that begins “Scientists say…” to be transformed into a textbook that begins “Science says…” When you read a story in the press, you should always look for the key indications that multiple and separate groups of scientists agree on the result — not necessarily that there is broad consensus, but at least that the scientists making the claim aren’t entirely out on their own.  [For the recent discovery of the Higgs particle, we have two different experiments making the claim.] If those indications are missing, I’d advise you to file the result under “unconfirmed,” and not to bet on it.

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12 Responses

  1. Somewhat off-topic. So now that it has been determined that the universe is flat and open, I would think that the flatness is 3-dimensional, I.e. it has a depth, or thickness. So what is the thickness of the universe? And is it exapnding in all 3 directions?

    1. Flatness simply means that parallel lines neither converge nor diverge as you move across the universe. There’s no notion of thickness associated to flatness.

  2. “… no model with new forces and forces seems to work very well.” If a model using SU(5) or SU(8) happens to be empirically valid, then would the predicted new effects be out of range vis-a-vis the contemporary technology of high-energy physics?

  3. “Scientists create plastic plant people that can do anything YOU want!”

    I don’t remember the source of my citation, but the author parodied the supermarket tabloid headline. There is a book, _Why People Believe Strange Things_ that delves into the subject.

    It is so much easier (by orders of magnitude) to read about discovery than to do it. The popular media are spoiled by the scheduled surprise of sports. On the other hand, the popular American reader is more likely to be able to play baseball than to do arithmetic with scientific expressions.

    Don’t even try to satisfy the popular media with science. As dear Professor points out, that way leads to cold fusion.

  4. Understood that without double/triple confirmation science stories should be labeled ‘unconfirmed’ as you said.

    However, I think there is a larger problem – there is a significant “demand” for science related stories and a lack of supply from the scientific community. At the very least, there are few well known resources that readers can go to. So this demand seems to be fulfilled by the next best thing – which may not always apply scientific rigor.

    My suggestion for a solution – more blogs such as this one. Perhaps a recognized news source from the scientific community that people can go straight to, rather than read it in yahoo news.

  5. In April 2011 the Fermilab CDF Detector experiment reported a statistically significant bump (3.2 sigma) in the di-jet invariant mass plot at about 140 GeV (see http://arxiv.org/abs/1104.0699). Two months later, the DZero Detector experiment, also at the Tevatron, reported that it found no evidence for this peak (see http://arxiv.org/abs/1106.1921). So this di-jet bump at 140 GeV still remains unconfirmed.

    1. That is correct; there has as yet been no confirmation of this effect. No other experiment has yet been able to weigh in, and the situation remains very controversial.

      The excessive top quark forward-backward asymmetry, on the other hand, http://profmattstrassler.com/articles-and-posts/tevatron-news/apparent-unexpected-asymmetries-in-the-production-of-quarks/ , appears to have been confirmed between CDF and DZero. The cause is still unknown; some suspect a subtlety with calculating things in the Standard Model, because no model with new particles and forces seems to work very well.

  6. One of the authors of the refuting papers (Rosie Redfield) has a good blog about biology research, see http://rrresearch.fieldofscience.com/ . I like it because it includes experiments from her lab that work, as well as the ones that didn’t. It shows the iterations needed to get results instead of just the finished product.

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