$1.5 billion Dark Matter Detector AMS is on ISS – Not Underground
Dark Matter Experiment Has Detected Nothing, Researchers Say Proudly, NY Times
“LUX is the latest in a long series of ever-larger experiments that have occupied and taunted the world’s physicists over the last few years. They are all in abandoned mines or other underground places to shield them from cosmic rays, which could cause false alarms. … Larger instruments are already on the drawing boards of LUX and other collaborations, but physicists say the experiments are already sensitive enough to test some versions of dark matter that have been proposed, including the idea that dark particles interact with ordinary matter by exchanging the recently discovered Higgs boson. Dr. Weiner said he held his breath every time new results from a dark matter experiment were released.”
Alpha Magnetic Spectrometer – 02 (AMS-02) Fact Sheet
“The Alpha Magnetic Spectrometer – 02 (AMS-02) is a state-of-the-art particle physics detector constructed, tested and operated by an international team. The AMS-02 uses the unique environment of space to advance knowledge of the universe and lead to the understanding of the universe’s origin by searching for antimatter, dark matter and measuring cosmic rays.”
Alpha Magnetic Spectrometer, WIkipedia
“In 1999, after the successful flight of AMS-01, the total cost of the AMS program was estimated to be $33 million, with AMS-02 planned for flight to the ISS in 2003. After the Space Shuttle Columbia disaster in 2003, and after a number of technical difficulties with the construction of AMS-02, the cost of the program ballooned to an estimated $1.5 billion.”
Keith’s note: $1.5 billion for a Dark Energy detector and … no one seems to talk about it when future dark matter detection instruments are discussed? AMS is not “underground” as the New York Times’ reporter claims all dark matter instruments are. AMS has been in the news with results – but mainstream media seems to not see it as being on a par with Earth-based dark matter gizmos. NASA PAO is not doing a very good job, so it would seem. Or maybe the New York Times is being lazy (it has happened before).
Today AMS reached 40,000,000,000 events recorded. All ops continue to be nominal.
— AMS-02 (@AMSISS) October 24, 2013
The AP article by Seth Borenstein mentioned AMS although not by name, it was referred to only as “A detector attached to the International Space Station”
Actual particles of dark matter react weakly with normal matter so they easily penetrate the atmosphere and there is no advantage to building a detector in space. But AMS is not intended to detect dark matter (or dark energy, for that matter) directly. It detects and analyzes high energy charged particles, which interact very strongly with matter and thus do not penetrate the atmosphere. That is why AMS must be in space. This data can support or refute a variety of theories, including aspects of dark energy and dark matter; cosmic rays were detected many years ago but their origins are still poorly understood.
Physics may explain the expanding universe, but even the most sophisticated science cannot explain the expanding budgets of so many NASA programs.
LUX doesn’t measure dark energy or dark matter directly, either. It detects photons and electrons theorized to be given off from the interaction of Xenon with dark matter. More often than not, scientific measurements are indirect.
What I meant to say was that AMS does not have to be underground because it does not detect (directly or indirectly) the prensence of dark matter in the detector.
The NYT needs to learn about Google and Google Scholar.
As a side note, the NYT, like pretty much all of the media, even much of the science media, talks about the Higgs Boson as if it were a proven fact. Science is slipping when it takes one interpretation of a single event, from an experiment made at a single site, and treats it as fact just because it fits with one man’s “what-if” theory. What happened to skepticism and repeatability as integral mechanisms of the scientific method? Has self-fulfilling prophecy replaced them?
This is a grotesque mis-representation of the discovery of the Higgs. There were two independent detectors at CERN, each of which were fed by an immense number of events. The Higgs signal built up slowly and passed a tremendous battery of statistical tests. The theory is not one’s man’s “what-if,” but can be traced to papers by six individuals. Its validity lies at the very heart of modern physics. It is a brilliant validation of the scientific method of hypothesis followed by test.
I think it’s well worth reading hep-expt-82’s comments above. Defining the sum of the work done with regard to collecting data on the Higgs-like particle discovered at LHC as a “single event” at a “single site” is at best misleading. Between the actual running of multiple, different experiments and the sheer number of individual individual events detected by each experiment, the work so far has gone well beyond any n=1 measurement/test. With more experiments yet to come at LHC, the repeatability will not be questionable. You should not that was scientific skepticism and the need for repeatability which drove the number of different experiments and the parameters for each experiment.
Your comment about one man’s “what-if” theory bears no relevance to reality. The theory that predicts the Higgs boson is far from the work of one man. I don’t know what your agenda was with that statement. It certainly is a slight against all of the people that contributed to said theory. Even the most perfunctory internet search will reveal that theory is more than one man’s “what-if”.
I’m not sure whether or not you meant to impugn the work of the people working at CERN and of science in general. I don’t know where you get your information about scientific research, but I suggest you go to actual scientific journals if you want to understand what’s actually going on. Certainly referencing pop media has no bearing on what is happening in science, and choosing pop media to support the maligning of work done is a mistake at best.
I suggest you learn the facts about the work done to date with respect to the Higgs boson, from the development of the theory to the work done to test the theory.
Normally you make well reasoned comments, but in this case your comments are on par with the comments made in pop media.
PsiSquared and Tod,
Sorry for the delay in responding. I started typing up an explanation of what I was trying to say, but it was getting way too long and I didn’t think it would accomplish anything useful, so I’ll go with the shorter version instead.
I was not in any way trying to impugn the accomplishments of the people at CERN or their work. In fact, the CERN web site is where I go to get information and updates on this topic, because their material is the horse’s mouth, and it is properly reviewed (unlike most web sites on almost any topic).
I’m sorry for the phrase, “one man’s “what-if” theory”; it was poorly chosen. What bothers me is that people theorized that if a new particle with a certain set of properties existed (Higgs boson), then it would explain some things that can’t currently be explained any other way. Experiments were then designed to look specifically for a particle with those properties. In the past, science performed experiments based on models of real world behavior and then an attempt was made to interpret the experimental data and measurements in order to formulate a theory, not theory first. Perhaps I’m making a distinction that isn’t really there, but it seems to me like a detective deciding at the beginning of his investigation who’s guilty and then spending all his time looking for evidence to confirm that person’s guilt. If he was wrong in his starting decision then all of his work will not accomplish what is necessary. As well, finding the Higgs particle is not necessarily, in my mind, proof of the existence of the Higgs field, and that makes the whole situation more still-to-be-proven than it’s being treated, in my opinion.
The Higgs field is a theory. The Standard Model is also a theory. Yet too many people, including particle physicists (which I certainly am not), talk about them as if they were proven facts. The Standard Model certainly stands up well in view of all the successful technologies based on it, yet it is still theory.
In my previous comment, typing in haste, I shamefully did what I’ve been known to criticize others for — I made incomplete, unqualified statements. Time and again we see sentences pertaining to science that are incomplete and therefore end up being incorrect. All I was really wanting to say is that the Higgs field/particle theory is not proven fact, and there are still questions to be answered, yet it is so often presented as if it were a finished task. As of October 2013, the CERN investigators themselves in what they write continue to qualify the Higgs project as still ongoing, with more to be done. Unless I’ve misunderstood things, it’s still an open question at CERN as to whether the “Higgs-like” particle that’s been detected is “the” Higgs particle theorized to be responsible for the Higgs field, or just one of a family of similar particles.
Clearly I struck a nerve with my poorly written comment. I apologize.
Steve
Sorry, but I don’t know what point you’re trying to make here, but the your understanding of history is again odd. Throughout history predictive theories have lead to the experimental detection of previously unrecognized phenomena. Certainly, a famous example has to be Hertz’s detection of radio waves, which were predicted from Maxwell’s equations. Nuclear chain-reactions are another. Gell-mann’s prediction of the Omega- particle, based on his theory of quarks, is a classical example in particle physics. Then there’s QM, and relativity to name a few minor parts of modern physics. I mean come on!
This is the whole point of theories! They are created to explain observed phenomena, but in doing so predict phenomena yet to be seen. The Higgs was advanced to solve a number of problems in particle physics. The theory predicted the existence of a boson with certain properties, so people went and looked for it. What more do you want??
Yes, there are some issues with the predictions versus the observations of the various branching various among the four major decay channels, so there is still work to be done.
The issue was your apparent brusque dismissal of an immensely sophisticated combination of theory and experiment as something that didn’t follow the scientific method, was accepted without skepticism, and was “self-fulfilling,” whatever that means in the context of mathematical physics…
It would appear to me that I’m out of my league on this topic, so I won’t comment any further other than to say that I think the line between theory and fact has become quite blurred in an increasing number of areas of science. Once things get written into the journals and text books, it becomes difficult for future generations when something turns out to be not as previously thought (for example, chemistry is full of names that don’t comply with the naming conventions because they were originally misunderstood; so now we have a lot of memorizing of exceptions).
Whether we’re talking humans or science, there seems to me to be a tendency to assume that we, now are at or near the end of that evolution, and that everything we now think is fact, which time and again turned out not to be true. I’m not saying that Higgs field theory is wrong; I’m saying I think it’s still too early to be quite so certain as is currently being presented. But in truth, I don’t know either way, and I don’t have enough relevant knowledge to have an informed opinion on the matter. I am speaking only from general principles.
Thank you for taking the time to explain things to me.
You are using “theory” and “fact” in ways that I do not understand as a scientist. A “theory” does not mean unproven hypothesis, and a fact is just a bit of information, nothing grander. I also don’t understand the complaint of “blurring the line between theory and fact.” Theories are based and built on facts and predict new ones. A theory provides an interpretive framework for facts. The facts that CERN produces is a mind-numbing number of particle events. It’s just data. You would never, ever in a billion years understand any of it without an interpretive theory to guide you.
Bingo! You’ve just got through to me why I’m getting myself into trouble (and confused) with all of this.
Although I studied physics and chemistry at College, I was basically trained as an engineer (at the time I didn’t think I had that extra spark and drive that it I felt it took to do science). But I went to college in the early 70’s, and most of what I’ve learned of science since then, on my own, came from library books and journals (I was addicted to the library long before there was a world wide web).
Way back then, we (as engineering students) were taught that a theory was an explanation that was unproved, but because it was self-consistent and was not contradicted by relevant experimental evidence, it was accepted as “a working explanation” until either it was contradicted by new experimental data or something better came along. But, a theory was not accepted as proven. Within the context of that definition, theories could either evolve or be replaced wholesale, depending on what new data showed, on a case by case basis. In other words, the difference between a scientific hypothesis and a scientific theory was only in the extent to which it had been experimentally tested.
I realize now that, as a scientist, you’re telling me that this is not an accurate understanding of the term theory. At this point, I can’t honestly say whether I was taught differently or it’s simply my brain getting old, but I can see the distinction now — a theory is considered to be an accurate explanation of the facts. This would also tend to explain why, historically, it has sometimes been such a battle to get existing theories replaced by newer theories.
Sorry to have generated so much ambiguity in my comments and thank you for setting me straight; it shows considerable patience on your part. Of course, now I’m going to have to go back and reread a lot of stuff from my changed perspective, but that is something I look forward to. Thanks again.
1) The NYT said “LUX is the latest in a long series of [dark matter] experiments” that are all underground. As a particle physicist myself, I think this is how virtually all my colleagues would say this. LUX is indeed the latest in the series of what are known as “direct detection” experiments.
AMS has many goals, but insofar as dark matter is concerned, it’s known as an “indirect detection” experiment, and as such is the latest in a *different* series of experiments, many of which are space-based, that attempt to see the signature of distant decays or annihilations of dark matter particles. Other such experiments include the Italian PAMELA spacecraft and the U.S. Fermi Gamma-Ray Space Telescope.
The Wikipedia article http://en.wikipedia.org/wik…
covers this in a sensible way.
There is also the possibility of direct *production* of dark matter in an accelerator and its detection by seeing a characteristic signature of missing energy and momentum.
These are really three completely different approaches, and I don’t fault the Times for concentrating on the “direct detection” family of experiments. Should they have spent another paragraph in this article on expanding on the diversity of approaches? I am OK with their focus, but this is debatable.
The Times even alludes to the alternatives in saying “Particle physicists have been hoping to produce these particles or other evidence of supersymmetry in the Large Hadron Collider outside Geneva or to read their signature in cosmic rays from outer space.”
And the Times covered the first results from AMS in April already:
http://www.nytimes.com/2013…
2) The comment about the Higgs is not accurate, nor, in my opinion, fair. There are in fact two independent detectors at the Large Hadron Collider. Each of them sees the signature of what many physicists are careful to call a “Higgs-like” particle in multiple channels, in datasets with large numbers of such events. To say it is a “single event” from “an” experiment is simply wrong. A “single site”, yes. I think the quality science media have reflected fairly clearly that there are a number of tests of the “Higgs-ness” of the particle observed that have yet to be performed, many of which can be done with longer runs, and higher energies, at the LHC. However, the data in hand already do match long-established models very well.
What happened to repeatability? Well, if repeatability is defined as having someone else read the publications and go out and do the experiment themselves completely independently, that’s a matter of billions, and it’s not going to happen for decades to come, most likely; the physics community has long since had to find other ways to achieve the same end. Thus, the LHC was designed with multiple experiments from the start, and each of them planned a suite of measurements, not just one, and so far they have all been in agreement within statistical uncertainties.
The media of course do like, and exaggerate, certainty. The particle physics community is quite clear that there are other experiments to do beyond the LHC – instead of just repeating it – to really nail this down, but at a cost of additional billions. Unless and until the world finds a way to justify and pay for them, and spend 10-15 years bringing them to fruition, this is what we have.