Here's a story I read about five days ago and cannot get out of my mind, even though it is on a physics result that is not merely null but highly incremental, and tentative. Furthermore, even if its implications bear fruit they will have no effect on matters of policy or daily habit. That is, the news can have no practical impact other than to encourage support for or perhaps participation in the arcane arts and hence build upon their splendid intellectual achievements. But a lot of science writers get by in large measure on just such stories. They are interesting to a few for whom such news is very interesting indeed.
- Inside Science News Service – Charles Q. Choi: To Date, Particle Supercollider Detects No Evidence Of Dark Matter ;
The news peg is a report in Physical Review Letters. The impetus for that is a small project that a group has underway using the Large Hadron Collider at the mammoth European CERN lab. Because of the machine's high energies it just might, theorists say, foment the formation in its Atlas Experiment collision chamber such intense little fireballs – where protons annihilate one another at near the speed of light – that almost any particle with a mass corresponding to or smaller than what's suddenly available just might congeal and scoot away. The newly-born debris, along with bosons of several sorts, conceivably includes unseeable, or nearly unseeable, particles of dark matter. Choi explains that the key will be to find a collision of known energy, measure the energy output reflected by photons and visible trails left by the hadrons, bosons and stuff, then tentatively chalk up any missing leftovers to thievery by dark matter escape artists. Sort of like that.
Dark matter! Great stuff. I first heard about it as a reporter nearly first-hand, from UC Santa Cruz astronomer Sandy Faber in the early to mid 70s. She had studied with Harvard's Vera Rubin as a grad student or post-doc or something in the late 60s. Among Rubin's many achievements – this one cooking while Faber was in her group – was to conclude and then persuade colleagues that galaxies rotate funny because most of their mass is not in stars or gases or regular stuff, but in something…..else. Sandy made vivid to me in her office among the redwoods how peculiar is the rotation of spiral and other disk galaxies. Rather than turn sort of like whirlpools, faster and faster in rpm nearer the center, their ensemble of jostling stars turns for much of the galaxy's radius more or less like a frisbee, each part going around in about the same time as the others. The outer parts of some galaxies are moving at such speed that they should career off into the void were not the gravity of some extended realm of extra mass holding them to their orbits. Weird. That'd be like Neptune's year having the same length as Mercury's and of all the other planets..
Anyway, back to Choi's news story. I read it and waited to see if anybody else picked it up. So far, zilch that I can find. Inside Science News Service, or ISNS, is a hybrid, non-profit outfit. It doesn't spawn copy cats and aggregators quite the way a BBC or NYTimes or even SF Chronicle does. The American Institute of Physics is its mothership. The AIP is closely affiliated with the American Physical Society, publisher of Physical Review Letters that ran the article Choi wrote up. Ergo it's not quite an independent gimlet eyed and suspicious news organization, but not quite a house organ either. Yet this is no press release. It is hard for me to nail down exactly what it is.
Choi did get reaction from experts outside the CERN team that so far has found no sign of dark matter. That means, his piece reports, that new limits on dark matter specifications have been set. It does not exclude it as a valid hypothesis but it does suggest that physicists are going to need a bigger boat than today's LHC to get some hard data.
One does wish Choi had reported what the new limits on the nature of any dark matter particles are, in some sort of unit. Electron volts, in proton masses, whatever. But he does well to have reported this at all. Somebody's gotta keep up on the incremental news so that they will be prepared when something tremendous happens.
Choi, a cheerful and energetic freelancer I have encountered several times over the years, does big news too. He tends toward fundamental research news across a large span of disciplines. His twitter (@cqchoi) autobio says 'I write about what happens at the edge of the world as we know it — the area lying between the unknown and the impossible'. He doesn't seem to have updated his story list in a few years but a sense of his productivity can be seen at his website.
Grist for the Mill: Physical Review Letters article abstract.
PS – Just read some of the comments to Choi's article. One is a gas. A commenter declares confidently that "Gravity always pushes. Doesn't pull. When you drop a ball, gravity is not pulling the ball. Space is pushing it." Quite pithy. Well-phrased, one ventures. One also wonders whether this writer is 1) Confusing dark matter somehow with the even-stranger pushy phenomenon of dark energy, 2) Has developed, or has fallen for, a crackpot theory of gravity or, 3) Has an unusual insight, in an inverted equivalency fashion, into relativity theory and why trajectories through space-time take an arcing path as they pass by concentrations of mass. Door number 2, one suspects.
A few other, recent dark matter news reports:
- PBS News Hour – Miles O'Brien: Scientists search for understanding of dark matter ; A visit to the Sudbury underground observatory in Canada ;
- IEEE Spectrum – Eliza Strickland: Deepest Underground Dark-Matter Detector to Start Up in China / The PandaX project will look for dark matter in the heart of a marble mountain ;
- Space.com via Discovery News – Katia Moskvitch: Dark Matter Mystery Could Be Solved in 10 Years ;
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