Scientists' Biggest Search For Dark Matter To Date Just Turned Up Nothing (sciencealert.com)

Peter Dockrill, reporting for ScienceAlert: For something that's hypothesised to make up more than 80 percent of the mass of the entire universe, it's no easy thing to detect the existence of dark matter. That's the conclusion the world is coming to today, after scientists announced that a massive $10 million experiment to find traces of elusive dark matter particles had failed after an exhaustive 20-month search. "We've probed previously unexplored regions of parameter space with the aim of making the first definitive discovery of dark matter," said physicist Cham Ghag from University College London in the UK, one of the scientists who took part in the Large Underground Xenon (LUX) project based in South Dakota. "Though a positive signal would have been welcome, nature was not so kind! Nonetheless, a null result is significant as it changes the landscape of the field by constraining models for what dark matter could be beyond anything that existed previously."Ars Technica has more details.

Comments

Re:Great news everyone

[lgw]

No, it is more than that. Astrophysicists give the attribute of "gravity" to dark matter. In fact, that was the reason they promulgated the idea, i.e., galaxies would fly apart otherwise so there must be something we cannot see which supplies the extra gravity.

They do not entertain the idea that maybe their laws are wrong, or that some other phenomenon might be affecting gravity.

That was true quite a few years ago, when there were many theories for galactic rotation rates, including MOND (precisely "the idea that maybe their laws are wrong"), hot dark matter, and cold dark matter which might be WIMPs or MACHOs.

Then we got more data.

WIMPs won out because they also explain gravitational lensing and the early universe. The cosmic microwave background radiation observations were decisive. The predictions made WIMPs were right on the money - turns out the early universe had just the predicted amount of (a) matter, that (b) wasn't moving near the speed of light, and (c) before block holes, brown dwarfs, etc could have formed.

That's how science works. Scientists do not lack creativity - there was a whole forest of ideas to explain galactic rotation rates. But as more observations of unrelated phenomena come it, only "some sort of particle" was left standing. Falsifiable theories were falsified.

This experiment was a bit silly IMO - it was just a detector much like the detectors we built for neutrinos, which had never shown any signs of dark matter before. It was very much a case of "well, we know how to build this sort of detector already, so let just build a big one and hope for the best".