Far out cosmology:Any explanation for dark matter? 2 (Introduction)

by David Turell , Saturday, September 10, 2016, 01:22 (2995 days ago) @ David Turell

Another commentary on not finding WIMPS to explain dark matter:-http://www.livescience.com/56041-dark-matter-just-got-murkier.html?utm_source=ls-newsletter&utm_medium=email&utm_campaign=20160909-ls-"The most recent contribution to our knowledge of dark matter was made by the Large Underground Xenon (LUX) collaboration. LUX is a vessel consisting of a third of a ton of liquid xenon and it is the most powerful dark-matter detector ever constructed.......And the thing is, it didn't detect anything. That non-discovery is what's causing physicists to rethink how they think about dark matter.-***-"We have never directly observed dark matter, but we know a great deal about what it must be: It must be massive (because it affects the rotation of galaxies); it must be electrically neutral (because we can't see it); it must be different from ordinary matter (because we see no evidence for it interacting with matter in the usual ways); and it must be stable (because it has existed since the dawn of the universe). These properties are unequivocal.-***- "It is the heavy mass and non-interacting qualities that make the sterile neutrino an ideal dark-matter candidate.-"Another possible dark-matter particle, the axion, was proposed in 1977 as a way to ensure that the strong nuclear force treated matter and antimatter on equal footing (so as agree with observations). The axion is a very light, but still massive, hypothetical particle. The LUX detector is not designed to study axions.-"Then, of course, there is the even more creative hypothesis, which suggests that dark matter isn't a single, neutral, non-interacting particle. After all, ordinary matter is pretty complicated. At the quantum scale, we have quarks and leptons and four forces. At the macro scale, we have you and me and sugar and stars and volcanoes and all the various ways they interact. Ordinary matter has all sorts of interactions and constituents. Why not dark matter?-***-"It's not fair to say that the LUX measurement leads to a crisis in particle physics and cosmology. But it certainly gives scientists pause and suggests that maybe we should take another look at this WIMP thing. Maybe other ideas need to be revisited. On the other hand, scientists who want to continue to pursue the WIMP idea still have something to look forward to as technology advances. LUX uses a third of a ton of liquid xenon. In 10 or 15 years, scientists are planning to build detectors that might contain 100 tons, providing even more chances of capturing that rare WIMP interaction. These are heady times to be a dark-matter scientist.-"But, in the end, we still don't know. We just know that the capabilities of LUX are good enough that maybe it's time to broaden our thinking. In the words of the rock band Buffalo Springfield, "There's something happening here. What it is ain't exactly clear...'"-Comment: The universe will one day reveal much more of its mysteries. Humans have the intelligence to do that. It is highly significant that life appeared quickly and resulted in organisms that can explore and interpret their own universe.