Thursday, July 22, 2010

Curiouser and curiouser

Like many SF aficionados, I enjoy time-travel stories. I've written them myself, most recently in Countdown to Armageddon.  So I enjoyed a recent article (although I was disappointed by its lack of detail) claiming that Physicists Tame Time Travel by Forbidding You to Kill Your Grandfather. As for the notion that time protects itself -- and grandparents -- by diddling with  probabilities -- I used that in "Grandpa?" in 2001.

You gotta love a particle so elusive that it passes through the Earth with effectively a zero probability of interacting with ... anything. A particle that may represent a fraction of the universe's mysterious dark matter -- and if it does, will raise questions about the long-lived, heretofore very successful Standard Model of particle physics. A particle that spontaneously cycles between various forms. That particle (more precisely, a class of particles), is, of course, the neutrino

Neutrino astronomers have studied solar neutrinos for years -- and now they're starting to look at Earth's own neutrinos. Since neutrinos are produced in nuclear decays, radioactive elements in the Earth's core are neutrino sources -- and a way to study Earth's deep interior. Details at Physicists hunt for a trace of the elusive, invisible geoneutrino.

And also in experimental science, recent measurements of the size of protons disagree with earlier estimates and theory. It's far too soon to guess whether measurement, interpretation, or theory is at fault here, but it's in surprises like this that we learn about the universe. Stay tuned.

(The second image is a particle detector at Fermilab. If you look closely, you'll find people in the picture [look for white dots: they're hard hats] for scale. All to find subatomic particles. Amazing.)  

And on a personal note: this entry is my 150th post, coming about a month before my second anniversary as a blogger. Those statistics somewhat surprise me -- but in a good way. I look forward to proclaiming #200 sometime soon.

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