By Science News Staff

Web edition: November 18, 2011
Print edition: December 3, 2011; Vol.180 #12 (p. 30)

Clocking neutrinos
In response to “Hints of a flaw in special relativity” (SN: 10/22/11, p. 18): When supernova 1987a was detected in the Large Magellenic Cloud (a distance of roughly 168,000 light-years) an influx of neutrinos was detected simultaneously (or nearly so) in Japan, the United States and Russia. Had these neutrinos traveled at the same speed (about 25 parts per million faster than light) as the CERN neutrinos detected by the OPERA experiment in Italy, they would have arrived roughly four years ahead of the visual display from 1987a, rather than at approximately the same time.
Paul White, Portsmouth, R.I.

The mathematical representations found in Einstein’s theory of special relativity do not predict an upper limit on speed. They predict a “real” bound on currently understood physical entities when speed approaches the speed of light from below.

We have exhaustively explored our familiar physical world below the speed of light. Possibly this is our first glimpse into the netherworld above the speed of light. Einstein lived in the world of thought experiments. Possibly Einstein’s mathematical representations work adequately to represent physical phenomena at subluminal speeds, but do not adequately represent physical processes at superluminal speeds. Possibly new thought experiments along with new mathematical representations are needed to analytically continue the classic representations into this new world.
Keith Mitchell, Westminster, Md.

Bat comeback
Regarding the article “Helping bats hold on” (SN: 9/10/11, p. 22), we have little brown bats that visit the field in back of our home to hunt each summer. Our experience with the bats is somewhat consistent with the information in the article, but there is a significant difference.

We were disturbed with the dwindling number of bats during the past few summers. In 2009 we encountered no bats. In 2010 I was joyous when I saw a single bat on two occasions. Then this summer, the bats came back in numbers as great as ever. Every night I checked, there was a wonderful show above the back field. Is my experience a signal of new developments? Are the bats recovering on their own?
Stu Vandermark, Framingham, Mass.

This local bat population’s apparent rebound is not typical. Researchers continue to report declining numbers across Canada and the eastern United States this year, as in the last few years. —Janet Raloff