Letters to the Editor

Neutrinos and Cosmic Rays

We were gratified to see the IceCube Neutrino Observatory labelled a “Physics Newsmaker for 2013” (APS News, February 2014, page 1).

However, we were confused by the second half of the discussion, “In August, researchers using data from IceCube’s surface detectors, IceTop, confirmed that, as scientists had long suspected, supernovaes are among the main sources of the high-energy protons known as cosmic rays.” IceCube has not made any conclusions about the sites of cosmic-ray acceleration.

Spencer Klein
Berkeley, CA

Olga Botner
Uppsala, Sweden

Francis Halzen
Madison, Wisconsin

Tom Gaisser
Newark, Delaware

Editor’s note: The quoted section should have read “Then in August, researchers from the Fermi Large Area Telescope collaboration confirmed that, as scientists had long suspected, supernovae are among the main sources of the high-energy protons known as cosmic rays.” We apologize for the error.

Women and the Nobel Prize

Congratulations for recognizing the gender imbalance in Nobel Laureates in Physics since their inception in 1901 (“This Month in Physics History,” APS News, December 2013). As of now, the Nobel Prize in Physics has been awarded to two  women and 193 men.

In addition to the three women mentioned, Lise Meitner, Chien-Shiung Wu, and Vera Rubin, whose contributions merited Nobel Prizes, there are others. For example, Marietta Blau, who pioneered the development of nuclear emulsions, the immensely important photographic method of studying particle tracks; Inge Lehmann — discoverer of the Earth’s inner core; Cecilia Payne-Gaposchkin — chemical composition of stellar atmospheres; Kathleen Lonsdale, who demonstrated benzene ring structure and that the molecule is planar and hexagonal; Katharine Blodgett — first monomolecular films on solid surfaces.

References to the original published papers and biographical data on these and other important female physicists can be found at the Contributions to 20th Century Women to Physics website. Scientific accounts and biographies of 40 distinguished and important 20th century female physicists can be found in the volume: Out of the Shadows, Contributions of 20th Century Women to Physics, N. Byers and G. Williams (eds.), Cambridge University Press, 2006.

Nina Byers
Los Angeles, California

Digital versus Analog

In “Digital versus Analog” (Letters, APS News, February 2014), Victor Alpher contests David Lide’s description of the telegraph as a digital instrument.

As Alpher stated, the Oxford English Dictionary indeed defines a digital signal as one that is “expressed as a series of the digits 0 and 1.…” He failed to note, however, that the dictionary also defines a telegraph to be “a system for transmitting messages from a distance along a wire, especially one creating signals by making and breaking an electrical connection.” This binary demarcation of an open (0) or closed (1) circuit is just what Oxford demands for a technology to be digital. Thus, Lide was correct in labeling the telegraph as a digital instrument.

Evan MacQuarrie
Ithaca, NY