Number 295, November 13, 1996 by Phillip F. Schewe and Ben Stein CAN HELIUM-3 HELP THE SOLAR NEUTRINO PROBLEM? The shortfall in the measured solar neutrino flux, especially arising from Be-7 and B-8 decays, may require a particle physics fix (the shortfall can be accounted for if neutrinos oscillate from one type to another) or a modification in the standard solar model. Wick Haxton of the University of Washington (haxton@emmy.phys.washington.edu) and Andrew Cumming of UC Berkeley, although interested in the neutrino oscillation solution, have in a new paper sought to re-examine the solar model, particularly the role of helium-3. He-3 is both produced (in fusion reactions such as p+p-->d followed by d+p-->He-3) and consumed throughout the sun's core. Over the long life of the sun the He-3 abundance will be much higher in the cooler, outer reaches of the core than at the center. Haxton and Cumming pose this speculative question: what if some of the He-3 sinks (much as convective plumes do in Earth's mantle) toward the center of the solar core where, producing an out-of-equilibrium concentration of He-3 which would favor He-3+He-3 reactions at the expense of He-3 +He-4 reactions; the latter contribute to the production of Be-7 and B-8, which in turn spawn exactly the high-energy neutrinos which are found lacking in earthly detectors. This He-3 transport scheme, if valid (both for the sun and for other stars), would nudge the expected neutrino fluxes much closer to the observed values. The cycling of He-3 would also manifest itself in other observable ways, such as in helioseismology and in the way red giant stars blow off He-3 into space. (Physical Review Letters, 25 November.) A GRAVITOMAGNETIC FIELD , according to the theory of general relativity, arises from moving matter (matter currents) just as an ordinary magnetic field arises from moving charges (electrical currents). The analogy is so apt that the equations describing this "magnetic" component of gravity can essentially be adapted from Maxwell's equations for electromagnetism by replacing the charge density with the mass density and the charge current with the mass current. The rotating Earth, containing a lot of matter in motion, is the source of such a very weak gravitomagnetic force. Indeed, measuring this field is one of the tasks of the upcoming Gravity Probe B a satellite. Near a rapidly rotating black hole the gravitomagnetic force is much more potent and rivals the static gravitational field in strength. Stuart Shapiro of the University of Illinois (shapiro@astro.physics.uiuc.edu) asserts that in analogy with the Faraday effect, whereby a changing magnetic force can induce electrical currents, a changing gravitomagnetic force emanating from a rapidly rotating black hole can induce matter currents inside a nearby object---say, a neutron star spiraling in toward the hole. This induced vorticity will influence the spin of the star, its internal structure, and its orbital motion. These effects in turn might be discernible in gravitational waves reaching the future LIGO and VIRGO detectors on Earth. (Phys.Rev. Lett., 18 November; figure available on 11/14 at www.aip.org/png.) A SEARCHABLE VERSION OF PHYSICS NEWS UPDATE can be found on the Web at this address: http://newton.ex.ac.uk/aip/. Organized by John Rowe of the University of Exeter (UK), this versatile service effectively puts six years of physics developments at your fingertips. It allows the user to access particular issues or to search the entire Update archive for specific topics.