SETI Physics News Update.432


Larry Klaes (lklaes@bbn.com)
Mon, 07 Jun 1999 21:01:00 -0400


>Date: Mon, 7 Jun 1999 15:28:48 -0400 (EDT) >From: AIP listserver <physnews@aip.org> >To: physnews-mailing@aip.org >Subject: update.432 > > >PHYSICS NEWS UPDATE >The American Institute of Physics Bulletin of Physics News >Number 432 June 7, 1999 by Phillip F. Schewe and Ben Stein > >ELEMENTS 118 AND 116 have been discovered at Lawrence >Berkeley Lab by crashing a beam of krypton atoms into lead atoms. >The three detectable atoms of element 118 have nuclei possessing >118 protons and 175 neutrons for a mass total of 293. The new >elements are even further along in the Periodic Table than element >114, whose existence was announced back in January 1999 by >scientists in Russia (see Update 412), and further into the "island of >stability," the supposed nuclear regime in which certain >combinations of neutrons and protons lead to a relatively long life. >For all that, the atoms of element 118 still decay after less than a >millisecond into element 116 plus an alpha particle. Element 116 >then promptly decays into element 114 plus another alpha particle. >Ken Gregorich (510-486-7860) led the LBL group that discovered >the new nuclei. Four of the team members are German nationals, >which prompted DOE secretary Bill Richardson to emphasize the >continuing value of international scientists working at US national >labs. (LBL press release, June 7.) > >THE SPEED OF LIGHT IS INDEPENDENT OF FREQUENCY to >within a factor of 6x10^-21. Bradley Schaefer of Yale (203-432- >3806, schaefer@grb2.physics.yale.edu) bases this estimate on the >observed arrival of gamma rays from distant explosive events in the >cosmos, such as gamma-ray bursters. If the speed of light (c) were >slightly different for the different frequency ranges, then some light >waves would show up before the others, but this is not the case. The >best previous effort to locate a frequency dependency for c, deduced >from light coming from the Crab pulsar, was at the 5x10^-17 level. >Why would c vary with frequency? Einstein's theory of relativity, >and its insistence on a universal light speed, might be at fault. Or >photons might have mass. Schaefer's analysis addresses this issue, >and puts an upper limit of 10^-44 g on any putative photon mass, >not quite as sharp a limit as those based on the observed strength of >the galactic magnetic field (a nonzero photon mass would allow the >fields to decay away). The new sharper limits on any possible >frequency-dependency for c is a vindication of relativity. By the >way, the prefix for anything as small as 10^-21 is "zepto." (Physical >Review Letters, tent. 21 June; journalists can obtain the article from >AIP.) > >THE SURFACE OF MARS has been mapped to 13-meter precision, >better than for some places on Earth. Laser light sent from and >returning to the orbiting Mars Global Surveyor spacecraft reveals >that the southern hemisphere is one big highland (6 km higher) >compared to the northern hemisphere. Surface water, if there was >any, would have collected in the North, although there is not yet >definitive proof of any boreal ocean. One thing that is known about >the northern lowland: it is the flattest place in the solar system. The >South's elevation is due at least in part to an immense amount of >material raised during an ancient impact which fashioned a huge >crater known as the Hellas basin. (Science, 28 May 1999.) > >THE PAINTINGS OF JACKSON POLLACK, famous for their >seemingly random distribution of drips and streaks, are fractal in >nature. Physicists at the University of New South Wales (Australia) >subjected Pollack's handiwork to the kind of mathematical scrutiny >usually given to fractures in crystals and distributions of galaxies. >They found that the paintings bore similar features at each of many >size scales, the hallmark of fractalness. The object's characteristic >"fractal dimensionality" is roughly related to the indentedness of the >object's texture. Apparently the dimensionality of Pollack's work >increased through the years. (Nature, 3 June 1999.) >



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