Number 142, September 1, 1993 by Phillip F. Schewe and Ben Stein TIME-DOMAIN OPTICAL MEMORY is a technique for storing multiple bits of information at a single location in a crystal. This technique, developed by Thomas Mossberg, now at the University of Oregon (503-346-3791), exploits the fact that molecules in crystals absorb and radiate light at many different frequencies, and has the potential of storing 1 million bits in a one-cubic-micron spot in a crystal. This corresponds to 100,000 atoms per bit--as opposed to the 50 trillion atoms per bit required for conventional data storage. To write information, a series of laser light pulses (constituting a binary message) burns a "spectral hole" at a tiny spot in a crystal. To read the information, a second series of pulses causes the crystal's molecules to radiate a frequency pattern identical to that of the first pulse. Recently, Ravinder Kachru (415-859-3727) of SRI International in California wrote 1,600 bits to a single 100-micron spot in a crystal. With a few advances in technology, it may be possible to store 50 million bits in the spot and read the information at a blazingly fast rate of 40 billion bits per second. However, practical crystalline materials must still be found for this technology. (Scientific American, September 1993.) IDA, A 20-MILE WIDE ASTEROID , was photographed from only 1500 miles away by the Galileo spacecraft on its way toward Jupiter. This was only the second encounter between an asteroid and a spaceprobe; the first was Galileo's 1991 flyby of the asteroid Gaspra. Galileo's antenna problem, which will diminish operations during its Jupiter-observing mission, also slows down the process of sending back pictures of Ida, which will be available in about a month. (AP in the Washington Post, 29 August.) GIANT MAGNETORESISTANCE (GMR) , the change of a material's electrical resistance caused by an applied magnetic field, can now be produced with low fields. Scientists at IBM ADSTAR in California have developed a structured material using nickel, iron, and silver atoms stacked in nm-thick layers, with neighboring layers having oppositely oriented magnetizations. The new material shows a 4-6% resistance change in applied fields of only 5-10 oersteds (at room temperature) rather than the 250 oersteds used previously. GMR studies, only 5 years old, are expected to lead to an increase in the density of data that can be stored in magnetic media. (Science, 20 August.) PHYSICISTS IN THE FORMER SOVIET UNION (FSU) are getting financial help from a number of sources. A European Community (EC) initiative established in June 1993 has already approved 16 physics projects, which will receive a total of about $1.8 million. Specific projects include a theoretical-physics linkup among six Russian institutes and the University of Paris and a research collaboration bringing together several FSU and EC labs for doing research using high magnetic fields. George Soros, a private financier, has previously announced a gift of $100 million, to be spent over the next two years, for helping FSU scientists. (Physics World, August 1993.) Individual western scientific societies have also helped out. For example, The American Physical Society, with money from Soros, the NSF, and a variety of private and foundation grants, has by June 1993 granted $1.3 million to roughly 2500 FSU physicists.