Caltech researchers have been able, for the first time, to watch viruses infecting individual bacteria by transferring their DNA, and to measure the rate at which that transfer occurs. Shedding light on the early stages of infection by this type of virus—a bacteriophage—the scientists have determined that it is the cells targeted for infection, rather than the amount of genetic material within the viruses themselves, that dictate how quickly the bacteriophage's DNA is transferred.

Caltech has taken over operation from NASA of the Galaxy Evolution Explorer (GALEX), a space telescope that for the last nine years has been surveying the cosmos in ultraviolet light. In this first agreement of its kind, NASA is lending the telescope to Caltech, which has led the mission and will continue operating and managing it through the support of private funders.

Scientists have further narrowed the search for a hypothetical particle that could be dark matter, the mysterious stuff that makes up 80 percent of all the mass in the universe. Caltech postdoc Jennifer Siegal-Gaskins presented the researchers' results, compiled from two years' worth of data from NASA's Fermi Gamma-ray Space Telescope, at a meeting of the American Physical Society in Atlanta earlier this week.