Gravitational lensing helps scientists Probe universe's dark matter


  • Randy Showstack


Gravitational lensing, a technique that explores the phenomena produced when light from a background source is changed by the gravitational pull of a massive object alongits path to the observer, has become a multipurpose tool for cosmologists.

Used one way, some scientists say the technique can help them directly see and measure possible dark matter of intervening objects—such as stars, galaxies, or clusters of galaxies—that is sensitive to gravity. Tony Tyson, an experimental physicist at Bell Labs, Lucent Technologies in New Jersey, and a pioneer in the field of gravitational lensing, is among the scientists who say that lensing can make it possible to see dark matter, which he and others estimates makes up 90% of the universe. He and others say that lensing and a better understanding of dark matter could help with some of the “big picture” questions about the universe: its evolution, mass, structure, and rate of expansion.