AMHERST, Mass. - A new member of the physics and astronomy department at the University of Massachusetts, James Lowenthal studies how galaxies are formed. There are two schools of thought, he said: one group believes that huge masses of gas collected, collapsed under their own gravity, and fragmented into galaxies and stars. Lowenthal and others contend that small clusters of stars were pulled together, again by gravity, but with smaller objects collecting to make larger ones, until the star clusters grew into present-day galaxies and galaxy clusters.
Galaxies can be disc-shaped, like the Milky Way, or elliptical or amorphous; astronomers are trying to determine how galaxies change shape over time. There are plenty to study: "If you hold your thumb up against the sky, your fingernail covers 1 million galaxies, each with 100 billion stars," said Lowenthal. Scientists estimate that there are 100 billion galaxies in the observable universe, he added.
Looking at distant galaxies is essentially like using a time machine, Lowenthal said. "Light takes a long time to get here; when we look at distant galaxies, we’re looking at light that has been traveling for 12 to 13 billion years. Although those galaxies are as old as our own, we’re seeing images of baby galaxies." Using powerful telescopes, such as the Hubble Space Telescope, which orbits the Earth, Lowenthal and other astronomers are now able to determine the sizes, ages, and masses of these distant, baby galaxies by analyzing their colors and spectra.
"The work that James is doing is at the cutting edge of modern astronomy and can help deepen our understanding of how the Universe evolved," said John Donoghue, head of the physics and astronomy department. Lowenthal earned his bachelor’s degree at Yale University and his Ph.D. at the University of Arizona. He held a joint postdoctoral research position at Johns Hopkins University and the NASA Space Telescope Science Institute, both in Baltimore, Md., and was also a Hubble Fellow at the University of California at Santa Cruz.