By Cynthia Marshall Schuman

The Milky Way galaxy was formed primarily through the accumulation of an invisible substance called dark matter and the stars and gas dragged along with it, according to a prominent UC Berkeley professor who spoke in Los Altos Hills last Wednesday.

Astronomy professor Leo Blitz spoke about the origins of the universe to close to 700 students, professionals and amateur astronomy hobbyists. His talk, “The Making of the Milky Way: Survival of the Fittest,” was the first presentation in the Silicon Valley Astronomy Lecture Series, which is being held at Foothill College.

Blitz, also director of the radio astronomy lab at UC Berkeley, maintains that the Milky Way arose from the merging of numerous small galaxies.

How these small galaxies moved toward one another is a subject of some debate. Movement of any sort requires gravity, and gravity exists only in the presence of matter. While galaxies undisputedly contain matter in the form of stars, clusters of stars, and gases, some scientists such as Blitz contend that the visible matter within these small galaxies does not have sufficient mass to facilitate the merging.

“The Great Nebula in Andromeda and the Milky Way are the largest galaxies in our local group of galaxies, making up 95 percent of the matter in that local group,” Blitz said. By implication, the remaining stars and galaxies contain negligible mass.

Proponents of dark matter believe that there is an additional source of matter surrounding the small galaxies like a halo. It is called dark matter because it isn’t luminous and has therefore never been seen with telescopes; its components are wholly unknown.

“If the theory of the accumulation of small galaxies to form the Milky Way is proven, it will discredit the earlier idea that the Milky Way formed from the collapse of a single, large cloud of gas,” wrote Blitz in electronic correspondence after his talk.

The Silicon Valley Astronomy Lecture Series is jointly sponsored by NASA Ames Research Center; Foothill College’s Division of Physical Science, Mathematics and Engineering; the Astronomical Society of the Pacific; and the SETI Institute. This is the series’ third year. It is aimed at sharing “the excitement of modern astronomy with teachers, with students, and with the public at large,” said Andrew Fraknoi, who chairs the department of astronomy at Foothill College.

November’s talk will be given by Dr. Arno Penzias, recipient of the 1978 Nobel Prize in physics. He will give a nontechnical, illustrated talk called, “A Personal View of the Big Bang.” The presentation is scheduled for 7 p.m., Nov. 13. For more information, call the series hotline at 949-7888.