Rein Silberberg; Unlocked Secrets of Cosmic Radiation

Rein Silberberg, 69, who helped unlock the secrets of cosmic radiation during a long career as an astrophysicist at the Naval Research Laboratory, died Friday at his home in Silver Spring, Md. He had cancer.

Born in Estonia, Silberberg came to the United States in 1950. In 1960, he joined the Naval Research Laboratory and studied the origins and behavior of high-energy atomic particles known as cosmic rays or cosmic radiation.

This radiation, which was discovered fewer than 100 years ago, consists of high-energy particles--pieces of atoms--that whiz through the galaxy at enormous speeds. They are often broken up by banging into the relatively sparse population of other particles found in the rarefied regions of interstellar space.

Ultimately, some of these particles make their way into the Earth’s atmosphere, where they have been detected by scientists, prompting questions about where their long journeys began and what they looked like when they started.

Along with colleagues Maurice Shapiro and C.R. Tsao, Silberberg was known for finding ways to trace the roots and sources of the bits of atoms--mostly protons--that ultimately reach the outer boundaries of Earth’s atmosphere.

He also was a pioneer in developing a theory for gaining information about the cosmos from studying the arrival on or near Earth of tiny subnuclear particles called neutrinos, which, like X-rays and gamma rays, help tell the story of the cosmos. Gamma ray astrophysics was among Silberberg’s specialties.

He had a progressive disability that impaired his hearing and left him partly paralyzed. In 1983, he was named the Navy’s outstanding handicapped employee of the year.

After suffering privations during World War II and during Communist rule in Estonia, Silberberg went with his family to Finland, Sweden and Canada before reaching the United States, where he obtained his doctorate in physics at UC Berkeley in 1960.

Silberberg was co-author or co-editor of several works in astrophysics, a consultant at Roanoke College and co-director of the International School of Cosmic Ray Astrophysics in Italy.

He is survived by his wife, two children and a granddaughter.