Robert George “Bob” Greenler

Greenler—Robert George “Bob” Greenler, 95, on September 21, 2025, at Oakwood Village retirement community in Madison, Wis., the home he and his wife, Nancy, shared for 16 years. Bob was born on October 24, 1929, to Ruth and Dallas Greenler in Dunkirk, Ohio. He studied at the University of Rochester in New York and attended graduate school at Johns Hopkins University in Baltimore, Md., earning a doctorate in physics in 1957.

As a young adult in the 1950s, Bob was drawn to Quakerism and became a member of Homewood Meeting in Baltimore. He met his first wife, Barbara, at Homewood. They married in 1954 and shared their Quaker journey until Barbara’s death in 2006.

Bob was a professor of physics at the University of Wisconsin–Milwaukee starting in 1962, where he was instrumental in developing the interdisciplinary Laboratory for Surface Studies. He was involved in the international scientific community, serving in various offices with the Optical Society of America, the American Institute of Physics, and the Council of Scientific Society Presidents. He was cofounder and director of the Science Bag, a long-running series of public science programs at the University of Wisconsin–Milwaukee. He authored several books including, Rainbows, Halos and Glories; and Chasing the Rainbow: Recurrences in the Life of a Scientist.

In 1954, he agreed to testify on behalf of a friend unjustly accused during the McCarthy hearings, an action that held potentially serious repercussions for him.

Bob and Barbara transferred membership to Milwaukee (Wis.) Meeting in 1957 where he was actively involved for almost 50 years, raising a family and serving in many capacities. In 1960, he served as the second clerk of the newly fledged Northern Half Yearly Meeting, the precursor to Northern Yearly Meeting. He later transferred his membership to Madison (Wis.) Meeting where it remained until his death. He found kinship and resonance in his Quaker communities for his personal convictions of nonviolence, fair housing, civil rights, right sharing of world resources, LGBTQ rights, and environmental stewardship.

Bob was enchanted by the beauty of the natural world. From making a crepe-paper-and-water laboratory of beautiful hues as a child, to studying spectral sky effects at the South Pole as an adult, he delighted in seeing, understanding, and sharing beauty. His pursuit for understanding was a form of play that led him to examine spinning tops, classical paintings, glass harmoniums, outdoor bench designs, local flora and fauna, and more. He also took great joy in teaching others to see and understand the world around them, whether it was through glorious sky effects, birdwatching, a restored prairie, or a natural oak preserve.

Bob balanced his deep desires to teach, research, and practice science with his commitments to family, friends, and many other interests. He delighted in keen observation of and engagement with the outdoor world through canoeing, camping, and wildlife photography. He biked for many decades and celebrated his ninetieth year by riding 900 miles. He delighted in game playing both as an intellectual challenge and social connection. He was an avid beekeeper and a skilled birdwatcher. Bob and Barbara spent almost 40 years “wilding” with native plants the property they lived on near Milwaukee. Then, for over two decades, Bob nurtured the Oakwood Nature Preserve in Madison, helping guide the property to a more ecologically based, sustainable, and educational prairie and oak woods ecosystem.

Bob was preceded in death by his first wife of 52 years, Barbara Greenler; and a sister, Dorothy Johnson.

He is survived by his wife, Nancy Simonsen; three children, Lee Greenler (Susan), Karen Greenler (Penny Majors), and Robin Greenler (John); six grandchildren; one sister, Phyllis Jacobson; and family friend Sue Coffin.