With the surname Kirkegaard one expects seriousness. Jacob Kirkegaard’s audio-visual installation, Testimonium, is both deadly serious and mystically alive and imaginative. It is an eight-channel sound piece that catches the inner life of detritus. Kirkegaard is a sound artist. He was born in Denmark in 1975 and made his first recording at age 6. Where others see “nothingness,” he sees—and hears—“being.” Kirkegaard has made sound art from melting snow in the Arctic, radioactivity in Chernobyl. To make Testimonium, he lowered vibration sensors into incinerators, mountains of organic matter, wastewater, and recycling facilities, capturing agitation and transmutation. As aural as it is visual, this exhibition is not a dystopian fiction. It is our world. —L.J.