Listening for cosmic whispers
In British Columbia’s Okanagan Valley, a area shaped by ancient glaciers provides natural shielding from the radio noise of modern civilization. This radio-quiet zone hosts the Dominion Radio Astrophysical Observatory (DRAO), established in 1960. The site's most striking instrument is the Canadian Hydrogen Intensity Mapping Experiment, or CHIME. It doesn't look like a typical telescope. Instead, four parallel, 100-meter-long half-cylinders give it the appearance of a massive snowboarding half-pipe array. Each cylinder is 20 meters wide, and together they create a collecting area of 8,000 square meters.
CHIME has no moving parts. It stares straight up, letting the Earth's rotation sweep a band of the northern sky across its view each day. Its purpose is to detect Fast Radio Bursts (FRBs)—intense, unexplained pulses of radio waves that last only a few milliseconds. Before CHIME began full operations in 2018, fewer than 150 FRBs had ever been recorded. In its first year alone, CHIME detected 535 new FRBs, dramatically increasing the known catalog of these signals. The telescope's powerful digital processors sift through a staggering amount of information, processing data at a rate of about 7 terabits per second.
A legacy of astronomical innovation
While CHIME is the newest instrument at the observatory, the DRAO has a long history of radio astronomy. The facility's first major instrument was a 26-meter (84-foot) dish, now named the John A. Galt Telescope. Since its completion in 1960, this classic dish has been used for numerous projects, including making detailed maps of the Milky Way and participating in the first successful Very Long Baseline Interferometry experiments, which link telescopes across continents to create a virtual instrument of immense size.
Another important instrument is the Synthesis Telescope. This is not a single dish but an array of seven 9-meter antennas positioned along a 600-meter east-west track. By combining the signals from these smaller dishes, astronomers can create highly detailed radio images of celestial objects. The Synthesis Telescope operates at wavelengths of 21 and 74 centimeters, allowing it to map cosmic components like atomic hydrogen and ionized gas. The observatory also helps with monitoring our own star. Since 1990, it has been the home of Canada's solar radio flux monitoring program, which provides one of the longest-running and most consistent records of solar activity, a dataset known as the F10.7 index, used worldwide for space weather forecasting.