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Canada's First Magnetic Observatory

The Toronto Magnetic and Meteorological Observatory, created in , is the oldest scientific institution in Canada. Its founder, Sir Edward Sabine, was an eminent English astronomer who spent most of his career studying the Earth's magnetic field. Toward the end of the 1830s Sabine took an interest in a question that was stirring passions in the scientific community: What causes the fluctuations in the Earth's magnetic field that throw off navigation compass readings?

The Sun's fluctuations affect the Earth's magnetic field, shown in blue. (Credit: SOHO, ESA, NASA)

To answer that question, a grand project was conceived under Sir Edward's direction: to build magnetic observatories throughout the British Empire, notably in Canada. Toronto was chosen as one site. Other observatories were built at that time in Cape Town, South Africa, on St.  Helena in the South Atlantic, and in Tasmania.

The Magnetic and Meteorological Observatory, at the University of Toronto, was used for many different research purposes, in particular to measure the direction and intensity of magnetic fields and to study meteorological models. Astronomical observations taken there allowed precise time calculations, and this contributed to a major scientific initiative: worldwide time standardization through the creation of time zones in .

This painting by W. Armstrong depicts the observatory on the grounds of King's College, now University of Toronto. (Credit: Environment Canada)

The observatory was a simple log structure equipped with copper and brass instruments. These materials were used so that measurements would not be influenced by magnetic variations from the laboratory environment. The manual readings were then analyzed in England by Sabine. The Toronto observatory quickly became pivotal in several discoveries.

In , Sabine realized that the fluctuations in the Earth's magnetic field could be reduced to a daily cycle marked by periods of irregularity. It seemed to him that these periods were closely linked to the number of sunspots, whose 11-year cycle had been established by . Sabine was first to recognize that activity on the Sun influences the Earth's magnetic environment.

The observatory in -. (Credit: University of Toronto)

By the late s, the University of Toronto campus was growing, whereas the Magnetic Observatory facility was becoming obsolete. Modern conveniences arriving on campus-in particular, electric streetcars-impaired the accuracy of scientific measurements. In , the observatory moved to a building it would occupy until it ceased its scientific activities in the s. The stone building now houses the offices of the Students' Administrative Council.

Sunspots are clearly visible on this image captured by the SOHO satellite in . (Credit: ESA, NASA)

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