The International Geophysical Year (IGY) was an international scientific project that lasted from July 1, 1957, to December 31, 1958. The IGY encompassed eleven Earth sciences : aurora and airglow, cosmic rays, geomagnetism, gravity, ionospheric physics, longitude and latitude determinations, meteorology, oceanography, seismology and solar activity.
Both the U.S. and the U.S.S.R. launched artificial satellites for this event; the Soviet Union's Sputnik 1 in October was the first successful artificial satellite. Other significant achievements of the IGY included the discovery of the Van Allen radiation belts and the discovery of mid-ocean submarine ridges, an important confirmation of plate tectonics.
Canada's IGY stamp, designed by Alan Pollock, was issued on March 5, 1958.
Essays

National Archives of Canada

National Archives of Canada
First Day Covers













Usages
Domestic Forward Letter

Dominion to Hamilton, June 4, 1958
5 cents forward letter rate

Regina to Ottawa, November 4, 1958
5 cents forward letter rate + 10 cents special delivery fee

Hearst to Toronto, April 24, 1958
5 cents forward letter rate + 20 cents registration fee
International Air Mail

Toronto to Penzance, March 31, 1958
15 cents one-half ounce air mail rate to Great Britain