IF YOU think Canadians weigh less than Americans, you’re right. It’s because over a large swath of Canada gravity is weaker than elsewhere. And now we know why.
Geophysicist Mark Tamisiea of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his team used the pair of satellites called Gravity Recovery and Climate Experiment (GRACE) to study the gravitational low over Canada’s Hudson Bay. GRACE can measure tiny changes in Earth’s gravity, allowing researchers to calculate the distribution of mass around the planet.
The Canadian low was noticed in the 1960s when Earth’s gravity fields were first mapped. Researchers have…
