When scientists surveyed Earth’s gravitational fields in the 1960s, they noticed something strange about Canada’s Hudson Bay, and surrounding area; the planet’s gravitational pull was slightly weaker there. While studies were conducted in 2007 to try and figure out this mystery, the debate still rages as to why Canada’s northern communities are a little “lighter” than the rest of the globe.
In 2007, NASA used its Gravity Recovery and Climate Experiment (GRACE) satellites to measure the changes in the Earth’s surface. Using microwaves, the satellites measured the distribution and difference of mass on the planet’s surface. As the highly sensitive satellites, which could detect changes to the micron, passed over the surface, the lead satellite would be pulled slightly closer to the Earth than the trailing satellite, hence getting a measurement of gravitational pull.
The initial theory proposed that this gravitational low was caused by an ancient glacier, the Laurentide ice sheet, which retreated thousands of years ago. Over the last several millennia, the land that was once under the sheet is beginning to bounce back, albeit very very slowly. As the glacier melted away, the mass of the land in Canada’s north dropped. In an interview with LiveScience in 2007, Jerry Mitrovica, a physicist at the University of Toronto, stated,
We are able to show that the ghost of the ice age still hangs over North America.
Another theory also involves the constantly moving and shifting mantle of the planet. Below the surface, the molten rock, as it cools, is pulled down towards the core, and then rises back up as it grows in temperature. This movement potentially drags the planet’s tectonic plates down, but much too slowly for the GRACE satellites to measure. However, this constant movement could also be responsible for the dip in gravitational pull.
With any strange natural phenomenon, the paranormal junkies and conspiracy theorists have also thrown in their two cents. Oddball theories that Hudson’s Bay was formed by a meteor impact, is home to a series of underground caverns, and being that it is often a site for military training, has led believers to think that the bay itself, and Canada’s north in general, is home to trans-dimensional gateways, underground alien civilizations, or crashed UFOs. A popular news story earlier this year that a strange ping was heard under the Arctic ice only added fuel to the fire.
While there is still continued research to be done in regards to the strange gravitational anomaly that resides near Hudson’s Bay, imaginations will continue to speculate the source. Neither of the theories have been completely confirmed, but one thing is for certain, the people who live in Canada’s north have a little more spring in their step than the rest of us.