Ontario is home to a weird gravity anomaly where things weigh less

If you've ever wanted to shave a tiny bit off the number on your scale, there's actually one place in Ontario where it's technically possible without you changing anything about your lifestyle.

The Hudson Bay area in Ontario is home to one of the world's most peculiar gravity anomalies, where the Earth's gravitational pull is slightly weaker than average, meaning you would weigh marginally less than you would normally anywhere else on the planet.

The phenomenon was first identified in the 1960s when scientists were mapping out Earth's global gravitational field and discovered that the Hudson Bay area mysteriously seemed to be "missing" gravity.

We hate to burst your bubble, but the difference isn't actually something you'd clearly notice by stepping onto a bathroom scale; rather, it's measurable using sensitive scientific instruments. Overall, gravity in the region is roughly 0.004 per cent weaker than Earth's average.

Since gravity is directly related to mass, areas with slightly less mass exert a weaker gravitational pull, and although we often think of Earth as having that same gravity everywhere, that's not actually the case.

The planet isn't a perfect sphere; it bulges slightly at the equator, and its mass isn't evenly distributed beneath the surface. As a result, two theories have emerged to explain the gravity anomaly observed in the Hudson Bay area.

The first theory dates back to the last Ice Age, approximately 20,000 years ago, when the massive Laurentide Ice Sheet covered much of Canada, including parts of Hudson Bay. The ice sheet was roughly 3.2 kilometres thick in most areas, which weighed down Earth's crust with immense force.

As the ice slowly melted, it left behind a huge depression in the crust, and although the land has been gradually rebounding ever since (rising by about 12 millimetres each year), it hasn't fully recovered just yet.

This lingering "dent" means that there's slightly less mass beneath Hudson Bay, which helps to explain the "weaker" gravity. However, that theory only accounts for about 25 to 45 per cent of the anomaly.

The second theory has to do with activity beneath the Earth's crust, where molten rock in the mantle slowly circulates in convection currents. As hotter material rises and cooler material sinks, movements can actually drag sections of the continental crust downward, resulting in a reduced amount of mass beneath certain areas.

Scientists confirmed that both theories are responsible after analyzing data from NASA and the German Aerospace Center's Gravity Recovery and Climate Experiment (GRACE) satellites, which orbited Earth starting in 2002.

The gravity anomaly won't be budging anytime soon either, as scientists estimate that Earth's crust around Hudson Bay still has hundreds of metres left to rebound — a process which could take a few thousand years to complete.