Why Does The Earth Spin?

A 2.5 ton granite sphere with 200ths of a millimeter tolerance is located at a local beach in West Vancouver, British Columbia, and floats on a thin layer of water.

The sphere presents an amazing opportunity to study inertia and understand why the Earth spins.

The sphere continuously spins without apparent external intervention.

The creator interviews people on the beach to discuss their theories about why objects like this sphere and the Earth rotate.

• Many people initially suggest gravity is responsible for causing objects to spin • One person proposes gravitational pull keeps objects down on the ground

• Some believe an angled upthrust from water pushes the spherical object at an angle, causing it to spin • Others suggest there is a force within the Earth's core that drives centrifugal force

People question what centrifugal force is and where it comes from.

Someone references the law of inertia as every action having an equal and opposite reaction.

Inertia is not a force, despite common misconceptions.

Inertia is the tendency of all objects with mass to maintain their state of motion.

• Objects at rest want to stay at rest • Objects in motion want to keep moving • Objects continue in their state of motion without any forces acting on them

Both the Earth and the spinning granite sphere maintain their rotation through inertia alone, without requiring continuous external forces.