A magnet can exert force over distance because it creates a magnetic field. A magnetic field is a region of space around a magnet where the magnetic force can be detected. The magnetic field is strongest near the magnet and gets weaker as you move away from it.

The magnetic field exerts a force on any object that has a magnetic moment. A magnetic moment is a measure of the strength of an object's magnetic properties. The greater the magnetic moment, the stronger the force that the magnetic field will exert on the object.

The force that a magnetic field exerts on an object is proportional to the strength of the magnetic field and the magnetic moment of the object. The force is also inversely proportional to the square of the distance between the object and the magnet. This means that the force gets weaker as the distance between the object and the magnet increases.

The magnetic force is one of the four fundamental forces of nature. The other three forces are the gravitational force, the electromagnetic force, and the weak nuclear force. The magnetic force is responsible for the attraction and repulsion of magnets.