Foucault pendulum 2010, the cable suspending the bob in the Musée des Arts et Métiers snapped, causing irreparable damage to the pendulum and to the marble flooring of the museum. An exact copy of the original pendulum has been operating under the dome of the Panthéon, Paris since 1995. At either the North Pole or South Pole, the plane of oscillation of a pendulum remains fixed relative to the distant masses of the universe while Earth rotates underneath it, taking one sidereal day to complete a rotation. So, relative to Earth, the plane of oscillation of a pendulum at the North Pole
Foucault pendulum vector diagrams of the pendulum swing the surface velocity vectors are angled upwards but on the opposite side the vectors are angled downwards. Since these vectors are all in the same plane as the pendulum swing there is no change of the surface in relationship to the plane of the pendulum swing. The surface velocity due to the Earth's rotation is a maximum at the Equator and is equal to the circumference (pi × the diameter of the Earth) per 24 hours (or 3.14159 × 12,756 ÷ 24 = 1670 km/h = 1 equatorial velocity unit, EVU). The time of an Earth's