A science-fiction tale describes an artificial "planet" in the form of a band completely encircling a sun, as shown in the figure(Figure 1) . The inhabitants live on the inside surface (where it is always noon). Imagine that this sun is exactly like our own, that the distance to the band is the same as the Earth-Sun distance (to make the climate temperate), and that the ring rotates quickly enough to produce an apparent gravity of g as on Earth.

What will be the period of revolution, this planet's year, in Earth days?