Which celestial body is directly overhead when at the North Pole?

At the North Pole, Polaris, commonly known as the North Star, is the celestial body that is directly overhead, positioned at the zenith. This is because Polaris is located nearly at the celestial north pole, making it an important reference point for navigation in the Northern Hemisphere. When standing at the North Pole, one would find Polaris at an altitude of 90 degrees, or directly overhead.

In contrast, the other celestial bodies mentioned are not positioned in the northern sky in the same way. Proxima Centauri is located in the southern hemisphere of the celestial sphere and cannot be observed directly from the North Pole. Betelgeuse, while visible from the Northern Hemisphere, is not located at the northern celestial pole and will be at a lower altitude in the sky. Similarly, Sirius, although it is one of the brightest stars and visible from many locations in the Northern Hemisphere, does not occupy the same pivotal point as Polaris within the celestial navigation framework at the North Pole.

Thus, Polaris serves as a crucial point for orientation and navigation for those located at the North Pole, marking the direction of true north.