The direction of A to B on a sphere is along the geodesic arc along the greatest circle defined by the center, A and B. So the chord AB is the direction of the vector pointing from A to B. Therefore, from point A anywhere on a spherical object, one simply pivots his/her head down in the direction of the chord AB, for example from the antipode the chord is along the diameter of the sphere,and he/she is facing point B, or the Sacred Mosque. Obviously this can be done on any spherical object, i.e. the Moon, Mars or any place in the
universe where the location of the Earth is known at a given local time.
Below I have pasted a neutrino image of the Sun taken by the Super-K detector. For neutrinos, the Sun is always visible no matter where you are on the Earth, day or night.
See the following website.
http://strangepaths.com/the-sun-seen-through-the-earth-in-neutrino-light/2007/01/06/en/
Image of the Sun taken through the Earth, in “neutrino light”, at the Super-Kamiokande detector (Japan). The image has been obtained with a 503-day exposure, by registering neutrinos emitted from the solar core and detected in a 50000-ton water pool located 1km underground. At night, neutrinos were transparently traversing the whole earth before being registered in this image.
Neutrino Light