In astronomy we use angles to measure the 'distance' between objects as seen from Earth, either with the naked eye, or with the aid of a telescope.

Both my Oxford and Collins dictionaries simply state that "UFO" is an abbreviation for "unidentified flying object". Think about it: a flying 'object' (it could be anything), which is unidentified at the time of sighting. That's all there is to it; or is it?

Twice a year the apparent path of the sun crosses the equator so that the sun is directly overhead at some point on the equator, giving rise to an equinox, which literally means "equal night".