Although the Moon is Earth's only natural satellite, there are a number of near-Earth objects (NEOs) with orbits that are in resonance with Earth. These have been called, inaccurately but provocatively, second, third or other moons of Earth. NEOs include quasi-satellites that orbit the Sun in resonance with Earth, which appear to orbit a point other than Earth itself, such as the orbital path of the NEO asteroid 3753 Cruithne.
Definition of CONVERGENCE. 1. : the act of converging and especially moving toward union or uniformity; especially: coordinated movement of the two eyes so that the image of a single point is formed on corresponding retinal areas.
What is convergence insufficiency? Convergence insufficiency is the inability to maintain binocular function (keeping the two eyes working together) while working at a near distance. Typically, one eye will turn outward (intermittent exotropia) when focusing on a word or object at near. In convergence insufficiency, eye misalignment occurs when focusing at near.