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.
Convergence Insufficiency or Excess. When an object is getting closer to you, your eyes have to converge to see it. Converge means to move the eyes in towards each other. Double vision is a common side effect of poor convergence ability. Convergence is the ability for the eyes to turn inward towards each other.