A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

O

Observable Universe:

The piece of the entire space that could be seen from Earth.

Opacity:

The degree to which light is banned from passing through an object or a substance. Opacity is the conflicting of transparency. As an object’s cloudiness increases, the amount of light transitory through it decreases. Glass, for example, is clear and most clouds are opaque.

Optical Telescope:

A telescope, which gathers and magnifies visible light. The two basic types of visual telescopes are refracting (using lenses) and reflecting (using mirrors). The Hubble Space Telescope is an instance of a reflecting telescope.

Ozone Layer:

A region in the higher atmosphere that has high concentrations of ozone (triatomic oxygen, 03). The ozone layers defend the Earth by fascinating the Sun’s high-energy ultraviolet radiation.