Basic Astronomy Word List
Astronomical Unit
The distance from the Earth to the Sun
- 93 Million Miles
Astronomy
The Science which deals with all Matter-Energy
in the universe
Big Bang
Universe exploded from a primordial atom
and will keep expanding forever
Black Hole
The volume of space surrounding a collapsed
star throughout which the
escape velocity equals or exceeds the
speed of light
Composition
The qualitative and quantitative chemical
makeup of matter
Distribution
The position or arrangement of matter-energy
throughout an area or space
Ecliptic
Reference plane of the solar system
which is created by the Earth orbiting the
Sun
Electromagnetic Spectrum
Gamma rays, X-rays, ultraviolet, visible,
infrared, microwaves, and radio
energy
Evolution
The process of change of the universe
over time from a beginning to an end
Galaxy
Basic manner in which matter congregates
in the universe; composed of
millions to hundreds of billions of
stars
Hydrogen
The most abundant element in the universe
composed of one proton and one
electron
Ion
An atom or molecule which is not electrically
neutral because it has either
gained or lost electrons
Light Year
Distance that light travels in one year
Movements
Change in the position of a heavenly
body due to a change in the position of
the earth or the body itself
Oscillating Universe
A big bang universe that has sufficient
matter to collapse once again
Physical State
Solid, liquid, gas, and plasma
Plasma
A hot ionized gas in which ions and
electrons are in free association
Rotation
The spinning motion of a body about
its axis
Revolution
The orbiting motion of one body around
another body
Solar System
Our Sun surrounded by its family of
nine planets, moons, and lesser bodies
Steady State
An outdated theory of the universe
which states that the universe is infinitely
old and infinitely expanding
Universe
All matter-energy everywhere
