E1.1
Outlining the structure of the solar system, these graphs represent the distance from the sun, plotted on the x-axis against the time taken for one orbit, on the y-axis. This represents the increase in orbital time for bodies that are further away from the sun.
The second graph supports Kepler's Third Law, using a squared value for the orbital time and cubed for the distance from the sun.
E1.2
A stellar cluster (a.k.a. globular cluster) are physically close to each other and this phenomena is linked to gravity. Constellations on the other hand do not necessarily have to have stars which are closer together, as they are merely patterns formed in the sky using stars to connect the dots. It is purely imagination based.
Asteroids are celestial bodies that orbit the sun, made of rock and metal, usually around the inner solar system. A comet also orbits in an elliptical pattern around the sun, however it is composed of rock and ice.
Meteorites are the remnants of those two which has reached the surface of Earth.
E1.3
Light year. The distance that light travels in one year 9.46E15
E1.4
Comparing the relative distances:
Visible Universe: 1.5E26
Local Group of Galaxies: 5E22
Our Galaxy: 1E21
Solar System: 1E13
During a twelve hour cycle above Bangkok, Orion will look like this: