Astrophysics

E.1.1

E.1.2
A Stellar Cluster is a group of stars that are physically close to each other in space, and are caused due to Gravity, a Constellation on the other hand are patterns of stars due to our imaginations and are not necessarily physically close to each other.

E.1.3
1 light year is defined as the distance light travels in 1 year

3.0 x 10^8 x 365 x 24 x 60 x 60 = 9.46 x 10^15m

E.1.4
Compare the relative distances between stars within a galaxy and between galaxies, in terms of order of magnitude

E.1.5

Constellations appear to move over the period of one night. They appear to rotate around one direction.
In the Northern hemisphere it seems to rotate about the pole star.

Over a year the positions of the constellations are the same relative to one another, however the position of the pole star changes slightly every night.

The sun continues to rise from the east to the west, but over the year the arc gets bigger and the sun climbs higher in the sky.

It only appears to be moving due to the Earths rotation and its movement through space.