E.1.2 Distinguish between a stellar cluster and a constellationStar clusters or star clouds are groups of stars. A globular cluster is a tight group of hundthousands of very old stars which are gravitationally bound. Stars in a cluster are relativelto each other. Omega Centauri is the most globular cluster in our Galax
E.1.2 Distinguish between a stellar cluster and a constellationConstellations are patterns formed by prominent stars in the night sky. Although they appclose to each other, stars in constellations can vary greatly in their distance from Earth. Cassiopeia
E.1.3 Define the light yearA unit of distance equivalent to how far light travels through space in one yearOur Sun is part of a large collection of stars called a galaxy (ours is called theMilky Way and consists of over 100 billion stars). Get used to vast distances!
E.1.4 Compare the relative distances between the stars within agalaxy and between galaxies in terms of order of magnitude.Nearest star to our Sun – Proxima Centauri 4.2 ly away.There are only 8 stars within 101 lyDiameter ofMilky Waygalaxy is 105 ly
Andromeda is our nearest neighborgalaxy – about 2.9 x 106 ly from theMilky Way
E.1.5 Describe the apparent motion of the stars/constellations overperiod of a night and over a period of a year, and explain theseobservations in terms of the rotation and the revolution of the EarthDiurnal motion - the apparent circular motion of stars around the EThis observation occurs because the Earth is rotating.
The apparent westward motion of constellation in the night sky over a period ofa year is due to the revolution of the Earth around the Sun.