We begin by pointing out that there are two primary kinds of star clusters: open cluster and globular cluster. We visit some very beautiful open clusters including: the Pleiades, the Jewel Box (NGC 4755), Pismis 24 in NGC 6357, and NGC 6791. And then we visit some spectacular globular clusters including: 47 Tucanae, Omega Centauri, the Quintuplet, and Arches cluster with the Pistol Star, and M30.
As we start Supernovas, we review the magnitude of a nova that created the Helix Planetary Nebula with the explosion that created the Crab Nebula. We take the opportunity to describe the size and densities of White Dwarfs as compared to Neutron Stars. We also take a look at what the daytime sky might look like if Betelgeuse were to supernova.
We then explain what a Type 1a Supernova is and how it works as a critically important standard candle. We show binary star matter flowing through the L1 Lagrange point, and mention Subrahmanyan Chandrasekhar’s solution to Einstein’s equations. We then take a look at the amazing remnants of past supernova explosions scattered across our galaxy including: Veil Nebula (NGC 6995), Cygnus Loop, Crab Nebula, SN 1006, RCW 86, Tycho Supernova SN 1572, Cassiopeia A, RCW 103, Kepler’s supernova SN 1604, N 63A, and Supernova 1987A. For RCW 103, we illustrate the impact on the Earth if it were Capella that went supernova. For Cassiopeia A, we illustrate ‘light echoes’.
We conclude by adding brightest globular clusters and Type 1a Supernova as key standard candle rungs on our distance ladder.