The Big Bang
Our solar system orbits the center of the Milky Way Galaxy. Assuming a circular orbit 30,000 ly in radius and an orbital speed of 250 km/s, how many years does it take for one revolution? Note that this is approximate, assuming constant speed and circular orbit, but it is representative of the time for our system and local stars to make one revolution around the galaxy.
Supernovae and their Remnants July 4, 1054 event Chinese, Japanese maybe even Anasazi record a new star in Taurus Peak apparent magnitude = -5 Supernova Light Curves Two classes Type 1: Bright at its peak. Bright, fast decaying Type 2: Doesn’t get as bright at its maximum much long, but lasts longer. Dimmer, slower decaying Type II SN – observations High mass stars Not as bright, slower dimming Find compact object in center: Neutron Stars Black Holes The Problem w/ Iron! Hydrogen, Helium, Carbon, Oxygen = Fusion releases energy Uranium, Lead = Fission releases energy Iron cannot fuse because it cannot make matter from energy Iron cannot fission Iron will collapse under gravity Iron core mass > 1.44 M Sun Electrons & Protons are smashed into Neutrons and then they burst into Neutrinos Type II SN – theory Fusing shells, Iron core Collapsing core P + e N Gamma rays and neutrinos are emitted Implosion sends out a shock wave when neutron core recoils Neutron star or black hole is left Star explodes because the dense matter transfers its momentum to light particles SN 1987A First SN in 1987 Supernova (SN) in Large Magellanic Cloud Closest one in modern times Neutrinos detected confirm theory Supernova Light Curves Brightness vs. Time Powered by Radioactive decay: 56 56 56 Ni Co Fe Evidence in the light curve shape Nucleosynthesis (all elements > Zn) Neutron Capture – free neutrons are capture by a heavy nucleus “Slow” or