Fate of Stars II

        Went for my evening walk and re-listened to “Fate of Stars II” about the processes that power stars. Hydrostatic equilibrium is where the outgoing thermal pressure is in balance with the gravity of incoming matter. This Hydrostatic equilibrium is caused by the fusion of four hydrogen atoms that overcome the Coulomb barrier (at high temperatures strips away electrons from the hydrogen atom leaving protons) that collide at high velocities forming a new helium atom. The energy left over after this process (a helium atom has less mass than four hydrogen atoms) is released in the form of neutrinos and high-energy photons. These photons eventually slow down as they make their way through to the stars surface and radiate into space. Our Sun converts hydrogen to helium at a rate of four million tons a second. After a star runs low on hydrogen (our Sun in about five billion years from now) will start fusing helium into carbon and oxygen and go off the main sequence of the HR diagram becoming a red giant. At this point blowing off its outer shells creating a nebula, and if it is below 1.4 solar masses, with a white dwarf at its center. Above 1.4 solar masses and depending on how massive the star is you can have a neutron star or a black hole (this will be discussed in the next lecture). The electron degeneracy pressure holds up a white dwarf core. Wow did I just write all this!
        Watched “Science Now” on PBS about Stem cells, filming underwater critters, SETI and the new Allen radio telescopes, and leaches used for modern medical purposes.
        I forgot to add that last night I setup my telescope (as I did tonight) to view Jupiter before the Moon came up. Well last night I believe I saw one of the moons go behind the planet: there was a little bump on Jupiter’s edge that slowly disappeared, cool! Tonight I saw four moons lined up.