The Origin of Stellar Energy (Lecture – 08) by Professor G Srinivasan скачать в хорошем качестве

The Origin of Stellar Energy (Lecture – 08) by Professor G Srinivasan

Summer course 2018 - A Random walk in astro-physics Lecture - 08 : The Origin of Stellar Energy by Professor G Srinivasan, Raman Research Institute (Retired) 10.00 to 12.00 Friday, 18 May 2018 Madhava Lecture Hall, ICTS Bangalore The range of densities, temperatures, magnetic fields, etc. that obtain in the Universe are staggering: from 10-27 g cm-3 to 1015 g cm-3, from 3K to 1010 K, from 10-6 G to 1015 G. Not surprisingly, the variety of physical phenomena one encounters during the study of celestial objects is truly impressive. This set of lectures is intended to illustrate the richness of Astrophysics. It will be a random walk in basic physics, with numerous illustrations from astronomy. The topics in physics that will be reviewed have been chosen on the basis of their importance in contemporary astronomy. Topics: Absorption and emission of radiation Radiation from relativistic electrons Compton scattering of radiation Spontaneous and stimulated emission Hyperfine splitting of energy levels Molecular spectra Astrophysical plasma. Quantum tunnelling. Nuclear matter Neutrino Oscillation Phase transitions and the early Universe During this random walk in physics, one will encounter a range of astronomical objects and phenomena, such as, Solar wind, gaseous nebulae, interstellar hydrogen clouds, giant molecular clouds, neutron stars and pulsars, supernova remnants, radio galaxies and quasars, active galactic nuclei, the cosmic microwave background, etc. https://www.icts.res.in/summercourse2018 Table of Contents (powered by https://videoken.com) 0:00:00 Summer course 2018 - A Random walk in astro-physics 0:00:10 The Origin of Stellar Energy (Lecture-08) 0:00:37 What are the stars? 0:02:44 Stars as globes of perfect gas 0:08:16 Hydrostatic Equilibrium 0:14:26 Boyle's Law 0:17:46 Equation of Hydrostatic Equilibrium 0:18:26 Stars are globes of gas in which the inward pull of gravity is balanced by the combined effect of the pressure of an ideal gas and the pressure of radiation. 0:19:26 Eddington's theory of stars 0:22:20 Radiation Pressure 0:22:23 Hydrostatic Equilibrium 0:25:19 Why do the stars shine? 0:27:04 Why does the Sun shine? 0:29:07 Virial Theorem applied to the Sun 0:30:09 How long will the heat last? 0:33:50 Sir Arthur Eddington 0:39:37 Mass Deficit 0:43:48 Proton - proton collision 0:48:25 Maxwell-Boltzmann Distribution 0:58:56 Quantum Tunnelling 1:02:35 Energy production in the Sun 1:06:51 proton - proton reaction 1:16:52 Nuclear cycles 1:24:07 To burn or not to burn? That is the question 1:25:43 Coulomb barrier 1:29:05 Fusion reactions 1:30:35 Onion skin model of a star 1:31:55 The composition of the core when nuclear reactions finally stop 1:35:05 Lifetime of stars 1:36:57 Why doesn't the Sun blow up? 1:37:26 The Safety Valve 1:46:10 Q&A