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Neutron stars and beyond

Neutron stars and beyond. There it is!. Cassiopeia A…the remnant of the supernova of 1680. How many pulsars (neutron stars) are there in the sky?. http://www.atnf.csiro.au/research/pulsar/psrcat. Neutron stars: from exotica to numerous astronomical objects.

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Neutron stars and beyond

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  1. Neutron stars and beyond There it is! Cassiopeia A…the remnant of the supernova of 1680

  2. How many pulsars (neutron stars) are there in the sky? http://www.atnf.csiro.au/research/pulsar/psrcat

  3. Neutron stars: from exotica to numerous astronomical objects

  4. A final mystery…pulsar masses are nearly all AT the Chandrasekhar Limit

  5. Neutron Stars – Extreme Objects Does it get any weirder?

  6. Basic physics suggests a way: the maximum mass of a neutron star What happens Here?

  7. Black Holes in Theory: you check in, but you don’t check out • Theoretical ways of describing them • (A) Classical physics: an object with escape speed greater than the speed of light (> c) • (B) General Relativity and Black Holes

  8. Black Holes in classical physics: Given a mass M, how compact (squished) does it have to be? Schwarzschild Radius Rs = 2GM c2

  9. Cramming something inside the Scharzschild Radius extreme matter Example: Planet Earth M= 5.97E+24 kilograms Rs = 9E-03 meters = 0.9cm !!!! DEMO But always ask: do they exist?

  10. General Relativity and Black Holes General Relativity: a theory of gravity Basic mathematical object: 4 dimensional spacetime

  11. Basic Ingredients of General Relativity • (A) Objects move between 2 points in spacetime on the shortest path between those points (geodesics) • (B) The presence of mass warps or bends spacetime The Einstein Field Equations

  12. General Relativistic Black Holes For sufficient concentration of mass in sufficiently small region, there is a rip or hole poked in spacetime Schwarzschild Radius DEMO with analogs

  13. But do they exist? Is nature capable of producing such strange objects? Question: what kind of astronomical objects, with what kind of quantitative properties, would you look for?

  14. They do exist, in two types Little Ones……and……

  15. ……Big Ones

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