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Black Holes

Black Holes . This one’s green. I like green. . What happens after a SN?. Material remaining after a supernova is 3 times more massive than the sun or more Pressure is strong enough to collapse the star beyond the neutron-degenerate pressure. Star remnant collapses and vanishes.

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Black Holes

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  1. Black Holes This one’s green. I like green.

  2. What happens after a SN? • Material remaining after a supernova is 3 times more massive than the sun or more • Pressure is strong enough to collapse the star beyond the neutron-degenerate pressure. • Star remnant collapses and vanishes.

  3. Characteristics of a black hole • MATTER IN A BLACK HOLE LOSES ALMOST ALL OF ITS ORIGINAL CHARACTERISTICS! • Retains only: • Mass (therefore the gravity) • Its angular momentum *** All other characteristics no longer exist! • concepts like protons, electrons, neutrons, molecules, compounds etc. no longer apply.

  4. ??? I have a headache. • Escape Speed- speed needed for an object to escape the gravity of another. • Bigger mass= bigger grav, then bigger ES • Smaller radius= bigger grav, then bigger ES • The escape speed for a black hole is greater than the speed of light. • Nothing can exceed the speed of light (except Bause when he runs towards the lunch line) SO nothing can escape a BH

  5. Singularity • General relativity (Einstein) predicts that in creating a black hole, matter compresses to infinite density. • ALL known laws of physics are invalid. • Recall Relativity explains the behavior of the really massive, quantum mechanics explains the behavior of the really small (subatomic stuff). A black hole is both REALLY massive and REALLY small.

  6. Schwarzschild radius • The radius that matter (any matter, does it matter?) must be compressed for it to have an escape speed equal to the speed of light. • All objects have a SR • Earth = 1 cm or a grape • Jupiter = 3 cm or 3 grapes (I’m not creative) • Sun = 3 km

  7. Event Horizon • The location around a black hole where the escape speed EQUALS the speed of light. • Everything in the EH is lost forever. No information can be gathered from within. • Outside of the EH, everything appears to “slow”… called gravitational redshift

  8. Gravitational Redshift • Speed of light is CONSTANT through constant medium. • In order for light to escape gravity it must work (use energy). Greater the grav, more energy. • SO, light will lose energy and shift towards red portion of electromagnetic spectrum (longer wavelength)

  9. Gravitational Lens • Gravity can bend light rays. • This can allow us to see objects normally too far for us to see. • Bause diagram.

  10. All galaxies… ranging from 3 bill. ly to 9 bill ly.

  11. Sphagettification?

  12. Infalling Matter • Matter closest to the BH will be pulled greater, stretching the matter. • Eventually pulled apart, atom by atom.

  13. Does a black hole last forever? • Nope. • They can evaporate through Hawking Radiation (more in your lab). • Process takes a LONG time. A 5 solar mass black hole would take 1062 years to evaporate. So, black holes that have formed, still exist today.

  14. Supermassive Black Holes • All elliptical and spiral galaxies seem to have one in the center. Irregular galaxies (aka dwarf galaxies) do not. • A black hole with the mass of millions to billions of Suns!

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