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by Paola Rebusco

Black Holes and Their Companions. by Paola Rebusco. Isaac Newton, A Treatise of the System of the World , London (1728). Escape Velocity V=(2GM/r) 1/2. FROM: http://www.jnul.huji.ac.il/dl/mss/newton/. Some History.

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by Paola Rebusco

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  1. Black Holes and Their Companions by Paola Rebusco

  2. Isaac Newton, A Treatise of the System of the World, London (1728) Escape Velocity V=(2GM/r)1/2 FROM: http://www.jnul.huji.ac.il/dl/mss/newton/

  3. Some History John Michell (1784) and Pierre-Simon Laplace (1796) propose the existence of “dark stars”…that lock in light (in Newtonian mechanics) Albert Einstein publishes his first paper on GR (1915) Karl Schwarzschild finds black holes as a solution to Einstein’s equations (1916) Subrahmanyan Chandrasekhar suggests that a massive star can collapse into something denser (1930) Robert Oppenheimer and Hartland Snyder predict that massive stars can collapse into black holes (1939) Roy Kerr finds the solution for rotating black holes (1963) Stephen Hawking considers quantum effects: quantum black holes are different from classical black holes (1974)

  4. Relativity • SPECIAL (1905) Time and space are relative, moving clocks run slower, moving objects are shorter, c300000 km/s, equivalence principle, E=mc2. • GENERAL (1915) Space-time is a dynamic entity, it is distorted by matter and it tells matter how to move. FROM: http://www.einstein-online.info/en

  5. What is a Black Hole? Black Hole

  6. Black Holes’ Anatomy Once they form they are left with ……… Mass Spin Charge km miles

  7. BH have NO HAIR By J.A. Wheeler

  8. Black Holes in Theory can have any Sizes!

  9. QUIZ #1 What would happen to the Earth’s orbit IF the Sun was to be replaced by a black hole of the same mass?

  10. IF black holes exist… how do they form?!

  11. REMEMBER: gravity against pressure gradient • High Temperature and Pressure: successive fusion reactions! Life Cycle of Massive Stars Fusing H into He, He into C,O, …and so on into Fe

  12. Iron is the most stable… Supernovae Type II and Hypernovae! • Collapse..250000000 km/h! • More energy released than our Sun in billions of years! What is left?

  13. Death of a Star - Birth of a Black Hole

  14. Mergers! Short Gamma Ray Bursts

  15. Quantum or Not Quantum? Any black hole emits Hawking black body radiation with The characteristic time for quantum effectsis For MBH= 1 MSUN ….

  16. QUIZ # 2 The energy reached by the Large Hadron Collider MAY produce micro black holes ( )…if this were to occur, would it be dangerous?Why?

  17. Commercial Break!!!(Further Reading) • Schutz, B. A First Course in General Relativity • Carroll, S. An Introduction to General Relativity: Spacetime and Geometry • D’Inverno, R. Introducing Einstein's Relativity • Wald, Robert. General Relativity • Hartle J. An Introduction to Einstein’s General Relativity • Thorne, K. Black Holes and Time Warps: Einstein's Outrageous Legacy • Begelman M. & Rees M. Gravity’s Fatal Attraction: BH in the Universe • Ferguson K. Prisons of Light -Black Holes

  18. Do Black Holes Exist? • Lasciate ogni speranza, • o voi ch’entrate. • Abandon all hope, • you who enter here. • Dante Alighieri • (Divina Commedia-Hell) Artist impression John Wheeler 1967- Physics Today

  19. Black Holes are not Alone! Binaries (BH+Companion) Live in Galaxies Affect the Motion of Stars

  20. X-ray Binaries Artist impression

  21. 1972: Cygnus X-1 • The first black hole candidate!!!!!!! • A blue supergiant (optically bright, X-ray dim) orbits an unseen (optically, but bright X-ray) companion! • Rapid X-ray variability

  22. Some X-ray Telescopes RXTE Timing XMM Newton Spectroscopy Chandra Imaging

  23. www.jwst.nasa.gov/ comparison.htm

  24. Radio Galaxies (A type of galaxy with an Active Galactic Nucleus=AGN) • fast (less than 1 yr) change in time • A lot of power in a small space • - Superluminal jets!

  25. Supermassive Black Holes powering AGN!!! NGC 1275 is very active… (radio,X,GAMMA) (Credit: Radio: NRAO/AUI/NSF)

  26. In our Galactic Center…

  27. ..or quiet : Sagittarius A* Infrared Observation 1 light year = 9.4605284 1015 m

  28. QUIZ # 3 Can you estimate the mass of Sagittarius A*?The star S2 got as close as 100 AU (astronomical units), with a velocity of about 10000 km/s.

  29. CONCLUSIONS: Many challenges! Gravitational Waves- Galaxy-Black Holes growth

  30. CONCLUSIONS: Many Challenges! Test GR What happens at the singularity? Understand Quantum Gravity!!!!!

  31. DO YOU HAVE ANY QUESTIONS? ALL THE ANSWERS? SEND A MAIL TO:pao AT space.mit.eduOR PASS BY:BLDG 37, Office 675 QUIZ DEADLINE:Saturday Jan 24 h 11.59 pm3 PRIZES :)

  32. QUIZ You can download this presentation from: http://space.mit.edu/home/pao What would happen to the Earth’s orbit IF the Sun were to be replaced by a black hole of the same mass? The energy reached by the Large Hadron Collider MAY produce micro black holes …if this were to occur, would it be dangerous?Why? Can you estimate the mass of Sagittarius A*?

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