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    The Science Behind The Science Fiction

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    9915622484
    This document discusses black holes, including what they are, how they form, and how astronomers detect them. It explains that black holes are formed when a star collapses under its own gravity and nothing, not even light, can escape from within the event horizon. Black holes are detected through observing accretion disks of gas orbiting them, jets of material ejected from near the event horizon, and gravitational lensing effects. The document notes that supermassive black holes are found at the centers of most galaxies and that there is a correlation between the mass of a galaxy and its central black hole.

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    The Science Behind The Science Fiction

    Uploaded by

    9915622484
    45 views40 pages
    This document discusses black holes, including what they are, how they form, and how astronomers detect them. It explains that black holes are formed when a star collapses under its own gravity and nothing, not even light, can escape from within the event horizon. Black holes are detected through observing accretion disks of gas orbiting them, jets of material ejected from near the event horizon, and gravitational lensing effects. The document notes that supermassive black holes are found at the centers of most galaxies and that there is a correlation between the mass of a galaxy and its central black hole.

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    Black Holes Ultimate211

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    This document discusses black holes, including what they are, how they form, and how astronomers detect them. It explains that black holes are formed when a star collapses under its own gravity and nothing, not even light, can escape from within the event horizon. Black holes are detected through observing accretion disks of gas orbiting them, jets of material ejected from near the event horizon, and gravitational lensing effects. The document notes that supermassive black holes are found at the centers of most galaxies and that there is a correlation between the mass of a galaxy and its central black hole.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    45 views40 pages

    The Science Behind The Science Fiction

    Uploaded by

    9915622484
    This document discusses black holes, including what they are, how they form, and how astronomers detect them. It explains that black holes are formed when a star collapses under its own gravity and nothing, not even light, can escape from within the event horizon. Black holes are detected through observing accretion disks of gas orbiting them, jets of material ejected from near the event horizon, and gravitational lensing effects. The document notes that supermassive black holes are found at the centers of most galaxies and that there is a correlation between the mass of a galaxy and its central black hole.

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    Black Holes

    The Science Behind The Science Fiction

    What is a black

    hole?

    Do BHs exist in Nature? YES! How do we find them? What do they look like?

    Stars Pressure Balances Gravity

    From www.astronomynotes.com

    The Sun

    Eluding Gravitys Grasp


    Escape Velocity

    2GM Vesc R
    Mass M Radius R

    Escape Velocity Speed Needed To Escape An Objects Gravitational Pull

    Earth: Vesc = 27,000 miles/hour (11 km/s) Sun: Vesc = 1.4 million miles/hour (600 km/s)

    Dark Stars
    Speed of light 1 billion miles/hour (3x105 km/s)

    What if a star were so small, escape speed > speed of light?

    A star we couldnt see!


    Vesc = speed of light

    Earth mass:
    Solar mass:

    R 1 inch R 2 miles

    1915: General Relativity, Einsteins Theory of Gravity 1916: Schwarzschilds Discovery of BHs in GR BHs only understood & accepted in the 1960s (Term Black Hole coined by John Wheeler in 1967)

    Albert Einstein

    Karl Schwarzschild

    Black Holes in GR
    If an object is small enough, gravity overwhelms pressure and the object collapses. Gravity is so strong that nothing, not even light, can escape.
    Radius of a BH
    2 miles for a solar mass 1 inch for an Earth mass

    NOT a solid surface


    All Mass at the Center (GR not valid there)

    Gravity bends the path of light

    Massive bodies and escape speed

    Gravity bends the path of light

    Three parameters completely describe the structure of a black hole

    .Mass
    .Total electric charge .Spin = angular momentum

    Seeing black holes

    Gravitational lensing

    Basic structure of black hole..

    Event horizon

    Rotating black holes

    A nonrotating black hole has only a center and a surface

    Intro: Of fourth dimension

    mass bends space-time

    Falling into a black holes

    Signals time dilated and red shifted . (external) No communication Incoming signals can enter Fall for a finite time in event horizon

    Falling into a black hole

    Gravitational redshift

    Falling into a black hole

    nuclei
    Spaghettification Atoms Electrons

    Protons Neutrons

    Ripped apart

    Quarks

    How do we find BHs in Nature?

    Its black, and it looks like a hole. Id say its a black hole.

    Where are BHs Found?

    Centers of Galaxies

    Binary Stars

    The Milky Way Galaxy: ~ 100,000 light-years across


    Scale: Size of Solar System: 0.01 light-years Typical Distance btw. Stars: 1 light-year

    4 106 Msun Black Hole

    Central Black Hole Mass: 4 million Msun Also ~ millions of 10 Msun BHs

    Stars in the Central Light-Year of the Galaxy

    Keep Zooming In

    Milky Way

    Black Holes and Galaxies: Chicken or Egg?


    A

    striking correlation was found between black holes and their host galaxies. 0.1%

    Directly proportional

    Techniques for finding black holes

    Accretion disks Gas jets Xray images Infrared images

    Seeing black holes

    Light From Gas Falling Into the Black Hole

    BH

    Infrared Image

    How do black holes forms ?

    Gravitational collapse Emerge due to attraction Big bang

    These are some of supernova explosion

    How do big Black Holes form

    36

    Dr. H. Fearn CSUF Physics

    Dispelling the Myths


    BHs are not cosmic vacuum cleaners: only inside the horizon is matter pulled extremely inward Far away from a BH, gravity is no different than for any other object with the same mass

    M87
    Look closer still: Disk of gas orbiting at 500 km/sec, around one billion solar masses crammed into 1 parsec. A black hole.

    Cen A
    Jets from a tiny region in the center power tremendous luminosity in radio and X rays. A black hole.

    The Moral of the Story


    Physicists said that Black Holes could exist

    Astronomers have found that BHs do exist BHs are responsible for the most dramatic and energetic phenomena in the universe

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