black hole vacuum cleaner of the universe. formation of black hole nuclear fusionnuclear fusion -...
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Black HoleBlack Hole
Vacuum Cleaner of the UniverseVacuum Cleaner of the Universe
Formation of Black HoleFormation of Black Hole
nuclear fusionnuclear fusion - tends to blow the star's - tends to blow the star's hydrogen outward from the star's centerhydrogen outward from the star's center
gravitationgravitation - tends to pull all hydrogen - tends to pull all hydrogen back in the direction it had comeback in the direction it had come
Mass of StarMass of Star OutcomeOutcome
< 1.4 solar mass< 1.4 solar mass White DwarfWhite Dwarf
> 1.4 solar mass &> 1.4 solar mass &
< 3.0 solar mass< 3.0 solar mass
Neutron StarNeutron Star
> 3.0 solar mass> 3.0 solar mass Black HoleBlack Hole
Formation of Black HoleFormation of Black Hole
primordial black holeprimordial black hole is formed upon extreme is formed upon extreme compression of matter by external forcescompression of matter by external forces
One possibility of the existence of such black One possibility of the existence of such black holes are during the early stages of the universe holes are during the early stages of the universe where high temperatures and pressures existedwhere high temperatures and pressures existed
Formation of Black HoleFormation of Black Hole
Structure of Black Hole (1)Structure of Black Hole (1)
Schwarzschild singularitySchwarzschild singularity: : a point of infinite densitya point of infinite density
Event horizonEvent horizon: boundary of : boundary of the region inside which light the region inside which light cannot escapecannot escape
Schwarzschild radiusSchwarzschild radius: : radius of the event horizonradius of the event horizon
Schwarzschild black hole (史瓦西黑洞 ) – a non-rotating black hole
Photon sphere
Outer event horizonOuter event horizon: Boun: Boundary inside of which nothing dary inside of which nothing can resist being can resist being dragged arodragged aroundund with the rotating mass with the rotating massInner event horizonInner event horizon: Bound: Boundary inside of which nothing cary inside of which nothing can escapean escapeErgosphereErgosphere: A particle ente: A particle entering it will be split into two: oring it will be split into two: one falls into the black hole, ane falls into the black hole, and the other ejected with mond the other ejected with more energyre energy
Structure of Black Hole (2)Structure of Black Hole (2)
Kerr black hole – a rotating black hole
Structure of Black Hole (2)Structure of Black Hole (2)
EvaporationEvaporation
energy is "borrowed" energy is "borrowed" from the vacuum, from the vacuum, creating a particle - creating a particle - antiparticle pairantiparticle pairOne particle of the pair is One particle of the pair is pulled into the black hole, pulled into the black hole, and the other escapes, and the other escapes, carrying with it some carrying with it some energyenergyA black hole of 1 solar A black hole of 1 solar mass would take ~ 10^66 mass would take ~ 10^66 years to evaporate years to evaporate completely completely
Curvature of space-timeCurvature of space-time
A A smallsmall celestial body celestial body with with large masslarge mass
Severe curvature of Severe curvature of space-timespace-time
Not even light can get Not even light can get out (light loses all energy out (light loses all energy in climbing out of such in climbing out of such holes)holes)
Detection of Black holeDetection of Black hole
If light is not given off If light is not given off by black holes, how do by black holes, how do
we detect them? we detect them?
Orbiting around nothing Orbiting around nothing
When a star changes into a black hole, the When a star changes into a black hole, the strength of its gravitational field remains strength of its gravitational field remains the samethe same
The planets in orbit would continue in their The planets in orbit would continue in their orbits as usual orbits as usual
The planets would appear to be orbiting The planets would appear to be orbiting around nothingaround nothing
X-ray telescopeX-ray telescope
The dust particles near the black hole The dust particles near the black hole speed and heat up, emitting x-raysspeed and heat up, emitting x-rays
Objects that emit x-rays can be detected Objects that emit x-rays can be detected by x-ray telescopes outside of the Earth's by x-ray telescopes outside of the Earth's atmosphere atmosphere
Gravity-lensingGravity-lensing
Gravity lensingGravity lensing occurs when a massive object occurs when a massive object passes between a star and the Earth. passes between a star and the Earth.
From an observer's point of view on the Earth, thFrom an observer's point of view on the Earth, the star would appear to brightene star would appear to brighten
Measuring massMeasuring mass
If a region has large amounts of dark If a region has large amounts of dark mass, one can suspect the presence of a mass, one can suspect the presence of a black holeblack hole
Falling into the black holeFalling into the black hole
Time dilationTime dilation
Gravitational redshiftGravitational redshift
(Observing outside event horizon)
Falling into the black holeFalling into the black hole(Observing inside event horizon)
WormholeWormhole
Developed by Albert EDeveloped by Albert Einstein and Nathan Roinstein and Nathan Rosen in 1935sen in 1935
Einstein-Rosen bridge Einstein-Rosen bridge
A shortcut between twA shortcut between two points in spaceo points in space
Connecting a black hoConnecting a black hole and a white holele and a white hole
E=mc^2E=mc^2
WormholeWormhole
Exotic matterExotic matter is requi is required to keep a wormholred to keep a wormhole openede opened
Exotic matter has –ve Exotic matter has –ve mass and energymass and energy
Gravitationally repulsivGravitationally repulsivee
Light rays passed through a Light rays passed through a wormhole are defocusedwormhole are defocused
Faster-than-light travelFaster-than-light travel
Special relativitySpecial relativity says that one cannot says that one cannot outrun a light signal in a fair raceoutrun a light signal in a fair race
It might be possible to beat a light signal It might be possible to beat a light signal by taking a different routeby taking a different route
The Twin ParadoxThe Twin Paradox
A person who leaves Earth in a spaceship, A person who leaves Earth in a spaceship, travels at near light speed and returns will travels at near light speed and returns will have aged less than someone who have aged less than someone who remains on Earthremains on Earth
http://webphysics.davidson.edu/physletprohttp://webphysics.davidson.edu/physletprob/ch10_modern/twin.htmlb/ch10_modern/twin.html
Time travelTime travel
If the traveler manages to outrun a light If the traveler manages to outrun a light ray, perhaps by taking a shortcut through ray, perhaps by taking a shortcut through a wormhole or a warp bubble, he may a wormhole or a warp bubble, he may return before he left return before he left
Grandfather ParadoxGrandfather Paradox
What happens if I go back in time and What happens if I go back in time and kill my grandfather, thus preventing my kill my grandfather, thus preventing my future existence? future existence?
Thank You
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