The genesis and characteristics of black holes
description
Transcript of The genesis and characteristics of black holes
The genesis and characteristics of black
holes
Marion Mikusch Physics institute, university of Graz
The contraction of a gas cloud molecules: do not have enough Ekin triggers: compressions Jeans mass and Jeans radius:
contraction Epot is released if heat is transported off collapse free falling time: protostar is born
A collapse sets in…
Different phases:
◦ hydrogen burning◦ helium burning◦ carbon, neon, oxygen, silicate burning
stage of equilibrium until fuel is depleted a new thermonuclear process starts Stars over 8 sm: also heavy elements are
built iron-nickel core is formed supernova
Stage of nucleosynthesis
neutron star: e+pn
until internal pressure prevents contraction
Star over 30 sm: unstoppable collapse a black hole is born
The unstoppable collapse
escape velocity reaches the speed of light
Schwarzschild radius: causal border
black hole with 10 sm: Rs = 29,5 km
event horizon: surface around the black hole
A black hole swallows everything…
interstellar matter approches in spiral tracks
X-ray emission
rotation space-time geometry is distorted
‘electromagnetic tornado‘
Accretion disc and matter jets
analogy between event horizon and entropy
entropy: disorder of missing information in a system
bit of information area of the event horizon
definition of entropy and temperature is possible
thermodynamical description
paradox: finite temperature emission of thermal radiation??
Quantum mechanics: uncertainty principle virtual particles can arise in pairs
they disengage for a short time and than annihilate
mass of the black hole decreases
total evaporation
Hawking radiation
Only 3 observable characteristics:
◦ mass◦ angular momentum◦ electric charge
huge information loss
but a swallowed bit is ‘saved‘ in an area of the event horizon like a hologram
3-dimensional object memorized by a 2-dimensional region
holographic principle