Transcript Black Holes - Elon University

Black Holes
Pierre Cieniewicz
What are they?
A Black Hole (BH) is a place in
space from which nothing can
The reason for this is gravity
escape
Some things are so dense that
even light cannot escape their
gravitational pull
Schwarzschild Radius
Example:
What
Earth’s
Schwarzschild
Thewould
size anthe
object
must
be in order
be?
to be denseRadius
enough
to not allow
light to escape its gravitational pull
Schwarzschild Radius
• G = 6.67 x 10-11 N m2 kg-2
• Mearth = 5.9736 x 1024 kg
Schwarzschild Radius
How big would *I* have to be to be a BH?
• G = 6.67 x 10-11 N m2 kg-2
• Mearth = 83.9 kg
Event Horizon
The point at which light can no
Thisescape
soundsaaBH’s
lot like
the
longer
gravity
Schwarzschild Radius…
Event Horizon vs Schwarzschild
Schwarzschild Radius is the
maximum size
RBH <= RS:
Schwarzschild Radius <= Event Horizon
Singularities
The center of a BH where v=0
and there is infinite density
Types of BHs
Stellar-mass
Intermediate-mass
Supermassive
Types of BHs
Stellar-mass: Collapse of a supergiant star or rapidly rotating
neutron star in a binary galaxy
Intermediate-mass: Unknown
Supermassive: Connected to the formation of galaxies
Characteristics
Only 3 properties:
• Mass
• Charge
• Angular Momentum
Spacetime Frame Dragging
Nothing can stay still in the Ergosphere
Angular Momentum
Ergosphere: Area of space outside the
BH which is forced into spinning
Spacetime Frame Dragging
BH
Ergosphere
Spacetime Frame Dragging
BH
Ergosphere
Spacetime Frame Dragging
BH
Ergosphere
Spacetime Frame Dragging
BH
Ergosphere
V>c
Hawking Radiation
BH
Black Holes can lose mass
E=Mc2
~13 billion years
Hawking Radiation
BH