& Neutron Stars
Binary star- Two stars that orbit around a
common center of mass.
White Dwarf- A star that has exhausted most of
its nuclear fuel and has diminished in size. Has
Solar Masses- A unit of mass equivalent to the
mass of the Sun.
Neutron Star- The imploded core of a massive
star produced by a supernova explosion.
Types of Supernovae
Type 1a: This type of supernova
results in binary star systems.
This comes about when a white
dwarf absorbs mass from a
companion. So much mass
piles up on the white dwarf that
its core reaches critical density.
This results in an uncontrolled
fusion of carbon and oxygen,
and the star detonates! Type 2
Type 2: These supernovae
occur at the end of a massive
star’s lifetime, when its nuclear
fuel has been exhausted.
Therefore, the star is no longer
supported by the release of
nuclear energy. If the star’s
core is massive enough, it will
collapse and become a
Where does the Core go?
When the core is lighter than
A Black Hole 5 solar masses, it is believed
that the neutrons are
successfully halting the
star’s collapse, causing a
When a core does collapse,
the central core becomes so
dense, that something would
have to travel faster than the
speed of light to escape!
This strong pull of gravity
creates a black hole from the
core of the original star.
What the heck are neutron stars?
Neutron stars are dense balls of
neutrons that remain at the core of a
star after a supernova explosion has
destroyed the rest of the star.
Typical neutron stars are about 20 km
wide big as Manhattan and contains
more mass than the sun. muy dense!
A pulsar is a rapidly rotating highly
magnetized neutron star, formed in the
supernova of a massive star.
These charged particles flow along
magnetic field lines, producing radiation
that beams outward as the star spins on
Last about 100- 1,000 years.
exotic objects in
the universe. A lump of neutron
star matter the size of a sugar cube
would weigh as much as all humanity,
and the stars have magnetic fields a
trillion times Earth's.
Recently the Rossi Explorer, a new X-ray
satellite, discovered a remarkable new
phenomenon of neutron stars that strip
matter from their companion stars:
their brightness varies almost periodically
more than a thousand times per second.
Pulsars are like lighthouses
because when the pulsar
rotates the beams of light
and radiation stretch across
great distances at set timed
“Glitches“- small increases in a
neutron star’s spin rate.
This is the youngest known
pulsar and lies in the center
of the Crab Nebula, the
supernova remnant of its
birth explosion, which was
witnessed by Europeans
and the Chinese in the year
1054 A.D. as a daytime light
in the sky. The pulsar
rotates about 30 times per
second and it sounds like…
M L B
E C K
Who, What & Where
Black Holes trap everything they consume.
Light is no exception.
Hence the name.
So……….how can they be detected?
Two ways: A star rapidly orbiting around
X-Ray evidence of an accretion disk from
a neighboring star.
A black hole is a region of space so
densely packed with matter that nothing,
not even light, can escape.
They have: Infinite density & zero
Boring far away, Large tidal forces, Time slows
Everythingmoves toward the center, Time and
space interchange roles.
The minimum speed
at which an object
can move away from
a source of a
Escape velocity is
proportional to the
square root of the
mass divided by the
square root of it
If you have infinite
mass and zero
Just before matter is gobbled up by a
hungry black hole, it's hurtling around
the monster at nearly the speed of
light. This heats up the material and it
can release a tremendous amount of
energy as X-rays. Different elements
release energy with a specific
fingerprint that astronomers can
Evidence of Black Holes in Binary
Just as with neutron
stars, if a black hole
is in a binary and it
strips gas from its
companion, we can
detect X-rays from
accretion disk. The
light from accretion
disks around a
black hole looks
very similar to the
light from disks
Astronomers have a candidate for a black hole
in the constellation Cygnus x-1 (X-ray source)
Discovered in the early 1970s
The X-ray emitting region is likely an accretion
disk formed as matter drawn from the visible star
is spiraled down onto the unseen component.
As the gas flows towards the black hole, it
becomes superheated and emits the X-rays just
before they are trapped forever below the event
Black Hole in the Constellation
Schematic of an x-
ray binary system
viewed edge on.
The orbital period of
both objects can be
as one body passes
in front of the other.
Black holes are NOT cosmic vacuum cleaners—they
will not consume everything!
One you step inside the event horizon, you are
trapped there forever.
A human would be stretched apart if they went any
closer this is known as spaghettification.
Tales of a
Supermassive Black holes
Not ready 2 b cene
Evidence of Black Holes in the
Centers of Galaxies
In the centers of galaxies, astronomers have found that stars and
gas are moving extremely fast, orbiting some very massive,
You can also understand the presence of a black hole in the center
of some galaxies. This is done by observing stars near the center
of the galaxy. If the stars are moving very rapidly around some
unseen object, Kepler's laws can be used to estimate the mass in
the center. In some cases the mass must be at least a hundred
million times our Sun's mass, in a region only a few light years
across. Astronomers are virtually certain that the only explanation
is a black hole, but we lack the direct evidence.
Masses range from millions to billions of times greater than the
Intense energy emission from the centers of these galaxies, and
short-timescale fluctuations in that emission, suggest the presence
of compact, massive objects.
Supermassive black holes are believed to exist at the center of
most galaxies. There is evidence that our own galaxy, the Milky
Way, harbors a 2.5 million solar mass black hole at its heart.
Super Massive Black Holes
Any clockwise rotation to the hole would appear to tick
more slowly than an equivalent clock on board the
Singularity is a point in the universe where
the density of matter and the gravitational
field are infinite.
The Laws of Quantum Gravity must be
understood to explain a black hole and
2 Theories of Relativity:
The Special Theory of Relativity
Proposed by Einstein in 1905
The general Relativity
Whatresults when gravity is included in the
framework of special relatiity.
The Schwarzschild radius is the radius at
which the outermost boundaries of the
black hole would start.
The event horizon of a black hole can only
increase, not decrease.
A ball of photons orbiting a black hole as a
result of the gravity pulling in the photons.
-The bend of
the light around
a black hole
makes it almost
-To detect a black hole, we
would have to observe it
passing in front (transiting)
-The black hole of a star.
-What happens is the
starlight would be deflected
when it passes the black
hole on the way to earth.
It’s almost like a solar
eclipse, where there is a
bending of starlight around
the edge of the sun.
Gravity waves are ripples in the curvature
of space-time continuum created by the
movement of matter.
They move across the space-time
continuum. This is the enmeshed
combination of our 3 perceived physical
dimensions + time. Thus the 4th
…and a half dowzen other known objects
in or near our galaxy that may turn out to
be black holes…(However, Cygnus,
LMCX-3, and AO620-00 are the strongest
the pattern of flow of matter from a normal star to a neutron star or black hole, which is
flattened and thus disk-like.
a quantum-mechanical phenomenon; fermions, such as electrons or neutrons, obey Pauli's
exclusion principle, so that no two fermions can occupy the same state. Thus, if fermions
are squeezed together they resist even if there is no temperature and no energy
generation. This resistance to squeezing is degeneracy pressure.
Equation of state:
the relation between the pressure and density of a given type of matter, which is an
indication of how the matter resists squeezing. If the matter resists squeezing strongly
(e.g., water), the equation of state is stiff; if it resists squeezing only weakly (e.g., air), the
equation of state is soft.
in a black hole, the point beyond which events cannot be detected. This is the point of no
return; an object that falls inside the event horizon can't get out.
rules for the orbital motion of planets or anything else bound by gravity. The law of most
interest here is that the square of the orbital period is proportional to the cube of the orbital
separation, and inversely proportional to the mass. Thus, if we see an orbital period, we
can estimate the mass or orbital separation and therefore constrain the mass and radius of
a neutron star.
in a black hole, the "center point", at which densities, tidal forces, and other physical
quantities become infinite. Our current physical theories break down at this point.
the force an object feels because of the differential pull of gravity at different distances.