Transcript project - Mindflight

Black Holes by Dalton, Connor, and
Bryan
What is a black hole?
The idea of black holes comes from the escape velocity. The
escape velocity basically says that if something goes fast enough it
can escape whatever is holding it back. Black holes are objects
that are so dense that even light can’t escape from them. A black
hole uses the same amount of force on any object far away from it
as anything else with the same mass. If our Sun was crushed into
something 1 mile in size, it would become a black hole, but the
Earth’s orbit around the sun wouldn’t change. Also if something
was going to be sucked in it would have to come within a mile of it.
How big are black holes?
• We can describe how big something is in
two ways. We can say how much mass it
has, or we can say how much space it
takes up.
• There are no limitations to how much
mass a black hole can have. Any amount
of mass can be made into a black hole if it
is compressed into a high enough density.
• We suspect that most of the black holes
that are actually out there were produced
in the deaths of massive stars, and so we
expect those black holes to weigh about
as much as a massive star. A typical mass
for a black hole would be about 10 times
the mass of the Sun
When black holes occur
A black hole occurs when a giant
star has completely used up its
nuclear fuel.
After that gravity forces the star to
collapse, then the outer layer of
the star goes supernova. Then the
core of the star becomes a
extremely dense black hole.
Accretion disks
Matter close to the black hole will spiral
down and create an accretion disk.
There are Gas and dust particles that
spin around the black hole and collide
with each other. The collisions heat up
the matter in around the accretion disk
and it may get so hot that it might emit
x-rays.
Jets of gas
Sometimes jets of gas are streaming
out of a black hole. The jets are
perpendicular to the accretion disk.
The jets of gas are charged particles
that spiral around magnetic field lines
that surround a black hole, and are
light years in length.
The event horizon
The event horizon is an imaginary sphere that
will trap any matter that reaches it, but if
matter is outside the event horizon it can
escape. All matter that enters the event
horizon will be crushed into a single point,
where it reaches infinite density.
Sources
http://www.msnbc.msn.com/id/5452537/
Hawking changes his mind on black holes
http://cosmology.berkeley.edu/Education/
BHfaq.htmlBlack Holes FAQ
Is a black hole really a hole? To find out go
to
http://amazingspace.stsci.edu/resources/explorations/blac
kholes/lesson/index.html