Black holes. What are black holes? A black hole is a region of space that has a
gravitational field so intense that no
radiation or matter can escape it.
Black holes are formed from the
gravitational collapse of supermassive
stars. They collapse into one-dimensional
singularities that hold all of the mass
of the original star. The singularity of
a black hole is so incredibly dense and
heavy that if you had a black hole that
weighed the same as the earth, it would
fit in the palm of your hand.
Since the singularity of a black hole is
so dense and heavy, it curves the fabric
of space-time, the four-dimensional
continuum that Einstein's general theory
of relativity predicted. For a moment,
let's imagine that this trampoline is
the fabric of space-time. As you can see,
every time I jump, my mass is curving the
space-time. It's pulling it down, so to
speak. Let's take a look at my model.
Imagine that this is the fabric of
space-time and this is the singularity
of a black hole. Super dense and heavy,
remember? Now imagine that this
singularity is here on the fabric of
space-time. You can see that its mass
curves the space-time. Now imagine
there was a star or a ball of gas or
another object floating through space. If
it was just floating through empty space, it would go straight across the fabric of
space-time, undisturbed. But if it was
rolling past this singularity, it would
begin to curve around it, going into an
orbit and eventually getting sucked into
the singularity. So, is there a way to
escape a black hole?
Well, after you pass a certain point
called the event horizon,
nope! You're stuck forever. But why? Well,
there's a certain speed you have to be
going to escape the gravitational pull,
called the escape velocity. The closer
you get, the stronger the pull, and at a
certain point, you just can't go fast
enough to escape. The escape velocity is
given where G is Newton's gravitational
constant, M is the mass of the object to
be escaped from, and R is the radius of
that object. The event horizon is a
series of points around a black hole
where the escape velocity is equal to
the speed of light. If an object passes
the event horizon, it needs to travel
faster than the speed of light to escape.
Since nothing travels faster than the
speed of light, the event horizon is the
point of no escape of a black hole.
Another phenomenon that happens when an
object is entering a black hole is
spaghettification. Spaghettification
occurs when there is a difference in the
strength of gravity between one end of
an object and the other. If you were
diving feet first into a black hole, the
difference in the strength of gravity
between your feet in your head would be
enormous! Because of this, your feet would accelerate towards the black hole faster
than your head. This would cause you to
be stretched out like a noodle, hence the
name spaghettification. You would spiral
into the black hole in one long stream
of atoms. By studying and observing black holes, we are questioning the very laws
that make up our universe! Black holes
allow us to test some of the fundamental
theories of our universe and lead us
into new areas we haven't even begun to
explore. As physicist Richard Feynman
once said, "I'd rather have questions that
can't be answered than answers that
can't be questioned"
