Tighter than you could possibly imagine.

Imagine:

A very large star in distant space.
As the star grows in size over the eons
it becomes harder and harder
for its rays of light to leave
the increasing pull of it's own
gravity.

The arches of light beams get tighter
and tighter.
Eventually gravity is so strong,
that all light becomes trapped
in around its atmosphere.
Think of it as an aura of light
around the entire sun,
but it couldn't be seen from any outside observer.
For none of it is able to leave the sun's grip.

Then gravity will cross that point
where all light starts to be sucked back
into the star.
The star is now SO heavy
that its own gravity is
pulling all of it's matter in upon
itself.

Matter
Light
Energy
All compacted in and crushed,
imploded.
Stuffed down by forces beyond
the reversal of any creator.
ALL of it,
crammed down to what scientist call
a singularity.

A singularity.
The mathematical representation
of a black hole.