Have you ever looked up into the night
sky and thought, "Man I like look of that
black hole"? No, of course you haven't
because you can't actually see a black
hole, right? Black holes aren't visible
to the naked eye because they absorb all
light. At least any light that's
being directly pointed at them, so no
light will pass through it. With that
being said, black holes are so massive
that they have a huge gravitational pull.
So, light that's not pointed directly at
them will actually bend
around the black hole. So, given that,
since we can't actually see them, the way
that we know they're there is by looking
at distant stars and distant galaxies
that are emitting light, and actually
tracking to see when they disappear. We
actually tell that a black hole exists
and where they are located by waiting
until they pass in front of the star and
then you can no longer see the star but
you'll see a distortion of its light
going around the black hole. But how are
they formed? Black holes are most
commonly formed when the center of a
very massive star collapses in on itself
supermassive black holes are a little
bit different, scientists believe the
supermassive black holes were formed at
the same time of the galaxies that they
are located in. Ok, but how long do they
last? Well while it was initially thought
that black holes may last forever,
Stephen Hawking postulated that black
holes emit a radiation, and thus would
evaporate over time. Hawking was shown to
be correct, and this form of radiation is
called Hawking radiation now. However,
even with Hawking radiation, it still
would take around 10 to the 67th power to
evaporate a black hole with the
approximate size of our Sun. So it's a
very long time. All right, so how big can
black holes get? Well, every galaxy has a
supermassive black hole at its center. In
fact, sometimes when galaxies are too
close together, their supermassive black
holes can actually combine to form one
even larger supermassive black hole.
These supermassive black holes are too
big to even estimate the size of. You
couldn't fathom how large they are, so
massive is the answer. All right, so now on to the
good stuff. Will our Sun ever become a
black hole?
The answer is no, our Sun is not large
enough, it's not massive enough to become
a black hole. It will expand and become a
red giant, and then it'll cool off as a
white dwarf, and end its life at that
point. Further, could a black hole ever
destroy Earth? Theoretically, yes, a black
hole could destroy the earth. But the
chances of doing so are very slim. Black
holes do abide by the laws of gravity, so
they can't just float around and suck up
everything in their path. A black
hole that were to suck up the earth
would have to come very
close to our solar system, and that sort
of thing just isn't very likely to
happen ,so there's really nothing to
worry about as far as black holes go. We
can study them from a distance, and
understand that they are a part of
nature, or a part of the universe at
least, and a pretty cool one at that.
