WEBVTT

00:01.735 --> 00:04.738 align:left position:10% line:77% size:80%
Hey, Stargazers! Nebulae are
often known for their
breathtaking beauty.

00:04.738 --> 00:08.141 align:left position:20% line:83% size:70%
They're star-forming
clouds of gas and dust

00:08.141 --> 00:10.210 align:left position:10% line:77% size:80%
and here are the five major
categories of nebulae and some
examples of each one.

00:15.515 --> 00:20.754 align:left position:10% line:71% size:80%
First, we have emission nebulae.
They get their name because they
emit their own light. The
ionized

00:20.754 --> 00:25.759 align:left position:10% line:71% size:80%
gas in this kind of nebula is
high energy, which is what
causes them to glow. A famous
example of

00:25.759 --> 00:31.164 align:left position:10% line:71% size:80%
an emission nebula is the Orion
Nebula, a huge star-forming
nebula in the constellation
Orion.

00:31.164 --> 00:34.300 align:left position:10% line:77% size:80%
This is the closest nebula to
Earth, so you can see it even
with the naked eye.

00:38.538 --> 00:44.310 align:left position:10% line:77% size:80%
Next are reflection nebula.
These nebulae reflect the light
from nearby stars.

00:44.310 --> 00:49.416 align:left position:10% line:71% size:80%
The stars aren't powerful enough
to energize the gas like
emission nebulae, but they are
powerful enough

00:49.416 --> 00:53.486 align:left position:10% line:71% size:80%
that their light scatters
throughout the gas often giving
it this bluish glow. Kind of
like

00:53.486 --> 01:00.060 align:left position:10% line:77% size:80%
a street lamp, illuminating the
fog. An example of a reflection
nebula is one called NGC 1999,

01:00.060 --> 01:03.730 align:left position:10% line:77% size:80%
which is illuminated by a bright
recently formed star close to
the famous Orion Nebula.

01:09.169 --> 01:13.406 align:left position:10% line:77% size:80%
The third category of nebulae is
what's called planetary nebulae.
They get their name from their

01:13.406 --> 01:17.577 align:left position:20% line:77% size:70%
fuzzy cloudy shapes that
resemble planets. However, these
nebulae actually have nothing

01:17.577 --> 01:22.482 align:left position:10% line:71% size:80%
to do with planets. They just
form during the death of
low-mass stars, no big deal.
When stars like

01:22.482 --> 01:28.488 align:left position:10% line:71% size:80%
that die, they expel shells of
gas into unique shapes. The
Helix Nebula is a great example
of

01:28.488 --> 01:30.723 align:left position:10% line:71% size:80%
a planetary nebula. It kind of
looks like a bubble or an eye
from Earth's point of view.
Pretty cool.

01:36.129 --> 01:41.167 align:left position:10% line:77% size:80%
So next category is what is
called supernova remnants. It's
a great band name. Supernovas

01:41.167 --> 01:45.105 align:left position:10% line:77% size:80%
happen when stars explode and
shoot their contents into space.
The debris left over

01:45.105 --> 01:48.708 align:left position:10% line:77% size:80%
from the explosion forms an
expanding nebula. One of the
most famous examples

01:48.708 --> 01:54.714 align:left position:10% line:77% size:80%
is the Crab Nebula, which was
created by a star explosion in
the year 1054. At the

01:54.714 --> 01:56.716 align:left position:10% line:77% size:80%
time, astronomers recorded it
being so bright that they could
even see it in the daytime sky.

02:02.589 --> 02:08.361 align:left position:20% line:71% size:70%
And finally we have dark
nebulae, otherwise known as
absorption nebulae. These clouds
contain such a

02:08.361 --> 02:13.266 align:left position:10% line:77% size:80%
large amount of gas and dust
that they don't emit or reflect
light and instead they block

02:13.266 --> 02:18.071 align:left position:10% line:71% size:80%
light coming from behind them
and what you see are oddly
shaped dark clouds against
brighter

02:18.071 --> 02:23.109 align:left position:10% line:71% size:80%
stars. An example of this is the
iconic Horsehead Nebula, which
is a favorite target for both
amateur

02:23.109 --> 02:27.247 align:left position:10% line:77% size:80%
and professional astronomers and
there you have it - the five
main categories of nebulae.

02:27.247 --> 02:31.818 align:left position:10% line:77% size:80%
These giant clouds of gas and
dust truly give us some of the
universe's most beautiful images

02:31.818 --> 02:37.557 align:left position:10% line:71% size:80%
in space and while we have
fantastic telescopes that give
us these images, many nebulae
are able

02:37.557 --> 02:40.360 align:left position:10% line:77% size:80%
to be seen from Earth during a
stargazing session. So remember
friends, keep looking up!