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Space
Nebulae & Black Holes
Nebula
• Derived from the Latin word for "clouds".
• Nebulae are the basic building blocks of the
universe
• They contain the elements from which stars
and solar systems are built.
• Most nebulae are composed of about 90%
hydrogen, 10% helium, and 0.1% heavy
elements such as carbon, nitrogen,
magnesium, potassium, calcium, iron.
Types of Nebulae
Emission Nebula
• A cloud of high
temperature gas. Within
this type of nebula, a star
energizes the atoms in the
cloud with ultraviolet
radiation. As these atoms
fall back to lower energy
states, they emit radiation.
The process is similar to
that of a neon light. This
causes the nebula to glow.
Emission nebulae tend to
be red in color because of
the abundance of hydrogen
Reflection Nebula
• A cloud of dust and gas
that reflects the light
energy from a nearby
star or group of stars.
Reflection nebulae are
frequently the sites of
star formation. They
usually tend to be blue
in color because of the
way that the light is
scattered. Blue light is
scattered more
efficiently
Planetary Nebula
• A planetary nebula is a
shell of gas produced by a
star as it nears the end of
its life cycle. They actually
have nothing to do with
planets. These nebulae
were given this name
because they often look
like planets due to their
round shape. The outer
shell of gas is usually
illuminated by the
remains of the star at its
center.
Supernova Nebula:
• Supernova remnants are
created when a star
ends it life in a massive
explosion known as a
supernova. The
explosion blows a large
amount of the star's
matter out into space.
This cloud of matter
glows with the remains
of the star that created
it.
Nebulae...the stellar nurseries!
• Nebulae are often the
sites of star formation.
In fact, all stars, planets,
and solar systems are
formed from nebulae.
• A nebula may lie
undisturbed for many
millions or billions of
years as it waits for just
the right conditions to
form stars.
Black Holes
Black Holes
• A black hole is a place in space
where gravity pulls so much
that even light can not get
out. The gravity is so strong
because matter has been
squeezed into a tiny space.
This can happen when a star is
dying.
Because no light can get out,
people can't see black holes.
They are invisible. Space
telescopes with special tools
can help find black holes
Black Holes
• Black holes can be big
or small. Scientists
think the smallest black
holes are as small as
just one atom. These
black holes are very
tiny but have the mass
of a large mountain.
Black Holes
• Another kind of black
hole is called "stellar."
Its mass can be up to
20 times more than the
mass of the sun. There
may be many, many
stellar mass black holes
in Earth's galaxy.
Black Holes
• Scientists think the smallest black
holes formed when the universe
began.
Stellar black holes are made when
the center of a very big star falls in
upon itself, or collapses. When this
happens, it causes a supernova. A
supernova is an exploding star that
blasts part of the star into space.
Scientists think super massive
black holes were made at the
same time as the galaxy they are
in.