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Nebulae
Space clouds
What is a Nebula?
• A nebula is an interstellar cloud of 90% hydrogen,
10% helium, & trace amounts of heavier elements
• Nebulae are the basic building blocks of our universe,
and contain the elements from which stars and solar
systems are made from.
• They are the biggest things in our galaxy. Ranging
from a dozen or to hundreds light-years across.
Different Types of Nebulae
There are five different types of Nebulae:
1. Emission
2. Reflection
3. Dark
4. Planetary
5. Supernova Remnants.
Emission Nebulae
• Usually red
• Are clouds of high temperature gas. Energized by
ultraviolet light from nearby stars they emit
radiation
• Usually the sites of recent and ongoing star
formation.
Reflection Nebulae
• Usually blue
• Clouds of dust that reflect the light from a nearby
star.
• Usually found at “star formation” sites and are
mostly found near Emission Nebulae
• Sometimes referred to as Defuse Nebulae.
Dark Nebulae
• Are so dense they
block the light
coming from
whatever is behind
it
•Dust grains
located at the
coldest densest
parts of the
molecular cloud
block the light.
Planetary Nebulae
• Shells of gas usually thrown out when stars similar to
our Sun die.
• Are usually one light-year across
• Once mistaken for planets they have nothing to do with
them.
• Have very short lives, only lasting a few ten thousand
years.
• The ultraviolet radiation from the core ionizes the
ejected layers and make them emit light.
Supernova
Remnants
• Created when a massive star ends its life in a
supernova.
• They have a chaotic appearance