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The space between stars holds an array of
vibrant clouds.

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Clouds that command our attention.

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Clouds that create spectacular displays.

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Clouds that seem familiar, tenuous, and fragile.

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Clouds that hold clues to star birth,
and death.

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NASA’s Hubble Space Telescope has imaged
hundreds of them in extraordinary detail.

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These vast swirls of gas and dust get their
name from the Latin word,

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nebula, meaning “cloud” or “mist."

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"Nebulae" is the plural of "Nebula," and they come

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in a wide range of shapes, sizes, and forms.

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Emission nebulae are some of the most spectacular.

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These opaque, gleaming clouds of gas and dust
radiate, or emit, their own light.

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Ultraviolet light from nearby stars energizes
atoms in the cloud.

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When the excited atoms lose that energy,

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they release the light that gives emission nebulae their glow.

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The Orion Nebula is one of the most famous
emission nebulae.

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Its core, called the Trapezium, holds four enormous young stars

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whose ultraviolet light powers the region’s intense glow.


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The Carina Nebula is another vast emission

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nebula and star-forming region in our galaxy.

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Within the nebula is a pillar three light
years tall, dubbed Mystic Mountain.

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It cloaks massive young stars, some with jets
emerging from the cloud.

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Hubble’s infrared view cuts through the
shroud of gas and dust,

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revealing these radiant jewels.

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Reflection nebulae shine by the reflected
or scattered light of nearby stars.

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They often have a bluish color because the
dust grains in the cloud scatter blue light

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more efficiently than red light.

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Not all nebulae shine brightly.

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Dark or absorption nebulae are inky-black
clouds of gas and dust that block the light

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coming from objects behind them.

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Because they are dark, absorption nebulae
are hard to find.

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We only see them as silhouettes against a
much brighter region of space.

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Most large nebulae are a combination of emission,
reflection, and absorption nebulae.

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Their dark dust lanes may give birth to new
stars

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that provide the light needed to illuminate the cloud.

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Planetary nebulae are a type of emission nebula
powered by a small to medium-sized dying star.

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As these stars run out of fuel, they periodically
blow off their outer layers.

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The expelled gas expands outward, away from the star,

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forming a bubble, or shell, around the star.

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Sometimes, the envelope of debris holds clumps
of dense gas

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that shine like the gems of a necklace.

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The term “planetary nebula” is misleading.
It comes from late eighteenth-century astronomers

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who thought their rounded shape looked similar
to planets in telescopes of that time.

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They named them “planetary nebulae" as
a result.

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Supernova remnants are the diffuse clouds
of expanding debris

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released by a massive star’s death explosion.

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The Cygnus Loop is a vast, expanding 110-light
year-wide supernova remnant.

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It is so large that Hubble can only image
small sections of it at a time.

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Some supernova remnants emit their light from
a shell of shocked material.

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Others, like the Crab Nebula, emit most of
their light from within the expanding shell.

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And still other supernova remnants shine as
a combination of the two.

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Nebulae are some of the most resplendent objects
in the universe,

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and thanks to the Hubble Space Telescope,

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we can study them in all
of their magnificent forms.

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