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The NASA / ESA
Hubble Space Telescope

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has recently revealed magnificent
sections of the Veil Nebula,

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the shattered remains of a supernova that
exploded some 5 to 10,000 years ago.

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The new Hubble images
provide beautiful views

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of the delicate wispy structure
resulting from this cosmic cataclysm.

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This is the Hubblecast.

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News and images from the
NASA / ESA Hubble Space Telescope.

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Travelling through time and space
with our host, Dr. J

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EPISODE 7: Uncovering the Veil Nebula.
Exploding stars.
a.k.a. Dr. Joe Liske.

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Welcome to the Hubblecast.

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Today we'll take a closer look at one of
the most violent events in the Universe:

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a supernova explosion.

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It is the debris from one
of this cosmic explosions

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that we can see with
unprecedented detail

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in this brand new images
from the Hubble Space Telescope.

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Although we don't usually think about it,
the stars twinkling in the night sky

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do not shine forever.

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How long a star lives depends
on how big and heavy it is.

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The bigger a star, the shorter its life.

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Now, a star shines because of
the nuclear fire burning at its center.

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And when a star significantly
larger than our Sun

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runs out of fuel for this fire,

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it first collapses and
then blows itself apart

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in a gigantic explosion
that we call a supernova.

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A supernova releases so much light

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that it can outshine all of the stars
of an entire galaxy put together.

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The explosion sweeps out
a huge bubble in its surroundings,

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and at the fringe of this bubble
we find the actual debris from the star

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as well as the material that has been
swept up by the blast wave.

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It is this glowing brightly-coloured shell
of gas that we see as a nebula

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and that astronomers refer to
as a 'supernova remnant'.

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The remnant can remain
visible for a very long time

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after the actual explosion
itself has faded away.

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Astronomers have pointed Hubble
towards the constellation of Cygnus

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to observe the Veil Nebula
in the wing of the Swan.

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Located at a distance
of 1,500 light years from Earth

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the Veil Nebula, which is
also known as Cygnus Loop,

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is one of the most spectacular
supernova remnants in the sky.

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The entire shell spans some 3 degrees,
corresponding to about 6 full moons.

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One of the most remarkable
parts of the remnant

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is the so called Witch's Broom Nebula.

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The bright blue star, dubbed 52 Cygnus,
is unrelated to the supernova explosion.

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It can be observed with the naked eye
on a clear summer's night.

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The small regions captured
in the new Hubble images

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provide stunning close-ups
of the Veil.

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Fascinating smoke-like wisps of gas
are all that remain visible

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of what was once
a Milky Way star.

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Scientists estimate that the supernova
explosion occurred some 5-10,000 years ago.

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What that means is that
it could have been witnessed

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and recorded
by ancient civilizations.

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What they would have seen is
a star increasing its brightness

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roughly to the brightness
of the crescent Moon.

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The intertwined rope-like filaments
of gas in the Veil Nebula

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result from the enormous energy
released as the fast-moving debris

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from the supernova explosion
ploughs into the surroundings

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and creates a shock front.

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This shock, driven by debris moving
at 600,000 kilometres per hour,

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heats the gas to millions of degrees.

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It is the subsequent cooling
of this material

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that produces the brilliantly
coloured glows.

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The Hubble images of the Veil Nebula
are striking examples

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of how processes that take place
hundreds of light-years away

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can sometimes resemble effects
we see around us in our daily lives.

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There are similarities
with the patterns formed

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by the interplay of light and shadow
on the bottom of a swimming pool,

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rising smoke or wispy cirrus clouds.

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So, why are astronomers interested

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in studying supernovae
and their remnants?

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The reason is that they
are extremely important

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for understanding the history
of our own Milky Way.

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Although only a few stars
per century in our Galaxy

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end their lives
in this spectacular way,

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these explosions are more or less
directly responsible

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for creating all the elements in our
Universe that are heavier than iron.

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For example,
all the copper, mercury...

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...gold, iodine and lead

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that we see on Earth
around us here today

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were forged in this violent explosions
billions of years ago.

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The expanding shells
of the supernova remnants

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eventually mixed with other
material in the Milky Way

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and this became the raw material for the
next generation of stars and planets

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including our own Solar System.

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So the chemical elements
that constitute the planets,

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the Earth, the plants
and animals around us

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and indeed our very selves,
were built deep inside ancient stars

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and in supernova explosions.

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So the green in the grass
and the red of our blood

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are in fact
the colours of stardust.

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This is Dr. J
signing off for the Hubblecast.

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Once again, nature has surprised us
beyond our wildest imagination...

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Hubblecast is produced
by ESA / Hubble

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at the European
Southern Observatory in Germany.

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The Hubble mission is a project
of international cooperation

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between NASA and
the European Space Agency.