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Astronomy:
What is the fascination?
Presented by Jim Burnell
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Nearly everything we see in
the sky is part of the great
cycle of stellar birth, life,
death and rebirth.
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Our fascination with
astronomy stems from our
own quest to understand our
place in the universe.
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The Birth of a Star
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Stars are born in groups, inside huge clouds of
gas and dust.
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These star forming regions are called nebulae
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The earliest nebulae contained only Hydrogen
and Helium, and a trace of Lithium
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NGC2237 – The Rosette Nebula
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M8 – The Lagoon Nebula
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M42 – The Orion Nebula
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IC1396
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VdB 142 – The Elephant’s Trunk Nebula
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M16 – The Eagle Nebula
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Nebulae
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Spiral galaxies, like our own Milky Way
are filled with these nebulae.
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The nebula are formed by denisty
waves that compress the gas and dust
in the interstellar medium.
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They trace out the spiral arms.
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M31 – The Great Andromeda Galaxy
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M33 – The Pinwheel Galaxy
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M51 – The Whirlpool Galaxy
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NGC253 – The Silver Dollar Galaxy
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NGC5198 – Centaurus A
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The Life of a Star
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Most stars are born in groups called
clusters.
Over time, these clusters often
dissipate, spreading the stellar family
across the galaxy.
Stars like our sun live for ~ 10 billion
years.
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M45 – The Pleiades
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M24 – The Sagittarius Star Cloud
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NGC2477
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The Double Cluster
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M46
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The Death of a Star:
a Peaceful Death
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Most stars die a gentle death, burning
their hydrogen, then their Helium and then
ejecting their outer layers.
This forms a so-called Planetary Nebula.
Planetary Nebulae are some of the most
beautiful objects in the universe.
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M27 – The Dumbell Nebula
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NGC7293 – The Helix Nebula
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M76 – The Little Dumbell Nebula
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M57 – The Ring Nebula (taken by the HST)
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The Death of a Star:
a Violent Death
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Large stars die a spectacular death,
exploding in a Supernova.
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The energy expended in a supernova can
briefly exceed all the energy radiated by the
host galaxy.
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Thousands of years after the explosion, a
cloud of debris expands many lightyears into
nearby space, dissipating.
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M1 – The Crab Nebula
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The Veil Nebula
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Simeis 147 – Supernova Remnant in Taurus
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Supernovae:
Fathers of the Next Generation of Stars
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Though the death of a star in a supernova
explosion is the most violent activity in the
universe, it is the furnace in which the heavier
elements are forged.
The supernova explosions seeds the
interstellar medium with these heavy
elements
Out of them the next generation of stars is
reborn.
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Supernovae:
The Precursors of Life
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These heavy elements are a critical part
of plant and animal (and human) life.
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