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0:00-0:10
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The
fly-through begins directly below the nebula and moves
northward toward its center. The nebula is carved out
of a giant, dark cloud of molecular gas and dust and is
painted on the cloud's surface by the intense radiation
from its brightest star. The direction to Earth is straight
up. The dark cloud at the top is the veil that obscures
part of the nebula when viewed from Earth.
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0:10-0:20
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The
central area of the nebula is called the Trapezium cluster.
It is dominated by four young, massive stars in a kite-like
arrangement. The brightest of these stars, which has a
luminosity 100,000 times that of the Sun, provides the
energy that creates the nebula as we see it. It produces
a flood of ultraviolet light that ionizes the surface
layers of the molecular cloud and causes them to glow.
This illumination makes it possible to study many features
that otherwise would be invisible.
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0:20-0:30
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These
bright stars are extremely young, less than 100,000 years
old. That means our distant ancestors were alive when
the nebula came into being.
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0:30-0:35
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The
nebula's irregular surface is caused by the intense starlight.
The radiation not only causes the gases in the cloud to
glow, but it also eats away at the material in the cloud,
forming ridges and valleys.
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0:35-0:45
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Circling
the Trapezium cluster, we travel underneath the foreground
veil. The Earth-side of the cloud is dark, but the inner
side, which faces the Trapezium, is painted in glowing
colors.
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0:45-0:50
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As
we loop inward toward the heart of the nebula, our course
takes us through the opaque veil.
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0:50-1:00
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The
fuzzy, teardrop-shaped objects are clouds of dust and
gas that contain newly formed stars. The teardrop shape
is an artifact of the strong illumination. Actually, the
clouds surrounding the young stars are nearly spherical.
New stars are created when knots of dust and gas collapse.
In the nebula, however, this process stopped when the
young central stars reached their full power. The radiation
they produce is so strong that it prevents new stars from
forming.
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1:00-1:10
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A
young star with a proto-planetary disk passes by. Ninety
percent of the newly formed stars in the cluster possess
such disks. The object, named HST10, is also the best
example of a dynamic phase in stellar creation: the formation
of strong, bipolar jets that blast twin streams of dust
and gas away from the star at hypersonic velocities.
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1:05-1:15
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In
the nebula today, the starlight is so intense that it
can blast away the material in a proto-planetary disk
in a few hundred thousand years. By comparison, scientists
think that it takes 10 million years for a planet to form.
So nine out of ten of the new stars formed in Orion are
unlikely to develop planetary systems.
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1:15-1:25
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As
we pull back from the Trapezium, two young stars still
shrouded by the cloud of dust and gas pass by. Because
they are farther from the central stars, they appear to
be more nearly spherical.
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1:25-1:50
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Our
path takes us above the foreground veil as we circle around
for a final pass of the Trapezium.
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1:50-2:15
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From
this angle the shockwaves produced by the jets streaming
from young, forming stars are clearly visible as translucent
crescents. Those that face the central star are shaped
by interaction with a wind of gas coming from the stars
along with the starlight. Those with other orientations
form by the interaction between the jets and the gas left
over from star formation.
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2:15-2:30
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Finally,
while we continue to face the center of the nebula, our
trajectory curves upward until we are traveling at a right
angle to our previous course and heading in the direction
of Earth. As we move farther and farther away, the familiar
outline of the nebula as seen from Earth falls into place. |
Produced by the American Museum
of Natural History under the direction of Carter Emmart.
Computer visualization by Jon
D. Genetti, David R. Nadeau and Erik Wesselak at the San Diego
Supercomputer Center.
Based on the nebula model provided
by C. Robert O'Dell of Vanderbilt University and Zheng Wen,
formerly of Rice University, and a stellar cluster model from
Lynne Hillenbrand of California Institute of Technology and
Lee Hartmann of the Center for Astrophysics.
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