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Part II explores
how the micro-world controls the stars. Stars have transformed the
cosmos from a cold, empty, lifeless void to a universe of spectacular
visions and endless possibilities. Stars enable life, sustain our
existence, and impact our future.
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Stars are Stable due to Balance
of Gravity & Pressure
Fig 18.2 Pressure pushing out from
the core is precisely balanced by gravity squeezing in. This balance
provides a long-term stable equilibirum. |
We will follow the lifecycle
of stars: their birth, the exquisite balance of their prime, their
rapid decline, and their ultimate deaths in immensely violent
explosions called supernovae. Through these explosive deaths, nature
recycles vital resources, plants the seeds of rebirth, and leaves
exotic remnants such as white dwarfs, neutron stars, and black holes.
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White Dwarfs
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Cat's Eye Nubula is 3,000
light-years away. |
Eskimo Nebula is 5,000 light-years away. |
White dwarfs: the central dots are
the collapsed cores of lighter stars. The stars' outer layers are
blown off into space by the explosion following core collapse. Images
by NASA Hubble |
With spectacular
photographs, we will examine the bizarre nature of each of these
exotic remnants, particularly the most enigmatic: black holes.
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Central Dot is accretion disk of a
black hole.
Jets from rotational axes span
over 500,000
light-years. Radio telescope image. |
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Einstein's Theory of General
Relativity is generally regarded as the most beautiful theory in
physics, and some even believe it is the greatest achievement of
human thought.
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"Einstein was a giant. His
head was in the clouds but his feet were on the ground. Those of us
who are not so tall have to choose"
-Richard Feynman
"Einstein was the greatest
mind and paramount icon of our age"
- Time Magazine named him person
of the centurey |
How can a theory be
beautiful? What is the beauty that scientists see in this theory?
General Relativity provides the foundation for our understanding of
stars, galaxies, and the universe. Einstein's theory also enables the
Global Positioning System (GPS) and leads us through the unknown.
We will learn about NASA's
wonderful space telescopes, particularly the Hubble Space Telescope,
the greatest advance in astronomy since Galileo pointed the first
telescope toward the heavens 400 years ago. NASA's Great
Observatories have opened up the heavens as never before.
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