Transcript Outline of the Course - UH Institute for Astronomy

Outline of the Course
TABLE OF CONTENTS
Part I—Developing Perspective
1. Our Place in the Universe
2. Discovering the Universe for Yourself
3. The Science of Astronomy
Part II—Key Concepts for Astronomy
4. Making Sense of the Universe:
Understanding Motion, Energy, and
Gravity
5. Light: The Cosmic Messenger
Part III—Learning from Other Worlds
6. Our Solar System and its Origin
7. Earth and the Terrestrial Worlds
8. Jovian Planet Systems
9. Remnants of Rock and Ice: Asteroids,
Comets, and Pluto
Part IV—Stars
10. Our Star
11. Surveying the Stars
12. Star Stuff
13. The Bizarre Stellar Graveyard
Part V—Galaxies and Beyond
14. Our Galaxy
15. A Universe of Galaxies
16. Dark Matter, Dark Energy, and the
Fate of the Universe
17. The Beginning of Time
Part VI—Life on Earth and Beyond
18. Life in the Universe
What You Should Learn From This Class
• ‘Facts’ about our Universe
• How we come to accept these facts—the
scientific methods
The objective of this course is to help you develop a basic
knowledge of the universe we live in. However, learning the
‘facts’ should not be the sole purpose of this course. The
scientific methods we employed to develop our vision of the
universe is also an important subject. It is important to keep in
mind that the ‘facts’ that we will be presenting in this course
are really our interpretations of the natural phenomena we
experienced and observed. Other interpretations may exist for
the same phenomena, and that even commonly accepted
interpretations today might be revised, or even be proven
incorrect in the future. Nevertheless, we have confidence in
these ‘facts’ because our interpretations are derived from
vigorous and self-consistent reasoning processes, and most of
the time, verified by independent experiments and
observations. So, in addition to learning the facts that are
The Scientific Methods
Define the problem
Make Observation
Make Hypothesis
And Predictions
Experiment to test the predictions
NO
Experimental results consistent with predictions?
YES!
Theory!
Our Place in the Universe
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Where are we?
Who are we?
What is around us?
Where did we come from?
Where are we going?
Hubble Deep Field…most of the
features seen in this picture are
galaxies. Can you identify the stars?
The ‘spiders’ that holds the
secondary mirror of
telescopes produces the
‘crosses’ seen around bright
stars.
Gemini
Telescope
on Mauna
Kea.
Where Are We?
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Earth,
Solar System,
Milky Way Galaxy,
The Local Group,
The Local Supercluster,
The Universe
Who Are We?
• How did life start?
– How did water get
here?
– How do we build life
from lifeless atoms?
• Are we alone in the
universe?
– What’s the chance
that other life forms
exist?
– How do we find them
if they are out there?
• Where are we?
• Who are we?
• What is around us?
• Where did we come from?
• Where are we going?
What is Around Us in our Universe?
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Stars
Planets
Moons (satellites)
Asteroids
Comets
Star systems
Star clusters
Interstellar medium
Galaxies
Galaxy clusters
Superclusters
What are Stars?
Stars are large, glowing ball of gas that generate energy through
nuclear fusion in its core.
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Also the objects that are in the process of becoming stars,
for example, the protostars.
The objects that are the remains of stars that have ‘died’,
for example, the neutron stars, or the white dwarfs.
A star is ‘dead’ after it had stopped generating energy
through nuclear fusion.
Nuclear Fusion:
The process of combining two lighter elements to make a heavier
element, and simultaneously convert some (just a little bit!) of the
masses into energy. The total mass of the new element is slightly
less than the original total mass.
=> Four hydrogen atoms can combine to make a Helium atom.
Planets
A planet is an object that
orbits a star, and shines
primarily by reflecting
the light from the star.
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Maybe made out of rocks,
Maybe made out of gas,
Maybe both rocky and icy,
Much smaller in size than a star,
Pretty large compared with other objects
in a star system.
Is Pluto a Planet?
• Pluto (1,160 km) is smaller than our moon (1,738
km)
• It is not like the rocky inner planets (Mercury,
Venus, Earth, and Mas), or the gaseous outer
planets (Jupiter, Saturn, Uranus, and Neptune)
• It is icy, and more like a comet.
Hubble Space Telescope image of Pluto and its
satellite Charon …
http://antwrp.gsfc.nasa.gov/apod/ap971228.html
Current Event:
International Astronomical Union is
currently meeting in Prague. One of
the issues that’s been debated now
(and many times before) is what
qualify as a planet…See what you
can find on the web about this
issue…What is the proposed criteria
for planet?
Discovery of Neptune and Pluto
The discovery of Neptune and Pluto are
good examples of the scientific method…
– Both Neptune and Pluto’s existence were
predicted based on the small discrepancy
between the observed and calculated orbits
of known planets.
– Their discovery at the predicted positions
further enhance the validity of the theory of
gravity.
Links to the history of Pluto’s discovery
• The discovery of Pluto
• Discovering new planets