Transcript Ch. 1 - Astro1010

Welcome
This is Phys 1040 and Astro 1040
Please pick up one each of the papers on the
table up front.
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Survey of Astronomy
Introduction
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Introduction
My e-mail
By far the best way to contact me
is by e-mail.
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Introduction
My Web Page
http://www.astro1010-lee.com/
Syllabus
Copies of my Slides
Lecture Notes
Links
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Introduction
Text There is no Text, only the Slides and
Lecture Notes
Tests
5 unit tests
NO comprehensive final
Must be taken on the day scheduled (I can change
the date but you can NOT)
Absolutely no late tests
May be taken early
I DROP YOUR LOWEST TEST SCORE
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Introduction
ASTROLAB
(SEE LINK)
•You need to attend one
• Dr. Powell offers only a finite number
• I recommend that you go to an early
one
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Introduction
Term Papers
Select from the list of Subjects that t
provide. These are designed to be
associated with the lectures. If you
email them to me on the designated
day you will get full credit, anytime
after that is half credit.
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Introduction
The purpose of this exercise is for the
student to determine the circumference of
the Earth using a variation of the
Erotosthenes method
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Exercise 1
Requires
Protractor
Thread
Tape
Weight
Find the North Star
Measure the angle from the
Horizon to the North Star
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Exercise 1
This is how your protractor should look
after you get it ready
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Exercise 1
NCP
NCP
θ1
θ2
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Exercise 1
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Chapter 1
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BEGINNINGS
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Chapter 1
Astronomy -- Study of the Universe
Universe -- everything that exists
Galaxy
The Milky Way is
our Galaxy
Stars
Open Star Clusters
Globular Star
Clusters
Nebulae
Sun
Solar System
Solar System
Planets
Moons
Asteroids
Comets
Other debris
Earth/Moon System
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Chapter 1
Subtend
When an object
just fills an angle
it subtends that
angle.
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Chapter 1
Angular Units
Degree (of arc) = 1/360 Circle
Minute (of arc) = 1/60 of a Degree
Second (of arc) = 1/60 of a Minute
Hour (of arc) = 360/24 = 15 degrees
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Chapter 1
Distance
Measure
in Space
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Chapter 1
OUR CODE
The Earth and the entire Universe
obey a single set of Laws
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Scientific Theory and the
Scientific Method
Scientific theories:
must be testable
must be continually tested
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Chapter 1
Scientific theories can be
proven wrong, but they
can never be proven right
with 100% certainty
should be simple
should be elegant
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Scientific Theory and the Scientific Method
•Observation leads to theory
explaining it
• Theory leads to predictions
consistent with previous observations
• Predictions of new phenomena are
observed. If the observations agree
with the prediction, more predictions
can be made. If not, a new theory can
be made.
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Early Discoveries
Pre-historic
Historic
Sun
Moon
Stars
Constellations
Planets
Movement of the Sky
Path of the Sun
Movement of the Moon
Cyclic nature of the Universe
….. led to calendars
Explanation of the phases of
the Moon
NCP
Celestial Equator
Explanation of the seasons
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Earth’s Orbital Motion
Daily cycle, noon to noon, is diurnal motion
– solar day
Stars aren’t in quite
the same place 24
hours later, though,
due to Earth’s
revolution around
Sun; when they are,
one sidereal day has
passed
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From season to season the stars that we see
change. This is because of the motion of the Earth
in it orbit. The ancients thought it was because the
Sun moved around the Earth
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The 12 constellations that the Sun appears to
move through during the year are called the
zodiac; the apparent path is the ecliptic
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The Earth revolves around the Sun once
each year causing the Sun to appear to
move around the sky
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•Time from one
vernal equinox to
next is tropical year
•Combination of
day length and
sunlight angle
gives seasons
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Precession:
rotation of Earth’s
axis itself; makes
one complete circle
in about 26,000
years
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The Terrestrial Coordinate System
Latitude is measured
north and south from
the equator
Longitude is measured
east and west from the
prime meridian
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Zenith is the point
directly overhead
Meridian is the line
from the north point
through the zenith
and on to the south
point.
Horizon is the line
on the sky made by
the plane that is
perpendicular to the
vertical line from you
to the zenith
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The Celestial Coordinate System
Reference
points and
planes on
Celestial
Sphere
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The Celestial Coordinate System
Right Ascension (RA)
or Hour Angle is
measured from the
point on the sky where
the Sun is at the Spring
Equinox
Declination (δ) is
measured north or
south from the Celestial
Equator
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Chapter 1
Go to Chapter 2
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Chapter 1