The Sun was shining on the sea,Shining with all his might;
He did his very best to makeThe billows smooth and bright-And this was odd because it was
The middle of the night.
from “The Walrus and the Carpenter” Through the Looking-Glass -- Lewis Carroll
Wednesday, September 7, 2011
Homework #1: due TODAY
Homework #2: due Monday, September 12Review Questions: 8, 9, 11Discussion Question: 3Learning to look: 3
Review Question: 1Problems: 2, 3Learning to look: 4
Last Day to Add: September 13
Quiz #1: Monday, September 12Chapters 1 and 2Extra Credit: know what phase the Moon is in that day
} Chapter 2
} Chapter 3
Wednesday, September 7, 2011
OutlineI. The Stars A. Constellations B. The Names of the Stars C. The Brightness of Stars D. Magnitude and Intensity
II. The Sky as a Dome Overhead A. The Celestial Sphere B. Sky Charts
III. Cycles in the Sky A. Diurnal Motion B. Annual Motion: Stars, Sun C. The Seasons D. The Moving Planets
Wednesday, September 7, 2011
The Celestial SphereVocabulary:
• longitude/latitude• celestial sphere• celestial pole/equator• horizon/zenith• constellation• ecliptic/zodiac• equinox• solstice
Wednesday, September 7, 2011
1) Sketch path of setting stars viewed from SJSU and then from Rio de Janeiro.
2) Earth spins counter-clockwise. What direction does it orbit the Sun?
3) What causes seasons?
4) Solstice, Equinox
Review
Wednesday, September 7, 2011
Based on this figure, in what constellation is the sun on July 1 each year?
1. Gemini2. Sagittarius3. Cancer4. Leo5. Aquarius
Wednesday, September 7, 2011
The Seasons
Wednesday, September 7, 2011
The Seasons
Sun is higher in the sky at noon in the
summerDay-light lasts
longerWednesday, September 7, 2011
The Seasons
Sun is higher in the sky at noon in the
summerDay-light lasts
longer
Sun is lower in the sky at noon in the
winterNight-time lasts
longerWednesday, September 7, 2011
The Seasons
Wednesday, September 7, 2011
The Seasons
As it orbits the Sun, the Earth maintains its orientation, at least on timescales of hundreds of
years.
Wednesday, September 7, 2011
The Seasons
As it orbits the Sun, the Earth maintains its orientation, at least on timescales of hundreds of
years.
Equinox
Equinox
Wednesday, September 7, 2011
The Seasons
As it orbits the Sun, the Earth maintains its orientation, at least on timescales of hundreds of
years.
Equinox
Equinox
Solstice
Solstice
Wednesday, September 7, 2011
Rising/Setting Sun
Where the Sun rises and sets also changes with the seasons.
Wednesday, September 7, 2011
The SeasonsEquinox:
• Occurs March 21 (vernal) and September 21 (autumnal)• length of day/night is 12/12 everywhere on Earth• Sun rises/sets due east/west for everyone
Solstice:• June 21: summer solstice in northern hemisphere (longest day-light of year); Sun rises/sets north of east/west• December 21: winter solstice in northern hemisphere (longest night-time of year); Sun rises/sets south of east/west• swapped in southern hemisphere!
Wednesday, September 7, 2011
Chapter 3: OutlineI. The Scale of the Earth/Moon System
II. The Changeable Moon A. The Motion of the Moon B. The Cycle of Phases
III. Lunar Eclipses A. Earth's Shadow B. Total Lunar Eclipses C. Partial and Penumbral Lunar Eclipses
IV. Solar Eclipses A. The Angular Diameter of the Sun and Moon B. The Moon's Shadow C. Features of Solar Eclipses D. Observing an Eclipse
Wednesday, September 7, 2011
The Scale of the Earth/Moon System
6.38 x 103 km1.74 x 103 km3.67:1
Radius of Earth =Radius of Moon = Ratio =
Wednesday, September 7, 2011
The Scale of the Earth/Moon System
6.38 x 103 km1.74 x 103 km3.67:1
Radius of Earth =Radius of Moon = Ratio =
Diameter of Earth =Distance to Moon = =
2 x 6.38 x 103 km384403 km~ 30 earth diameters
Wednesday, September 7, 2011
Phases of the Moon
Picture taken of Earth/Moon from 6.2 million km away on December 16, 1992, by Galileo spacecraft on its way to Jupiter.
Wednesday, September 7, 2011
Phases of the Moon
Wednesday, September 7, 2011
Phases of the Moon
1. Your head is the Earth2. Moon orbits in counter-clockwise direction3. Place Moon in direction of Sun to begin4. Move Moon 45 degrees at a time in its orbit.
At each position, sketch the Moon.
example:
Don’t let your head (or that of another student!) get in the way.
Activity with styrofoam balls (Moon) and light (Sun)
Wednesday, September 7, 2011
Phases of the Moon
Wednesday, September 7, 2011
Labeling the Phases
New
Waxing CrescentFirst QuarterWaxing Gibbous
Full
Waning GibbousThird QuarterWaning Crescent
New
} right side illuminated
} left side illuminated
Wednesday, September 7, 2011
Phases of the Moon
Can you ever see the Moon during the daytime? If not, why? If so, what phases?
Wednesday, September 7, 2011
Phases of the Moon
Can you ever see the Moon during the daytime? If not, why? If so, what phases?
Is there any phase of the Moon that you can never see at night?
Wednesday, September 7, 2011
Phases of the Moon
Can you ever see the Moon during the daytime? If not, why? If so, what phases?
Is there any phase of the Moon that you can never see at night?
The full moon is at its highest position in the sky. About what time is it?
Wednesday, September 7, 2011
Phases of the Moon
Wednesday, September 7, 2011
Phases of the Moon
You see the Moon rising in the East at dinner-time. What phase is the Moon in?
A third quarter moon is setting in the West. About what time is it?
Wednesday, September 7, 2011
Phases of the Moon
You see the Moon rising in the East at dinner-time. What phase is the Moon in?
A third quarter moon is setting in the West. About what time is it?
The first quarter moon is rising in the east. About what time is it?
Wednesday, September 7, 2011
The Moon’s Orbit
Synodic Period = 29.53 days (relative to Sun)Sidereal Period = 27.32 days (relative to stars)
Wednesday, September 7, 2011
The Moon’s Orbit
Synodic Period = 29.53 days (relative to Sun)Sidereal Period = 27.32 days (relative to stars)
Wednesday, September 7, 2011
The Moon’s Orbit
Wednesday, September 7, 2011
The Moon’s Orbit
The Earth exerts tidal forces on the moon’s rocky interior.
Wednesday, September 7, 2011
The Moon’s Orbit
The Earth exerts tidal forces on the moon’s rocky interior.
→ It is rotating with the same period around its axis as it is orbiting Earth (tidally locked).
Wednesday, September 7, 2011
The Moon’s Orbit
The Earth exerts tidal forces on the moon’s rocky interior.
→ It is rotating with the same period around its axis as it is orbiting Earth (tidally locked).
→ We always see the same side of the moon facing Earth.
Wednesday, September 7, 2011
The Moon’s Orbit
The Earth exerts tidal forces on the moon’s rocky interior.
→ It is rotating with the same period around its axis as it is orbiting Earth (tidally locked).
→ We always see the same side of the moon facing Earth.
Wednesday, September 7, 2011
The Moon’s OrbitMoon’s orbit about Earth is not perfectly circular. The consequence is that the Moon gets slightly larger and smaller in the sky. The change is only about 12%!
Wednesday, September 7, 2011
The Moon’s Orbit
Inclination of orbital plane relative to the ecliptic is 5.14 degrees.
= ~10 moon diameters
From: http://www.astronomynotes.com/nakedeye/s13.htm
Wednesday, September 7, 2011
When I heard the learn’d astronomer,When the proofs, the figures, were ranged in columns before me,When I was shown the charts and diagrams, to add, divide, and measure them,When I sitting heard the astronomer where he lectured with much applause in the lecture room,How soon unaccountable I became tired and sick,Till rising and gliding out I wander’d off by myself,In the mystical moist night air, and from time to time,Look’d up in perfect silence at the stars. - Walt Whitman
Wednesday, September 7, 2011