Earth and Sky - Cabrillo College

Earth and Sky - Cabrillo College

Chapters 1, 2: Introduction, Earth and Sky Orientation to the Universe - sizes and distances Frames of Reference: equator, ecliptic, horizon

The Seasons Eclipses of the sun and moon Key Points The most abundant element in Universe: Hydrogen Know how the sky turns if you are on the Earths equator,

mid-latitudes, and poles. Know the seasons and where the sun is during each of them. Earths orbit is elliptical, closest to sun Jan 4, farthest on July 4, but only different by 2% Know why summers warmer than winters

Lunar eclipses: moon passes into Earths shadow, always at Full moon phase Solar eclipse: moons shadow cast onto Earth, always at New Moon phase. Just know the basic names of the phases of the moon, for reference when we get to tides and eclipses

Dimensions, Units Distance often given terms of light travel time @ speed of light = 300,000 km/sec Moon is 2 light seconds away Sun is 8 light minutes away

Astronomical Unit = 1 AU = ~avg distance Earth-to-sun Solar system is ~1 light day across Nearest star is 4 light years away Milky Way Galaxy is ~100,000 light years across Andromeda Galaxy nearest galaxy like our own

is 2 million light years away The observable universe is 13.7 BILLION light years radius 1 light year = about 63,241 AU And What is Most of what we

see made of? Hydrogen! = 1 proton and one electron zipping around it. The simplest atom 90% of all atoms in the universe are hydrogen atoms

Dont be fooled You, me, this room all are very Untypical in their chemical composition. The 4 Forces Governing the Universe

All (almost all?) natural processes can be described by just 4 fundamental forces of nature in order from strongest to weakest: Two Short Range (Nuclear) forces: 1. The Strong Force (acts between baryons: [protons, neutrons, pions])

2. The Weak Force acts between certain other elementary particles And Two Long Range Forces: 3. Electromagnetism (acts between charges) 4. Gravity (acts between masses)

Back to Earth lets get started How does the sky behave, and why? What causes the seasons? The earth and its motions and how this affects the sky

Did all the Ancients figure the Earth was Flat? You might think so, but the ancient Greeks figured out it was a sphere. How? By watching eclipses of the moon

and noting they always happened 180 degrees away from the sun, and cut a circular shadow regardless of time of day. Only one figure cuts a circular shadow no matter how its turned - a sphere

They even measured how big it was, correctly! Way back in ~250BC. StarTrailsKilamanjaro The Seasons

Primary cause Earths rotation axis is tilted relative to orbital axis Why warmer in summer.(1) more daylight hours, and (2) daytime sun is higher in the sky Earths orbit is nearly a circle: 92 million miles at closest, 94 million at farthest conclusion:

not much, and so doesnt affect annual temperatures much At Santa Cruz latitude, distance only makes 4% difference in heating, while seasonal effect is a factor of 2; i.e. much larger.

Axis vs orbit tilt Solstices and Equinoxes Equinox Equal periods of Night. Everywhere gets 12 hours of daylight, 12 hours of night. Solstice - sun stands still. The sun has reached

farthest north or south of the celestial equator, and reverses direction. Winter Solstice: Dec 21. Sun is farthest south, 23 degrees south of the celestial equator Spring Equinox: Mar 21. Sun crosses the celestial equator heading north

Summer Solstice: June 21. Sun is farthest north, 23 deg north of the celestial equator Fall Equinox: Sept 21. Sun crosses the equator heading south. Seasons diagram

Precession Axis Tilt, not Distance to Sun, Causes Seasonal Temperature Differences

Common misconception sun is farther in winter, closer in summer. Nope! Earths orbit IS elliptical and distance to the sun does vary, but not by much; 91.9 million miles vs 94 million miles. How much would you expect this would affect

temperatures? (follow Rick on the white board) Interesting Facts: Were closest to the sun on January 4th Were farthest from the sun on July 4th

(plus or minus a day or two because of leap year) Eclipses of the Sun and Moon Eclipses happen when earths shadow

follows on the moon (Lunar Eclipse), or moons shadow falls on the earth (Solar Eclipse). How would this affect when/if eclipses happen?

Solar eclipse types SanDiegoAnnular Ponder what are the circumstances which would make for the largest

annular ring of sunlight during an annular eclipse. How far should be the sun? the moon? What day would you want? What time of day?

Solar eclipse sequence Solar Totality from Space Antarctic Eclipse, grazing shadow geometry

Time Lapse Total Lunar Eclipse Total lunar eclipse from the moon

lunarEclUmbraPenumbra Lunar eclipse types Penumbral eclipse sequence

CompleteLunarEcl Varying shadow colors as sunlight refracts through Earths atmosphere to hit the totally eclipsed moon

totalEclipseZubenalgenubi The Phases of the Moon Half the moon is always sunlit and half always dark, obviously. But the amount of the sunlit side we see

varies as the moon orbits the Earth Full moon when its opposite the sun and so its fully sunlit. New moon when its in the same direction as the sun so the dark side faces us

How do the Moons phases look, from high above the Earth/Moon system, compared to here on the ground? This link tells all! Very nice.

http://aa.usno.navy.mil/graphics/Mo on_movie.gif The Phases of the Moon These 3 quantities are related. Given any

two, you can ponder and see what the third must be 1. The phase of the moon 2. The time of day 3. The place of the moon in the sky This used to be one of my favorite quiz

questions! This Photo is a Tease! Well Discuss in Chapter 4 Chap 2 Earth and Sky; Key Points

The most abundant element in Universe: Hydrogen Know how the sky turns if you are on the Earths equator, mid-latitudes, and poles. Know the seasons and where the sun is during each of them. Earths orbit is elliptical, closest to sun Jan 4, farthest on

July 4, but only different by 2% Know why summers warmer than winters Lunar eclipses: moon passes into Earths shadow, always at Full moon phase Solar eclipse: moons shadow cast onto Earth, always at New Moon phase.

Just know the basic names of the phases of the moon, for reference when we get to tides and eclipses

Recently Viewed Presentations

  • PowerPoint-presentatie

    PowerPoint-presentatie

    The Mandelbrot fractal. Filmpje duurt 1,41 minuut. Soms duurt het even voor hij opstart. Beweeg met de muis en klik op het pijltje. ... MR7 Calcium and Terrains . Contains Earth element, where the cycle ends, where a regenerative phase...
  • Building Resource Consumption Accounting Expertise

    Building Resource Consumption Accounting Expertise

    RCA Discussion: RCA's Focus on Consumption Larry R. White, CMA, CFM, CPA, CGFM Executive Director Resource Consumption Accounting Institute * Accountants typically focus on Product or Service cost and our systems focus on providing that with some level of detail.
  • Europe in the Middle Ages 1000-1500 - Weebly

    Europe in the Middle Ages 1000-1500 - Weebly

    initiated many reforms for the church. These reforms became known as the Gregorian reforms. Pope Gregory Stated: The Church was founded by God Alone. The pope alone can with right be called universal. The pope alone can depose or reinstate...
  • Invest in America Act of 2011

    Invest in America Act of 2011

    Nationally Significant Freight and Highway Projects . Up to $500M of multiyear total can go towards multimodal projects including maritime ports. ... Maritime Industry Joint Venture. A . joint venture . between AAPA, a working group of 57 industry expert...
  • Water: The Natural Choice

    Water: The Natural Choice

    EER and COP. SEER. IEER vs IPLV . IEER is an integrated performance for a central chiller. Validity is possible because of diversity. All chillers would use the same raring points and conditions. IEER loses validity for unitary equipment when...
  • MEMORY Memory Memory: persistence of learning over time

    MEMORY Memory Memory: persistence of learning over time

    Iconic Memory: a momentary sensory memory of a ... Learning new vocabulary terms, memorizing historical events/chronology, etc. ... simple rote repetition of information in consciousness or even more successfully by . elaborate rehearsal: processing of information for meaning which can...
  • Title III Preparing for FPM

    Title III Preparing for FPM

    The academy was planned under a grant from the U. S. Department of Education (USED). However, the content does not necessarily represent the policy of the USED, and you should not assume endorsement by the federal government.
  • What if teaching...

    What if teaching...

    Can we have triple chocolate? Beyond words! Beyond words! What If Learning: Connecting Christian Faith and Teaching. What about teaching and learning? Does Christianity have anything to say about that? Can we have "triple chocolate cake," where Christianity influences the...