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Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Sun, Earth, Moon

Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

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Page 1: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

Sun, Earth, Moon

Page 2: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Cartoon of the Day

“From now on we live in a world where man has walked on the Moon. It's not a miracle; we just decided to go. “

-- Tom Hanks

Page 3: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Announcements

• HW Kepler, Gravity Light due

• CoC Star Party tomorrow

• Grading up to date!

Star Party

Join us for a

Friday,

OCT 16

7 – 9:30 p.m.Carl A Rasmussen AmphitheaterCollege of the Canyons Canyon Country Campus17200 Sierra Highway, Santa Clarita, CA 91351

COLLEGE OF THE CANYONS • Canyon Country Campus

STAR FORMATION: Light Beyond The VisiblePresented by Dr. Luisa RebullResearch Scientist, SSC and IRSA, IPAC, CaltechFeaturing: • Hands-on interactive demonstrations and activities

• COC student clubs and academic departments highlighting innovative approaches to understanding the science that governs the universe

• Gaze at the stars through a variety of telescopes

Food and beverages will be available for purchaseFor more information visit

www.canyons.edu/ccc • COL

LEGE OF THE CANYONS •

CANYON COUNTRY

Tallest TowerBuilding CompetitionSign-up online!

www.canyons.edu/Offices/CCC/Pages/StarParty.aspx

Page 4: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Last Class

• Midterm debrief

• Multi-wavelength Astronomy

• Intro to the Solar System

• LT Sun Size (completed, not debriefed)

Page 5: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

This Class

• Grade Status

• Debrief LT Sun Size & do questions

• Sun

• Earth

• Moon

Page 6: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

Grade Status

Page 7: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Grade Status

Letter Midterm Course

A 9 13

B 7 18

C 14 8

D 12 4

F 7 6

Page 8: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

Debrief LT Sun Size

Page 9: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Sun has a diameter of approximately 1.4 million kilometers. Roughly how many Earths would fit across the diameter of the Sun?

A. 10

B. 100

C. 1000

D. 10,000

E. 1 million

Page 10: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Let’s Practice

Page 11: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The image at right shows a picture of the Sun. The dark spots located on this image are sunspots. How does the size of Earth compare to the size of the sunspot that is identified on the right side of the image of Sun?

A. Earth and the sunspot are about the same size.

B. The sunspot is much, much larger than Earth.

C. The sunspot is much, much smaller than Earth.

Sun Size – Instructor’s Guide 129

© 2013 Pearson Higher Education, Inc. Instructor’s Guide for Lecture-Tutorials for Introductory Astronomy

Third Edition

diameter by that of the Moon. Here is an opportunity to talk about proportional reasoning skills.

9) [ 220 orbital diameters ]

Since 110 Sun diameters would fit between Earth and the Sun and 2 orbital diameters of the Moon would fit across the Sun, then 220 Moon orbital diameters would fit between the Sun and Earth.

ADDITIONAL QUESTIONS 1) The image at right shows a picture of the Sun. The dark spots located on this image are

sunspots. How does the size of Earth compare to the size of the sunspot that is identified on the right side of the image of Sun?

a) Earth and the sunspot are about the

same size. b) The sunspot is much, much larger than

Earth. c) The sunspot is much, much smaller than

Earth.

2) Which statement do you think best represents the size comparison between the diameter of the Sun and the distance between the Moon and Earth? The Sun’s diameter is a) smaller than the distance between the Moon and Earth. b) approximately equal to the distance between the Moon and Earth. c) larger than the distance between the Moon and Earth.

3) If you were constructing a scale model of the solar system that used a Sun that was the size of a basketball (approximately 12 inches in diameter), which of the following lengths would most closely approximate the scaled distance between Earth and the Sun? a) 3 feet (length of an outstretched arm) b) 10 feet (height of a basketball goal) c) 100 feet (height of an 10 story building) d) 300 feet (length of a football field)

Page 12: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Which statement do you think best represents the size comparison between the diameter of the Sun and the distance between the Moon and Earth? The Sun’s diameter is

A. smaller than the distance between the Moon and Earth.

B. approximately equal to the distance between the Moon and Earth.

C. larger than the distance between the Moon and Earth.

Page 13: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

If you were to construct a scale model of the solar system that used a 2 cm cherry to represent the Moon, how large of a ball would you need to represent the Sun?

A. 4cm

B. 30cm

C. 110 cm

D. 440 cm

E. 880 cm

Page 14: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

The Sun

Page 15: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

THE SUN IS A STAR

Page 16: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

What is a star?

• A sphere of hot gas

• mostly hydrogen & helium

• Interior hot enough to undergo nuclear fusion in core

• core above 107 K = 10 million K (18 million °F)

Page 17: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Why Stars Shine

• Visible Sun is a hot layer of gas

• about 5800 K (5525°C, 9980°F)

• not as hot as the center!

• Gives off light the same way that hot metal glows red, yellow or white

• Thermal radiation or blackbody

• This is why stars have different colors

Page 18: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Basic Data

• Fairly average star

• It rotates

• faster at the equator (25 days) than at the poles (31 days)

• Entirely gas: Hydrogen (80%) and Helium (19%)

• Central Temperature 15,000,000 K

• Surface Temperature 5800 K

http://www.kidsgeo.com/geography-for-kids/0003-how-big-is-the-earth.php

Page 19: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

What Type of Star is the Sun?

• Main Sequence Star

• most stars spend most of their “life” on the Main Sequence

• energy source thermonuclear fusion

• H fusing to He in the core

Page 20: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

What Type of Star is the Sun?

• Spectral Type G2

• Lifetime on Main Sequence 10 billion years

Page 21: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

Page 22: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Core

• compact: center to about 25% radius

• 15 million K

• atoms completely ionized

• e- “blasted off”

• Where thermonuclear fusion is taking place.

Page 23: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Radiative zone

• 0.25 - ~ 0.7 solar radii

• Energy from core transferred by EMR

• Convective zone

• above radiative zone

• Energy transferred to surface by convection

Page 24: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Convection

Bubbles of hot gas rising up

Cool gas sinking down

Page 25: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Let’s Practice

Page 26: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Sun’s Luminosity comes primarily from

A. chemical burning

B. gravitational contraction

C. nuclear fusion

D. nuclear fission

Page 27: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The energy produced by the Sun is produced

A. in a very small region at the center of the Sun

B. Uniformly throughout the Sun

C. At the surface of the Sun

Page 28: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

THE OUTER LAYERS OF THE SUN

Page 29: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Photosphere

• Visible surface of the Sun

• Apparently smooth layer of gas

• 500 km thick

• 5800 K

• Sunspots

Page 30: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Granulation

• Up close, photosphere has a mottled appearance (granulation) due to convection cells.

• These cells form and fade and shift on a time scale of tens of minutes.

Page 31: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Sunspots

• well-defined surface areas that appear darker than their surroundings because of lower temperatures.

• Associated with sun’s magnetic field

• convection is inhibited by strong magnetic fields, reducing energy transport from the hot interior to the surface http://

Page 32: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Chromosphere

• Atmospheric layer above the photosphere.

• 1000x fainter than the photosphere, but hotter!

Page 33: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Chromosphere

• Pink color during a total eclipse.

• Filaments (dark regions) & Spicules/prominences (jets).

Page 34: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Solar Prominence

Page 35: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Let’s Practice

Page 36: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Sunspots appear dark because

A. They are holes in the photosphere allowing a view of deeper layers

B. Are large opaque structures that block the light from the interior

C. Are slightly cooler than the surrounding areas, appearing dimmer

D. Are burning holes in your retina

Page 37: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

THE CORONA, SOLAR WIND AND SOLAR WEATHER

Page 38: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The structure of the Sun

• Corona

• Outermost atmospheric layer.

• Extending outwards 20 times the Sun’s radius.

• Heated by magnetic field interactions.

• solar wind • 300 - 1000 km/s

• Loses 10 million tons/yr

http://antwrp.gsfc.nasa.gov/apod/ap080920.html

Page 39: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Solar Weather

• In addition to sunspots, solar activity results in

• Solar flares

• Aurora Borealis

• Coronal Mass Ejections

• Geomagnetic Storms

• http://spaceweather.com/, http://www.swpc.noaa.gov/

(Ultraviolet images)

Page 40: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Aurora Borealis

Page 41: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Solar Weather and Humans

• Solar flares

• really refer to increased brightness

• Coronal Mass Ejection

• Interferes with Satellites

• Geomagnetic Storms

• In rare cases causes power grid issues

Page 42: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

FATE OF THE SUN

Page 43: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Endgame for our Sun

• A star’s fate is pretty much determined at the moment of it’s “birth” by its mass

• and the company it keeps

• High mass stars, ~ 8x Sun, explode

• supernovae

• Low mass stars like the Sun have a different fate

• Sun does NOT!!!!! “go supernova”

Page 44: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Main Sequence to Red Giant

• After the core becomes depleted of H, the Sun will become a red giant

• A much larger, cooler star

• Earth, in all likelihood, gets swallowed up

Ar#sts  concept  of  the  Sun  as  a  red  giant:  

Image:  ESA

He  core

H  burning    shell

Page 45: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Red Giant to White Dwarf

• Eventually the red giant exhausts the H in its shell

• throws off up to half its mass

• “planetary nebula”

Spitzer  Space  Telescope  Image  of  a  PN  the  Helix  Nebula

Page 46: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Fading away...

• Core becomes a white dwarf

• Squeezed into size of Earth

• Maximally compressed into a degenerate gas

• In isolation, very slowly cools and fade away

Artist’s conceptImage ESA/NASA

Page 47: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Let’s Practice

Page 48: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Sun will ultimately

A. Go Supernova

B. Become a white dwarf

C. Become a black hole

Page 49: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Which of the following are the most potentially damaging consequences of solar activity

A. Solar flares & Aurora Borealis

B. Coronal Mass Ejections & Geomagnetic storms

C. Promenences and Spicules

Page 50: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

The Earth as a Planet

Page 51: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Comparison of the “Terrestrial” Planets

Page 52: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The “Habitable Zone”

• In astronomy and astrobiology, the habitable zone is the region around a star where a planet with sufficient atmospheric pressure can maintain liquid water on its surface.

www.astrobio.net

Page 53: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Statistics

• Equatorial Diameter = 12,756 km • Mass = 5.98 x 1024 kg • av. density = 5.5 g/cc • surface T = -50°C to +50°C • a = 1.00 AU • P = 1.00 year • e = 0.0167

Page 54: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Uniqueness

• Every major process on any rocky world in our solar system is represented in some form on Earth.

• Unique in 2 important ways

1. Surface water (75% of the surface is water)

• No other SS body has surface water currently

2. Life

• No other SS body has been found to have life. Yet.

Page 55: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Early History

• Formed 4.6 billion years (4.6 x 109) ago from the inner solar nebula.

• 4 Stages of Evolution: • Differentiation

• Heavy Bombardment: Cratering

• Flooding

• Slow Surface Evolution

Page 56: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Structure — Core

• Hot as the Sun’s surface (~6000 K)

• Solid inner core

• liquid core surrounding it

• Source of Earth’s magnetic field

• Dynamo effect

Page 57: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Structure — Mantle

• Solid (“plastic”) Mantle

• As in deformable, not as in manmade

Page 58: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Structure — Crust

• Solid

• Thicker under land (60 km)

• thinner under oceans (10 km)

• Brittle: Broken into tectonic plates

• only terrestrial planet with plate tectonics

Page 59: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Magnetic Field

• Is Useful

• Likely helps birds & fish know where N and S are for migration

• Compasses

• Most importantly, it protects us from the solar wind

• which would otherwise slowly strip the Earth’s atmosphere away...which would NOT be good!

• Is generated by the dynamo effect

Page 60: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Magnetic Field via Dynamo Effect

• 2 Key components

• Liquid conductor

• Rotation

• Earth

• ample liquid iron outer core, plus

• fairly brisk 24 hr rotation, yields

• strong magnetic field image from: http://www.abc.net.au

Page 61: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Core and the Dynamo

• Earth’s core consists mostly of iron + nickel

• high electrical conductivity.

• A conductor in motion creates a magnetic field

• The liquid core convects and the Earth Rotates

• Results in a dipole field

Page 62: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

PLATE TECTONICS

Page 63: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Plate Tectonics

• Plates are moved by convective motion in the mantle

• hot material rises and cools, cool material sinks

Page 64: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Tectonic History

Page 65: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

LET’S PRACTICE

Page 66: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

If the Earth’s rotation were to slow down drastically which of the following would most likely happen?

A. Runaway Greenhouse effect, leading to unsurvivable surface temperatures

B. Diminishment of Earth’s magnetic field, leading to loss of protection from the solar wind

C. Diminishment of atmospheric friction, leading to dramatic cooling of the surface

D. Diminishment of gravitational force, leading to loss of the Moon.

Page 67: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Plate tectonics exists on Earth because _____.

A. convection in the mantle causes motion

B. the crust is thin and broken into pieces

C. both of these

D. neither of these

Page 68: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

EARTH’S TIMELINE

Page 69: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

History of Geological Activity

Page 70: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Earth’s Atmosphere

• 76% Nitrogen, 23% Oxygen, 1.3% Argon & a smattering of other stuff

• (water and carbon dioxide included).

• Ozone (O3) protects the surface from UV radiation (26 km up).

• Carbon Dioxide i s a “greenhouse gas:” it is transparent to visible light, but opaque to infrared light

Page 71: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Evolution of Atmosphere

• Primordial Atmosphere

• Whatever was outgassed by the geologic activity (volcanoes) of ~4 billions years ago.

• carbon dioxide (CO2), nitrogen, water vapor.

• The CO2 levels decreased

• As Earth cooled, water vapor condensed. Oceans formed!

• The oceans absorbed CO2 (CO2 is soluble in water… think carbonated drinks!)

• The CO2 reacted with other elements in the water

Page 72: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Evolution of Atmosphere

• O2 levels increased

• Initially, any oxygen present reacted with minerals to form iron oxide, etc…

• The rise of oxygen levels in the Earth’s atmosphere is tied to life.

• Specifically photosynthesis

• evolved 2.7 - 2.4 billion years ago

• picked up when the oceans developed plant life 2-2.5 billion years ago

• Oxygen exists because of life, not vice versa!

Page 73: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Where Water Came From

• Not completely well understood. Several hypotheses:

• Older hypothesis: Primordial content and Vulcanism

• When a volcano erupts, 50-80 % of the gas is water vapor.

• Newer understanding: Primordial outgassing

• Earth formed so rapidly that it was substantially heated by the impacts of infalling material, as well as by radioactive decay.

• Molten surface -> continuous outgassing

• straight to the volcanic “ secondary atmosphere” without a hydrogen- rich primeval atmosphere.

• Some of the water may have arrived late in the formation as a bombardment of volatile-rich planetesimals

• studies of Comet LINEAR, which broke up in 1999 as it passed near the sun, support this

Page 74: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 — Elementary Astronomy LA Mission College

Spring F2015

The Moon

The Moon

Page 75: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Importance of the Moon

• Moderates wobble of Earth’s axis

• stabilizes climate

• Tides

• Cultural and Historical importance

• Only place aside from Earth we have visited in person

• Lunar Ranging

Image Credit: NASA

Galileo Image taken on way to Outer Solar

System

Apollo 16, Image Credit: NASA

Page 76: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

CHARACTERISTICS OF THE MOON

Page 77: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Moon Earth

• Equatorial Diameter = 3476 km

• mass = 7.35 x 1022 kg

• average density = 3.4 g/cc

• surface temp = -170°oC to

+130°C

• a = 384,400 km (from Earth!)

• P = 29.5 days (around Earth!)

• e = 0.055

• Equatorial Diameter = 12,756

km

• mass = 5.98 x 1024 kg

• average density = 5.5 g/cc

• surface temp = -50°C to +50°C

• a = 1.00 AU

• P = 1.00 y

• e = 0.0167

Page 78: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Key Characteristics of the Moon

• No magnetic field

• Small core, no iron

• No atmosphere

• Too small & hot to hold onto gases

• gas molecules readily reach escape velocity!

• Very dry

• no sedimentary rock

• some ice may exist under the surface

Oblique View of the Lunar Crater Tycho

Credit: NASA/GSFC/Arizona State University

Page 79: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Moon: The View from Earth

• Tidally coupled to the earth

• rotation = revolution

• always see same side

• Heavily cratered highlands

• Smoother, darker lowlands

• maria (“seas”)

• flooded by lava

• Cool

Farside from LRO

Credit: NASA/GSFC/Arizona State University

Nearside from LRO

Page 80: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Lunar Craters

• Numerous!

• >300,000

• Named after people: scholars, scientists, explorers

• Typical crater morphology Tycho

CopernicusKepler

Plato

Aristarchus

MareTranquillitatis

MareSerenitatis

MareCrisium

MareImbrium

Oceanus

Procellarum

MareNubium

Page 81: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Lunar Maria

• large, dark, basaltic plains

• lava flooded low-lying areas

• more prevalent on near side

• 1.2-4.2 billion y.o.

• radiometric dating

• crater counting

Tycho

CopernicusKepler

Plato

Aristarchus

MareTranquillitatis

MareSerenitatis

MareCrisium

MareImbrium

Oceanus

Procellarum

MareNubium

Page 82: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

LET’S PRACTICE

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Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

There is very little atmosphere on the Moon because

A. dry rocks on the moon absorb gases as soon as they are created.

B. it was blown away by meteor bombardment.

C. its low mass and high temperature allowed most gases to escape.

D. the gravitational tidal forces from the Earth stripped it away.

Page 84: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Moon

A. always points the same face towards the Sun.

B. does not rotate.

C. rotates at the same rate as the Earth rotates -- once per day.

D. rotates at the same rate as it revolves around Earth -- once per month.

Page 85: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

LUNAR EXPLORATION

Page 86: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

History of Lunar Exploration

• 1st visited by the USSR's Luna 1 and Luna 2 in 1959.

• These were followed by a number of U.S. and Soviet robotic spacecraft. US sent:

• Rangers (1961-1965) were impact probes,

• Lunar Orbiters (1966-1967) mapped the surface

• Surveyors (1966-1968) were soft landers.

• Apollo program -- Men on the Moon

• Lunar exploration resumed in the 1990s

• Clementine & Lunar Prospector

Page 87: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Manned Lunar Exploration

• May 25, 1961 -- President John Kennedy committed the United States to landing a human being on the moon by 1970.

• Vehicle hefty enough to get to moon would be difficult to land: Two-module design with “disposable” lander • Command module

• The lunar landing module ( LM )

• The first human- piloted lunar landing was made July 20, 1969.

• July 1969 -- December 1972,: • 12 people reached the lunar surface

• collected 380 kg ( 840 lb) of rocks and soil

Page 88: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Apollo Landing Sites

• First Apollo missions landed on safe, smooth terrain.

• Apollo 11: Mare Tranquilitatis; lunar lowlands

• Later missions explored more varied terrains.

• Apollo 17: Taurus-Littrow; lunar highlands

Page 89: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

The Apollo Missions

• Hoax Believers, please check out Mr. “Bad Astronomy” Phil Platt’s extensive rebuttal:

• http://www.badastronomy.com/bad/tv/foxapollo.html

• And this filmmaker’s assessment of why faking it would have been harder than making it

• http://www.space.com/19531-moon-landings-faked-filmmaker-says-not-video.html

Page 90: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Moon Landing Remastered

• http://video.nationalgeographic.com/video/news/space-technology-news/1969-moonlanding-vin/

Page 91: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Moon Rocks

• Igneous (solidified lava)

• No sedimentary rock

Vesicular (= containing holes

from gas bubbles in the lava) basalts, typical of

dark rocks found in maria

Breccias (= fragments of different types of rock

cemented together), also containing anorthosites (= bright, low-density rocks

typical of highlands)

Older rocks become pitted

with small micrometeorite

craters.

Page 92: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

LUNAR FORMATION

Page 93: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Must Explain

• Similar oxygen isotopic composition to Earth

• But different chemical composition -- low density

• No magnetic field

• All igneous rock

• Same age as Earth

• Maria and Highlands

Page 94: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Moon formation

• Fission Hypothesis

• Earth broke in two (if it were spinning quickly enough)

• Condensation Hypothesis

• Earth & Moon formed as a double planet system

• Capture Hypothesis

• Earth gravitationally captured a pre-existing body

• Large-impact hypothesis

• Early earth and moon formed from the glancing collision of two protoplanets

• Resulting large body became the earth and ejected debris formed the moon

• Could have caused Earth’s 23° tilt

Page 95: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Large Impact Hypothesis

• Impacting body about the size of Mars — Theia

• Impact heated material enough to melt it

• consistent with “sea of magma”

• Collision not head-on

• Large angular momentum of Earth-moon system

• Collision after differentiation of Earth’s interior

• Different chemical compositions of Earth and moon

• Earth absorbed iron core of impactor

• Molten remnant material coalesced into Moon

Page 96: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

LET’S PRACTICE

Page 97: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Which proposed explanation for the Moon’s origin was ruled out when the Apollo mission revealed similar abundances of isotopes of oxygen in lunar rock as on Earth?

A. that the Moon broke off from the Earth

B. that the Moon and Earth formed together out of the same material

C. that the Moon was a passing body that was gravitationally captured by the Earth

D. that the Moon was formed when a large object impacted the proto-Earth

Page 98: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

WRAP-UP

Page 99: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Topic for Next Class

• Mercury, Venus, Mars

• Greenhouse effect

Page 100: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Reading Assignment

• Astro: 7

• Astropedia: 8

Page 101: Sun, Earth, Moon - Los Angeles Mission College Sun • Earth • Moon Astronomy 1 — Elementary Astronomy LA Mission College Spring F2015 Grade Status Astronomy 1 - Elementary Astronomy

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

Homework

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