Astronomy: The study of the ___________, ___________ and ___________of all objects in space. The Solar System Our solar system includes: a) ___________ b) ___________ c) _________________________________ Planets (2 types) ___________ (inner) planets:

- small - contain mostly rocky material - includes Mercury, Venus, Earth and Mars

___________ (outer) planets - large - composed of huge quantities of different gases - includes Jupiter, Saturn, Uranus and Neptune

Note: Pluto is classified as neither a terrestrial or gaseous planet – it is now classified as a “minor planet” Minor Bodies Types of Minor Bodies: a) __________ b) __________ c) __________

Asteroids – “minor planets” • Irregular shaped __________ bodies • “__________” from planet formations. • Asteroid belt – between _____ and ______ (most asteroids exist there). • Size: 16 km in diameter to 955 km.

Meteors – “stones from the sky”

• Small chunks of ___________ or __________ that burn brightly as they enter Earth’s atmosphere.

• Friction causes the meteor to __________, producing streaks of light (“shooting stars”)

• Large meteors that pass through the Earth’s atmosphere and land on the Earth’s surface are called _____________.

• Meteoroids (rocks drifting through space) are thought to be from the ___________ belt or fragments from ___________.

• Meteors may also come from material left behind from ___________.

Comets – “travellers”

• Rocky metallic ___________ coated with frozen ___________, ammonia, methane and carbon dioxide;

• As comets move closer to the sun they reflect ___________.

• Some of the solid ice begins to change to ________ as the comet gets closer to the sun, forming a ___________.

Earth’s Motion (Chapter 25) Rotation: ___________ motion of the Earth Axis of Rotation:

• imaginary straight line through Earth

between the _________ and

___________; slightly tipped (23.5o)

• angle of the axis does not change as

Earth moves on its path around the

________.

Evidence of Rotation: 1. Foucalt Pendulum

• Foucalt observed a pendulum over the course of a day, and found the

the swing ___________ over time. • Once it is set in motion, a pendulum can not change its ___________

of swing • Therefore, the ___________ must have instead shifted beneath the

pendulum. 2. Coriolis Effect

• Winds and ocean currents are ___________ to the right in the northern

hemisphere and to the left in the southern hemisphere. • This would only occur if the earth is rotating ________________.

Effects of Rotation:

• Length of ___________ (time for earth to turn once on its axis) • _____________ (only half of Earth is facing sun at any time) • Amount of __________ (longer nights when northern hemisphere is tilted

away from the Sun) • Direction of _______________ – Earth rotates counterclockwise (turns

from west to east), so the sun rises in the east and sets in the west. Earth’s Revolution:

• Movement of Earth in its ___________ around the Sun • The Earth (and all planets) revolve ______________ around the sun

(when viewed from North Pole) • Earth travels in an ___________ orbit (distance between Earth and Sun

changes over the year).

- perihelion – Jan. 2 (closest point to the Sun)

- aphelion – July 4 (furthest point from the Sun)

• 1 revolution = 365.24 days (1 year)

Evidence of Revolution: Parallax:

• _______ stars appear to shift position when compared to _______ stars (pencil demonstration)

Seasonal Changes in Constellations

• Different _____________ are visible at different times of the year Effects of Earth’s Revolution

• Hemisphere that leans towards the sun has a longer period of _______

and the density of incident light rays from the sun is _______. This

results in _________ temperatures (summer)

• Areas near the equator do not experience _________ changes in

daylight periods, or in the angle of sunlight and therefore do not have

_________.

Seasons

• Summer _________ – longest daylight period: June 21st • Winter _________ – shortest daylight period:December 21st • Equinoxes – when sun is directly overhead of the Equator, and day time =

night time • _________ (Spring) Equinox: March 21st • _________ Equinox: September 22nd

THE MOON Rotation: the moon turns on its axis over the same ___________ it orbits

around the Earth; therefore, the same side of the moon _________ faces Earth.

Surface of the Moon:

• Composed of:

1. Highlands – light areas

2. Craters – basins and plains (also called _________)

• Dark side has a thicker crust (100 km vs. 60 km – due to Earth’s

gravitational pull?)

History of the Moon:

• Likely formed from collision between the _________ and a _____-sized

object approximately 4.6 billion years ago (when the earth was newly

formed)

• Mass of _______________ was knocked into space and cooled to form

the moon.

• Initially, the surface was bombarded with particles, forming large and small

_________;

• Later, _________ poured out of gaps in the larger basins for nearly 1

billion years, forming the maria.

• For the last 3 billion years, no volcanoes have erupted; the moon is

geologically _________.

Moon’s Orbit

• The Moon revolves around Earth from _________ to _________ in an

elliptical orbit (27 1/3 days)

• Distance is about _________ km from Earth

• Closest point in its orbit is called the _______, furthest is the _______.

Moon’s Phases

• Daily changes in the Moon’s ___________

• The sun lights the half of the moon _________ it

• However, the half of the moon that faces Earth is _________the half lit by

the sun.

• The face changes from all dark to all light over two weeks – _________

• The face changes from all light to all dark over the next two weeks -

_________

THE MOON The moon is Earth’s only natural satellite. The moon is a cold, dry orb whose surface is studded with craters and strewn with rocks and dust (called regolith). The moon has no atmosphere. Recent lunar missions indicate that there might be some frozen ice at the poles. The same side of the moon always faces the Earth. The far side of the moon was first observed by humans in 1959 when the unmanned Soviet Luna 3 mission orbited the moon and photographed it. Neil Armstrong and Buzz Aldrin (on NASA's Apollo 11 mission, which also included Michael Collins) were the first people to walk on the moon, on July 20, 1969 If you were standing on the moon, the sky would always appear dark, even during the daytime. Also, from any spot on the moon (except on the far side of the moon where you cannot see the Earth), the Earth would always be in the same place in the sky; the phase of the Earth changes and the Earth rotates, displaying various continents. THE MOON'S ORBIT The moon is about 384,000 km from Earth on average. At its closest approach (the perigree) the moon is 356,410 km from the Earth. At its farthest approach (its apogee) the moon is 406,700 km from the Earth. The moon revolves around the Earth in about one month (27 days 8 hours). It rotates around its own axis in the same amount of time. The same side of the moon always faces the Earth; it is in a synchronous rotation with the Earth. The Moon's orbit is expanding over time as it slows down (the Earth is also slowing down as it loses energy). For example, a billion years ago, the Moon was much closer to the Earth (roughly 200,000 kilometers) and took only 20 days to orbit the Earth. Also, one Earth 'day' was about 18 hours long (instead of our 24 hour day). The tides on Earth were also much stronger since the moon was closer to the Earth. SIZE, MASS, AND GRAVITY The moon's diameter is 3,476 km, 27% of the diameter of the Earth (a bit over a quarter of the Earth's diameter). The moon's mass is 7.35 x 10 22 kg, about 1/8 of the Earth's mass. The moon's density is 3340 kg/m 3. This is about 3/5 the density of the Earth. The moon's gravitational force is only 17% of the Earth's gravity. For example, a 100 lb. person would weigh only 17 lbs. on the Moon. The gravitational tidal influence of the Moon on the Earth is about twice as strong as the Sun’s gravitational tidal influence. The Earth:moon size ratio is quite small in comparison to ratios of most other planet:moon systems (for most planets in our Solar System, the moons are much smaller in comparison to the planet and have less of an effect on the planet). TEMPERATURE The temperature on the Moon ranges from daytime highs of about 130°C to night time lows of about -110°C. ATMOSPHERE The moon has no atmosphere. On the moon, the sky is always appears dark, even on the bright side (because there is no atmosphere). Also, since sound waves travel through air, the moon is silent; there can be no sound transmission on the moon.

MARE Mare (plural maria) means "sea," but maria on the moon are plains on the moon. They are called maria because very early astronomers thought that these areas on the moon were great seas. The first moon landing was in the Mare Tranquillitatis (the Sea of Tranquility). Maria are concentrated on the side of the moon that faces the Earth; the far side has very few of these plains. Scientists don't know why this is so. CRATERS The surface of the moon is scarred by millions of (mostly circular) impact craters, caused by asteroids, comets, and meteorites. There is no atmosphere on the moon to help protect it from bombardment from potential impactors (most objects from space burn up in our atmosphere). Also, there is no erosion (wind or precipitation) and little geologic activity to wear away these craters, so they remain unchanged until another new impact changes it. These craters range in size up to many hundreds of kilometers, but the most enormous craters have been flooded by lava, and only parts of the outline are visible. The low elevation maria (seas) have fewer craters than other areas. This is because these areas formed more recently, and have had less time to be hit. The biggest intact lunar crater is Clavius which is 100 miles (160 km) in diameter. MOON OR DOUBLE PLANET? The Earth and the Moon are relatively close in size (4:1 in diameter, 81:1 in mass), unlike most planet/moon systems. Many people consider the Earth and Moon to be a double planet system (rather than a planet/moon system). The moon does not actually revolve around the Earth; it revolves around the Sun in concert with the Earth (like a double planet system). LUNAR EXPLORATION There have been many missions to the moon, including orbiters missions and moon landings. NASA's Apollo missions sent people to the moon for the first time. Apollo 11's LEM (Lunar Excursion Module) landed on the moon on July 20, 1969 with Neil Armstrong and Edwin "Buzz" Aldrin (Michael Collins was in the orbiter). Neil Armstrong was the first person to set foot on the moon. His first words upon stepping down the Lunar Module's ladder onto the lunar surface were, "That's one small step for man, one giant leap for mankind." Aldrin described the lunar scenery as "magnificent desolation." Apollo 12-17 continued lunar exploration. MOON ROCKS NASA astronauts have retrieved 842 pounds (382 kg) of moon rocks (in many missions), which have been closely studied. The composition of the moon rocks is very similar to that of Earth rocks. Using radioisotope dating, it has been found that moon rocks are about 4.3 billion years old. THE ORIGIN OF THE MOON Most scientists believe that the moon was formed from the ejected material after the Earth collided with a Mars-sized object. This ejected material coalesced into the moon that went into orbit around th Earth. This catastrophic collision occurred about 60 million years after Earth itself formed (about 4.3 billion years ago). This is determined by the radioisotope dating of moon rocks BLUE MOON When two full moons occur in a single month, the second full moon is called a "Blue Moon." Another definition of the blue moon is the third full moon that occurs in a season of the year which has four full moons (usually each season has only three full moons.)

THE MOON REFER TO THE HANDOUT “THE MOON” TO ANSWER THE FOLLOWING QUESTIONS 1. Is the moon smaller than the Earth, the same size as the Earth or larger than the

Earth?_____ ___

2. Explain why we never see the dark side of the moon from Earth. ______________________________________________________________________________________________________________________________

3. What shape are most lunar craters?_______________________

4. Does the moon have an atmosphere?_______________________

5. Who were the first two people to walk on the moon? _______________________

6. In what year did this first moon walk occur? _______________________.

7. Does a blue moon refer to a blue-colored moon? Explain.

______________________________________________________________________________________________________________________________

8. Are tides influenced more by the gravitational pull of the moon or the Sun?

__________

9. What is the name of material that is thrown from an impact crater? _______________

10. During a lunar eclipse, the shadow of what celestial body blocks our view of the

moon? _________ 11. If you weighed 70 pounds on Earth, what would your weight be on the moon? ____ 12. Explain how scientists determined how old the moon is:

_______________________________________________________________ 13. What colour is the sky on the moon during the daytime? ______At night?______ 14. Explain why the Earth and Moon are sometimes considered a double planet system

as opposed to a typical planet and its moon. ______________________________________________________________________________________________________________________________

Lunar Exploration

Program # of Missions

Major Accomplishments

Luna (USSR)

Pioneer

Mercury

Gemini

Apollo

Space Shuttle

1. How far away is the moon? _________________

2. Before 1959, how did astronomers study the moon?

3. What role did the Ranger and Surveyor Lunar Probes play in lunar exploration?

4. What kinds of measurements were made by instruments left by the Apollo missions on the moon?

The Sun: An Average Star

• As the closest star to Earth, it provides _________ and _________.

• The energy from the sun comes from __________________, where

_________ atoms fuse together to form _________ atoms, releasing heat,

light, and other forms of energy.

Features of the Sun

SUN’S “BODY”

Core: _________ of the sun (15 million oC); made up of gas; where _________ occurs Radiative Zone: surrounds core (temp 2.5 million oC); energy moves _________ through _________ Convection Zone: surrounds radiative zone (Temp: 1 millionoC); energy transferred through _________ SUN’S ATMOSPHERE Photosphere: _________ layer of sun’s atmosphere; 6000 oC; ‘_________’ of the sun, gives off visible _________ Chromosphere: Lies above the ____________ (temp: 4000 – 50,000 oC); thin layer of gases that has a _________ glow Corona: _________ layer of atmosphere; blends into _________ (about 2 million oC) FEATURES OF THE SUN

Granules: _________ texture of the photosphere, caused by _________ currents Sunspots: cool, _________ areas of gas in the photosphere that are caused by powerful _________ fields Solar Prominence: clouds of _________ gases which follow curved lines of _________ force between sunspots; last weeks or months Solar Wind: _________ charged particles that stream out into space through holes in the corona Solar Flares: _________ of hot gas that shoot outward from the chromosphere but quickly fade away Magnetic Storms: particles flung out by solar _________ increase solar wind and can disturb the earth’s _________ field and interfere with _________ communications

The Sun Name: ____________ Date: _____________ 1. The sun is ______________ times great in diameter than the earth.

2. The Sun’s volume is more than a ___________________ times the earth’s volume.

3. The Sun is a tad on the hot side.

a. Interior temperature is _______________°C

b. Surface temperature is ________________°C

4. Describe the three regions of the Sun’s atmosphere.

a. ___________________: ____________________________________________________

b. ___________________:____________________________________________________

c. ___________________:____________________________________________________ 5. Describe a solar prominence:

6. Sunspots: a. Appear as: _____________________________________________________________ b. Their size: _____________________________________________________________ c. Their magnetism: _______________________________________________________ d. Temperature: ___________________________________________________________

7. How do sunspots show the Sun’s rotation? Explain.

8. Sunspot cycle:

a. What is it? _______________________________________________________________

b. How often do they occur? ______________years

c. Their cause? _____________________________________________________________ 9. What is solar wind? 10. What are the sources of solar wind? Describe them.

a. ____________ ____________: _____________________________________________

b. ___________ ______________: ____________________________________________

11. Describe three problems or effects the solar wind causes here on earth.

a. _______________________________________________________________________

b. _______________________________________________________________________

c. _______________________________________________________________________

12. The Sun is fusing hydrogen into ________________. The slight mass lost during the fusion is

converted to _______________. This process is expected to last another _____________ years.

Match the following terms

______

1. Centre of the sun (15 million oC); made up of gas; where fusion occurs

2. surrounds core (temp 2.5 million oC); energy moves outward through radiation

3. surrounds radiative zone (Temp: 1 million oC); energy transferred through convection

4. innermost layer of sun’s atmosphere; 6000 oC; ‘surface’ of the sun, gives off visible light

5. Lies above the photosphere (temp: 4000 – 50,000 oC); thin layer of gases that has a reddish glow

6. outermost layer of atmosphere; blends into space (about 2 million oC)

7. grainy texture of the photosphere, caused by convection currents

8. cool, dark areas of gas in the photosphere that are caused by powerful magnetic fields

9. clouds of glowing gases which follow curved lines of magnetic force between sunspots; last weeks or months

10. ionically charged particles that stream out into space through holes in the corona

11. jets of hot gas that shoot outward from the chromosphere but quickly fade away

12. particles flung out by solar flares increase solar wind and can disturb the earth’s magnetic field and interfere with radio communications

a) chromosphere

b) convection zone

c) core

d) c Sunspots

e) orona

f) granules

g) magnetic storm

h) photosphere

i) Radiative zone

j) Solar flares

k) Solar prominence

l) Solar wind

Distances to the Stars

• When studying the solar system, distances are often described using the astronomical unit (A.U.):

- 1 A.U. = distance from ______ to ________ = 1.50 x 108 km

• When studying the universe, we deal with ______ distances • For convenience, the ____________ was developed.

Light-year: distance ____________travel in one year.

In one second, light travels ____________ km. In one year, light travels 9 460 000 000 000 km = ____________ 1. To find # of light years (given km): #L.Y. = distance in km 9.5 x 1012 km/L.Y. 2. To find # of kilometres (given L.Y.): #km = (distance in L.Y.) x (9.5 x 1012 km/L.Y). Examples: 1. Alpha Centuri is 41 trillion km away , or 4.1 x 1013 km 2. Betelgeuse is 490 L.Y. away.

Distances to Stars Worksheet: Star Distance in km Distance in L.Y. Sirius

8.6

Procyon

1.0 x 1014

Altair

17

Vega

2.3 x 1014

Acrux

270

Antares

3.8 x 1015

Rigel

900

Deneb

1.4 x 1016

Optical Telescopes Read Chapter 20, p. 359-364 to answer the following questions:

1. a) What are the functions of a telescope?

1. _________________________________

2. _________________________________

3. _________________________________

b) Where are optical telescopes best located?

2. a) What is the name for any telescope that uses lenses or mirrors to gather starlight?

b) Why does a lens with a 2-cm diameter have 4 times the light gathering power of a 1-

cm lens?

c) List three reasons why it important to keep the temperature of a telescope’s mirror or

lens constant? 1. __________________________________________________ 2. __________________________________________________ 3. __________________________________________________

d) Why must telescopes be able to move at the same rate that Earth turns?

3. a) Explain how a refractor works. b) Explain why refractors are not being built today.

4. Using a diagram, explain how a single mirror reflector works (fig. 20.3).

5. a) Describe how a multiple-mirror telescope works. b) What is the major advantage of the multiple-mirror telescope over the single mirror

reflector telescope.

6. a) Describe the design and use of the Schmidt telescope. b) Why did scientists place the Hubble Space Telescope into space?

7. Name two advantages to using photographic film to make observations over those made with the human eye.

Brightness of Stars Magnitude: the “____________” of a star. Apparent Magnitude: Brightness of a star as it __________ to us on earth. Luminosity: __________ amount of light energy given off by a star at a

standard distance.

Absolute Magnitude:

• expresses the luminosity

• Equals to apparent magnitude if the star was placed ________. away from

earth.

• Determined using

1) __________________

2) __________________

Worksheet – Star Magnitudes Name: ________ Use the following table to answer the questions below. Date: ________ Rank Star Constellation Apparent

Magnitude Absolute Magnitude

Distance from Earth (L.Y.)

- The Sun -- -26.72 +4.8 -- 1 Sirius Canis Major -1.46 +1.4 8.6 2 Canopus Carina -0.72 -2.5 74 3 Alpha Centauri Centaurus -0.27 +4.4 4.3 4 Arcturus Bootes -0.04 +0.2 34 5 Vega Lyra +0.03 +0.6 25 6 Capella Auriga +0.08 +0.4 41 7 Rigel Orion +0.12 -8.1 900 8 Procyon Canis Minor +0.38 +2.8 11 9 Archenar Eridanus +0.46 -1.3 75 10 Betelgeuse Orion +0.50 -7.2 1,500 11 Hadar Centaurus +0.61 -4.3 300 12 Altair Aquila +0.77 +2.3 17 13 Acrux Crux +0.79 -3.8 270 14 Aldebaran Taurus +0.85 -0.2 65 15 Antares Scorpius +0.96 -4.5 400 20 Deneb Cygnus +1.25 -7.2 1500

1. a) What is the brightest star in the sky (other than the sun!)? _____________ b) What is its apparent magnitude? ___________ c) What constellation is it in? ___________ d) How far away is it? ______________

2. The closest star is ___________ at ___________L.Y. away. The farthest star

is ___________ at ___________ L.Y. away.

3. a) Which constellation has two of the brightest stars in the sky? ___________ b) Name one star ___________ apparent magnitude ___________ c) Name other star ___________ apparent magnitude ___________

4. In your own words, what is the difference between absolute and apparent

magnitude?

5. Rank these stars in order from brightest to dimmest apparent magnitude: Vega, Archenar, Aldebaran, Arcturus, Hadar, Canopus, Procyon

Star Classification Spectroscopy

• Scientists use ____________ to split light energy given off by the sun

and other stars.

• Each chemical element shows a unique __________ when viewed

through spectroscope.

• The spectrum of a star can then tell us:

! The __________ that make up a star;

! __________ of the different elements;

! How fast the star is _____ toward or away from the Earth.

Spectral Types

• Colour of a hot object changes as temperature increases:

Dull Orange Yellow Bluish Red White

• Using spectroscopes, scientists have grouped stars into 7 colour types

called spectral types. Table: Spectral Types of Stars

Type Colour Temp. Range (oC) Example(s) O Blue 25 000 – 50 000 Zeta orionis B Bluish-white 11 000 – 25 000 Rigel, Spica A White 7500 – 11 000 Vega, Sirius F Yellowish-white 6000 – 7500 Polaris, Procyon G Yellow 5000 – 6000 Sun, Alpha Centauri K Orange 3500 – 5000 Arcturus M red 2000 – 3500 Betelgeuse

Hertzsprung-Russell (H-R) Diagram of Star Types

• Graph of surface ____________ vs. ________ magnitude

• Shows that usually the ____________ of stars increases as the surface

temperature ____________

• Divides stars into four groups, based on where they lie on the diagram:

1) __________________

– band running through middle of diagram, including our Sun

2) __________________

- cool, but very large and bright stars (upper right of diag.)

3) __________________

- extremely large, bright stars (top of diagram)

4) __________________

- hot, but very small and dim stars (lower left of diag.)

Read p. 385-388 from text and answer the following questions: TOPIC 10

1. a) What is a diffuse nebula?

b) Where are stars formed? c) What is a protostar? d) What reaction occurs in a protostar that has become very hot? e) When does a star stop contracting?

TOPIC 11

2. a) What does it mean when a star is in the “stable state”? b) When does the stable state end? c) Explain how a star becomes a red giant.

TOPIC 12 3. a) How does a star become a white dwarf?

b) Summarize our Sun’s probable past and future.

TOPIC 13

4. a) What characteristic determines whether a star becomes a supernova? b) Describe a supernova. c) What is a neutron star?

TOPIC 14

5. a) Explain why a neutron star is very dense.

b) How are black holes thought to form?

c) Why are black holes thought to be even more dense than neutron stars?

d) What evidence is there that black holes exist?

Structure of the Universe Universe: consists of _____________ that exists, all the matter and all the energy, as well as the space between the matter.

In the Past • Ancient astronomers believed that the Earth was _____________, while

everything else moved around it –

• This was known as an __________________________.

1600s

• Galileo Galilei improved the telescope and determined that __________ were much further away than the _____________.

• He suggested that planets and the Earth ___________ around the sun (__________________________)

Today’s Ideas • Sun and other stars are also _____________;

• Stars are gathered in large groups surrounded by gas and dust (______).

Galaxies • Huge collections of ____, ______, and hundreds of millions of _______.

• Our sun is part of the __________________________.

Types of Galaxies Edward Hubble developed a classification scheme for galaxies, based on four types:

1. _________ • No spiral structure • Almost round to cigar-shaped

2. _________ • Outstretched, curved arms, like a pinwheel

3. _________ • Similar to spiral, but also has a prominent bar through the nucleus

4. _________ • Lacks either spiral structure or nuclear bulge, and doesn’t have the

symmetry of an elliptical galaxy (random collection of stars)

Origins of the Universe

Big Bang Theory • Approximately 10 –20 billion years ago, the universe was an___________

____________

• This mass exploded and started __________________________.

• As the universe ___________ and ___________, the galaxies and solar nebulas formed.

• Next, _____________ and ____________ formed from individual solid particles combining with other particles.

• Smaller planetisimals either collided with larger ones to form ___________, or became ____________ and/or ____________.

Oscillating Theory

• Like the Big Bang Theory, it suggests that the universe is still currently _____________.

• It will continue to expand to some _____________, and then will begin to _____________.

• Contraction will continue until the universe becomes ________________ enough for another explosion and expansion to occur.

Evidence for Big Bang/Oscillating Theory Red Shift – galaxies observed through a spectroscope have a longer ____________ than normal, suggesting these galaxies are _____________.

Background Radiation – unexpected _____________ has been observed coming from all directions in space, suggesting it may be a remnant of the radiation from the initial __________________________.