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mrstorie.wikispaces.com 10F Science Exploring the Universe

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Exploring the

Universe


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Unit D – Exploring the Universe

D1 – Celestial Motion

Outcome Questions Vocabulary & People Concepts Information Activities

S1-4-03:

Why were the position and motion of visible celestial objects important to past cultures?

Constellation Text:

p. 352-353

p. 364

p. 366-367

What do You Know?

S1-4-01:

How can you measure the location of objects in the sky?

Polaris Star Planet

Astrolabe

Text:

p. 354-355

p. 357-361

p. 371

p. 374

Astrolabe Construction

S1-4-04:

What evidence is there that the sun is the centre of our solar system?

Retrograde

Ptolemy Copernicus Galileo Kepler

Geocentric Vs.

Heliocentric

Text:

p. 368-373

p. 376-380

Retrograde Motion

Evidence for Sun-Centred

S1-4-05:

How does the position and motion of Earth produce day/night, the phases of the moon, and the seasons?

Solstice Equinox

Earth Orbit

and Seasons

Phases of the Moon

D2 – Origin of our Universe

S1-4-08:

What objects make up our solar system and Universe?

Core Nebula Supernova Black hole Galaxy Asteroid Belt Kuiper Belt Oort Cloud Moon Asteroid Meteoroid Meteor Meteorite Comet

Nuclear Fusion

Gas giants Vs.

Terrestrial

Text:

p. 399-406

p. 434-435

p. 390-392

p. 444-450

Components of the

Universe


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S1-4-06:

How do astronomers measure the great distances in the universe?

Light-year Astronomical Units

Text:

p. 436-437

Relative Distance in

the Universe

S1-4-07:

What is the evidence for the Big Bang Theory?

Astronomy Cosmology Apparent magnitude Absolute magnitude Spectroscope Electromagnetic Spectrum

Red Shift

Text:

p. 356

p. 428-433

Light, Stars and Life

D3 – Space Exploration

S1-4-09:

What is the purpose of the various objects humans put in space?

Escape velocity Geosynchronous Satellites GPS Probes Rovers ISS

Text:

p. 412-420

p. 456-463

Hubble Webquest

S1-4-11:

What are advantages and disadvantages of using robots in space?

Text:

p. 461-464

Great Astronomical

FIB


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WHAT DO YOU KNOW? PART 1: 1. Under What I Know consider all of the “space objects” that you have ever heard of and list the objects you

think are found in that section of space.

2. Under Questions I Have write at least one question per section that you would like to know more about.


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PART 2:

1. What is meant by a “day?” What is meant by a “year?”

My answer:

My partner’s answer:

2. Why does the “north star,” Polaris, stay in one place while the other stars appear to move?

My answer:


3. How can the sun and moon appear to be about the same size in the sky?

My answer:


4. Why is it winter in Australia when it is summer in here? And vice versa.

My answer:



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RETROGRADE MOTION ACTIVITY S1-4-04: What evidence is there that the sun is the centre of our solar system?

"Backward" Motion of Planets

Planets tend to move across the sky in an easterly direction. Occasionally, something strange occurs. A planet

appears to slow down and begin moving backward toward the west. In this activity you are going to find out

why this happens. The diagram below represents a part of our solar system. Earth and Mars are shown at several

positions in their orbits around the sun. Each position is labelled with the name of the month when the planet

will be located there.

Procedure

1. In the diagram below, draw a line from each Earth position through the Mars position for the same month.

Extend the line approximately 1 cm past the dashed line.

2. Place a dot at the end of the line and label the dots in order, with the dot on the January line being number 1,

the dot on the February line being number 2, and so on. Note: If paths cross draw the lines slightly long and

place the dots slightly farther away than you did for the other lines. Notice that the line for January is

already drawn, but the dot is yet to be labelled.

3. Using a pencil, start with the dot labelled "1" and carefully connect the dots in order (This line represents

the path the planet Mars would follow in its orbit around the sun as seen from Earth.)

The dots that you put at the ends of the lines represent the positions where an observer on Earth would see Mars

for the month indicated on the diagram. The line you drew connecting the dots represents the path Mars appears

to follow.

Critical Thinking and Application

1. What movement does Mars actually experience from January through August?

2. To an observer on Earth, what movement does Mars appear to experience during that time period?

3. During which months does Mars appear to be moving backward in its orbit?

4. Carefully observe what is happening to Earth and Mars in their orbits when Mars seems to loop "backward."

What causes Mars to seem to move backward in its orbit?

5. Do you think that to an observer on Earth all the planets visible in the night sky would appear at some point

to go backward?


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EVIDENCE FOR SUN-CENTRED S1-4-03: Why were the position and motion of visible celestial objects important to past cultures?

S1-4-01: How can you measure the location of objects in the sky?

S1-4-04: What evidence is there that the sun is the centre of our solar system?

1. What to reasons prompted human beings to look at the Sun and stars more closely?

2. How does an astrolabe work and what coordinates are used to identify celestial objects?

3. What would be the coordinates of the following objects:

a) A star that is directly above you and North

b) The Moon when it is Southwest and halfway between the horizon and directly overhead

c) A star directly east and right on the horizon.

4. Place a word in the space provided to make the sentence true:

a) Ptolemy: __________ centric, or model. Stated that the goes around

the .

b) Copernicus: __________ centric, or model. Stated that the goes around

the .

c) Galileo : first to use a __________ to discover that other planets had __________ and _________.

d) Kepler: build on Brahe’s observations to describe the three __________________________________.

5. Explain the terms retrograde motion.

6. Why was Ptolemy's model accepted for so long?

7. Why was Copernicus' theory not readily accepted?

8. How did the telescope allow Galileo to demonstrate that celestial objects were not perfect?

9. If Tycho Brahe had lived longer, why would he be disappointed with Kepler?


EARTH ORBIT AND SEASONS S1-4-05: How does the position / motion of Earth produce day/night, the phases of the moon, and the seasons?

1. Label the Diagram:

a) Based on your observations of Earth’s position relative to the Sun as well as the tilt of Earth’s axis, on the diagram label each Earth with the

correct season.

b) Label the date of the appropriate equinox/solstice for each season.

c) Using the terms fastest and slowest, place the correct word that describes Earth’s orbital speed for Earths 1 and 3.

d) Using the terms greatest and least, place the correct word that describes the gravitational attraction between the Earth and the Sun for positions 1

and 3.

e) On each of the 4 Earth’s colour the area that would be in shade (not receiving the sun’s ray). Use a pencil or light colour to shade lightly so the

equator and axis are still visible through your shading.

f) Using a yellow coloured pencil, colour the portion of each of the 4 Earth’s that would be receiving the Sun’s rays.

2. Questions:

a) What geometric shape is used to describe Earth’s Orbit? _____________________

b) How long does it take for Earth to complete one revolution around the Sun? _______________

c) Make a general statement about Earth’s position relative to the Sun and Earth’s orbital speed.

d) Make a general statement about Earth’s position relative to the Sun and the gravitational attraction between the Earth and the Sun.

e) Make a general statement about a planets distance to its Sun with respects to the gravitational attraction between the two and the planet’s orbital

speed.


f) Consider where you labeled summer, what conclusions can you make concerning the effect of distance to the Sun and our yearly temperature

variations?

g) There are 2 main factors that cause our seasons to occur on Earth. Explain them:

Season: _________

Date: __________

Orbital Speed:__________

Gravitational attraction: _________

Season: _________

Date: __________

Orbital Speed:__________

Gravitational attraction: _________

1 3

2

4

Season: _________

Date: __________

Season: _________

Date: __________


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PHASES OF THE MOON S1-4-05: How does the position / motion of Earth produce day/night, the phases of the moon, and the seasons?

This site will allow you to interact and discover the positions of the Earth, Sun, and Moon and how they are

related to each other:

http://astro.unl.edu/naap/lps/animations/lps.swf

1. Working in pairs, find a computer go to the following website:

2. Spend some time getting familiar with the applet before answering specific questions.

3. Click on the “show angle” box, and the other tools. See what extra information they provide.

4. Using the applet demonstrate what the following moon phase looks like:

(sketch what you see on the screen in the space provided)

New moon Waxing Crescent moon First Quarter moon

Full moon

Waning Gibbous moon

Third Quarter moon

1. Do any of these results surprise you?

http://astro.unl.edu/naap/lps/animations/lps.swf


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2. What explains any trend you see when observing the moon in this simulation?

Read the following questions and determine whether or not they are correct

If they are incorrect, try your best to modify them so they are right

(Use the simulation or search with Google if you are unsure)

a) The moon rotates on its axis every 27.3 days.

b) A solar eclipse is when the sun is between the Earth and the moon.

c) When we see more than half of the moon lit, we call that a waning.

d) The moon is a very large star.

e) We see a full moon when it is closest to the sun.

f) The moon is said to be waxing when it is getting larger.

g) The moon is a natural satellite that orbits around Earth.

h) It is unsafe to look directly at a lunar eclipse.

i) When we see less than half of the moon lit, we call that a crescent.

j) The pull of the moon’s gravity on the oceans produces tides.


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COMPONENTS OF THE UNIVERSE S1-4-08: What objects make up our solar system and Universe?

1. What is a nebula?

2. What is our closest star and second closest star?

3. Where is the sun's energy produced?

4. What is the difference between fusion and fission reactions?

5. Describe what happens in a fusion reaction.

6. Complete the flow chart to show the death of a small, medium, and large star when it runs out of hydrogen:


Properties of Planets in the Solar System

Property Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto

Avg. Distance

from Sun

(x 106 km)

57.9 108 150 228 778 1427 2870 4497 5900

Orbital Duration 88.0 d 224.7 d 365.26 d 687 d 11.9 yrs. 29.5 yrs. 84.1 yrs. 164.8 yrs. 247.7 yrs.

Avg. Diameter

(km) 4880 12100 12750 6790 142800 120700 50800 48600 2300

Rotational

Duration 59 d 243 d 24 h 24 h 39 min 9 h 50 min 10 h 39 min 17 h 18min 15 h 40 min

153 h 18

min

Main

Atmosphere

Components

None CO2,

nitrogen nitrogen,

oxygen

CO2,

nitrogen

hydrogen,

helium,

methane (CH4)

hydrogen,

helium,

CH4

hydrogen,

helium,

CH4

hydrogen,

helium,

CH4

None

Avg. surface

temp. (°C) –180 to 426 470 –85 to 58 –120 to 30 –160 –180 –210 –220 –220

Density (g/cm3) 5.44 5.25 5.52 3.95 1.31 0.70 1.18 1.66 1.1

Surface gravity (compared to Earth)

0.39 0.90 1.0 0.38 2.58 1.11 1.07 1.4 0.08

Note that numbers for Pluto are estimates, since little is known about this planet. Pluto rotates in the opposite direction to that of other planets.


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7. Why do you suppose Mercury and Pluto lack an atmosphere? Explain.

8. Which planets are most like Earth? Which planets are least like Earth? Explain why.

9. Which planet seems to fit in a category all by itself?

10. Which planets have very low densities? What can you conclude about these planets?

11. Would the atmospheres of the four largest planets support Earth-like life forms? Why or why not?

12. Where do asteroids and comets come from?

13. Describe with the right terms what could happen when a meteoroid enters Earth’s atmosphere.

14. Label the following diagram:


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RELATIVE DISTANCE IN THE UNIVERSE S1-4-06: How do astronomers measure the great distances in the universe?

The distance between the Earth and the Sun is 149,597,870 km. As distances in space are so immense, we tend

to measure them in a larger scale to avoid the extremely long numbers that would be encountered if we simply

expressed them in kilometers. One astronomical unit (AU) is equal to the distance from the Earth to the Sun.

1AU = 149,570,000 km or 1.50 x 108 km

This is a handy way to compare distances without using huge numbers. It is also more meaningful than a huge number as

we can compare how far something is from Earth. (Venus can be as close as 0.3 AU)

For our representation, we will use the additional scale 100 m = 1 AU

Convert the needed values to create a scale solar system:

Table 1:

Body Diameter

(km)

Diameter

(AU)

Scale

Diameter

(cm)

Orbit Radius

(km)

Orbit Radius

(AU)

Scale Orbit

Radius

(cm)

Sun

1391900

Mercury

4866 57950000

Venus

12106 108110000

Earth

12742 149570000

Mars

6760 227840000

Jupiter

139516 778140000

Saturn

116438 1427000000

Uranus

46940 2870300000

Neptune

45432 4499900000

Pluto

3400 5913000

Sample calculation:

123456 km x ___1 AU____ x _100 m_ x _100 cm_ = 8.2 cm (scale)

1.5 x 10 8 km 1 AU 1 m


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Questions:

1. What are the advantages of using astronomical units instead of kilometres?

2. Suppose you wanted to build a 3-D model of the Solar System, and you wanted to show the relative sizes.

What could you use to represent each of the planets?

3. Now that we know the distances of each planet from the Sun, let’s work backwards and determine some of

the planet’s distances from Earth:

a) Using the information in the chart, calculate the average distance from Neptune to Earth

Hint: use the distances of Neptune and Earth from the Sun.

In km:

In AU:

b) If I were in a spaceship travelling 876km/h, how many hours would it take me to get from Earth to

Neptune?

4. Describe what you notice about the size and distance of the inner planets compared with the outer planets.

5. What is the value for the speed of light and what does it mean to say that an object is 5 light-years away?

6. Calculate the distance (in AU and light-years) to Proxima Centauri (the nearest star to the Sun). The real

distance from the Sun to Proxima Centauri is 39,900,000,000,000,000 (3.99 x 1015) km.


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LIGHT, STARS AND LIFE S1-4-07: What is the evidence for the Big Bang Theory?

1. One night, you observe two stars that have the same apparent magnitude. Could these two stars be giving

off different amounts of light? Explain.

2. What is a spectrum and how is it unique?

3. What instrument does an astronomer use to measure the spectrum of a star?

4. What does “red shift” mean?

5. If an astronomer saw ‘blue shift” in a star, what could she conclude?

6. How does the Big Bang theory explain the expanding universe?

7. How does a theory differ from a belief?

8. Based on what we’ve learned to date in this unit, do you think that other life exists in our solar system? In

the universe?


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THE GREAT ASTRONOMICAL FILL-IN-THE-BLANK

Instructions: Complete each statement using the words and phrases below. This should be a useful review of

many of the terms you have encountered in your introduction to astronomy. Some of the words can be used

more than once. The numbers are used only once.

Halley Cultures and religions Minerals White dwarf

Apparent The Earth Star Galaxies

Hydrogen Pluto 1000 Jupiter

The Sun Expansion Solar Verification

Comet Nuclear fusion Instabilities One million

Suns Moons Gravity Galaxy

Contraction Alpha Centauri Light Heliocentric

Supernovas Black hole Ellipse Planet

Nine 150 million One year 63,000

Hubble Aurora Borealis Dispersed Light spectrum

Mass Geocentric Four to five Blue

Sirius Neptune Ray of light Asteroids

Pressure Cloud of gas and dust Red Uranus

Years 10-15 billion years ago Neutrons Helium

Radio waves 100-400 billion Ring Astronomical

Light-year Galaxies Yellow-orange Saturn

Nebulae

1. A _________________ is a celestial body that has an orbit around a central _________________. Our solar

system has _________________ of them, and some astronomers speculate that the belt of

_________________ between the orbits of Mars and Jupiter was once a tenth planet that has been

destroyed.

2. It is the force of _________________ that holds the planets in orbit around the _________________, and

also causes the entire solar system to orbit around the _________________.

3. _________________ are natural satellites of planets. The large number of small bodies between Mars and

Jupiter are called the _________________, which means “star-like.” Certain planets also have a

_________________ system that encircles them, comprised of thousands of small, rocky and icy pieces of

material left over from the disintegration of a once-large satellite.

4. Certain asteroids, called the Trojans, cross the orbit of Mars and make close approaches to the Earth. Their

maximum size is about _________________ kilometres across. Due to the fact that asteroids and moons

are composed of rocky material, some people would like to exploit them as sources of _________________.

5. The largest planet in the solar system is _________________, and the smallest is _________________. The

“third rock” from the Sun is _________________.


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6. The four giant gas planets, listed in order of increasing distance from the Sun are_________________,

_________________, _________________, and _________________. They all have large families of

_________________ orbiting them.

7. An _________________ unit (AU) is the average distance between _________________ and the

_________________. It is equivalent to about _________________ kilometres. A _________________ is

a much larger distance unit used by astronomers, and is the distance that a _________________ traverses in

_________________. A light-year is equivalent to about _________________ AU’s.

8. A _________________ is a solar system object that can have a gas and dust tail exceeding millions of

kilometres in length. These celestial wonders of ice, rock, and organic compounds travel around the Sun in

elongated orbits called an _________________. In 1997, Hale-Bopp was one of the most brilliant to

recently enter the inner solar system, and was visible to the unaided eye for months. However, it is

_________________ that is the most celebrated _________________, returning to put on a show with a

period of about 76 years.

9. The Sun is a _________________, an enormous sphere of gas that emits its energy through the process of

_________________. The temperatures in the extreme outer layer of the Sun’s atmosphere, the “solar

corona,” can reach _________________ degrees Celsius. Every 10 years or so, _________________ flares

erupt from the Sun’s surface layers, eventually disturbing communication systems on Earth. The beautiful

_________________ near the North Pole is caused by streams of charged particles which are emitted by the

Sun and interact with the magnetic field of the Earth high in the atmosphere.

10. The nearest star to the Earth is the _________________. The next nearest star system to ours is

_________________, which is a triple-star system approximately _________________ light-years from

Earth. The colour of its three stars, indicating that they are Sun-like, is _________________. The hottest

stars are _________________ in colour, and the coolest stars are _________________.

11. The _________________ magnitude (brightness as seen from the Earth) of a star differs from its absolute

magnitude (a truer measure of a star’s brightness) because of the great distance between the star and the

Earth. This affects the quantity of _________________ that is observed in the night sky. The brightest star

in the sky from our point of view is _________________ in the constellation Canis Major (the Great Dog),

but it is actually much less luminous than the nearby red giant, Betelgeuse, in the constellation Orion. Very

often, stars appear bright simply because they are close to us.

12. A _________________ is the remains of a supermassive star that is apparently invisible due to the fact that

tremendous _________________ forces do not permit its visible _________________ to escape and be

seen.

13. Neither the _________________ model of the universe (with Earth at the centre) nor the

_________________ model (with Sun at the centre) represents the actual conceptions of the cosmos

accepted by astronomers today. The solar system is just on small fraction of the galaxy called

_________________. The universe is comprised of perhaps hundreds of billions of _________________

like the nearest great spiral galaxy to ours, the Andromeda Galaxy.


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14. A _________________ is actually an enormous collection of stars, dust, and various gases, all bound

together by gravitational attraction. The Milky Way contains somewhere in the neighbourhood of

_________________ stars. Some galaxies have a pinwheel-like appearance, and are called

_________________ galaxies (like the Milky Way). Still others are irregular in form (like the Large

Magellanic Cloud, for instance). Quasars (which is a loose acronym for “quasi-stellar objects”) are strange

sources of _________________, and can emit as much energy as an entire galaxy of stars.

15. A large cloud of gas and dust called a _________________ is often called the “birthplace of stars.” These

clouds of gases, mostly _________________ and _________________, contract under the influence of

_________________. A star is born when its _________________ furnace inside ignites as temperatures

rise to millions of degrees Celsius.

16. Depending on the initial _________________ of the material from the nebula that coalesces to form a star,

the resulting star can end its life span as a small_________________, or as a spectacular

_________________ explosion that leaves behind a super-dense remnant called a _________________ star.

The most massive stars, those about 25 times heavier than our Sun, have the potential to become a

_________________, from which time and space cannot escape. All of the chemical elements that make

up other stars, planets, and matter (including living beings like you) are made from the exploding stars.

17. By analyzing the rainbow-like colours of a _________________ from a celestial body (for example, a star

beyond our Sun), it is possible to detect planets around it by looking for small _________________ in the

motions of the central star. The _________________ Space Telescope has already confirmed the existence

of a number of planetary systems around stars other than our Sun.

18. According to cosmologist (scientists studying the ultimate fate of the cosmos), it is thought that after the

universe’s initial period of _________________, a period of _________________ will result in what has

been called the “Big Crunch.” After that, another _________________ could give rise to a whole new

universe.

19. The _________________ Theory also proposes that all the material that now comprises the universe was

originally concentrated in an exceedingly small volume of space-infinitely small. This mass was under

great _________________, and upon exploding rapidly outward, _________________ the enormous mass

of material that ultimately gave rise to stars, galaxies, and a host of other celestial bodies.

20. A diversity of peoples, _________________ have proposed their own particular explanation for the origins

of the universe, but these perspectives have not utilized the methods and habits of mind traditionally use in

the scientific _________________ of ideas.

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