Sky science   Unit C 6.7.1 - PowerPoint Presentation

Slide1

Sky science 

Unit CSlide2

6.7.1 

Recognize that the

Sun and stars emit the light by which they are seen and that most other bodies in space, including Earth’s Moon, planets and their moons, comets and asteroids are seen by reflected light.Slide3

Objects in Space that Emit and Reflect Light

Many objects in the universe can be seen in the night sky. Some of these objects can be seen because they produce, or give off, their own light. These objects

emit

light. Other objects can be seen because they

reflect

light from objects that emit lightSlide4

Objects in Space that Emit Light

Object

Image

Explanation

Sun

The sun is a star

that produces its own light. This happens when hydrogen is converted to helium through a nuclear fusion reaction.Other StarsStars throughout the universe produce their own light. The emitted light travels through space.GalaxiesGalaxies are made up of billions of stars. These stars all emit light. Billions of stars grouped together emit an enormous amount of light. Slide5

Objects in Space that Emit Light

Object

Image

Explanation

Emission

Nebulae

Nebulae are clouds of dust and gases. Some nebulae are the debris left over from star explosions. Other nebulae are star nurseries where stars are created. An emission nebula is a cloud of glowing gas. The gas atoms of the nebula are energized by the stars in the nebula, causing them to emit light.Meteors in Earth’s atmosphereMeteors are meteroids that have entered Earth’s atmosphere from outer space. These rock and iron pieces burn up and emit light as a result of the friction created as they travel through the atmosphere.Aurora borealisSolar

wind and streams of electrons and protons from the sun are caught in Earth’s magnetic field. The particles of the solar wind collide with atoms of gas in the atmosphere. This causes the gases to glow like neon lights. Different colours are produced when different gases glow.Slide6

Objects in Space that Reflect Light

Object

Image

Explanation

Comets

Comets are made up of rock, dust and ice. As a comet moves closer to the sun in its orbit, the ice begins to melt, which produces a gas vapour trail. The trail of gases reflects sunlight, and this reflection is what

can be observed.PlanetsPlanets are large celestial bodies made up of solids, liquids or gases. Some planets can be seen from Earth with the unaided eye because they reflect the light of the sun.Asteroids and meteroids in spaceAsteroids and meteroids

are chunks of rock and metal found in outer space. Asteroids orbit the sun and are larger than meteroids. Both asteroids and meteroids

reflect the light of the sun.Moons or natural satellites

A number of planets, such as Earth, have natural satellites, or moons. These moons can be seen because the sun’s light reflects off their surfaces.

Artificial Satellites

Artificial satellites, such as the Hubble Space Telescope, are objects sent into orbit. They do not emit light. These objects can be seen because they reflect the light of the sun.Slide7

The planet Jupiter can be seen when looking through a telescope because of light that is

Emitted

Reflected

Refracted

absorbedSlide8

Which of the following lists contains a celestial object that does not reflect light?

Meteroid

, a moon, Earth

Asteroid, a satellite, Saturn

Moon, Venus, International Space Station

Space probe, Orion nebula, Halley’s cometSlide9

Lights seen shooting through the atmosphere at night are

most likely

stars

comets

planets

meteorsSlide10

Comets can be seen in the night sky because they

Emit their own light

Reflect light from the sun

Reflect light from the moon

Burn up as they enter the atmosphereSlide11

While looking up at the night sky, you remember that an object that emits its own light is called

A moon

A star

A planet

An asteroidSlide12

6.7.2 

Describe the location and movement of individual stars and groups of stars (constellations) as they move through the night sky.Slide13

Constellations

On a dark, clear night, a first glance at the sky might reveal hundreds of stars. Look a little closer, and it might seem as through some stars appear to form patterns. You can see these patterns night after night, year after year. In fact, people around the world have been studying and naming star patterns for thousands of years. These star patterns are called

constellations

.

There are 88 constellations recognized by the International Astronomical Union (IAU). Many of these were mapped out by the ancient Greeks thousands of years ago.Slide14

Asterisms

There are also many unofficial star groups called

asterisms

. The stars in an asterism, like a constellation, form a recognizable pattern in the sky. However, an asterism could be a small part of a larger constellation, or it could contain stars from more than one constellation. One of the most well-known groups of stars, the Big Dipper, is an asterism. It is part of a much larger constellation called

Ursa

Major, or the great Bear. Another familiar asterism is the Summer Triangle. It is made up of three bright stars from three constellations – Cygnus the Swan, Aquila the Eagle, and Lyra the Harp.Slide15

Ursa Major, the Great BearSlide16

Markers in the sky

Constellations and asterisms are useful markers in the sky.

When people are new to viewing the night sky, they often look for these familiar groups of stars to help them find other stars and objects.Slide17

Star patterns

It is important to remember that stars in a constellation often do not have any relationship to each other in outer space.

In fact, most of the stars in a constellation are light years away from each other.

If you viewed the same stars from a different part of the galaxy, you would probably not see the same star patterns.Slide18

Polaris

If you spend any amount of time watching the stars, you will see that all the stars appear to move3 across the night sky except for one.

This star is Polaris.

Polaris can be found in the northern part of the sky.

Because it does not move, Polaris has been used for navigation.

If you are facing Polaris, which is sometimes called the North Star, you are facing north.Slide19

Circumpolar constellations

Some constellations can be seen year round.

These are called

circumpolar constellations.

Each night, the circumpolar constellations circle around a single point.

They are always visible.

The point they circle around is Polaris.The main circumpolar constellations include the Great Bear (Ursa Major), the Little Bear (Ursa Minor) and Cassiopeia.Some other constellations that appear to move around Polaris are Draco the Dragon and Cepheus.Slide20

Circumpolar constellation movement

Circumpolar constellations appear to move over the course of an evening.

This is because Earth is rotating underneath your feet.Slide21

Cassiopeia

If you were able to observe the position of Cassiopeia over the course of 24 hours, the drawings you would make would most likely look like the following illustrationSlide22

Positions change with seasons

The positions of circumpolar constellations change as the seasons change.

You can see these changes in the Big Dipper and how it appears with Polaris.Slide23

Cassiopeia over the course of a year

If you were able to observe the position of Cassiopeia at midnight over the course of one year, the drawings you would make would most likely look like the following illustration:Slide24

Polaris does not change position

Notice that Polaris does not change position.

All the other stars appear to move around it.

This is because Polaris is the only star in the Northern Hemisphere that has the axis of Earth pointing directly at it.Slide25

The Great Bear constellation is also called

Dubhe

Polaris

Leo Minor

Ursa

MajorSlide26

If you are looking directly at Polaris, the direction to your left is

South

North

West

eastSlide27

Cassiopeia is a cluster of stars that is associated with an image. Such images are called

Constellations

Solar clusters

Solar systems

galaxiesSlide28

6.7.3 

Recognize that the apparent movement of objects in the night sky is regular and predictable, and explain how this apparent movement is related to Earth’s rotation.Slide29

Apparent movement of objects in the sky

Every day, the sun rises and sets.

At night, the stars and moon also rise and set.

However, some stars seem to circle around the sky.

These are things that humans have observed for thousands of years.Slide30

Earth’s rotation

When people say the sun, moon and stars are rising and setting, they are actually incorrect.

It is, in fact, Earth’s motion that makes it appear as if these objects were moving across the sky.

Earth rotates, or spins, on its axis.

This spinning makes it look like the sun, the stars and the moon are moving across the sky.

Earth spins in a

counterclockwise direction.This is why the sun looks like it is rising in an easterly direction and setting in a westerly direction.Slide31

Sun’s position in the sky

Depending on the time of day, the sun will appear to be different heights in the sky.

The sun is highest in the sky at noon and lowest in the sky at sunrise and sunset.Slide32

Some stars are visible during some seasons but not during other seasons as a result of

The movement of the stars

The movement of the universe

Earth’s revolution around the sun

Earth’s revolution around the solar systemSlide33

To a person on Earth, stars do not appear to move relative to each other because they are

Very small

Very far away

All part of the same galaxy

All attracted to each other by gravitySlide34

When looking up to the night sky, you are able to see

Different constellations at different times, although you can see some constellations all year long

The Big Dipper and the Little Dipper during the winter and Cassiopeia during the summer

The Big Dipper and the Little Dipper during the summer and Cassiopeia during the winter

The same stars and constellations, in approximately the same positions, all year longSlide35

Use the following information to answer the next question

While camping, Amanda and her mother were locating constellations in the night sky. Amanda noticed that, as time passed during the night, the constellations appeared to move.Slide36

The constellations appeared to move because of Earth’s

Tilt on its axis

Weather systems

Rotation on its axis

Orbit around the sunSlide37

During the night, the stars appear to move across the sky from east to west because of the

Rotation of the Earth

Gravity of the sun

Movement of the stars

Effect of prevailing windsSlide38

6.7.4

Understand that the Sun should never be viewed directly, nor by use of simple telescopes or filters, and that safe viewing requires appropriate methods and safety precautions.Slide39

Safely viewing the sun

It is important to remember that direct viewing of the sun, even for a short time, can cause burns to the retina of the eyes.

These burns are not felt, but they can produce a permanent blank spot in the field of vision.

Earth’s atmosphere reduces harmful rays, but it does not eliminate them.

Scientists use special lenses or cameras to look at the sun.

When viewing the sun from home, you can either use a number 14 welders glass or a device called a pinhole projector that will only reflect small amounts of light to your eye.Slide40

Matteo’s teacher informed the class that they were not to look at the sun directly when carrying out investigations dealing with the sun. The most likely reason that Matteo’s teacher asked the class not to look at the sun directly is that

Looking at the sun would cause them to see blue spots for a few minutes afterward

Bright light from the sun could cause permanent eye damage

They may get headaches from squinting at the sun

The bright sunlight would make their eyes reddenSlide41

6.7.5 

Construct and use a device for plotting the apparent movement of the Sun over the course of a day; e.g.: construct and use a sundial or shadow stick.Slide42

Plotting the course of the sun

In ancient times, sundials were used to tell time.

The length of a shadow depends on where the sun is in the sky.

In the morning, a shadow from the sun is long because the sun is low in the sky.

The length of the shadow gradually gets shorter as the sun rises in the sky.

When the sun is directly overhead, there is hardly any shadow.

This usually happens around noon.As Earth rotates, the sun becomes lower on the horizon.The shadow gradually starts to increase in length until the sun sets in the west.Slide43

6.7.6

Describe seasonal changes in the length of the day and night and in the angle of the Sun above the horizon.Slide44

Seasonal Changes in Day and Night and the Angle of the Sun

The seasons are the result of Earth tilting on its axis and revolving around the sun.

Earth’s axis is tilted by 23.45°.

It takes Earth 365.25 days (1 year) to revolve around the sun.

This is what creates the four seasons of the year: spring, summer, fall and winter.

Since the axis is tilted, different parts of Earth are turned toward the sun at different times of the year.Slide45

Summertime

The Northern Hemisphere is tilted toward the sun during the summer.

In Canada, summer is warmer than winter because Canada gets more direct sunlight during summer than during winter.

The sun has more warming power when it is directly overhead

.Slide46

Length of days

The days are much longer during the summer than in winter, so the sun warms Earth for a much longer time.

The Northern Hemisphere is tilted away from the sun in winter.

During the winter, the days are very short, and the sun’s rays hit Earth at an extreme angle.

You do not feel as much direct heat from the sun in the winter.Slide47

Earth’s SeasonsSlide48

Position of the Sun

The sun also appears higher and lower in the sky as the seasons change.

These changes occur because Earth Slide49

6.7.7

Recognize that the Moon’s phases are regular and predictable, and describe the cycle of its phases.Slide50

6.7.8

Illustrate the phases of the Moon in drawings and by using improvised models. An improvised model might involve such things as a table lamp and a sponge ball. Slide51

Phases of the Moon

The light from the moon is light reflected from the sun.

As the moon orbits Earth, you are able to see different parts of the sunlit side of the moon.

These are called phases of the moon

.

The cycle takes about 28 days and occurs month after month as the moon orbits Earth.

The cycle of the phases of the moon begins with a new moon. During this phase, you do not see the moon because only the far side of the moon is illuminated by the sun.Slide52

Phases of the moon

On Earth, you never see the far side of the moon.

Regardless of which phase the moon is in, the same side of it always faces Earth.

As the moon moves in its orbit, you gradually see more of its sunlit side.Slide53

Phases of the moon

The next phases are the

waxing crescent

and

first quarter

.

These are followed by the waxing gibbous phase.This is the phase in which the moon is starting to become round. In the full moon phase, you are able to see the entire sunlit side of the moon. Throughout the next three phases, you gradually see less and less of the sunlit side.These phases are the waning gibbous, last quarter and waning crescent.Slide54

Phases of the moon viewed from earthSlide55

6.7.9

Recognize that the other seven known planets, which revolve around the Sun, have characteristics and surface conditions that are different from Earth; and identify examples of those differences.Slide56

Planets in the solar system

The sun and all of the bodies that orbit it make up the solar system.

This includes the planets and their moons, as well as comets, asteroids,

meteroids

, and any other bits of rock and dust.

The main bodies in the solar system are the eight planets, an asteroid belt, and five dwarf planets.Slide57

planets

Planets are balls made of rocks, gases, or both rocks and gases.

Planets orbit a star.

The four planets closest to the sun are known as the inner planets.

They are small, rocky planets.

These planets are Mercury, Venus, Earth and Mars.Slide58

Mercury

The smallest of the eight planets

Closest to the sun

Small, rocky planet covered with craters

Has almost no atmosphere

Has no moonsSlide59

Venus

Second planet from the sun

Small, rocky planets

No moons

Has a thick atmosphere mostly made up of carbon dioxide

There are also many miles of thick sulfuric acid clouds that completely cover the planet.

The clouds and the atmosphere trap heat on the surface of the planet.The hottest planet in the solar system, reaching temperatures well over 465 degrees Celcius.No chance that life can exist on Venus.Slide60

Earth

Third planet from the sun

Receives a steady flow of heat and light from the sun, which allows for a gentle heating of the atmosphere.

Small, rocky planet with a surface of rock and water

Only planet that is known to support life

One moonSlide61

Mars

The fourth planet from the sun

Has permanent icecaps at both of its poles

Ice is made up of frozen water and carbon dioxide.

Strong winds and dust storms occur regularly in Mars’ atmosphere

Surface is covered in iron-rich dust, which gives its reddish appearance

Has two tiny moons that orbit very closely to its surfaceSlide62

The Asteroid Belt

The asteroid belt lies between the inner planets and the outer planets.

It is a collection of rocks, ice and metal.

Just like the planets, the asteroid belt orbits the sun.

Scientists believe that this material is the debris left over from the formation of the solar system.Slide63

The outer Planets

The next four planets are called the

outer planets.

They are also called the

gas giants

because they are made up of mostly gas and are much larger than the inner planets.

These planets are: Jupiter, Saturn, Uranus and Neptune.Slide64

Jupiter

The fifth planet from the sun

The largest of all eight planets

Made up of about 90% hydrogen and 10% helium.

About 1000 times the size of Earth

Known for its

Great Red Spot, which is believed to be a huge stormIt’s so big, that it can attract smaller bodies in space into its orbit because of its gravityHas 63 known moonsSlide65

Saturn

The sixth planet from the sun

The second largest planet

Made of materials that are lighter than water

About 75% hydrogen and 25% helium

Rings are mostly frozen water, but they also include rocks that are covered in ice

Has 61 moonsSlide66

Uranus

Seventh planet from the sun

Third largest of the eight planets

Made of rock and ice

Its atmosphere has hydrogen and a little helium in it

Spins differently than most of the other planets

Seems to be tilted sideways instead of right-side upHas 27 moonsSlide67

Neptune

The eighth planet from the sun

Its orbit crosses over the orbit of the dwarf planet Pluto

Likely has an inner core made up of different types of ice and rocks

Blue colour comes from the gas methane that makes up its atmosphere

Winds are the fastest in the solar system, reaching 2000 km/h

Has 13 moonsSlide68

The Dwarf Planets

There are also some bodies in the solar system that are too small to be called planets but are too large to be called asteroids

There are five known dwarf planets in the solar system:

Ceres, Pluto,

Makemake

, Eris

and HaumeaHaumea and Makemake are in the same orbit as Pluto in the Kuiper Belt.Ceres is found in the asteroid belt within the solar system.Pluto has three moons and is usually found farther from the sun than Neptune. Its orbit sometimes crosses over Neptune’s orbit, bringing it closer to the sun than Neptune.Eris is in orbit even farther out in space than Pluto, and it has one moon.Eris is the largest of the five dwarf planets.Slide69

6.7.10

Recognize that not only Earth, but other planets, have moons; and identify examples of similarities and differences in the characteristics of those moons.Slide70

Moons in the Solar System

Moons are

naturally occurring satellites

that orbit most planets.

Only the two planets closest to the sun, Mercury and Venus, do not have moons.

Each of the other planets has a different number of moons.Slide71

Moons in the Solar System

Planet

Number of Moons

Mercury

0

Venus

0Earth1Mars2Jupiter63Saturn61Uranus

27

Neptune13Slide72

Moons in the Solar System

Scientists have found that these moons can be very different from each other.

For example, Earth’s moon is a rocky, dusty place with no atmosphere.

Io, one of Jupiter’s moons, is very different. It is the most volcanically active body in the solar system.

Volcanic plumes rise 500 km above the surface of Io. Slide73

Mars’ moons

Phobos

and

Deimos

are Mars’ moons.

Both

Phobos and Deimos are made up of carbon-rich rock and ice.Both have heavily cratered surfacesPhobos is shaped like a potatoSlide74

Jupiter’s moons

Besides

Io

, Jupiter has three other moons of particular interest.

Callisto

has a layer of ice and many craters from comets and asteroids crashing on it.

Europa has a surface covered with a layer of ice. This layer also has dark lines, which are cracks in the ice.Ganymede is the largest moon in the solar system. It is larger than Mercury or Pluto. It is made up of silicate rock and ice.Slide75

Saturn’s moons

Titan

, the largest of Saturn’s moons, is larger than Mercury and has an atmosphere of nitrogen and methane gas.

It is mainly made up of ice and rocky material.

Iapetus

is the outermost of Saturn’s satellites. One side is very dark, while the other side is very bright.Slide76

Neptune’s Moons

The biggest of Neptune’s moons is

Triton

. Triton’s orbit is reverse to the natural movement of other moons. It has a crust of frozen nitrogen and a rocky metal core. The crust has many geysers that are believed to be erupting nitrogen.Slide77

6.7.11

Identify technologies and procedures by which knowledge, about planets and other objects in the night sky, has been gathered.Slide78

Technologies used in space exploration

There are many different tools and technologies used in space exploration.

These tools include telescopes and spacecraft.Slide79

Telescopes

Optical telescopes

are used to view a variety of space objects.

Some telescopes are used to see stars, planets, and other objects in the solar system.

Other optical telescopes are so large that they are housed in buildings called

observatories

.These are used to explore far-off nebulae, stars and galaxies.Slide80

Space Telescopes

Space telescopes

, like the

Hubble Space Telescope

, are in orbit around Earth.

The advantage of using space telescopes is that the weather and pollution in Earth’s atmosphere do not affect them because there is no air in space.Slide81

Radio telescopes

Radio telescopes

do not use light to view objects.

Radio telescopes collect radio waves that are analyzed by a computer.

The computer translates the information into a picture of the objects found by radio telescopes in outer space.Slide82

rockets

Much of what is known about the solar system has been learned through space exploration.

Rockets

have been used to explore space.

The first

liquid-fuelled rocket

was launched in 1926.The ion rocket was the first rocket that did not burn chemicals to propel spacecraft.Solar power is used as a power sourceThe ion rocket works by accelerating ions, or positively charged atoms.Slide83

Space probe

A

space probe

is a robotic spacecraft that leaves Earth’s orbit.

It gathers information about planets, moons, or other objects or places in space.

Some space probes return to Earth with the information they gathered.

Other space probes send information back to Earth.Slide84

Orbital Spacecraft

Orbital spacecraft

orbit Earth or other planets and are often called

satellites

.

Weather satellites and the

International Space Station are both considered orbital spacecraft, even though a weather satellite is unmanned, and the International Space Station (ISS) has a crew.Space shuttles are also orbital spacecraft. They are reusable, rocket-launched vehciles designed to go into orbit around Earth.Slide85

Space Stations

Space stations

are orbiting spacecraft that have living quarters, work areas, and all the support systems needed for crew members to live and work for long periods in space.Slide86

landers

Some spacecraft called

landers

have landed on other planets or moons.

For example, the

Mars Rovers

have landed on the planet Mars.They collect data on rocks and soils on Mars, mainly to see if water once existed or still exists on the planet.Slide87

6.7.12

Understand that Earth, the Sun and the Moon are part of a solar system that occupies only a tiny part of the known universeSlide88

The Solar system in the universe

The universe consists of all the matter and energy that exists in time and space.

This includes Earth, the sun, the stars, the planets, the moons, comets, asteroids, light and other forms of energy, and interstellar dust and gas.Slide89

You in the Universe

Your address in the universe, going from most specific to least specific, may look something like this:

House or apartment number

Street address

City

Province

CountryContinentPlanetSolar SystemGalaxy UniverseSlide90

It’s so big!

The universe is so big that it is thought to be infinite.

That means the universe goes on and on forever with no end.

The universe is so large that distances between objects cannot be measured in kilometers.

Distances in the universe are measured in

light years

.Light is thought to be the fastest thing in the universe.Its speed is about 300 000 km/s. A light year is the distance light travels in one year.If light can travel 300 000 km in one second, it could travel 9 400 000 000 000 km in one year.Slide91

How did it all begin?

No one really knows how the universe began.

There are many theories or ideas about what happened and is still happening in the universe.

These theories vary from the universe expanding, contracting, moving back and forth, to just standing still.Slide92

The Big Bang

One popular theory is that the universe was created 13 billion years ago by a huge explosion.

This theory is called the

big bang theory

.

Since that explosion, galaxies of stars appear to be flying out and expanding outward from each other.

This idea is supported by the red shift of light coming from distant stars.If an object is moving toward Earth, the spectrum shifts toward the blue end of the spectrum.If the object is moving away from Earth, the spectrum from that distant light moves toward the red end of the spectrum.Most galaxies show a red shift, which means they are moving away from Earth.