Astronomy.ppt

(1)

(2)

Earth/Sun/Moon

System

(3)

Electromagnetic

Radiation

 Electromagnetic Radiation includes Electromagnetic Radiation includes visible light, infrared and ultraviolet visible light, infrared and ultraviolet

radiation, radio waves, microwaves, radiation, radio waves, microwaves,

(4)

Electromagnetic

Radiation

 _____________________ is classified by _____________________ is classified by it’s wavelength

it’s wavelength

 Wavelength is the distance between Wavelength is the distance between peaks on a wave

peaks on a wave

Electromagnetic radiation

(5)

Telescopes

 Refracting Refracting

Telescopes use Telescopes use lenses to bring lenses to bring

visible light to a visible light to a

focus focus

 Reflecting Reflecting

Telescopes bring Telescopes bring

visible light to a visible light to a

(6)

The Moon

 Astronomers have learned much Astronomers have learned much

about the moon from telescopes and about the moon from telescopes and

spacecraft spacecraft

 Our moon is one of the largest in the Our moon is one of the largest in the solar system

solar systemThe MoonThe Moon The EarthThe Earth Mass (kg)

Mass (kg) 7.349 X 10^227.349 X 10^22 5.9736 X 10^245.9736 X 10^24

Radius (km)

Radius (km) 1737.41737.4 6378.16378.1 Volume(km3)

Volume(km3) 2.1968 X 10^102.1968 X 10^10 1.08321 X 10^121.08321 X 10^12 Density(kg/

Density(kg/ m

m33) ₎

3340

(7)

The Moon

 Because the moon has no atmosphere Because the moon has no atmosphere there are extreme differences in the

there are extreme differences in the

moons temperature

 The surface of the moon consists of:The surface of the moon consists of:

 HighlandsHighlands  MariaMaria

 Impact CratersImpact Craters  EjectaEjecta

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The Moon

 Radiometric dating suggests the moon Radiometric dating suggests the moon

is between 3.8-4.6 Billion Years Old is between 3.8-4.6 Billion Years Old

 It is believed that the moon was It is believed that the moon was

heavily bombarded during it’s first heavily bombarded during it’s first

800 million years 800 million years

 Maria are between 3.1 and 3.8 Billion Maria are between 3.1 and 3.8 Billion

Years old Years old

 They are believed to have been craters They are believed to have been craters that have been filled up with lava

that have been filled up with lava

Radiometric dating suggests the Radiometric dating suggests the

moon is between 3.8-4.6 Billion Years moon is between 3.8-4.6 Billion Years

Old Old

It is believed that the moon was It is believed that the moon was

heavily bombarded during it’s first heavily bombarded during it’s first

800 million years 800 million years

Maria are between 3.1 and 3.8 Billion Maria are between 3.1 and 3.8 Billion

Years old Years old

• They are believed to have _{They are believed to have} been craters that have

been craters that have been been filled up with lava

(9)

The Moon

 Scientists believe that the moon is not Scientists believe that the moon is not

tectonically active

 The moon is made up of layers like the The moon is made up of layers like the

Earth

 The moon does experience quakes The moon does experience quakes

however they are incredibly weak

 There are no active volcanoes and no There are no active volcanoes and no

magnetic field so scientist theorize that

the moon is tectonically inactive

(10)

Formation of the Moon

 Capture Theory-A large object came too Capture Theory-A large object came too near to the Earth and was caught in it’s

near to the Earth and was caught in it’s

gravitational pull

 Simultaneous theory-Earth and Moon Simultaneous theory-Earth and Moon formed at the same time

formed at the same time

 Impact Theory-Earth and another object Impact Theory-Earth and another object collided 4.5 Ga. Materials from the

collided 4.5 Ga. Materials from the

incoming body collided, were ejected out

into space and merged together to form

the moon

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Earth/Sun/Moon System

 Solar Day-Time period from sunrise Solar Day-Time period from sunrise to sunset

to sunset

 The length of the day and The length of the day and

temperature varies depending on temperature varies depending on

the latitude the latitude

 The plane in which Earth orbits The plane in which Earth orbits around the sun is ecliptic

(12)

The Earth’s Tilt

 The Earth is tilted on its axis at The Earth is tilted on its axis at about 23.5 degrees

about 23.5 degrees

 For 6 months the Northern For 6 months the Northern

Hemisphere is tilted towards the sun Hemisphere is tilted towards the sun

and for the next 6 months the and for the next 6 months the

Southern Hemisphere is tilted Southern Hemisphere is tilted

towards the sun towards the sun

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Solstices/Equinox

 Summer Solstice-June 21Summer Solstice-June 21stst, Maximum _{, Maximum}

amount of daylight for the Northern amount of daylight for the Northern

Hemisphere Hemisphere

 Autumnal Equinox-September 21Autumnal Equinox-September 21stst, Equal _{, Equal}

amount of sunlight for both Hemispheres amount of sunlight for both Hemispheres

 Winter Solstice-December 21Winter Solstice-December 21stst, Maximum _{, Maximum}

amount of daylight for the Southern amount of daylight for the Southern

Hemisphere Hemisphere

 Vernal Equinox-March 21Vernal Equinox-March 21stst, Equal amount _{, Equal amount}

(15)

Phases Of The Moon

 Due to the Due to the

movement of the movement of the Moon around the Moon around the

Earth our Earth our

viewpoint changes. viewpoint changes.

 The Moon appears The Moon appears

to go through to go through

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Notice the changing diameter of the Moon during the 'moonth'. As the Moon's orbit brings it closer to earth (perigee) at the New Moon, it appears larger to us. Also notice how the Moon 'rocks' up and

down and back and forth. That happens because the Moon's orbit takes it above the Earth's equator (allowing us to see more of the south polar region) and

below the equator revealing more of the north polar region of the

Moon. The back and forth (east-west) rocking is due to the

(19)

Eclipses

 A solar eclipse A solar eclipse occurs when the

occurs when the

moon passes directly

between the Earth

and the Sun and

blocks our view of

the sun

 A lunar eclipse A lunar eclipse occurs when the

occurs when the

Moon passes through

Earth’s shadow

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A view of a Solar Eclipse as

Seen from Space

 http://www.stormcenter.com/media/

(21)

Overview Of The

Solar System

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Solar System

 Earth is one of 8 planets revolving or Earth is one of 8 planets revolving or orbiting around the sun

orbiting around the sun

 When viewed from Earth the planets When viewed from Earth the planets seem to change position in relation seem to change position in relation

(23)

Solar System

 Early astronomers believed that the Early astronomers believed that the Sun, planets and stars all revolved Sun, planets and stars all revolved

around the Earth. around the Earth.

(24)

Solar System

 Most planets move toward the East Most planets move toward the East in relationship to Earth

in relationship to Earth

 Retrograde Motion is when a planet Retrograde Motion is when a planet moves in the opposite direction, in moves in the opposite direction, in

(25)

Solar System

 Nicolaus Copernicus suggested that Nicolaus Copernicus suggested that the sun was the center of the solar the sun was the center of the solar

system, which is called system, which is called

(26)

Solar System

 Copernicus’s ideas were initially Copernicus’s ideas were initially rejected

rejected

 Tycho Brahe later made Tycho Brahe later made

observations of planetary positions observations of planetary positions  By using Brahe’s data Johannes By using Brahe’s data Johannes

Kepler determined that each planet Kepler determined that each planet

orbits the Sun in a shape called an orbits the Sun in a shape called an

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(28)

Kepler’s 1st Laws Of

Planetary Motion

 Each planet moves in an ellipse Each planet moves in an ellipse rather than a circle

rather than a circle

 1.496 X 101.496 X 1088 = 1 Astronomical Unit(AU). _{= 1 Astronomical Unit(AU).}

 Perihelion-When a planet is closest to Perihelion-When a planet is closest to

the sun the sun

 Aphelion-When a planet is at it’s Aphelion-When a planet is at it’s

furthest distance from the sun furthest distance from the sun

 Eccentricity-the ratio of the distance Eccentricity-the ratio of the distance

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Kepler’s 2nd Laws Of Planet

ary Motion

 Kepler’s second law says that an Kepler’s second law says that an

imaginary line between the sun and imaginary line between the sun and

a planet sweeps out equal amounts a planet sweeps out equal amounts

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Kepler’s 3rd Laws Of

Planetary Motion

 Kepler derived a mathematical Kepler derived a mathematical

relationship between the size of a relationship between the size of a

planet’s ellipse and it’s orbital planet’s ellipse and it’s orbital

period period

 PP22 = a_{= a}33

 P = Time in Earth YearsP = Time in Earth Years

 a = semimajor axis of the orbital a = semimajor axis of the orbital

(32)

(33)

Solar System

 While Kepler was developing his While Kepler was developing his ideas Galileo Galilei became the 1 ideas Galileo Galilei became the 1stst

person to use a telescope person to use a telescope

 His most well known discovery was His most well known discovery was of 4 moons of Jupiter

of 4 moons of Jupiter

 Lead to the idea that the Earth is not Lead to the idea that the Earth is not the center of the solar system

(34)

Solar System

 Issac Newton developed an Issac Newton developed an understanding of gravity by understanding of gravity by

observing the Moon’s motion , the observing the Moon’s motion , the

orbits of the planets and the orbits of the planets and the

acceleration of falling objects on acceleration of falling objects on

(35)

Solar System

 Newton’s law of Universal Gravitation Newton’s law of Universal Gravitation states:

states:

 F = GF = G((m((m₁₁mm₂₂))

rr22

F= Force measured in newtons

G= Gravitational constant (6.6726 X 10

G= Gravitational constant (6.6726 X 10-11-11

m

m33/kg/s_/kg/s22)₎

m

m₁₁ and m and m₂₂= Mass of two bodies in kg= Mass of two bodies in kg

r = distance between the 2 bodies in meters

(36)

Center Of Mass

 Newton determined that each planet Newton determined that each planet orbits a point between it and the Sun orbits a point between it and the Sun

called the center of mass called the center of mass

 Newton stated that the center of Newton stated that the center of mass is closer to the more massive mass is closer to the more massive

(37)

Newton’s

Laws of

Motion

_I._I._{Law of Inertia}_{Law of Inertia}

II.

II. F=ma F=ma

III.

(38)

While most people

know what Newton's laws

say, many people do not

know what they mean (or

simply do not believe what

they mean).

(39)

Newton’s Laws of Motion



1

stst

Law

_{– An object at rest will stay at}_{– An object at rest will stay at}

rest, and an object in motion will stay

in motion at constant velocity, unless

acted upon by an unbalanced force.



2

ndnd

Law

_–_–_{Force equals mass times}_{Force equals mass times}

acceleration.



3

rdrd

Law

_–_–_{For every action there is an}_{For every action there is an}

equal and opposite reaction.

(40)

1

stst

Law of Motion

(Law of Inertia)

An object at rest will stay

at rest, and an object in

motion will stay in motion

at constant velocity, unless

acted upon by an

unbalanced force.

(41)

1

stst

Law



Inertia is the

tendency of an

object to resist

changes in its

velocity:

whether in

motion or

motionless.

(42)

1

stst

Law



Once airborne,

unless acted on

by an

unbalanced

force (gravity

and air – fluid

(43)

1

stst

Law



Unless acted

upon by an

unbalanced

force, this golf

ball would sit

on the tee

(44)

Why then, do we observe

every day objects in motion

slowing down and becoming

motionless seemingly

without an outside force?

It’s a force we sometimes cannot see

– friction.

(45)

Objects on earth,

unlike the frictionless

space the moon travels

through, are under the

influence of friction.

(46)

 There are four main types of friction:There are four main types of friction:

 Sliding friction: Sliding friction: ice skating  Rolling friction: Rolling friction: bowling

 Fluid friction (air or liquid): Fluid friction (air or liquid): air or water resistance  Static friction: Static friction: initial friction when moving an

object

What is this unbalanced force that acts on an What is this unbalanced force that acts on an object in motion?

(47)

Slide a book across

a table and watch it

slide to a rest

position. The book

comes to a rest

because of the

presence

presence of a force of a force - that force being

- that force being

the force of friction

- which brings the

book to a rest

position.

(48)

 In the absence of a force of friction, In the absence of a force of friction, the book would continue in motion the book would continue in motion

with the same speed and direction - with the same speed and direction -

forever! (Or at least to the end of the forever! (Or at least to the end of the

(49)

Newtons’s 1

stst

Law and

You

Don’t let this be you. Wear seat belts. Don’t let this be you. Wear seat belts.

Because of inertia, objects (including you) Because of inertia, objects (including you) resist changes in their motion. When the resist changes in their motion. When the car going 80 km/hour is stopped by the car going 80 km/hour is stopped by the

brick wall, your body keeps moving at 80 m/ brick wall, your body keeps moving at 80 m/ hour.

(50)

2

(51)

2

ndnd

Law

The net force of an

object is equal to the

product of its mass and

acceleration, or F=ma.

(52)

2

ndnd

Law

 When mass is in kilograms and When mass is in kilograms and

acceleration is in m/s/s, the unit of acceleration is in m/s/s, the unit of

force is in newtons (N). force is in newtons (N).

 One newton is equal to the force One newton is equal to the force

required to accelerate one kilogram required to accelerate one kilogram

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2

ndnd

Law (F = m x a)

 How much force is needed to accelerate

a 1400 kilogram car 2 meters per second/per second?

 Write the formulaWrite the formula  F = m x a

 Fill in given numbers and unitsFill in given numbers and units

 F = 1400 kg x 2 meters per second/second  Solve for the unknownSolve for the unknown

(54)

(55)

Newton’s 2

Newton’s 2ndnd Law_Law proves that different masses _{proves that different masses}

accelerate to the earth at the same rate, but with

different forces.

 We know that We know that

objects with

different masses

accelerate to the

ground at the same

rate.

 However, because of However, because of

the 2

the 2ndnd Law we know _{Law we know}

that they don’t hit

the ground with the

same force.

same force. _{F = ma}_{F = ma}

98 N = 10 kg x 9.8 m/s/s 98 N = 10 kg x 9.8 m/s/s

F = ma F = ma

9.8 N = 1 kg x 9.8 m/s/ 9.8 N = 1 kg x 9.8 m/s/

(56)

(57)

(58)

3

rdrd

Law



For every action, there is

an equal and opposite

(59)

3

rdrd

Law

According to Newton, According to Newton,

whenever objects A whenever objects A and B interact with and B interact with

each other, they exert each other, they exert

forces upon each forces upon each

other. When you sit in other. When you sit in your chair, your body your chair, your body

exerts a downward exerts a downward

force on the chair and force on the chair and

the chair exerts an the chair exerts an

upward force on your upward force on your

(60)

3

rdrd

Law

There are two There are two

forces resulting forces resulting

from this from this

interaction - a interaction - a

force on the chair force on the chair

and a force on your and a force on your

body. These two body. These two forces are called forces are called

action

action and and reactionreaction

(61)

Newton’s 3rd Law in Nature

 Consider the propulsion of Consider the propulsion of

a fish through the water. A

fish uses its fins to push

water backwards. In turn,

the water

the water reactsreacts by by

pushing the fish forwards,

propelling the fish through

the water.

 The size of the force on The size of the force on

the water equals the size of

the force on the fish; the

direction of the force on

the water (backwards) is

opposite the direction of

the force on the fish

(forwards).

(62)

Other examples of Newton’s

Third Law

 The baseball forces The baseball forces

the bat to the left the bat to the left

(an action); the bat (an action); the bat

forces the ball to forces the ball to

the right (the the right (the

(63)

3

rdrd

Law

 Consider the motion Consider the motion

of a car on the way

to school. A car is

equipped with

wheels which spin

backwards. As the

wheels spin

backwards, they

grip the road and

push the road

backwards.

(64)

3

rdrd

Law

The reaction of a rocket

The reaction of a rocket

is an application of the

third law of motion.

Various fuels are burned

in the engine, producing

hot gases.

The hot gases push

The hot gases push

against the inside tube of

the rocket and escape out

the bottom of the tube.

As the gases move

As the gases move

downward, the rocket

moves in the opposite

direction.

(65)

The value of the space

program

 _{Personal Computers}

 _{Colorization of black and white movies}  _{Solar powered calculators}

 _{Aluminized bags for snack food}  Weather satellites

 _{Halogen lights for cars}  _{Sports domes}

 Microwave Ovens  _{Pocket calculators}  _{Phone calls by satellite}  Laser guided missiles  _{"Mylar" balloons}

 _{"Blue Blocker" sunglasses}  Digital watches and thermometers  _{"DirecTV", "Dish Network", etc}  _{"Kevlar" for bullet proof vests}  "Mini Mag" flashlights

 _{Fishing line}

 _{Fiber optics for phone calls}  _{"Vortec" engines in GM cars}

 "Ovation" guitars and helicopter blades

 _{Medical scanners}

 _{Electronic ignition in automobiles}  _{Laser scanners in stores}

 _{"Bulb Miser" devices for long life light bulbs}  Weather Maps on television

 _{Juice boxes for "Hawaiian Punch", etc}  _{"The Patch" medical device}

 Breathing systems for Mt. Everest climbers,

Scuba divers and firefighters

 “Flexon" eyeglasses and dental braces  _{Cellular phones and beepers}

 _{Cable Television, H B O, Showtime, etc}  Pens that write upside down and under

water

 Anti corrosive paint for bridges, boats &

Statue of Liberty

 _{Scratch resistant coatings on sunglasses}  Football helmets for the NFL

 _{Pacemaker batteries that last 20 years and}

can be recharged through the skin.

 _{Compact Disks}

(66)

Planets

(67)

Planets

 The eight planets of the solar system The eight planets of the solar system can be grouped into two categories: can be grouped into two categories:

 Terrestrial Planets-Inner 4 planets that Terrestrial Planets-Inner 4 planets that

are similar in size and composition to are similar in size and composition to

Earth Earth

 Gas Giant Planets-Larger, more gaseous Gas Giant Planets-Larger, more gaseous

(68)

Mercury

 The closest planet The closest planet

to the sun to the sun

 Has no moonsHas no moons

 Has no atmosphereHas no atmosphere  Has the largest Has the largest

nightime-daytime nightime-daytime

difference in difference in

(69)

Mercury

 The surface of Mercury is heavily The surface of Mercury is heavily cratered

cratered

 The plains however are not cratered The plains however are not cratered and are believed to have been

and are believed to have been formed from lava flows

formed from lava flows

(70)

Venus

 Like Mercury Venus Like Mercury Venus

has no moons

 Composed of thick Composed of thick

clouds which

prevent astronomers

from observing the

surface

 Rotates very slowly Rotates very slowly

(one Venus day is

243 Earth Days)

(71)

Venus

 Venus rotates clockwise as opposed Venus rotates clockwise as opposed to other planets (Retrograde motion) to other planets (Retrograde motion)  Average surface temperature is 464 Average surface temperature is 464

C, which is due to the greenhouse C, which is due to the greenhouse

effect caused by the clouds effect caused by the clouds

 Atmosphere is composed of mostly Atmosphere is composed of mostly CO

(72)

Earth

 33rdrd planet from the _{planet from the}

sun

 Earth’s vast Earth’s vast

abundance of liquid

water has been

important for the

existence of life

 Earth’s atmosphere Earth’s atmosphere like Venus also

like Venus also

causes a greenhouse

effect

(73)

Earth

 Earth has a tilt and is responsible for Earth has a tilt and is responsible for the seasons

the seasons

 Earth’s tilt is caused by gravitational Earth’s tilt is caused by gravitational force on the Earth

force on the Earth

 Precession is the wobble in Earth’s Precession is the wobble in Earth’s rotational axis

(74)

At the equator, rotation is 40,074 km/day or 1670 km/hr (1,037 m/hr)

At NC 31,200 km/day or 1,461 km/hr (860 m/hr)

At the poles _{0 km/day or 0 km/hr}

The Earth’s Rotation does

not have the same speed all

over

(75)

Mars

 44thth planet from the _{planet from the}

sun sun

 Known as the “red Known as the “red

planet” planet”

 Has 2 moons: Has 2 moons:

Phobos and Phobos and

Deimos, most Deimos, most

likely captured likely captured

(76)

Mars

 Mars does not have a strong Mars does not have a strong

greenhouse effect like Venus due to

low density and pressure

 It is theorized that there was great It is theorized that there was great

lava flow in the Northern Hemisphere

causing the smooth surface

 Mars has polar ice caps covering both Mars has polar ice caps covering both

poles

(77)

Jupiter

 55thth planet from the sun_{planet from the sun}

 Largest planet in the Largest planet in the

solar system solar system

 Has a low density Has a low density

because it is because it is

composed of light composed of light weight elements weight elements

 Hydrogen and Helium Hydrogen and Helium

make up the majority make up the majority of the atmosphere

(78)

Jupiter

 Jupiter’s 4 largest moons are:Jupiter’s 4 largest moons are:

 IoIo

 EuropaEuropa

 GanymedeGanymede

 CallistoCallisto

 All are bigger than Pluto All are bigger than Pluto

 Io contains massive volcanic activityIo contains massive volcanic activity

 Europa is believed to have a surface Europa is believed to have a surface of liquid water

(79)

Saturn

 66thth Planet from the _{Planet from the}

sun, 2

sun, 2ndnd largest_largest

 Has a very low Has a very low

density, less than

water

 Like Jupiter it Like Jupiter it

rotates rapidly for

it’s size, has

flowing belts and

zones

(80)

Saturn

 Most striking feature is it’s ring Most striking feature is it’s ring

system

 Are composed of pieces of rock and iceAre composed of pieces of rock and ice

 Rings are less than 200 m thickRings are less than 200 m thick

 Saturn’s gravity keeps them close to the Saturn’s gravity keeps them close to the

planet

 Saturn’s largest moon is Titan, Saturn’s largest moon is Titan,

Saturn has many other smaller moons

(81)

Uranus

 77thth Planet from the _{Planet from the}

sun sun

 Was discovered Was discovered

accidently in 1781 accidently in 1781

 Uranus’s two Uranus’s two

largest moons are largest moons are

Titania and Oberon Titania and Oberon

(82)

Uranus

 Has a blue atmosphere caused by the Has a blue atmosphere caused by the

methane gas in Uranus’s atmosphere.

methane gas in Uranus’s atmosphere.  Most of the atmosphere is composed of Most of the atmosphere is composed of

hydrogen and helium however

 The rotational axis has tipped over so The rotational axis has tipped over so

far that the North Pole lies in it’s

orbital plane. Believed to have been hit

by a massive object

 Uranus spends 42 years in darkness, 42 Uranus spends 42 years in darkness, 42

in sunlight

(83)

Neptune

 88thth planet from the _{planet from the}

sun

 Was predicted Was predicted before it was

before it was

discovered

 Smaller than Smaller than

Uranus but 4 times

as large as Earth

 Bluish color is Bluish color is

caused by methane

(84)

Neptune

 Great Dark Spot is a persistent Great Dark Spot is a persistent storm in Neptune’s atmosphere storm in Neptune’s atmosphere  Triton is Neptune’s largest moonTriton is Neptune’s largest moon

 Has retrograde motionHas retrograde motion

(85)

Formation of the

Solar System

(86)

•_{Stars and Planets form from}_{Stars and Planets form from} clouds of gas and

clouds of gas and dust called dust called interstellar clouds

interstellar clouds

•_{Interstellar clouds consist of gases}_{Interstellar clouds consist of gases} such as

such as hydrogen and heliumhydrogen and helium

•_{Interstellar clouds can condense}_{Interstellar clouds can condense} as a result of

as a result of gravity and _{gravity and} become concentrated enough

become concentrated enough to to form a star or a planet

(87)

Interstellar Clouds

 At first the collapse is slow but it At first the collapse is slow but it begins to accelerate and the cloud begins to accelerate and the cloud

becomes dense in the center becomes dense in the center  The cloud soon flattens and The cloud soon flattens and

becomes a rotating disk with a dense becomes a rotating disk with a dense

(88)

Solar Nebula

 A solar nebula is the disk of dust and A solar nebula is the disk of dust and

gas that formed the Sun and the gas that formed the Sun and the

planets planets

 The dense center became the sunThe dense center became the sun

 As the disk began to cool different As the disk began to cool different

substances began to condense substances began to condense

 Depending on the distance from the Depending on the distance from the

sun different elements were able to sun different elements were able to

(89)

Planetesimals

 As the condensing slowed the grains As the condensing slowed the grains began to accumulate into large

began to accumulate into large bodies

bodies

 These large bodies are known as These large bodies are known as

planetesimals and can be hundreds planetesimals and can be hundreds

(90)

Merging Into Planets

 The 1The 1stst planet to form was Jupiter_{planet to form was Jupiter}

 Jupiter formed by merging of icy Jupiter formed by merging of icy

planetesimals and it’s gravity began to planetesimals and it’s gravity began to

attract gas, dust, and planetesimals attract gas, dust, and planetesimals

and began to grow larger and began to grow larger

 The other gas giants formed similarly The other gas giants formed similarly  Many disks formed nearby and this Many disks formed nearby and this

(91)

Merging Into Planets

 The Inner planets were formed by The Inner planets were formed by

planetesimals merging together planetesimals merging together

 Due to the elements that condensed Due to the elements that condensed

near the sun these planets were rocky near the sun these planets were rocky

and not gaseous and not gaseous

 Many inner planets have little to no Many inner planets have little to no

moons because the sun swept up moons because the sun swept up

much of the matter which prevented much of the matter which prevented

(92)

Asteroid Belt

•The asteroid belt is located between Mars and Jupiter

•Asteroids are planetesimals that were not ejected out of the solar system

•Jupiter’s gravitational force

(93)

Meteors

 Meteor Showers result mainly from Meteor Showers result mainly from

debris from the orbit of the comet. debris from the orbit of the comet.

 If the Earth crosses the path, the If the Earth crosses the path, the

debris will fall to Earth as a visible debris will fall to Earth as a visible

meteor or “shooting star.” meteor or “shooting star.”

 If the rock is big enough it will survive If the rock is big enough it will survive

the fiery entry into the atmosphere the fiery entry into the atmosphere

(94)

Asteroids

 Asteroids were originally thought to be Asteroids were originally thought to be planets that had been destroyed

planets that had been destroyed

 Asteroids often collide and break into Asteroids often collide and break into fragments

fragments

 Meteoroid- Any interplanetary material falls Meteoroid- Any interplanetary material falls towards Earth and enters Earth’s

towards Earth and enters Earth’s

atmosphere

 Meteor-When a meteoroid burns up in Meteor-When a meteoroid burns up in Earth’s atmosphere

Earth’s atmosphere

 Meteorite-When a Meteor collides with the Meteorite-When a Meteor collides with the ground

(95)

Comets

 Comets are small, icy bodies that Comets are small, icy bodies that

have highly eccentric orbits around have highly eccentric orbits around

the sun the sun

 The Kuiper Belt is near Pluto (30-50 Au) The Kuiper Belt is near Pluto (30-50 Au)

and is a cluster or cloud of comets and is a cluster or cloud of comets

 The Oort Cloud is more than 100,000 The Oort Cloud is more than 100,000

(96)

Comets

 The head of a comet consists of the The head of a comet consists of the coma

coma

 Coma-An extended volume of glowing Coma-An extended volume of glowing

gas gas

(97)

Comets

•_{Tails are pushed away from the coma}_{Tails are pushed away from the coma} by particles from the Sun

by particles from the Sun

•Comets point away from the sun no _{Comets point away from the sun no} matter which direction it is coming matter which direction it is coming

from from

(98)

Comets

 Periodic comets are comets that Periodic comets are comets that

repeatedly orbit into the inner solar repeatedly orbit into the inner solar

system system

 Halley’s Comet has a 76 year period. Last Halley’s Comet has a 76 year period. Last seen in 1986. Will be seen again in 2061

seen in 1986. Will be seen again in 2061

 A meteor shower is when Earth A meteor shower is when Earth

intersects a cometary orbit and intersects a cometary orbit and

particles burn up when entering particles burn up when entering

(99)

The Sun

(100)

The Sun

 The sun is the The sun is the

largest object in the

solar system

 The sun is 330,000 The sun is 330,000

times as massive as

Earth, 1048 times as

massive as Jupiter

massive as Jupiter  Contains 99% of all Contains 99% of all

mass in the solar

system

(101)

The Sun

 The sun’s average density is similar The sun’s average density is similar to the gas giants

to the gas giants

 However the center of the sun is However the center of the sun is about 13X the density of lead

about 13X the density of lead

 The interior is about 10,000,000 KThe interior is about 10,000,000 K

 Many of the gases are completely Many of the gases are completely ionized, composed of only atomic ionized, composed of only atomic

(102)

The Sun’s Atmosphere

 Layers of the SunLayers of the Sun

 PhotospherePhotosphere

 ChromosphereChromosphere

(103)

Photosphere

 The most inner layer of the sun is The most inner layer of the sun is the Photosphere

the Photosphere

 This is the visible surface of the sunThis is the visible surface of the sun

 Most of the light emitted by the sun Most of the light emitted by the sun comes from this layer

comes from this layer

(104)

Chromosphere

 The 2The 2ndnd layer of the sun is the layer of the sun is the

chromosphere chromosphere

 Usually only seen during a solar Usually only seen during a solar eclipse

eclipse

(105)

Corona

 The top layer is known as the coronaThe top layer is known as the corona

 The temperature can range from 1 The temperature can range from 1 Million

Million  2 Million degrees Kelvin_{2 Million degrees Kelvin}  The gas is so dim it can only been The gas is so dim it can only been

seen when the photosphere is seen when the photosphere is

(106)

Solar Winds

 Solar winds are gases Solar winds are gases

that flow outward from

the corona at high

speeds

 Solar winds flow at Solar winds flow at

about 400 km/s

 When they reach the When they reach the

Earth they are trapped

in the Earth’s magnetic

field

 This causes what we This causes what we

know as Auroras

(107)

Solar Activity

 Sunspots-Dark spots Sunspots-Dark spots

on the surface of the on the surface of the Photosphere. Appear Photosphere. Appear

dark because they are dark because they are

cooler than the cooler than the

surrounding Sun surrounding Sun

 Solar Flares-Violent Solar Flares-Violent

Eruptions of particles Eruptions of particles

and radiation from the and radiation from the

surface of the sun surface of the sun

 Prominence-Arc of gas Prominence-Arc of gas

that is ejected from that is ejected from

(108)

Solar Interior

 Within the core of the sun where Within the core of the sun where

pressure and temperature are high pressure and temperature are high

fusion occurs fusion occurs

 Fusion-Combining of lightweight nuclei Fusion-Combining of lightweight nuclei

with heavier nuclei with heavier nuclei

 Fission is the splitting of heavy Fission is the splitting of heavy

atomic nuclei into smaller atomic atomic nuclei into smaller atomic

(109)

Spectra

 Spectrum is visible light arranged Spectrum is visible light arranged according to wavelengths

according to wavelengths

 Continuous-Produced by a glowing solid or Continuous-Produced by a glowing solid or

liquid liquid

 Absorption-There are a series of dark bands Absorption-There are a series of dark bands

which are caused by different chemical which are caused by different chemical

elements that absorb light at specific elements that absorb light at specific

wavelengths wavelengths

 Emission-Comes from a non-compressed gas, Emission-Comes from a non-compressed gas,

you can see bright lines at different you can see bright lines at different

(110)

(111)

Stars

Sta

rs

(112)

Constellations

 Constellations are groups of stars Constellations are groups of stars

named after animals, mythological

characters or everyday objects

 Some can only be seen in the northern Some can only be seen in the northern

hemisphere (circumpolar constellations)

 Ursa MajorUrsa Major

 Some can only be seen at certain times Some can only be seen at certain times

because of Earth’s changing position in

orbit

(113)

Star Clusters

 Some stars appear to be close together Some stars appear to be close together

because the human eye can’t distinguish because the human eye can’t distinguish

how far or near they truly are how far or near they truly are

 Clusters are stars that are gravitationally Clusters are stars that are gravitationally

bound to each other bound to each other

 When only 2 stars are gravitationally When only 2 stars are gravitationally

bound together they are called a binary bound together they are called a binary

star star

(114)

Position and Distance

 Light year-The distance that light Light year-The distance that light

travels in one year (9,461,000,000,000

km)

 Parsec = 3.26 ly ( 30,860,000,000,000)Parsec = 3.26 ly ( 30,860,000,000,000)  Astronomers use parallax which is the Astronomers use parallax which is the

apparent shift in position caused by the

motion of the observer to estimate the

distance of stars from Earth

(115)

Position and Distance

 As Earth moves stars appear to shift, As Earth moves stars appear to shift, the closer the star the larger the

the closer the star the larger the shift

(116)

Properties of Stars

 Magnitude-How bright a star isMagnitude-How bright a star is

 Apparent Magnitude-How bright a Apparent Magnitude-How bright a star appears to be

star appears to be

 Absolute Magnitude-The brightness Absolute Magnitude-The brightness an object would have if it were

an object would have if it were placed at a distance of 10 pc placed at a distance of 10 pc

 Luminosity=The energy output from Luminosity=The energy output from a star

(117)

Classification

 Stars are assigned classes based on Stars are assigned classes based on their properties:

their properties:

 O, B, A, F, G, K, M O, B, A, F, G, K, M

 Each is subdivided into 0-9Each is subdivided into 0-9

 Each class is based on it’s stellar Each class is based on it’s stellar temperature, O is the hottest, M is temperature, O is the hottest, M is

the coolest ( 50,000 K

(118)

Wavelength Shift

 Blueshift- If a star is moving toward Blueshift- If a star is moving toward the observer

the observer

 Redshift- If a star is moving away Redshift- If a star is moving away from the observer

(119)

H-R Diagram

(120)

Properties Of Stars

 Red Giants-Cool yet luminous stars. Red Giants-Cool yet luminous stars. They are cool because they are

They are cool because they are massive

massive

 White Dwarfs-Dim, hot stars, must White Dwarfs-Dim, hot stars, must be small or else they would be more be small or else they would be more

(121)

Stellar Evolution

 A star begins with a cloud of A star begins with a cloud of

interstellar gas and dust called nebula interstellar gas and dust called nebula

 As it begins to collapse it’s rotation As it begins to collapse it’s rotation

causes it to form a disk shape with a causes it to form a disk shape with a

hot center called a protostar hot center called a protostar

 When the protostar gets hot enough When the protostar gets hot enough

nuclear fusion begins and it begins on nuclear fusion begins and it begins on

(122)

Stellar Evolution

 The star continues to burn hydrogen The star continues to burn hydrogen into helium

into helium

 As the outer most layer expands it As the outer most layer expands it begins to cool and becomes a red

begins to cool and becomes a red

giant. It cool due to it’s expansion

 When the helium burns up the star is When the helium burns up the star is left with a core made of carbon

left with a core made of carbon

 Now it’s size has decreased and it Now it’s size has decreased and it becomes a white dwarf

(123)

Life Cycles of Stars

 More massive stars begin the same More massive stars begin the same way but much higher on the main

way but much higher on the main

sequence

 It’s life time is shorterIt’s life time is shorter

 The star becomes a red giant more The star becomes a red giant more quickly and may develop into a

quickly and may develop into a

supergiant

 These stars may end up as white These stars may end up as white dwarves as well

(124)

Stellar Fusion

(125)

Hydrogen nucleus (Proton)

(126)

Mass=1.008

2.016

Mass=4.0026

1.008 x 4 = 4.032

(127)

E=mc

2

E = energy

m = mass

c2 = speed of light squared

(128)

Life Cycle Of Stars

 A star that begins with a high mass will A star that begins with a high mass will

end up with a core that is too massive

to be supported by electron pressure

to be supported by electron pressure  When this happens the core collapses When this happens the core collapses

on itself

 These are called neutron stars which These are called neutron stars which

have a mass of 1.5-3 times the suns but

only 10 km in diameter

 When the outer portion of the star is When the outer portion of the star is

blown off it is called a supernova

(129)

Black Holes

 Some stars are too massive to form Some stars are too massive to form neutron stars

neutron stars

 This could eventually form a black This could eventually form a black hole

hole

 A black hole is a small but extremely A black hole is a small but extremely dense object.

dense object.

 Gravity is so immense that nothing Gravity is so immense that nothing (even light) can escape

(130)

The Life of a Star

Cloud of gas

Contracts

Heats up

Fusion

(131)

If the star is 7x the sun or smaller:

(132)

If the star is 7x the sun or larger:

Swell up to a red giant Shrink collapse and

(133)

(134)

(135)

(136)

(137)

(138)

(139)

explode as a supernova Dies as a rapidly

(140)

(141)

(142)

The Milky Way Galaxy

 The Milky Way is a giant disk made The Milky Way is a giant disk made of stars orbiting a central point in of stars orbiting a central point in

the disk the disk

 The sun is one of 100 Billion Stars in The sun is one of 100 Billion Stars in the Milky Way

(143)

Variable Stars

 Variable Stars are stars in the giant Variable Stars are stars in the giant branch of the H-R Diagram

branch of the H-R Diagram

 Astronomers are able to estimate the Astronomers are able to estimate the distance to clusters by observing

distance to clusters by observing variable stars

variable stars

 Astronomers have estimated that the Astronomers have estimated that the galactic center is near the

(144)

Spiral Arms

 Astronomers have Astronomers have

determined that determined that

our galaxy has our galaxy has

spiral arms spiral arms

 Most of the young Most of the young

stars are located in stars are located in

the spiral arms the spiral arms

where gas is where gas is

(145)

Mass of the Milky Way

 Astronomers have estimated that the Astronomers have estimated that the galaxy is about 100 billion times the galaxy is about 100 billion times the

mass of the sun mass of the sun

 Astronomers have used that number Astronomers have used that number to estimate that the Milky Way

to estimate that the Milky Way contains 100 Billion Stars

(146)

Other Galaxies

 Edwin Hubble first discovered the Edwin Hubble first discovered the Andromeda Galaxy.

Andromeda Galaxy.

 By studying these objects he By studying these objects he

concluded that they were much too concluded that they were much too

far away to be located in the Milky far away to be located in the Milky

Way Way

•_{Edwin Hubble first discovered the}_{Edwin Hubble first discovered the} Andromeda Galaxy.

Andromeda Galaxy.

•_{By studying these objects he}_{By studying these objects he} concluded that they

concluded that they were much too were much too far away to be located in the

far away to be located in the Milky Milky Way

Way

(147)

Classification

 Hubble later went on to categorize Hubble later went on to categorize galaxies based on their shapes

galaxies based on their shapes  Spiral GalaxiesSpiral Galaxies

 Barred Spirals-Have elongated central Barred Spirals-Have elongated central

region or a bar from which the spiral region or a bar from which the spiral

arm extends arm extends

(148)

Classification

 Normal and barred spirals are subdivided Normal and barred spirals are subdivided based on how tightly the spiral arms are

based on how tightly the spiral arms are

wound

 The letter a represents tightly wound arms The letter a represents tightly wound arms and c represents loosely wound

and c represents loosely wound

 Elliptical galaxies are galaxies that are Elliptical galaxies are galaxies that are

flattened into disks and do not have spiral

arms

 Round ellipticals are classified as E0Round ellipticals are classified as E0

(149)

(150)

Expanding Universe

 Hubble discovered that the universe is Hubble discovered that the universe is

expanding.

 He found a direct relationship between He found a direct relationship between

the speed at which a galaxy is moving

versus it’s distance

 V = HdV = Hd

 V=Speed at which galaxy is moving (km/s)V=Speed at which galaxy is moving (km/s)

 d= distance to that galaxy (Mega parsecs, 1 X d= distance to that galaxy (Mega parsecs, 1 X

10

1066 pc)_pc)

(151)

Infant Galaxy

 Scientists discovered in the 1960’s Scientists discovered in the 1960’s star like objects but emitted

star like objects but emitted emission lines in their spectra emission lines in their spectra

instead of absorption lines instead of absorption lines  These are known as quasarsThese are known as quasars

 Quasars are much father away than Quasars are much father away than any galaxies due to their larger

any galaxies due to their larger redshift

(152)

Quasars

 Because quasars are far away it Because quasars are far away it takes light a long time to reach takes light a long time to reach

Earth Earth

 It takes light 8 minutes from the sun It takes light 8 minutes from the sun to reach Earth

to reach Earth

 Looking at an object through a Looking at an object through a

telescope is a lot like looking back telescope is a lot like looking back

(153)

Big Bang Theory

 The big bang theory states that the The big bang theory states that the universe began as a point and has universe began as a point and has

been expanding ever since been expanding ever since

 The fact that the universe is The fact that the universe is

exp