Stars and Galaxies

Topic: Our Sun• Objectives: Day 1 of 4

• I will learn the definition of a star

• I will learn the process of fusion in the sun’s core

• I will be able to distinguish between the inner and outer layers of the sun

Unit: Stars & Galaxies

Quickwrite:Answer one of the questions below in

1-2 sentences:

• What do you think fuels the sun???? A big tank of gas??? Nuclear energy????

• How long do you think it takes light to reach earth from the sun????

• How do you think energy from the sun reaches earth???

Radio WavesRadio Waves are given off by the Sun. These are long wavelength waves and create the static you get on your radios and TV’s

InfraredInfrared or heat waves have a shorter wavelength than radio waves.Heat Waves or radiation form the sun is what controls our weatherVisible LightLight from the Sun has an even shorter wavelength.

Light waves are the only type of radiation we can see.

Ultra Violet (UV) radiation from the Sun has an even shorter wavelength. UV Radiation is absorbed by the earth’s ozone layer & can cause skin cancer

Due to their short wavelength, X-RaysX-Rays are even more hazardous to your health.This is why doctor’s put a lead vest over you when you get X-rays for an injury

GammaGamma Radiation has the shortest wavelengths of all radiation and is therefore Just small amounts can be fatal.

What is a Star?

• A sphere of gases that produces heat and light through the ____ of hydrogen

• Our sun is average star

Answer Bankstars

TransferCool

fusionphotosphere

4

Inner layers

• Core

• Radiative Zone

• Convection Zone

Core• The core lies in the heart of the

sun and is 15,600,000 degrees Celsius

• The nuclear process know as hydrogen fusion occurs in the core

• During Hydrogen Fusion, 4 hydrogen combine to form 1 helium nucleus releasing

tremendous amounts of energy

• 4 H = 1 He + energyenergy• Think Hydrogen Bomb!Think Hydrogen Bomb!

H

H

H

H

He

HeHe

He

In the Core, Pressures and Temperaturesare high enough for Fusion to take place

Fusion occurs when 4 hydrogen atoms (light element) combines to form 1 Helium atom (heavier element)

Hydrogen, a lighter element is converted into a heavier element, helium

In the process, energy is released in the form of light &radiation

The core, where nuclear

fusion takes place

let’s zoom in and

what happens

What is Fusion?

Answer Bankstars

TransferCool

photosphere4

H

H

H

H

He

HeHe

He

H

H

H

H

He

HeHe

He

H

H

H

H

He

HeHe

He

H

H

H

H

He

HeHe

He

• The combining of lighter elements to form heavier elements

• In the Sun’s core, ___ hydrogen atoms (a

light element [don’t write] ) combine to form 1 helium atom (a heavier element [don’t write] ) & energy is released

Radiative Zone• In the radiative

zone, energy moves radiates outward from the core in the form of light & radiation

• It takes light thousands of years to move from the core to the next layer

• Temperature is 8,000,000 degrees Celsius

Convection Zone

• Energy moves through this zone by convection

• Hot gases rise toward the surface while cooler gases sink back down

• It’s behaves like a giant pot of boiling water

• Temp = 2,000,000 degrees Celsius

Outer Layers• Photosphere

• Chromosphere• Corona (not visible)

Photosphere

• Often called the surface of the sun

• Where light is given off

• Temperatures are around 6,000 degrees Celsius

Chromosphere• Above the

photosphere is the chromopshere

• It’ temperature is 20,000 degrees Celsius

• Reddish in color

Corona• Largest layer of the

sun • Extends millions of

kilometers in to space• Hottest layer

• Temp= 2,000,000 C°• Charged particles

leave the corona creating a solar wind

The Coronaseen during an eclipse

What are the Layer’s of the Sun?

• Core- produces energy from _______ Fusion

• Radiative Zone• Convection Zone • Photosphere- gives off light, surface of the

sun

• Chromosphere• Corona- seen during an_____, gives off

solar wind

Answer Bankstars

TransferCool

hydrogen4

eclipse

Sunspots• “Cool” dark areas on

the Sun’s surface• By studying sunspots,

we have discovered that the Sun rotates

• Sunspots can last from a few days to a few months

• They represent areas of intense Magnetic activity

• Every 11 years our sun goes through a Sunspot cycle

• Our Sun has periods of sunspot maximums where many sunspots are visible

• Our Sun also has periods of sunspot minimums where only a few sunspots are visible

Sunspot CycleMaximums and Minimums

Solar Flares

• A solar flare is a violent explosion in the Sun's atmosphere

• They release tremendous amount of radiation or energy in the form of UV Rays, X-rays, and gamma rays

http://en.wikipedia.org/wiki/Sun

Prominences

• Prominences are huge arching columns of gas on the surface of the sun

• They erupt at speeds ranging from 600-1000 km/s

• Ultraviolet light and x-rays from prominences can reach earth and cause disruption in radio signals

What Features can be found on the Sun?

• Sunspots – _____dark areas on

the surface of the sun that occur in an 11 year cycle (maximums/minimums)

• Prominences – Huge arching

columns of gas

• Solar Flares– violent ____ of

energy (radiation)

Answer Bankstars

TransferburstsCool

photosphere4

Summarize:

• Our sun is a star made mostly of ______ and helium gases

• _____ is the combining of lighter elements to form _____ elements

• In the Sun’s____, 4 hydrogen atoms a combine to form 1 ____ atom & energy is released

Answer Bankheavier

HydrogenfusionHelium

core

Topic: Light years & Stars• Objectives: Day 2 of 4

• I will understand the concept of a light year and how we use them to measure distances to Stars and galaxies

• I will understand how stars vary in their size, color, temperature and brightness

• I will learn how to classify stars on a H-R Diagram


Quickwrite:Answer one of the questions below in 1-2

sentences:

• If you were traveling at the speed of light, how many times do you think you could go around the earth in one second????

• If a star 10 light years away exploded today, how long would it take you to see it????

• Compared to other stars, do you think our sun is hot or cool star??? Large or small star????

•

Light Years

• When astronomers first realized how far away stars actually are, it became apparent that a new unit of measurement would be needed to record their distances

• Stars are much farther away than the planets in our solar system

• Distances between stars are measured in light years!

Light Years• A light year is the distance that light travels in

a year• We use the light year to measure very distant

objects such as stars and galaxies• Light travels at 300,000 km/s or about 9,500,000,000,000 trillion kilometers in one

year (9.5 x 1012 km/yr) 299 ,792 km/ s • Nothing is faster than light• If you travel at the speed of light, you would

become light

How Fast is That?• A traveler, moving at the speed of light,

would circum-navigate the equator approximately 7.5 times in one second

• How long do you think it takes light to reach Earth from the Sun?

What are Light Years?

• A light yr is the distance that light travels in a ______

• In 1 yr, light travels 9.5 trillion kilometers or 300,000 km/s

• Light years are used to measure very distant objects such as stars and galaxies

Answer BankAverage

TemperatureAbsoluteDistance

Year90%hot

Parallax!• How do we know the stars are farther away than the

planets in our solar system? We use parallax!• The distance of a star is found by using parallax parallax• ParallaxParallax is the apparent shift in the position of an

object when viewed from two different positions• You can easily observe parallax• Hold your hand at arm’s length and look at one finger

with your left eye and then with your right eye• What you will notice is that your finger appears to

change position with respect to the background

Parallax Continued…..

• Now try the same experiment with your finger closer to your face

• What do you observe? • The closer an object is to the observer,

the greater its parallax• We can measure parallax of relatively

close stars in order to determine their distance from earth

Calculating Parallax

What is Parallax?

• Parallax is how we measure the ____ to stars in light years

• It is found by viewing an object from 2 fixed locations

Answer BankAverage


Year90%hot

Blue Stars are large hot and bright

Star Characteristics

Red Stars are small cool and dim

Yellow Stars like are Sun are average in

brightness & temperature

• Large Blue-white stars are ___ & bright

• Red stars are cool & dim• Yellow stars, like our sun are

____ in temperature and bright ness

What’s the relationship between star color, size, & temperature?

Answer BankAverage


Year90%hot

H-R Diagram

• In the early 1900’s, Ejnar Hertzsprung and Henry Russell found a way to classify stars

• They classified stars by their temperature and brightness http://www.youtube.com/watch?v=HEheh1BH34Q&feature=fvw

Hot White Dwarfs

Red Dwarfs

Sun

Blue Massive Stars

Giants

Supergiants

Cool RedDim Stars

Hot Bright Blue Stars Yellow Orange

Average Stars

http://www.youtube.com/watch?v=HEheh1BH34Q&feature=fvw




H-R Diagram• Hertzsprung and

Russell came up with a graph that shows the relationship between temperature and brightness

• Notice where the cool small red dwarfs stars are located

• Notice where the massive hot blue dwarfs stars are located

Hot White Dwarfs

Red Dwarfs

Sun

Blue Massive Stars

Giants

Supergiants

Cool RedDim Stars


Average Stars

What is the H-R Diagram?

• A graph that compares the brightness, ______ and color of a star

• _____ magnitude is the true brightness of a star

Answer BankAverage


Year90%hot

Main Sequence Stars• Our sun is a yellow

Main Sequence Star

• Main Sequence Stars that fit into a diagonal band that run from the upper left to the lower right corner

• Main Sequence Stars contain large, hot blue stars, as well as small cool red stars

• 90 % of all stars are Main Sequence

Red Dwarfs

Sun

Blue Massive Stars

Cool RedDim Stars


Average Stars

What are Main Sequence Stars?

• The diagonal band of stars in an H-R diagram

• Blue, white, yellow, orange, red stars

• ____ of the stars we see at night are main sequence

Answer BankAverage


Year90%hot

Summarize:

• _______ is how we measure star distances when viewed from two fixed locations as we orbit the sun

• Large stars are ____ and small stars are ____

• Hot stars are ______ in color• Cooler stars are ______in color• An H-R diagram is a graph that

relates star ________ to star ________

Answer BankBrightness

temperatureParallax

brightAbsolute

bluereddim

Topic: Star Lifecycle• Objectives: Day 3 of 4

• To learn the difference between the lifecycle of a massive blue main sequence star with a yellow main sequence star like our sun

• To understand how nucleosynthesis occurs in stars

• Star size: http://www.youtube.com/watch?v=HEheh1BH34Q


Quickwrite:Answer one of the questions below in 1-2

sentences:

• What do you think will happen to our Sun when it runs out of hydrogen fuel?????

• Everything around us is made of elements. Where do you think these elements are made????

• Why do you think some star’s become black hole’s and other like Sun do not????

All star’s form in a nebulaA star will begin it’s main sequence when hydrogen fusion begins

But what determines the size of a star?

Gravity wants to crush the starSo why doesn’t it?

Because the outward pressureOr force of energy from Fusion balances out the inward force of gravity

This keeps the star in a state of balance or equilibrium!

Star Size

What determines the size of a main sequence star?

• A balance between the ____ pull of gravity and the outward push of energy created by fusion

Answer BankNeutronLighterInward

RedFusion

White dwarfshort

Star like our Star like our sun havesun have

average livesaverage lives

Small Red dwarf Small Red dwarf stars have long lives stars have long lives

because of cooler because of cooler temperatures temperatures

in the corein the core

Large massive Large massive blue stars haveblue stars have

Short livesShort lives Because they have Because they have higher pressures & higher pressures & temperatures in the temperatures in the Core, therefore theyCore, therefore theyrun through their run through their

Hydrogen fuel Hydrogen fuel source fastersource faster

Hydrogen

Empty Full

Hydrogen

Empty Full

Hydrogen

Empty Full

Temperature & PressureAffect Star Life

How does temperature and pressure effect the life of a star?

• Temperature and pressure increase the rate of fusion in a stars core

• Hot blue stars have ____ lives• Cooler ___ stars have long lives• Yellow stars like our sun have

average lives


RedFusion

White dwarfshort

Helium

In a massive blue stars core, hydrogen fuses together to form Helium for most of its

short Main sequence life

Eventually hydrogen starts to run out and helium starts to accumulate

Carbon

Helium

Over time the outward pressure or force of energy from fusion becomes

stronger than the inward force of gravity & the star begins to swell & cool changing its color in the process

Massive Blue Star Lifecycle

As a result gravity wants to crush the star, pressures &

temperatures increase, & the star begins fusing helium into carbon

Temperatures continue to increase in the core, & the star begins fusing Carbon

into Oxygen

Carbon

Helium

Oxygen

Carbon

Helium

Hydrogen

At this point the star is now a supergiant

But fusion doesn’t stop Just yet!!!!!


Carbon

Helium

Oxygen

Carbon

Helium

Hydrogen

Iron

Oxygen

CarbonHelium

Hydrogen

Finally, as temperatures continue to increase the star will begin fusing oxygen into Iron

Near the end of it’s lifeThe blue massive star

resembles an onion with layers of different elements

This process is called Nucleosynthesis—Where

Lighter are elements are created into heavier elements through

Fusion in a star


Carbon

Helium

Oxygen

Carbon

Helium

Hydrogen

Iron

Oxygen

CarbonHelium

In massive blue starsElements up to the size of

Iron-element 26 are createdThrough fusion


Carbon

Helium

Iron

Oxygen

Carbon

Helium

Hydrogen

At a certain temperature, Fusion can no longer occur and the outward energy stops,

at this point gravity takes Over and crushes the star

The star explodes into a super nova!!!

Depending upon the stars initial mass or size, It will end up

as either a neutron star or Black hole

Black HoleNeutron Star


Carbon

Helium

Iron

Oxygen

Carbon

Helium

Hydrogen

When the star explodes, it blasts all The elements into space, seeding the universe with Elements

to make new stars, planets, people and buildings Supernovas are so hot & bright, They produce

all other elements heavier than iron


What is Nucleosynthesis?

• The creation of new elements in stars by fusing lighter elements into heavier elements (fusion)– Fusion in Blue Massive stars create

elements as heavy as ______– At this point fusion stops and the star goes

supernova – When a super giant star goes supernova

(explodes) it creates elements _____than Iron such as gold and lead


RedIron

heaviershort

Yellow Star (Sun) Star Lifecycle

HeliumHeliumCarbon

Helium

HeliumHeliumCarbon

Helium

Over time the outward pressure or force of energy from fusion becomes stronger than the inward force of gravity & the star

begins to swell & cool changing its color in the process

Throughout this time Helium Will accumulate in its core

Our sun’s core will fuse hydrogen into Helium for most of its 10 billion

year old Main sequence life

As a result of gravity crushing the star, pressures

& temperatures increase & the star begins fusing helium into carbon

HeliumCarbon

Helium

Oxygen

Carbon

Helium

Hydrogen

Temperatures continue to increase in the core, & the star begins fusing Carbon

into Oxygen

At this point the star is now a Red Giant

Unlike a blue star, temperatures and pressure are not high enough

To produce Iron through fusion Fusion stops at OXYGEN


HeliumCarbon

Helium

Oxygen

Carbon

Helium

Hydrogen

Instabilities in the balance Between Gravity & outward force or Pressure of fusion result in abrupt explosions

that blow away the outer layers

of the star

The result is a planetary nebula with a hot white

dwarf star in the middle


Eventually theGases are expelled

Leaving behind A white dwarf star

A white dwarf star is what remains of an average star like our sun after

Running out of fuel

It’s about the size of earth


Summarize:

????

????????

????

Answer BankWhite dwarfBlack hole red giant

Supernova10

????????

• Our sun has ______ billion year life span

Topic: Galaxies & The Big Bang

• Objectives: Day 4 of 4

• I will be able to define a galaxy and classify the 3 different types of galaxies

• I will understand the Big Bang theory and the evidence supporting it


Quickwrite:Answer one of the questions below

in 1-2 sentences:

• Earth orbits the sun, but does our sun orbit anything????

• How old do you think the universe is????

• What sort of shape do you think the milky way galaxy has???

Galaxies• We are on earth, all

going around the sun• However, does the sun

orbit anything?• The sun is one star

among many in our Galaxy

• A galaxy is a group of billions of stars, gas and dust held together by gravity

Billions and Billions

• When we look out into deep space we see billions of galaxies

• Each galaxy contains billions of stars

• So space is made mostly up of star and galaxies

http://search.aol.ca/redir?urn=http://homepage.mac.com/kvmagruder/images/hdf.jpg&rank=%20&source=googleImage&searchType=IS&partner=Google&query=deep%20hubble

• A galaxy is a group of billions of stars, gas and dust held together by gravity

• We classify galaxies into 4 types:

Galaxies: 4 Types

Elliptical: sphererical or oval shaped more common

Irregular: small irregular shaped less

common

Barred spiral: same as spiral but has

bar going through the middle of it

Spiral: disc shaped, have long spiral arms

http://search.aol.ca/redir?urn=http://www.astro.unibas.ch/forschung/og/ngc4486.gif&rank=%20&source=googleImage&searchType=IS&partner=Google&query=elliptical%20galaxy

What is a Galaxy?

• A group of billions of ___, gas and dust held together by gravity

• 4 types: -Spiral: disc shaped, have long spiral arms -Barred spiral: same as spiral but with bar in the

middle-Elliptical: most common, spherical or oval shaped-Irregular: least common, small irregular shaped

Answer Bank30,000

Red shiftmicrowaves

Stars100,000

expansion

Milky Way Galaxy

• Contains around 500 billion stars• The visible disk of stars is about 100,000 light

years across• The sun is located 30,000 light years out from its

center• All stars orbit around the central region• Based on a distance of 30,000 light-years and a

speed of 235 kilometers a second, the sun orbits around the center of the galaxy once every 240 million years

http://search.aol.ca/redir?urn=http://seds.lpl.arizona.edu/messier/Pics/More/mwbarsuns.jpg&rank=%20&source=googleImage&searchType=IS&partner=Google&query=milky%20way%20galaxy

• The Milky Way is usually classified as a spiral galaxy

• It is difficult to know for sure because it is impossible to see our galaxy from the outside

• You can see the Milky Way stretching across the night sky as a faint band of light

• All of the stars you can see in the night sky belong to the Milky Way

Milky Way Continued…..


Our SunOur Sunis 1 staris 1 staramong among

500 billion500 billion

Our Milky Way Our Milky Way galaxy is 100,000 galaxy is 100,000 light years acrosslight years across

Our Sun and Our Sun and Solar SystemSolar System

Is located 26,000 Is located 26,000 Light years form Light years form

Our galactic centerOur galactic center

What is the Milky Way Galaxy?

• A 10 billion year old barred spiral galaxy made up of around 500 billion stars and _____ light years across

• Our sun and solar system is located ____ light years from the center bulge Answer Bank

30,000Red shift

microwavesStars

100,000expansion


Big Bang Theory

• It is believed our billion our universe formed 10–20 billion years ago

• All matter existed in an incredibly hot dense state of hydrogen and helium

• After it exploded, it expanded & cooled into stars & galaxies

Big Bang Theory

• The big bang theory or model states that all matter in the universe was released in a massive expansion of time and space about 10-20 billion years ago

Over TimeGalaxies and stars continue

to expand, moving farther apart and cooling in the process

13.7 billion years agoTime started when all Matterbegan to expand outward and fill an empty universe

with stars and galaxies

The Big Bang Theory

What is the Big Bang Theory or Model?

• Theory or model that states that all matter in the universe was released in a massive ____ of time and space 10-20 billion years ago

Answer Bank30,000

Red shiftmicrowaves

Stars100,000

expansion

Evidence for the Big Bang Theory

• Evidence for the big bang theory came through two huge pieces of evidence:

• Red Shift and cosmic background radiation in the form of radio waves and microwaves

Red Shift

• Red shift showed that all galaxies and stars are moving away from each other and in fact expanding

• If objects are expanding then at one point they must have been closer together

• Here’s how it works:

Background Radiation

• When Scientists look out into space, they detect cosmic background radiation left over from the Big Bang

• This radiation is just “drifting” in the background of space and is one of the reasons we get static on out TV’s and Radio’s

The Big Bang released high energy gamma waves

Background Radio Waves & Microwaves

As the universe expanded, high energy gamma waves

became stretched out

After 10 billion years, these waves stretched out even

more, eventually becoming microwavesmicrowaves and and radio wavesradio waves

These microwaves and radio waves makeup the background radiation scientists

have detected drifting through space

What evidence supports the Big Bang Theory?

• Red shift from distant stars and galaxies

• Cosmic background radiation in the form of _______ and radiowaves

Answer Bank30,000

Red shiftmicrowaves

Stars100,000

expansion

Summary

• A ___ is a group of billions of___, gas and dust held together by gravity

• We live in the ___ ___ which is _____ light years across

• ___ ____ and ____ radiation is evidence for the big bang & an expanding universe

• Our universe is ____ BYO (billion years old), our galaxy is ____ BYO

Answer BankGalaxy

13.7Red shift

microwavesStars

100,00010

Milky way

Stars and Galaxies

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