Stars and Galaxies
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Transcript of Stars and Galaxies
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
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
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
Unit: Stars & Galaxies
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
TemperatureAbsoluteDistance
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
TemperatureAbsoluteDistance
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
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
Hot Bright Blue Stars Yellow Orange
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
TemperatureAbsoluteDistance
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
Hot Bright Blue Stars Yellow Orange
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
TemperatureAbsoluteDistance
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
Unit: Stars & Galaxies
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
Answer BankNeutronLighterInward
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!!!!!
Massive Blue Star Lifecycle
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
Massive Blue Star Lifecycle
Carbon
Helium
Oxygen
Carbon
Helium
Hydrogen
Iron
Oxygen
CarbonHelium
In massive blue starsElements up to the size of
Iron-element 26 are createdThrough fusion
Massive Blue Star Lifecycle
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
Massive Blue Star Lifecycle
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
Massive Blue Star Lifecycle
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
Answer BankNeutronLighterInward
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
Yellow Star (Sun) Star Lifecycle
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
Yellow Star (Sun) Star Lifecycle
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
Yellow Star (Sun) Star Lifecycle
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
Unit: Stars & Galaxies
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
• 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
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
• 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