Stars and Galaxies - PowerPoint PPT Presentation

Loading...

PPT – Stars and Galaxies PowerPoint presentation | free to download - id: b5349-ZjlmM



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Stars and Galaxies

Description:

Stars and Galaxies. Space Science for Middle School at HCDE. February 20, 2009. Created by the ... Galaxies. Different types of stars ... – PowerPoint PPT presentation

Number of Views:287
Avg rating:3.0/5.0
Slides: 89
Provided by: christin227
Learn more at: http://www.lpi.usra.edu
Category:
Tags: galaxies | stars

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Stars and Galaxies


1
Stars and Galaxies
Created by the Lunar and Planetary Institute For
Educational Use Only LPI is not responsible for
the ways in which this powerpoint may be used or
altered.
  • Space Science for Middle School at HCDE
  • February 20, 2009

Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2009/07/image/g/results/50/

2
Welcome!
  • Please complete the pre-assessment
  • Its for usits not about you
  • Please let us know how much YOU know, not how
    much your friends sitting next to you know

3
What are we going to cover?
  • Our Place in the Universe
  • The Electromagnetic Spectrum
  • Classifying Stars
  • Classifying Galaxies
  • History of the Universe

4
First up
  • Our Place in the Universe
  • What is our Universe made of?
  • How big are things? How far away?
  • How do we know?

5
What is our Universe made of?
What was in your drawing?
  • Stars and planets
  • Gas and dust
  • Organized into star clusters
  • Organized into nebulae
  • Organized into galaxies
  • Other things
  • Black holes
  • Dark matter
  • Dark energy

Image from http//galileo.rice.edu/lib/student_wor
k/astronomy95/orionpleiades.html
6
Activity!!
  • Use the Venn diagrams to place the stickerswhere
    does everything go?
  • After youre finished, lets discuss

7
Examining the Components
  • Stars
  • Gas and dust (Nebulae)
  • Star clusters
  • Galaxies

8
Different types of stars
Image from http//hubblesite.org/newscenter/archiv
e/releases/star20cluster/globular/2003/21/image/a
/results/50/
9
Types of Stars
  • Big
  • Small
  • Red
  • Blue
  • Yellow
  • In groups
  • Alone
  • More later

10
What is a star cluster?
  • stars formed together at same time
  • stars may be gravitationally bound together
  • two types open (galactic) and globular

Image at http//hubblesite.org/newscenter/archive/
releases/star20cluster/globular/2007/18/image/a/f
ormat/web/results/50/
11
Open Clusters
  • dozens to thousands of stars
  • young stars! only a few million years old
  • may still be surrounded by nebula from which they
    formed
  • located in the spiral arms of a galaxy
  • example Pleiades

Image at http//hubblesite.org/newscenter/archive/
releases/star20cluster/open/2004/20/image/a/resul
ts/50/
12
More open star clusters
Image from http//hubblesite.org/newscenter/archiv
e/releases/star20cluster/open/2006/17/image/a/res
ults/50/
13
Globular Clusters
  • millions to hundreds of millions of stars
  • old! 6 to 13 billion years
  • mostly red giants and dwarfs
  • stars are clumped closely together, especially
    near the center of the cluster (densely)
  • surround our disk as a halo

Image at http//hubblesite.org/newscenter/archive/
releases/star20cluster/globular/1999/26/image/a/r
esults/50/
14
What is a nebula?
  • A cloud in space
  • Made of gas and dust
  • Can have stars inside
  • Most of the ones we see are inside our Milky Way
    Galaxy
  • Different types

Orion image at http//hubblesite.org/newscenter/ar
chive/releases/2006/01/image/a/results/50/
15
Large, massive, bright nebulae
  • Emission Nebula
  • The hot gas is emitting light

Orion image at http//hubblesite.org/newscenter/ar
chive/releases/2006/01/image/a/results/50/
16
Colder, darker nebulae
Dark dust blocking the hot gas behind it
NOAO/AURA/NSF Image from http//hubblesite.org/new
scenter/archive/releases/nebula/dark/2001/12/image
/c/results/50/
17
Leftovers from an Explosion
Supernova remnant (smaller, less gas)
Image at http//hubblesite.org/newscenter/archive/
releases/nebula/supernova-remnant/2005/37/results/
50/
18
What is a galaxy?
  • A large group of stars outside of our own Milky
    Way
  • Made of billions to trillions of stars
  • Also may have gas and dust
  • Spiral, or elliptical, or irregular shaped

Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2007/41/results/50/
19
Spiral galaxy--Andromeda
NOAO/AURA/NSF Images at http//www.noao.edu/image_
gallery/html/im0606.html and http//www.noao.edu/i
mage_gallery/html/im0685.html
20
Elliptical Galaxies
Images at http//hubblesite.org/newscenter/archive
/releases/galaxy/elliptical/2007/08/image/a/format
/large_web/results/50/ and http//hubblesite.org/n
ewscenter/archive/releases/galaxy/elliptical/1995/
07/results/50/
21
Irregular Galaxies
NASA and NOAO/AURA/NSF Images at
http//hubblesite.org/newscenter/archive/releases/
galaxy/irregular/2005/09/results/50/ ,
http//www.noao.edu/image_gallery/html/im0560.html
, and http//www.noao.edu/image_gallery/html/im09
93.html
22
Our Galaxy the Milky Way
  • has about 200 billion stars, and lots of gas and
    dust
  • is a barred-spiral (we think)
  • about 100,000 light-years wide
  • our Sun is halfway to the edge, revolving at half
    a million miles per hour around the center of the
    Galaxy
  • takes our Solar System about 200 million years to
    revolve once around our galaxy

23
The Milky Way
Image at http//news.nationalgeographic.com/news/b
igphotos/1945371.html
24
Mapping the Milky Way
How do we know what our Galaxy looks like?
  • We can see stars
  • star clusters
  • nebulae
  • Galaxies
  • Lets try to Map our Galaxy

25
Measuring Distances
  • Parallax (lets model it)
  • As Earth orbits the Sun, we see nearby stars move
    relative to more distant stars
  • How many degrees did the plate move, relative to
    the background?
  • Can you calculate the distance to the plate?
  • Sine of the parallax (angle) x Earths distance
    to the Sun Distance to the star
  • The angles involved for strellar observations are
    very small and difficult to measure. Proxima
    Centauri, has a parallax of 0.77 arcsec. This
    angle is approximately the angle subtended by an
    object about 2 centimeters in diameter located
    about 5.3 kilometers away.

26
Measuring Distances
  • What is a Light Year?
  • A light year is the distance light travels in a
    year. Light moves at a velocity of about 300,000
    kilometers (km) each second how far would it
    move in a year?
  • About 10 trillion km (or about 6 trillion miles).
  • Why do we use light years?
  • Show me how far 5 centimeters is.
  • Now show me 50 centimeters.
  • Now tell me (without thinking about it, or
    calculating it in meters) how far 500 centemeters
    is. 2000? 20,000?
  • We need numbers that make sense to us in
    relationship to objects we scale up and use
    meters and kilometers for large numbers.

27
Time for a Break! Next Up
  • Our Place in the Universe
  • The Electromagnetic Spectrum
  • Classifying Stars
  • Classifying Galaxies
  • History of the Universe

28
Lets check your knowledge
  • Please draw an electromagnetic spectrum on a
    sheet of paper, and label the parts.
  • You can work in groups.

29
Radiation
  • There are lots of types of light (radiation),
    including visible and invisible

Electromagnetic spectrum http//coolcosmos.ipac.c
altech.edu/cosmic_classroom/ir_tutorial/what_is_ir
.html .
30
Lets Observe A Spectrum
  • What will the spectrum look like with a red
    filter in front of your eyes? A blue filter?
  • Hypothesize and test your hypothesis.
  • Now lets examine the invisible partsusing our
    cell phones and a solar cell.

31
  • There are different types of spectra
  • Continuous
  • Emission or Bright Line (from ionized gas, like a
    nebula or a neon sign)
  • Absorption or dark line (from stars)

Illustration at http//imagine.gsfc.nasa.gov/docs/
science/how_l1/spectra.html
32
Radiation
  • All stars emit radiation
  • Radio, infrared, visible, ultraviolet, x-ray and
    even some gamma rays
  • Most sunlight is yellow-green visible light or
    close to it

The Sun at X-ray wavelengths Image at
http//imagine.gsfc.nasa.gov/docs/science/know_l1/
sun.html
Image and info at http//imagine.gsfc.nasa.gov/doc
s/teachers/gammaraybursts/imagine/page18.html
.
33
Using a Stars Spectrum
  • We can use a stars spectrum to classify it.

NOAO/AURA/NSF image at http//antwrp.gsfc.nasa.gov
/apod/ap010530.html
34
Stellar Evolution
35
Time to Create a Stellar Graph
  • Everyone will receive several stars
  • Place them on the large paper, according to their
    color and their brightness
  • This is a version of the Hertzsprung-Russell
    diagram.

36
Hertzsprung-Russell Diagram
Images from http//www.nasa.gov/centers/goddard/ne
ws/topstory/2007/spectrum_plants.html and
http//sunearthday.gsfc.nasa.gov/2009/TTT/65_surfa
cetemp.php
37
Young stars form in nebulaefrom Small
Magellanic Cloud
Image at http//hubblesite.org/newscenter/archive/
releases/2007/04/image/a/results/50/
38
Star-forming region in the Large Magellanic
Cloud http//hubblesite.org/newscenter/archive/re
leases/2008/31/image/a/results/50/
39
Orion image at http//hubblesite.org/newscenter/ar
chive/releases/2006/01/image/a/results/50/
40
Interstellar eggs
Movie at http//www.stsci.edu/EPA/PR/95/44/M16.mpg

41
Our Sun is a Regular/ Small Star
On the Main Sequence
Image at http//www.gsfc.nasa.gov/topstory/2001121
0insidesun.html
42
In a few Billion years Red Giant
Image at http//hubblesite.org/newscenter/archive/
releases/1997/26/image/a/
43
Our Suns Habitable Zone
  • Billions of years ago, things may have been
    different
  • The Sun was cooler (by up to 30!)
  • Earths atmosphere was different (thicker, carbon
    dioxide)
  • Conditions will be different in the future
  • By many accounts, increases in the Suns
    temperature will make Earth uninhabitable in 1
    billion years or less
  • These changes will also affect other planets
    Mars?

Animation at http//www.nasa.gov/97994main_BHabita
bleZone.MPG
44
By 5 billion years White Dwarf
Small, but very hot
Image at http//hubblesite.org/newscenter/archive/
releases/nebula/planetary/1998/39/results/50/
45
Image at http//hubblesite.org/newscenter/archive/
releases/nebula/planetary/2000/28/image/a/format/w
eb_print/results/50/
46
Image at http//hubblesite.org/newscenter/archive/
releases/nebula/planetary/2004/27/image/a/format/l
arge_web/results/50/
47
Massive Stars are different
On the Main Sequence but not for long
Image from http//hubblesite.org/newscenter/archiv
e/releases/nebula/emission/1997/33/results/50/
48
BetelgeuseRed Supergiant
Image from http//hubblesite.org/newscenter/archiv
e/releases/star/massive20star/1996/04/image/a/res
ults/50/
49
SupernovaMassive Star Explodes
Images at http//hubblesite.org/newscenter/archive
/releases/star/supernova/2004/09/results/50/
http//hubblesite.org/newscenter/archive/releases/
nebula/supernova-remnant/2005/37/results/50/ http
//chandra.harvard.edu/photo/2009/casa/
50
Neutron Star or Pulsar
Image at http//hubblesite.org/newscenter/archive/
releases/nebula/supernova-remnant/2002/24/results/
50/
51
Black Hole
Image at http//hubblesite.org/newscenter/archive/
releases/2002/30/image/a/results/50/
52
Classifying Galaxies
53
Galaxies
  • come in different sizes (dwarf, large, giant)
  • come in different shapes and classifications
  • Spirals
  • Ellipticals
  • Lenticulars
  • Irregulars
  • are fairly close together, relative to their sizes

54
Spiral Galaxies
  • have flat disk, spiral arms, central bulge, and a
    surrounding halo
  • some have a barred bulge
  • are fairly large (no dwarf spirals)
  • have lots of gas and dust and younger stars in
    their arms, but older stars and little gas or
    dust in their halos and central bulges

55
Galaxies
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2005/01/results/50/
56
Spiral galaxy--Andromeda
NOAO/AURA/NSF Images at http//www.noao.edu/image_
gallery/html/im0606.html and http//www.noao.edu/i
mage_gallery/html/im0685.html
57
Spiral Galaxy on Edge
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2006/24/image/a/results/50/

58
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2007/41/results/50/
59
Elliptical galaxies
  • range from spherical to football shaped
  • range from very small to giant
  • have very little gas or dust
  • mostly old stars
  • similar to the central bulge of a spiral galaxy

60
Elliptical Galaxies
Images at http//hubblesite.org/newscenter/archive
/releases/galaxy/elliptical/2007/08/image/a/format
/large_web/results/50/ and http//hubblesite.org/n
ewscenter/archive/releases/galaxy/elliptical/1995/
07/results/50/
61
Lenticular
  • have a disk but no arms
  • have little or no excess gas and dust

Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/elliptical/2002/07/results/50/
62
Irregular Galaxies
  • any galaxy that isnt a Spiral, Elliptical, or
    Lenticular
  • usually have lots of gas and dust and young stars
  • may have a distorted shape from interaction with
    another galaxy

63
Irregular Galaxies
NASA and NOAO/AURA/NSF Images at
http//hubblesite.org/newscenter/archive/releases/
galaxy/irregular/2005/09/results/50/ ,
http//www.noao.edu/image_gallery/html/im0560.html
, and http//www.noao.edu/image_gallery/html/im09
93.html
64
Collisions!
  • We now think that galaxies in groups and clusters
    often collide
  • The Milky Way is moving at 300,000 mph toward the
    Andromeda Galaxy
  • They may collide in about 5 billion years
  • Stars dont usually collide
  • New orbits, gas piles up to form new stars

65
Interacting
Image from http//hubblesite.org/newscenter/archiv
e/releases/galaxy/interacting/2000/34/results/50/
66
the Antennae or Mice
Information at http//hubblesite.org/newscenter/ar
chive/releases/galaxy/interacting/1997/34/results/
50/
67
The occasional results of two galaxies colliding
ringed galaxies
Images from http//hubblesite.org/newscenter/archi
ve/releases/galaxy/spiral/2002/21/image/a/results/
50/ and http//hubblesite.org/newscenter/archive/r
eleases/galaxy/spiral/1999/16/image/a/results/50/
68
Various galaxies (can you identify types?)
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/cluster/1999/31/results/50/
69
Supermassive black holes
  • almost every medium to large galaxy weve check
    has a supermassive black hole at the center
  • the larger the galaxy, the more massive the black
    hole
  • we dont know which comes first, the galaxy or
    the black hole
  • we think that these black holes are responsible
    for some of the galaxies with jets and lobes
    which give off radio waves, x-rays, etc.

70
Active galaxy
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/spiral/2000/37/results/50/
71
at the center of a large galaxy
Image at http//hubblesite.org/newscenter/archive/
releases/exotic/black-hole/1998/22/results/20/
and http//hubblesite.org/newscenter/archive/relea
ses/exotic/black20hole/2000/21/image/a/format/web
_print/results/20/
72
Galaxy Clusters
  • the Local Group
  • includes the Milky Way, the Andromeda, and over
    30 other smaller galaxies
  • the Virgo Cluster
  • hundreds to thousands of galaxies, 60 million
    light-years away
  • giant elliptical at center, formed by galactic
    cannibalism
  • the Local Group is falling toward the Virgo
    Cluster at 60 to 250 miles per second!

73
Coma Cluster
Image at http//hubblesite.org/newscenter/archive/
releases/galaxy/cluster/2008/24/image/a/results/20
/
74
Superclusters!
  • clusters are bound together in larger structures,
    called superclusters
  • these superclusters have been mapped, and are
    grouped into long strings
  • 300 million to a billion light-years long
  • 100 to 300 million light-years wide
  • and only 10 to 30 million light-years thick
  • in between these strings are huge voids of
    galaxies, although some astronomers may have
    detected hot gas

75
Evolution of Galaxies
Image at http//www.galex.caltech.edu/media/glx200
7-05f_img01.html
76
Origin of the Universe
  • Big Bang
  • Dominant scientific theory about the origin of
    the universe
  • Occurred 13.7 billion years ago
  • What is the Big Bang?
  • How do we know?

77
What is the Big Bang?
  • Infinitely dense point not governed by our
    physical laws or time
  • All matter and energy contained in one point

Image from http//www.newscientist.com/articleimag
es/dn11799/0-did-antimatter-factory-spark-brightes
t-supernova.html
78
Building a Universe
  • Instantaneous filling of space with all matter

79
History of the Universe
  • 10-43 seconds - gravity separates from other
    forces
  • 10-35 to 10-32 seconds - fundamental particles -
    quarks and electrons
  • 10-6 seconds - quarks combine into protons and
    neutrons
  • 1 second - electromagnetic and weak nuclear
    forces separate
  • 3 minutes - protons and neutrons combine into
    atomic nuclei
  • 105 years - electrons join nuclei to make atoms
    light is emitted
  • 105-109 years - matter collapses into clouds,
    making galaxies and stars

Orion Nebula - http//stardate.utexas.edu/resource
s/ssguide/planet_form.html
80
History of the Universe
Image from http//dsc.discovery.com/space/top-10/s
trange-universe/space-10-weirdest-things-universe-
10.html
81
Later History
Image at http//www.galex.caltech.edu/media/glx200
4-01r_img02.html
82
Big Bang Theory
  • In 1915, Albert Einstein concluded that the
    universe could not be static based on his
    recently-discovered theory of relativity and
    added a "cosmological constant" to the theory of
    relativity because astronomers assured him that
    the universe was static
  • Aleksandr Friedmann and Abbe George LeMaitre are
    credited with developing the basics of the Big
    Bang model between 1922 and 1927 their
    calculations suggested that universe is
    expanding, not static.
  • Years later, Einstein called his cosmological
    constant the biggest mistake of his career

Image at http//map.gsfc.nasa.gov/universe/bb_theo
ry.html
83
Expanding Universe
  • In 1929, Edwin Hubble showed that most galaxies
    are red-shifted (moving away from us), and that a
    galaxys velocity is proportional to its distance
    (galaxies that are twice as far from us move
    twice as fast)

Image from http//imagine.gsfc.nasa.gov/docs/scien
ce/mysteries_l1/origin_destiny.html
84
Hubbles Evidence
  • Doppler shifting - wavelength emitted by
    something moving away from us is shifted to a
    lower frequency
  • Sound of a fire truck siren - pitch of the siren
    is higher as the fire truck moves towards you,
    and lower as it moves away from you
  • Visible wavelengths emitted by objects moving
    away from us are shifted towards the red part of
    the visible spectrum
  • The faster they move away from us, the more they
    are redshifted. Thus, redshift is a reasonable
    way to measure the speed of an object.
  • When we observe the redshift of galaxies, almost
    every galaxy appears to be moving away from us
    the Universe is expanding.

85
Predictions for the Big Bang Model
  • The expansion of the Universe
  • Edwin Hubble's 1929 observation that galaxies
    were generally receding from us provided the
    first clue that the Big Bang theory might be
    right.
  • The abundance of the light elements H, He, Li
  • The Big Bang theory predicts that these light
    elements should have been fused from protons and
    neutrons in the first few minutes after the Big
    Bang.
  • The cosmic microwave background (CMB) radiation
  • The early universe should have been very hot. The
    cosmic microwave background radiation is the
    remnant heat leftover from the Big Bang.

86
Evidence for Big Bang
  • Red shift - as light from distant galaxies
    approach earth there is an increase of space
    between earth and the galaxy, which leads to
    wavelengths being stretched
  • In 1964, Arno Penzias and Robert Wilson,
    discovered a noise of extraterrestrial origin
    that came from all directions at once - radiation
    left over from the Big Bang
  • In June 1995, scientists detected helium in the
    far reaches of the universe - consistent with an
    important aspect of the Big Bang theory that a
    mixture of hydrogen (75) and helium (25) was
    created at the beginning of the universe

87
When Did the Universe Form?
  • 13.7 billion years ago
  • How do we know?
  • Spreading (Red Shift) - know distances, rates of
    retreat, relative positions
  • Pervasive background radiation of 2.7C above
    absolute zero - afterglow of the Big Bang

Cosmic background radiation temperature on
celestial sphere
http//timeline.aps.org/APS/resources/85_06a.jpg
88
Feedback, Questions
  • Reach us online at http//www.lpi.usra.edu/educati
    on/
  • For more information, contact
  • Christine ShuplaLunar and Planetary
    Institute3600 Bay Area BlvdHouston, TX 
    77058(281) 486-2135shupla_at_lpi.usra.edu
About PowerShow.com