Transcript Passport Stars, Galaxies and the Universe

Passport Science
Space Unit –
Part 1 of 3
PowerPoints
(Textbook reference Chapters 12, 13, 14, 15 and 16)
1
What is astronomy?
•Stars
•Nebula
•Planets
•The Sun
•The Great Andromeda Galaxy
by George Greaney
•Star clusters
•Galaxies
•Galaxy clusters
•Dark matter
•Black holes
What is astronomy?
Astronomy is a science that attempts
to understand the make-up and the
M83 in Hydra
history of the universe.Galaxy
by George Greaney
M33, The Pinwheel Galaxy in Triangulum
by George Greaney
What is astronomy?
M33, The Pinwheel Galaxy in Triangulum
by George Greaney
Basically, if its off this planet its a study
of some realm of astronomy.
As one might imagine that covers an awful lot
of subjects, even more than we know right
now.
•NGC 253, galaxy in Sculptor
Key Ideas
• Galaxies: clusters of stars; different shapes
• Stars: Sun; differ in size, temperature and
color; source for all bright objects
• Gravity: planets, stars, solar system
• Know the appearance, composition,
position and size, and motion of objects in
our solar system
• Astronomical units for measuring
7
What is a Meteor?
What is a Star?
?
?
?
What is an Open Cluster?
What is a Nebula?
What is a Comet?
?
?
?
What is a Quasar?
What is a Black Hole?
What is an
astronomer
?
Galileo Galilei (1564-1642)
A night watchman with a college education?
An astronomer is a
scientist, skilled in
mathematics,
physics, and
astronomy.
Most professional
astronomers work
for universities or
government
agencies.
Galileo Observatory in Italy
Source: The Berkeley Cosmology Group
Few astronomers spend
much time looking through a
telescope. Most operate
telescopes from a control
room or even from their
computer at home via the
Internet.
Typical astronomers only
spend one or two weeks each
year observing, and the rest
of their research time
analyzing their data.
Source: Applied Theoretical and Computational Physics Division
Los Alamos National Laboratory
Astronomer Serena Kim at work
At Cerro Tololo in Chili
What is an amateur
astronomer?
Amateurs and
their tools
What is an amateur
astronomer?
Although the term has
different meanings for
different people, a basic
definition would include
anyone who looks into
the sky, and wants to
see or learn more.
What is space like?
• No air
• No gravity-when you’re
not very close to a planet,
sun, or moon
• No wind
• No friction
• No real “up” or “down”
• No pressure
The Expanding Universe 15-5
• The Big Bang Theory
15
What is a “galaxy”?
(Textbook reference 15-4)
• 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
– The Milky Way Galaxy is a spiral galaxy.
Image at http://hubblesite.org/newscenter/archive/releases/galaxy/spiral/2007/41/results/50/
Spiral galaxy--Andromeda
NOAO/AURA/NSF Images at http://www.noao.edu/image_gallery/html/im0606.html and
http://www.noao.edu/image_gallery/html/im0685.html
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/newscenter/archive/releases/galaxy/elliptical/1995/07/results/50/
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/im0993.html
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 (a measure
of distance)
• 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
The Milky Way
Image at http://news.nationalgeographic.com/news/bigphotos/1945371.html
Mapping the Milky Way
How do we know what our galaxy looks like?
We can see
– stars
– star clusters
– nebulae
– galaxies
Reviewing Galaxies
• Groups of stars,
planets, and space
debris
• Irregular, Elliptical,
Spiral
• Milky Way is our
galaxy
23
What
Is a
Star?
Image of the Sun from Goddard Space Flight Center
What is a Star?
Our Sun is the closest star.
At the simplest, a star is just a ball of gas
that has condensed out of interstellar
material.
The largest part of its lifetime is spent as a
main sequence star during which hydrogen
is being converted to helium balancing
gravitational contraction so that the radius
and energy output remain almost constant.
Source: The British Astronomical Association
Stars (Textbook reference 15-2 and 15-3)
• Bodies of gases that
give off tremendous
amounts of radiant and
heat energy
• Constellations are
patterns of stars used
for navigation,
storytelling, honoring
heroes
Life Cycle of a
Star Video
26
Nearby Stars:
Name
Distance from Earth
Sun
93 million miles (8 light minutes)
Proxima Centauri
4.22 Light Years
Alpha Centuri A,B
4.39 Light Years
Barnards Star
5.94 Light Years
Wolf 359
7.8 Light Years
Lalande 21185
8.3 Light Years
Sirius A,B
8.6 Light Years
Image courtesy of Dave Dockery
Astronomical Society of Las Cruces
Source: The British Astronomical Association
Evolution of Stars
28
How do Black Holes form?
29
Black Holes
• Remains of a neutron star
that has collapsed due to
intense gravity
30
Hertzsprung-Russell Diagram
Video on the
Hertzsprung-Russell
Diagram
The Doppler Effect:
Spectroscopy Video
Red Shift – stars moving away from Earth
Blue Shift – stars moving toward Earth
31
Hertzsprung-Russell Diagram
The coolest
stars are bluewhite in color.
Images from
http://www.nasa.gov/centers/goddard/news/topstory/2007/spectrum_plants.html and
http://sunearthday.gsfc.nasa.gov/2009/TTT/65_surfacetemp.php
Using a Star’s Spectrum
• We can use a star’s spectrum to classify it.
NOAO/AURA/NSF image at
http://antwrp.gsfc.nasa.gov/apod/ap010530.html