Science Journals – 3-25-14
• The light from Alpha Centauri A takes 4.3
years to reach Earth. The light from Ross 154
takes 9.7 years to reach Earth. The light from
Luyten 726-8A takes 8.7 years to reach Earth.
The light from Procyon A takes 11.4 years to
reach Earth. The light from Sirius B takes 8.1
years to reach Earth.
1. What is the order of the following stars from
the closest to Earth to the farthest from
Earth?
Science Journals – 3-25-14
1. Alpha Centauri A at 4.3 lightyears (closest to
Earth)
2. Sirius B at 8.1 lightyears
3. Luyten 726-8A at 8.7 lightyears
4. Ross 154 at 9.7 lightyears
5. Procyon A at 11.4 lightyears (farthest from
Earth)
WEATHER REPORT
The LIGHT-YEAR
• A light-year is a measure of distance. It is not a
measure of time.
• A light-year is the distance that light travels in
one year.
• It is equal to about 6 trillion miles.
• 6,000,000,000,000 miles.
It’s A Great Big Universe!
Let’s See What’s Out There…
TEKS 8.8 A
The student is expected to describe
components of the universe,
including stars, nebulae and
galaxies, and use models such as
the Hertzbprung-Russell diagram
for classification.
Fabulous Fact or
Mystical Myth
Stars have always “been there”
MYTH! Stars are born from a cloud of gas
and dust called nebula.
Fabulous Fact
Mystical Myth
Galaxies are all the same.
MYTH! Galaxies are classified by
their shape.
or
Lesson Objectives
1. Students will understand what is in the
universe.
2. Students will be able to describe stars
and their life cycle, from nebulae to
dwarf stars and black holes.
3. Students will be able to classify stars via
the HR Diagram.
4. Students will be able to describe the
components of a galaxy and the three
types of galaxies: elliptical, spiral and
irregular.
Engage
Show video clip:
First 3 Minutes of “Contact”
• What’s past our solar system?
• How many stars do you think are out
there?
• How far do you think they are from Earth?
From each other?.
• Why did the sounds get more quiet the
further away we got from Earth
• How far out do you think we traveled?
Explore
Activity: Universal Concentration
• What will you find in the universe?
• How old is the universe?
• Are we alone?
Star
A self-luminous celestial body consisting of a
mass of gas held together by its own gravity in
which the energy is generated by nuclear
reactions in its interior
The “Discovery” of Galaxies
At the beginning of the 20th century, what we now
call spiral galaxies were referred to as “spiral
nebulae” and most astronomers believed them to
be clouds of gas and stars associated with our own
Milky Way. The breakthrough came in 1924 when
Edwin Hubble was able to measure the distance to
the “Great Nebula in Andromeda” (M 31, at right)
and found its distance to be much larger than the
diameter of the Milky Way. This meant that M 31,
and by extension other spiral nebulae, were galaxies
in their own right, comparable to or even larger
than the Milky Way.
(NOAO/AURA Photo)
Edwin P. Hubble (1889-1953)
Types of Galaxies I. Spirals
Spiral galaxies are so-named because of the graceful
shapes of arms emanating from a bright central
nucleus. Spirals are classified according to how
tightly or loosely wound the arms are, and it turns
out that the brightness of the central nucleus is
correlated to the tightness of the arm. The galaxies
M 104 (below) and M 51 (right) respectively show
tightly and loosely wounds. Notice the effects of
dust in both galaxies. (NOAO/AURA Photos)
Types of Galaxies II. Ellipticals
Elliptical galaxies lack spiral arms and dust
and contain stars that are generally identified
as being old. The elliptical galaxies M 32
(below) and M 110 (right) show varying
degrees of ellipticity.
(NOAO/AURA Photos)
Types of Galaxies III. Irregulars
Irregular galaxies lack any specific
form and contain stars, gas and dust
generally associated with a youth.
The irregular galaxy at right is the
Large Magellanic Cloud, a satellite of
the Milky Way located about 180,000
light years from the sun. The LMC is
about 60,000 light years across. The
bright reddish feature in the upper
right is the “Tarantula Nebula” a
region of star formation in the LMC.
(NOAO/AURA Photo)
Galaxies in Collision
In this close encounter between two spiral galaxies, their arms are dramatically warped and massive
star formation is triggered when the hydrogen gas clouds in the two collide. It is believed the Milky
Way may have “cannibalized” small galaxies in the past through collision.
Hubble Space Telescope Image
Explore
Activity: Name That Galaxy!
• Galaxies are classified by shape.
• The shapes are irregular, spiral &
elliptical.
• What do you think a galaxy with that
shape would look like?
www.waidobservatory.com
Life Cycles
Explore
Activity: A Star’s Life
• Are all stars “born” the same way?
• Do all stars “die” the same way?
• How is a star’s life cycle similar to a
human life cycle?
www.universetoday.com
Explain
What is the universe?
All that is in existence.
What’s in the universe?
Galaxies, stars, gases, planets, dust, other matter.
What is a galaxy?
Collection of stars, dust, and gases held together by
gravity.
What’s our galaxy?
The Milky Way
Is ours the only one?
No. There are billions of galaxies in the universe.
What is in a galaxy?
Stars, gases, planets, asteroids, comets, etc.
Explain
How do scientists classify galaxies?
By shape. Elliptical is round/oval shaped, spirals are
pinwheel shaped and irregular have no specific shape.
What are stars?
Balls of luminous gases of various mass and temperature
held together by gravity.
How do stars form?
They are formed from compressed gas and dust found in
nebulae.
Do all stars “die” the same way?
Lower mass stars form small “dwarf” stars while larger
mass stars can explode in a supernova. Some high mass
supernova will form black holes.
Elaborate I
Activity: Starlight, Starbright
Students will examine stars of different color,
temperature and luminosity and plot them on
an HR-Diagram, while observing patterns and
trends in the placement.
Elaborate I Debriefing
•What patterns did you notice when
examining the stars’ colors?
•What patterns did you notice when
examining the stars’ temperatures?
•What patterns did you notice when
examining the stars’ luminosity?
•Why do you think the HR-Diagram is
useful to scientists when it comes to
classifying stars?
Evaluate
•
•
•
•
•
•
•
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•
All that exists (matter and non-matter) make up the
__________________.
___________________are collections of stars, gas &
dust held together by __________________.
Luminous balls of gas in space are called ___________.
Stars are created from clouds of gas and dust
called___________.
Stars in the middle of their lifespan are called
________________.
As stars age, their color changes and their
temperatures_________.
A violent explosion of a high mass star at the end of its
life is called a ________________________________.
Galaxies are classified by _____________.
The three types of galaxies are ________________,
___________________, and _______________.