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					Astr                nomy
 Part 1 – Earth in the Universe
The Big Bang Video
• The universe started with a concentrated
  area of matter and energy.

• 15-20 billion years ago.

• Then, it exploded and has been expanding
  ever since.
• Matter began to clump together
  forming stars and galaxies.

• The universe continued to expand
  and is still expanding today.
Our Expanding Universe Video
         Regents Question
Which celestial feature is largest in
  actual size?
(1) the Moon
(2) the Sun
(3) Jupiter
(4) the Milky Way

Answer is…
4
• How do we know the universe is expanding?

• Pg. 14 in the ESRT shows the
  electromagnetic spectrum.

• Notice that in the visible spectrum there
  are all the colors of the rainbow.
• When looking at the visible spectrum
  wavelengths are shifted either to the blue
  end (shorter wave) or the red end (longer
  wave).

• This shift in wavelengths is called the
  Doppler Effect.

• If they are shifted towards red, they are
  moving away from you.

• If they are shifted toward blue, they are
  coming towards you.
• When scientists look at the
  universe, they see a red
  shift. This proves it is moving
  away from us, thus,
  expanding!
A Quick look at the Doppler Affect
       Using a police car
Another look at the Doppler Affect
          using sound
Earth
Science   Light from galaxies moving away
Rocks




                     Notice the shift
                     towards red
Earth          Light from galaxies moving toward us
Science
Rocks




          Notice the shift
          towards blue.
• A galaxy is a collection of billions of stars
  and gas and dust.

• Our solar system is part of the Milky Way
  Galaxy.

• The Milky Way is a spiral-shaped galaxy.
           Regents Question
The Milky Way Galaxy is best described
 as

(1) elliptical
(2) circular
(3) irregular
(4) Spiral
Answer is…
4
Earth
Science
Rock



    • A star is usually a large ball of gas held
      together by gravity.


    • Energy is produced by nuclear fusion –
      combination of nuclei of smaller elements to
      form nuclei of larger elements.
             Regents Question
Which star color indicates the hottest
 star surface temperature?

(1) blue
(2) yellow
(3) white
(4) Red
The good
news!!
This is all
for free
on pg. 15
of the
ESRT!
         Regents Question
Which star color indicates the hottest
  star surface temperature?
(1) blue
(2) yellow
(3) white
(4) Red
Answer is…
1
         Regents Question
In the main sequence, compared to the
  surface temperature and luminosity of
  massive stars, the smaller stars are

(1) hotter and less luminous
(2) hotter and more luminous
(3) cooler and less luminous
(4) cooler and more luminous
Answer is…
3
Life and Death of a Star Video Clip
1.What is the most massive star on the
   chart?
                DENEB
________________________________

2. What is the temperature and luminosity
                      5,600 ºK
   of the Sun? __________________ and
 Luminosity = 1
________________

3. What group is a star in during a late
stage?
               White Dwarfs
   ________________________________
What is the temperature and luminosity of
                        3300ºK
  Betelguese? ___________________
  and ___________________
               200,000


What color would a star be if it was
  15,000ºK?
                   Blue White
  ________________________________

What group of star is Albebaran in?
  ________________________________
                    Giants
7. What temperature and color is Proxima Centauri?
           2800ºK                     Red
    __________________ and __________________

8. Massive stars are (more / less) luminous. (Circle
    one)

                            Procyon B or Eridani B
9. Name a White Dwarf star. __________________

10. What stage are Main Sequence stars in? _______
                                            Early
• The solar system is
  the sun and all
  objects that orbit
  the sun under its
  gravitational
  influence.

• Our solar system
  has 1 sun and 8
  planets.
         Regents Question
The Sun’s position in space is best
  described as the approximate center of
(1) a constellation
(2) the universe
(3) the Milky Way galaxy
(4) our solar system
Answer is…
4
       Regents Question
Compared to Earth’s solar system,
 the universe is inferred to be

(1) younger and larger
(2) older and larger
(3) younger and smaller
(4) older and smaller
Answer is…
2
Pluto?
New Chart in your ESRT…
     Sorry Pluto…
           Regents Question
Which event takes the most time?

(1) one revolution of Earth around the Sun

(2) one revolution of Venus around the Sun

(3) one rotation of the Moon on its axis

(4) one rotation of Venus on its axis

Answer is…
1
• An ellipse is an oval shape.

• Earth’s orbit around the sun is an ellipse.

• Within an ellipse, there are two fixed points
  called foci.

• In our solar system, the sun is ALWAYS
  ONE of those foci.
• The degree of flatness or
  “ovalness” of an ellipse is
  measured by eccentricity.

• This formula is on page 1 of your
  ESRT!
• The more oval the orbit is, the more
  eccentric it is, or the higher the
  eccentricity.




         Increasing Eccentricity
• Calculating Eccentricity:



                                  Major Axis

            X        X

   Foci 1                     Foci 2
An ellipse is an example   You can make an ellipse with 2 tacks and a
of a “conic section”.      string. The tacks are the “foci”, and if you put
Circles and hyperbolas     them further apart, the ellipse is more
are others. All are        “eccentric” (one tack makes a circle).
possible forms for
orbits.
• Calculating Eccentricity:

• When you measure those 2 distances
  and calculate them, you will NEVER
  get higher than 1!!
• The closer to 1 you are the MORE
  oval or eccentric the orbit.
• The closer to 0 you are the LESS
  oval or eccentric the orbit.
         Regents Question
Which planet’s orbit around the Sun is
 most nearly circular? (ESRT 15)

(1) Mercury
(2) Pluto                        No More
                                 Pluto 
(3) Neptune
(4) Venus
Answer is…
4
• The closer 2 objects are to each other,
  the greater the gravitational pull between
  them.

• Therefore, during the perihelion – when
  Earth is closer to the sun, there is a
  greater gravitational pull between it and
  the sun.

• This makes the Earth speed up a bit in its
  orbit around the sun during that time.
Earth
Science
Rocks




          Perihelion   Aphelion
       Planets move quicker
      What do you notice about the
       the closer they are to
        planets orbital velocity?
               the Sun


Aphelion                        Perihelion
Kepler’s Second Law
            Regents Question
Compared to Neptune, Mercury moves more
 rapidly in its orbit because Mercury

(1) is larger
(2) is more dense
(3) is closer to the Sun
(4) has a more elliptical orbit
Answer is…
3
Distance
between
foci
                                length of Major Axis


                X           X




  Write the formula for eccentricity below:
                                            Page 1 of
                                            ESRT’s

  Calculate the eccentricity of the ellipse.
                                    6.4
  Distance between foci: ______________
  Length of major axis: ______________
                                 8.8
  Eccentricity= ______________
                      .72
Distance
between
foci
                              Length of Major Axis


                    X   X




Calculate the eccentricity of the ellipse.
Distance between foci: ______________
                             1.3
Length of major axis: ______________
                               5.4
Eccentricity= ______________
                 .24
What is the minimum value that eccentricity
  can be? ________
              0

Doesn’t a circle look  The more eccentric
like a zero????        the more stretched
                       out until you get a
                       straight line




                                      Look
What is the maximum value that        the #
                         1
eccentricity can be? ________         one.
  What is the maximum value that
                          1
  eccentricity can be? ________


The more eccentric
the more stretched
out until you get a
straight line


                                   Look
                                   the #
                                   one.

				
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