**Lesson: Using the Discovery of an Intermediate Mass Black Hole to
Reinforce Reading Comprehension**

**By Michael Sivell**

**Hammond High School**

**Howard County Public Schools**

**Columbia, Maryland**

**Teacher Instructions:**

1.  Show the May 1, 2008 "Astronomy Picture of the Day" image entitled
    "The Giants of Omega Centauri" to the class reading the explanation.

    a.  Site: <http://antwrp.gsfc.nasa.gov/apod/ap080501.html>

    b.  Explain that Omega Centauri has some peculiarities for being a
        globular cluster and that new results obtained by the NASA/ESA
        Hubble Space Telescope and the Gemini Observatory have provided
        a surprising explanation.

    c.  Ask students to imagine what scientists may have discovered.

2.  Watch Hubblecast #14: Black Hole Found in Enigmatic Omega Centauri.

    a.  (Running time: 5:53)

    b.  Site:
        <http://www.spacetelescope.org/videos/html/mov/180px/heic0809a.html>

    c.  Questions to ask class following Hubblecast:

        i.  What does Omega Centauri appear to harbor in its center? *An
            elusive intermediate-mass black hole.*

        ii. What did astronomers measure to discover the black hole?
            *Astronomers measured the motions and brightnesses of stars
            at the center of globular cluster.*

        iii. How massive is this black hole? *It has 40 thousand solar
             masses which makes it an intermediate mass black hole. It
             is a lot bigger than the stellar mass black holes that we
             find in our galaxy but much smaller than the supermassive
             black holes that we find at the center of galaxies.*

        iv. What does this discovery imply Omega Centauri is and is not?
            *One implication of this discovery is that it is very likely
            that Omega Centauri is not a globular cluster at all, but a
            dwarf galaxy stripped of its out stars and dark matter.*

3.  Using a "Reciprocal Teaching" technique have students read the
    scientific paper "Gemini and Hubble Space Telescope Evidence for an
    Intermediate Mass Black Hole in omega Centauri" by Eva Noyola and
    Karl Gebhardt.

    a.  Paper cited as "ApJ preprint doi:10.1086/'529002"

    b.  Site:
        <http://www.spacetelescope.org/news/science_paper/omegacentauri.pdf>

    c.  Have students read the Abstract while completing the "Reciprocal
        Teaching Worksheet." Go over students' summaries, questions,
        clarifying statements, and predictions from the abstract.

    d.  Reinforce student understanding of abstract by reading April 2,
        2008 Gemini Observatory press release entitled "Spectacular Star
        Cluster May Host Black Hole Missing Link." Site:
        <http://www.gemini.edu/index.php?option=content&task=view&id=284>

    e.  Have students read section 1 Introduction using the "Reciprocal
        Teaching Worksheet." Go over summary and questions to hear
        student responses.

    f.  Repeat reading technique for sections 2, 3, 4.1, 4.2, and 5.
        Section 3 is optional.

*For a summary of Reciprocal Teaching go to:*
<http://www.ncrel.org/sdrs/areas/issues/students/atrisk/at6lk38.htm>

**Going further:**

1.  For a discussion on other galaxies cannibalized by our Milky Way
    galaxy see the November 4, 2007 "Astronomy Picture of the Day"
    entitled "The Closest Galaxy: Canis Major Dwarf."
    <http://antwrp.gsfc.nasa.gov/apod/ap071104.html>

2.  For a discussion on the supermassive black hole located at the
    center of the Milky Way galaxy see the July 29, 2007 "Astronomy
    Picture of the Day" entitled "The Center of Centaurus A."
    <http://antwrp.gsfc.nasa.gov/apod/ap070729.html>

3.  For an student centered activity to measure the mass of the black at
    the center of the Milky Way galaxy go to
    <http://www.astroex.org/english/exercise6/>

**Reciprocal Teaching Worksheet**

**"Gemini and Hubble Space Telescope Evidence for an Intermediate Mass
Black Hole in omega Centauri" by Eva Noyola and Karl Gebhardt.**

> Name \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
>
> Date \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
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> Period \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Complete each step of the reciprocal teaching strategy.

**Read**
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**Summarize** Tell what the selection is about in a "nutshell."

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**Question** What questions do you have for the group?

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**Clarify** Tell what might be hard to understand.

Reread and discuss words or points that were not clear.

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**Predict** Tell what will happen or what you will learn in the next
section.

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