Unit 3 WebQuest - Internet
|Pluto is Falling From Status
as Distant Planet
USA Today, March 28, 2001
Like any former third-grader,
Catherine Beyhl knows that the solar system has nine planets,
and she knows a phrase to help remember their order: "My
Very Educated Mother Just Served Us Nine Pizzas."
she recently visited the American Museum of Natural History's
glittering new astronomy hall at the Hayden Planetarium and
found only eight scale models of the planets. No Pizza - no
"That's because the museum
doesn't consider Pluto to be a planet," docent Marjorie
Kagan explained to Beyhl and other senior citizens on a trip
organized by the Westbury Public Library. "Poor Pluto
has been downgraded, knocked down."
interjected Beyhl, who got her basic astronomy from the nuns
at St. Sylvester's Grammar School in Brooklyn in the 1930s.
And now here was Kagan, preaching
heresy. "We think Pluto is probably a comet. It's very
small, very icy, and it has a very eccentric orbit,"
she told the visitors. Some looked as if they'd just been
told "A" isn't a vowel or September hath 31 days.
"There is a lot of disagreement about this, even in the
scientific community," Kagan added. "But we think
within five years everyone will agree with us."
"I don't think it's gonna
be missed," muttered one member of the group.
"If it's a comet,"
replied another, "where's the tail?"
The Westbury seniors had stumbled
into a debate that might rewrite schoolbooks, render a million
classroom astronomical charts obsolete and change how generations
yet to be born build model solar systems. Is Pluto really
a planet? And if not, what is it? Last year, the museum opened
its astronomy exhibit inside a giant glass cube that's about
10 stories high and contains the Hayden Planetarium. The display
grouped eight of the planets into two "families"
- the "terrestrials" (Mercury, Venus, Earth, Mars)
and the "gas giants" (Jupiter, Saturn, Uranus, Neptune).
The ninth, Pluto, was quietly consigned to the Kuiper Belt,
"a disk of small, icy worlds" beyond Neptune.
But in 1999, the leading international
organization of astronomers rejected a move to list Pluto
as both a planet and Kuiper Belt object. Those who call Pluto
a planet note that it has an atmosphere and a moon, Charon.
It also is larger than any object yet observed in the Kuiper
Other major museums still consider
Pluto a planet, and some astronomers were appalled by the
revisionism in New York. David Levy, the noted comet-finder,
said the demotion was "off base." Alan Stern of
the Southwest Research Institute's space studies department
called it "absurd."
Many non-scientists also spoke
up for the outerdog planet. Docents at the Museum of Natural
History get many questions from children, some of whom asked,
"Where's my friend Pluto?"
So this month, the museum installed
a plaque titled "Where's Pluto?" and programmed
an electronic kiosk to make the case to confused visitors.
It goes like this: Science is
the classification of similar things. Pluto has little in
common with the two nearest planets, Uranus and Neptune. They
are made of gas (Pluto is ice and rock) and are much larger
than Pluto (which is smaller than Earth's moon). Also, Pluto's
elliptical orbit is tilted 17 degrees from those of the other
planets. So what is Pluto? "A breed of comet that lives
in the outer solar system, never venturing near the sun,"
the display reports. "If Pluto were close to the sun,
it would grow a glowing tail of sun-blown ice vapor."
Compared with the other planets, it's "peculiar,"
"weird," "an oddball."
Pluto's very planethood, the
museum argues, is a historical accident. When Pluto was discovered
in 1930, astronomers mistakenly believed it was roughly the
size of Earth and alone in space. Not until the 1990s were
many other chunks of rock and ice seen orbiting beyond Neptune
in what is now called the Kuiper Belt.
There is even a historical precedent
for demoting Pluto. About 200 years ago, the asteroid Ceres
was briefly labeled a planet when it was discovered between
Mars and Jupiter. But then astronomers realized there were
many such bodies in that ring of space and reclassified Ceres
Not content to question Pluto's
identity, the museum's astronomers argue that there's no generally
accepted definition of the word planet. If Pluto is one, says
Michael Shara, curator of the museum's astrophysics department,
then so is Earth's moon and hundreds of other hunks of debris
floating around the sun. Having said that, he added, "I
just don't think Pluto is a planet."
Some visitors take his word
"It's a surprise,"
Annie Prince of Manhattan said with a gulp. "But if they
say it's so, I can live with it."
Others, perhaps out of a sense
of loyalty to lonely Pluto, refuse to be swayed. "I'll
believe it's a planet until I see proof otherwise," said
Evelyn McConnell, a mother chaperoning a class trip from Northport,
N.Y. "It's nice to have all nine of 'em." But Neil
de Grasse Tyson, director of the Hayden Planetarium, has been
quoted as saying: "There is no scientific insight to
be gained by counting planets. Eight or nine, the numbers
Which is not something Catherine
Behyl would have dreamed of telling the nuns at St. Sylvester's.
Since 1997, NASA has sponsored an
annual Space Day in which schools everywhere can participate.
Your school will be joining in the celebration this coming
year by investigating space and technology for the entire
day. Your class has been assigned to design a display about
the planets in our solar system. Each student in your class
needs to contribute some type of planetary information that
can be described using mathematics. For this project you need
to present your information in a brochure, on a poster, or
on a Web page. Be sure you include the following information:
- the data about planets that you
will use for your project;
- three graphs, tables, or calculations
that present the data you are using in some way. You can
use all graphs, all tables, all calculations, or a combination
of the three methods;
- diagrams or pictures that will
make your project visually appealing.
To successfully complete this project,
you will need to complete the following items.
Here are some additional questions
and ideas you may want to consider for your project.
- What missions to investigate the planets of our solar
system have been completed or are in progress? What were
the results of these missions?
- How many moons do the various planets have? Have there
been any space missions to these moons?
- Have other solar systems been located? If so, how far
are they located from Earth?
- How do telescopes work? What is the history of telescopes?
- How do the missions and research conducted by NASA benefit
people on Earth?
- Have any companies begun to develop plans for space travel
for civilians? What are the advantages and disadvantages
of such programs?
- Investigate Kepler's Laws. Verify the third law for each
of the nine planets.
- What is a light-year?
- What discoveries have been made by the Hubble Space Telescope?
- What is the eccentricity of an orbit? How is it calculated?
Find the eccentricity of the orbit of each planet.
Here are some ideas for concluding
- Present your project to your class
or at a family night.
- Present the information on a Web
page. Have other students critique your project and help
you to make improvements to your project.
- Write a one-page summary of what
you have learned from completing this project.
For her project, Priscilla finds these data about the planets
on a Web site. The table shows the perihelion (closest point
to the Sun), the aphelion (furthest point from the Sun), and
the average surface temperature for the nine planets. Notice
that all distances are given as 106 miles.
- Copy the table and rewrite all
the distances in scientific notation.
- For which planet is the difference
between the aphelion and perihelion the greatest?
- Draw a scatter plot for the perihelion
distance and the average temperature. Let distance be on
the horizontal axis and temperature on the vertical axis.
- Describe the scatter plot.
For his project, Tyler makes a table that would help students
and teachers make a scale model of the solar system. To start,
he decides to average the perihelion and aphelion distances
for the model. The table shows the distances.
- Fill in the average distance column.
Write your answers as values in 106 miles.
- What is a common factor of all
the distances in column four?
- Suppose you round each value in
column 4 to the nearest 10. What is the greatest common
factor of each distance then?
- How can factoring the values for
the distances help Tyler to make a scale model of the solar
For her project, Ingrid decides to find the surface area
of each planet. She makes this table that shows the diameter
of each planet.
- In a reference book, Ingrid finds
that the surface area of a sphere is found by multiplying
times the radius squared. The formula is written SA
= 4 ×
× r2. Fill in column three by finding
the radius of each planet. Then fill in column four by finding
the surface area of each planet. Use 3.14 for
and round each answer to the nearest whole number.
- Next, Ingrid decides to make a
scatter plot of the data. She writes the ordered pairs (radius,
surface area) and plots the points. Draw this scatter plot.
Describe the scatter plot.
- Ingrid uses graphing software
to find an equation for the scatter plot. The equation is
y = 12.56x2. Explain why this equation
fits the data.
- The graph of y = 12.56x2
lies in quadrants I and II. In which quadrant does the graph
have no meaning for the surface area of the planets? Explain.