CLICK & DOUBLE CLICK: IS PLUTO A PLANET, ASTEROID, COMET OR DOG? INTERNET PROVIDES ANSWERS (COLUMN 124)

What's Pluto? If you answered "Mickey Mouse's dog" you may have the best answer. Astronomers seem to be lost in debate over the definition of the other Pluto, a ball of gas or stone hurling through space at the edge of our solar system.

Joni: Poor Pluto. Its days as one of the nine major planets in our solar system may be numbered.

Peggy: It seems two groups in the International Astronomical Union are looking at reclassifying the puny planet. One wants to call it an "iceball." The other wants to call it "Trans-Neptunian Object No. 1."

Joni: The latter sounds like a bad science-fiction movie, doesn't it? I think this deserves more investigation. Let's learn more about Pluto. First let's jet off to NASA's Johnson Space Center.

sn-io.jsc.nasa.gov/sn

Peggy: Here's something called "Welcome to the Planets." Ah yes, here's some hard data. Pluto has its own moon named "Charon." In Greek mythology, Charon is the ferryman who takes the dead to the underworld.

Joni: NASA has a nice view of Pluto and its moon taken by the Hubble Space Telescope. The telescope offered lots of new information about Pluto, especially about its size and surface. It says here Pluto's days are 6.39 Earth days long. I've had days like that. Haven't you?

Peggy: Definitely. NASA still lists Pluto as a planet. Surely its scientists are the experts. Let's go to the Nine Planet page (Notice: not the eight planet page).

www.deepspace.ucsb.edu/ia/nineplanets/nineplanets.html/

Joni: They provide a multi-media tour of the solar system. You can learn about all the planets and all their moons.

Peggy: OK, Pluto is smaller than seven of the solar system's moons. It says here that in Greek Pluto is the God of the underworld, and that perhaps it got its name because it is the farthest from the sun and in perpetual darkness.

Joni: It was discovered quite by accident by the Lowell Observatory in Arizona in 1930. Apparently there was a big discussion about naming the new discovery. The name Pluto was first suggested by an 11-year-old schoolgirl in Oxford, England.

Peggy: Let's go directly to the International Astronomical Union to find out what it has got against Pluto.

www.intastun.org

Joni: Some scientists suggest that Pluto be classified as the largest asteroid instead of the smallest planet. Another says it's an icy satellite. They agree that there is no official definition for a planet.

Peggy: Did you know the word "planet" comes from the Greek word for wanderer?

Joni: Interesting. This is a long, complicated scientific thesis. At the end, they give you some choices, including "I'm tired, and I want to go back." Let's hop off to the Lowell Observatory, where Pluto was first discovered, and see what they say.

www.lowell.edu

Peggy: This observatory was founded in 1894 to explore the possibility that intelligent life might exist on Mars. It quickly expanded into research of other areas. They are credited with discovering evidence of the expansion of the universe in 1910 and of course the discovery of Pluto.

Joni: They also have discovered many white dwarf stars. Currently, they operate eight telescopes in Flagstaff, Ariz., and one in Perth, Australia. I'd like to visit the off-campus site.

Peggy: The Pluto controversy seems to be ignored by Lowell. In fact, in Dr. Marc Buie's Pluto information page, he describes Pluto as the ninth planet: Cold and dark, but still a great vacation spot.

Joni: I like this, a scientist with a wry sense of humor. He asks, "So" what is Pluto really? A planet, asteroid, comet, dog?" He answers it's really -- drum roll please -- a planet.

Peggy: He says we shouldn't be in such a hurry to re-write the textbook and explains why. And he suggests that time would be better spent learning more about Pluto, like how cold is it?

Joni: It must be somewhere from minus 378 to minus 396 degrees on the surface of Pluto. Indeed a very cold place. The Hubble Telescope has provided some interesting insight on Pluto since it visited in the spring of 1996. Let's look at the Hubble photographs.

oposite.stsci.edu.pubinfo/pictures.html

Peggy: This is the Space Telescope Science Institute, operating the Hubble. You can see pictures by year from 1994 through 1999, or pictures are organized by subject.

Joni: Wow. These are some really cool pictures. We of course want to look at Pluto. Hubble provides scientists with the first information about the surface of this far-away planet.

Peggy: Here's a quote from Dr. Buie: He says the Hubble data brought Pluto from a fuzzy, distant dot of light to a world which we can begin to map and watch for surface changes. It may be paving the way for the first space mission to Pluto in the next century.

Peggy: This sure sounds like a planet to us. It's a small planet, two-thirds the size of the Earth's moon, but a planet nonetheless.

Joni: Of course, the Internet can also help you learn more about the other Pluto, you know the cartoon dog, from Disney.

disney.go.com

Peggy: We learned that Pluto has starred in 48 cartoons. His master's name is Mickey, and his hobbies include lip-synching to "The Three Caballeros" and digging up Minnie's garden.

Joni: Pluto first appeared unnamed in a Disney cartoon in 1930 -- the year of the planet Pluto's discovery. Perhaps it's no coincidence that Mickey's dog was named Pluto the next year, 1931.

Peggy: In case NASA is interested, we're backing Pluto as a planet. I'm sure the scientific world will take notice. What do you think? E-mail us at click@semissourian.com

See you in Cyberspace.

~Peggy Scott and Joni Adams are members of the Southeast Missourian online staff.