Despite Pluto’s dwarf planet status, the countdown continues: a short essay


Here’s how one artist imagines the sun would look as soon from Pluto’s surface.

Much has happened since Pluto was first discovered by the late Dr. Clyde Tombaugh in 1930.

In 1978, Pluto was discovered to have a moon. The moon, later christened Charon, resulted in new calculations being done regarding Pluto’s size. The verdict? Pluto, once thought to be roughly the size of Mars, was discovered to be smaller. Much smaller, even smaller than the earth’s moon.

In 1985 and confirmed three years later, tiny Pluto was discovered to have an atmosphere. But because it’s so cold on Pluto (an estimated -382 degrees Fahrenheit), the surface gases are said to freeze into ice and fall like snow to the surface during the tiny planet’s aphelion (when it’s farthest from the sun).

In 2005, two more tiny satellites were discovered orbiting Pluto. Unlike Charon, which is about half Pluto’s size, Nix and Hydra are much smaller.

On January 19, 2006, after delays due to weather problems, the New Horizons spacecraft launches on its 9.5-year voyage to finally explore Pluto. The craft has successfully received a gravity assist from a brief orbit around Jupiter and is scheduled to rendezvous with the tiny, frozen world on July 14, 2015 (I’m 36 now and I’ll be 42 when this happens). For now, Pluto remains a reddish-brownish-goldish enigmatic blip.

And now, the planet Pluto is officially the dwarf planet Pluto after the International Astronomical Union voted later in 2006 to demote Pluto. Pluto’s orbital plane is very eccentric, rising far above and below other planets and looping inside Neptune’s orbit 20 years of its estimated 248-year orbit. The biggest reason given for Pluto’s demotion is that it doesn’t clear out its own orbit. IAU’s decision has been both praised and criticized, with critics pointing out that few members actually voted and that the definitions of a planet are vague and subjective. Under the criteria, they say, other Solar System planets could lose their planetary status.

It’s possible that the decision may be reversed when the IAU meets again later this year in Rio de Janeiro, Brazil.

What also complicates the Pluto issue is that Pluto isn’t even the largest dwarf planet. That honor belongs to Eris, discovered in 2005 and estimated to be thrice Pluto’s size and about 27% more massive. Eris, estimated to reach a distance of about 14.6 billion miles from the sun and takes more than 500 years to complete its orbit, even has its own satellite—Dysnomia.

Will the controversy around Pluto be resolved in 2015 when we finally start receiving detailed images of what Pluto looks like? Hard to say. All we know for certain is that space, though the final frontier, is by far the most complex frontier.


One comment on “Despite Pluto’s dwarf planet status, the countdown continues: a short essay

  1. It should be noted that the IAU’s controversial demotion of Pluto is very likely not the last word on the subject and in fact represents only one interpretation in an ongoing debate. Only four percent of the IAU voted on this, and most are not planetary scientists. Their decision was immediately opposed in a formal petition by hundreds of professional astronomers led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto. Stern and like-minded scientists favor a broader planet definition that includes any non-self-luminous spheroidal body in orbit around a star. The spherical part is important because objects become spherical when they attain a state known as hydrostatic equilibrium, meaning they are large enough for their own gravity to pull them into a round shape. This is a characteristic of planets and not of shapeless asteroids and Kuiper Belt Objects. Pluto and Eris both meet this criterion, as do Ceres, Haumea, and Makemake, and therefore, all are planets.

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