Dis­tant cousin

Pluto is Pluto. And that is enough

Cape Breton Post - - EDITORIAL -

Pity poor Pluto. The once full- fledged planet has inspired many an earthly trib­ute, from a ra­dioac­tive sub­stance ( Plu­to­nium is num­ber 94 on the Ta­ble of El­e­ments) to a colour­ful ca­nine in the Dis­ney cast of char­ac­ters.

But Pluto’s sta­tus suf­fered a ma­jor blow a few years ago.

In 2006, the In­ter­na­tional As­tro­nom­i­cal Union shocked the world when it an­nounced Pluto would no longer be con­sid­ered a planet. It is, they said, a dwarf planet. That left us with only eight bona fide plan­ets in our so­lar sys­tem, a fact that must have had Gus­tav Holst, com­poser of “The Nine Plan­ets,” spin­ning in his grave.

It’s true that Pluto was al­ways the least un­der­stood among its plan­e­tary sib­lings. In fact, its ex­is­tence was only con­firmed very late in the game.

The man who dis­cov­ered it was Amer­i­can as­tronomer Clyde Tom­baugh, who was hired by the Low­ell Ob­ser­va­tory in 1929. Uranus and Nep­tune had al­ready been dis­cov­ered in 1781 and 1846, re­spec­tively, but there were still dis­crep­an­cies in the move­ment of the lat­ter that sug­gest a ninth body be­yond.

Tom­baugh spent eons pour­ing over pho­to­graphic im­ages. In Fe­bru­ary 1930, he fi­nally no­ticed an ob­ject mov­ing across the field of a pair of im­ages taken a month be­fore­hand. Af­ter ver­i­fy­ing the find­ing, the Low­ell Ob­ser­va­tory of­fi­cially an­nounced the dis­cov­ery of the ninth planet on March 13.

For­tu­nately, Tom­baugh died in 1997, and did not wit­ness the de­mo­tion of his beloved Pluto.

The down­grad­ing to dwarf sta­tus — and who would dare sug­gest dwarf plan­ets are not full, par­tic­i­pat­ing mem­bers of planet so­ci­ety any­way? — just hap­pened to oc­cur af­ter the launch of New Hori­zons, a Pluto probe that has started trans­mit­ting star­tling photos back to Earth within the past few days.

Ear­lier this week, the NASA probe cap­tured its latest snap­shot of the ninth rock from the sun from less than eight mil­lion kilo­me­tres away.

It’s now less than six mil­lion kilo­me­tres away, and is ex­pected to make a his­toric flyby next week. Here’s the funny part, though. Ex­cited by this first close en­counter of a dis­tant cousin, a cam­paign to re­in­state Pluto’s sta­tus has gained new vigour.

And Alan Stern, prin­ci­pal in­ves­ti­ga­tor with the mis­sion, is right on board.

He thinks once the public starts see­ing pic­tures of the lit­tle tyke, they’ll want to call it a planet again. And if it doesn’t fit the ex­ist­ing def­i­ni­tion, well, just change the def­i­ni­tion.

It’s all a lit­tle silly, re­ally. Pluto is even smaller than our moon. In fact, there are four other dwarf plan­ets in our sys­tem: Ceres, Haumea, Make­make and Eris. Should we pro­mote them all to plan­ets?

Per­haps we should just stop ob­sess­ing over ter­mi­nol­ogy al­to­gether. Pluto is Pluto. And that is enough.

As for Tom­baugh — the probe is car­ry­ing a small por­tion of the late as­tronomer’s ashes on its jour­ney.

Now that is truly cos­mic.

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