Exoplanet Excursions: December 2014

Jon journeys to one of Pluto’s compatriots, a dwarf planet in our own Kuiper Belt

Having pushed the Cruiser Globe to its limits recently, I’m mindful to stay more local this excursion.

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Credit: Illustration by Mark Garlick

So a fascinating and relatively unknown area of our Solar System beckons – the Kuiper Belt, situated a mere 4.5 billion km from the Sun. I’ve fond memories of the Kuiper Belt after causing hearty laughs in a 1980 geography class by misspelling it as ‘the Kipper Belt’.

The Kuiper Belt is symbolised in my mind by the summer that a big barn was built at my Uncle Richard’s mushroom farm. Once completed, there was a zone circling 20m around the barn composed of scattered concrete, metal bolts and lumps of wood, all left over from the barn’s construction. The Kuiper Belt is our Solar System’s version of this outer debris zone – all the cast-out fragments of its formation.

Here’s where we find the eerie conglomeration of the dwarf planets, those trans-Neptunian objects floating around as if occupying a cosmically huge lava lamp. The Kuiper Belt has a most alien feeling while being tantalisingly close. Evocative of a hidden alleyway between the shed and Victorian coal house in your grandparents’ garden. Spooky, dark and unnerving but full of curious objects and deliciously close by, ready to fire the imagination of inquisitive minds.

The dwarf planets are generally Pluto-sized and although the IAU have designated only five officially, it’s believed there could be many thousands of them. One such dwarf world has a name like a holiday camp rapper, ‘MakeMake’ (pronounced ‘MarkayMarkay’). This curious lump is 710km in diameter, taking 310 years to complete one orbit.

From the Cruiser Globe, the cratered, pitted surface below looks like a coral ornament on a fish-tank floor. Its surface of frozen nitrogen and methane gives off a pale terracotta hue. MakeMake’s orbit could presently be at its closest to the Sun as a little of the nitrogen and methane surface ice seems to be gently vaporising, creating a temporary, delicately thin atmosphere. Against the jet-black sky from this distance, our Sun still shines with an arresting brightness, like an LED placed at the far end of an aircraft hangar. Piercingly luminous, it’s reassuring how the Sun punches above its weight from 50 AU away.

It’s easy to imagine this world being mined for its resources by aggressively industrial humans in the far future. Calm and silence reigns for now, as does a charmingly alien sight. A collision between two objects around the size of Rosetta’s target comet has resulted in a cloud of fragments, each around the size of a Routemaster bus. It resembles the close-up images of Saturn’s rings, with individual boulder chunks appearing to unite as a swarm of jagged crescent Moons, and the release of icy material produces a rainbow effect like patches of multicoloured nebulosity.

It’s pleasing to know our Kuiper Belt can serve up the most profoundly alien views equivalent to the most jaw dropping in the Universe.


Jon Culshaw is a comedian, impressionist and guest on The Sky at Night
This column appeared in the December 2014 issue of BBC Sky at Night Magazine
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