Exoplanet Excursions: November 2015

Jon scouts out Earth’s ‘bigger, older cousin’, the remarkably similar Kepler 452b.

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Image Credit: 
Mark Garlick
 

Kepler 452b has been described as the most ‘Earth-like’ planet ever found. How fascinating would it be to take a trip and see precisely how similar it is to our pale blue dot. I’ve set coordinates set for its parent star Kepler 452, which sits 1,400 lightyears away in Cygnus. Kepler 452 is quite like our Sun though 1.5 billion years older, 20 per cent brighter and four per cent more massive. It shines the reassuring solar yellow of a star still in the surety of the main sequence.
 
Steering into the system’s habitable zone, the magnificent ‘super-Earth’ Kepler 452b appears with imposing majesty. It’s strangely disconcerting. Similarities to our own Earth – the swirling white and blue, the ochre, green and khaki – bring a feeling not of confidence in familiarity but of caution and not wishing to fall into a false sense of security. There could be an infinite number of ways that this planet is different to our own. I steer the Perihelion with great trepidation as if driving into a part of town with a volatile reputation.
 
Upon landing, the sense of confusion grows. At first view, this world appears 
so very much like ours, it’s quite bizarre to take in. There’s an expectation for exoplanets to be profoundly different, odd and alien. This localised area is something like Earth’s Oligocene epoch around 30 million years ago.
 
After a time, once you’ve got your bearings, the fascinating unique features of this world start to become apparent – similar to becoming dark adapted. There’s evidence of volcanic and geologic activity leaving results quite unlike those we see on Earth. The larger scale of this world and much greater gravity has fashioned what I can only describe as a furiously whisked and churned geology. It looks to have been busier, faster and more intensive than the processes we studied in Mr Malley’s geology lessons at school.
 
I fly 300km to be greeted with a totally alien vista – a staggering feature befitting the super-Earth status of the planet. Ahead of me is an immense canyon, rolling forward as far the eye can see, on the scale of the Valles Marineris on Mars. But this resembles the Valles Marineris of a terraformed Mars in the far future. There are pockets of sandy-coloured liquid lakes with dark green foliage resembling giant, leathery rhubarb leaves. They’re probably photosynthesising perfectly happily.
 
An Earth-like world with its terrain and gold starlight. A Mars-like world with geological landscapes on colossal scales. It’s perhaps becoming a Venus-like world too? This planet receives 10 per cent more energy from its star than Earth does from the Sun, so maybe a runaway greenhouse effect is underway? The patchwork of lakes does look like it has been evaporating into the atmosphere.
 
Such a diverse world inspires more questions than answers. The gravity here too, on a planet 60 per cent more massive than Earth, is utterly punishing. I feel 
I’m being pushed back inside a whirling, fairground centrifuge ride. Although once adapted to it I’ll be confident enough to duke it out with a heavyweight boxer all the way back on Earth.

Jon Culshaw is a comedian, impressionist and guest on The Sky at Night.

This column originally appeared in the November 2015 issue of BBC Sky at Night Magazine.

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