Page 23 - BBC Sky at Night - September 2017 UK

EXOPLANET EXCURSIONS SEPTEMBER 23

JON CULSHAW’S

EX PLANET

EXCURSIONS

Jon explores an ancient planetary system and its close-knit companions

ir Patrick Moore frequently is the smallest and completes an orbit that makes Stonehenge seem like a
spoke of the unfathomably in 3.6 days at a distance of 0.04 AU. new-build garden installation at a
huge distances and enormous My observing point is nestled at the Wetherspoon’s pub.
Sspans of time involved in side of Kepler 444f, the largest and outer The lack of atmosphere makes for a
astronomy, far beyond the parameters planet of the system. Despite being the jet-black sky festooned with thousands
we would ordinarily deal with as human farthest out, it’s still relatively close to of stars in unfamiliar constellations.
beings. But as he said, “Nevertheless, its home star at only 0.08 AU, making Letting my imagination construct some
we simply have to accept them.” one orbit in just under 10 days. asterisms of its own, in a few minutes
The system we’re visiting this month Being so close to their star, all of I’ve created a triceratops, a TARDIS
is believed to be 11.2 billion years old. these planets are far too hot to support and the Angel of the North.
At around 80 per cent the age of the life as we know it. I decide to make a Launching from the surface of Kepler
Universe, Kepler 444 is the oldest cautious landing on the surface of the 444f and making a looping fly-past so all
planetary system that we know of. It dark, cooler side of Kepler 444f. There’s planets come into view, it’s amazing to
centres on an ancient red star and formed a sobering sense of age on the surface see what a tight, compact system this is:
MAIN ILLUSTRATION: MARK GARLICK, SPACECRAFT: PAUL WOOTTON, PHOTO: EMMA SAMMS when our Galaxy was a mere toddler at
of this world. Stepping out onto those reminiscent of a Pocketeer maze game,
just two billion years old, proving stable oldest surfaces of lava and igneous with its concentric ball bearings whizzing
planetary systems formed very early on rock brings a sense of deep, deep time round a central circle. The soft shimmer
in the history of the Milky Way. of Kepler 444 and its planets close by,
You can see mag. +8.9 Kepler 444 many with visible volcanic activity, takes
from Earth with a small telescope or on the collective look of a Christmas orb
binoculars: it is 117 lightyears away surrounded by miniature scarlet baubles,
in the constellation of Lyra. But I’m occasionally emitting subtle glints of
piloting my ship closer, to the outer tangerine and amber light.
limits of the system, to see if I’ll use this image as a temporary
its great age has resulted in screensaver on board the Perihelion.
a situation of settled calm Farewell until our next voyage!
or instead, perpetual chaos Perhaps we’ll travel to a giant icy
and orbital eccentricity. moon that exists in a permanent
There are five planets silvery dusk, bathed strongly in
orbiting this star. All are its own version of earthshine.
terrestrial and smaller than
Earth, ranging in size from Jon Culshaw is a comedian, impressionist
Mercury to Venus. Kepler 444b and guest on The Sky at Night