Page 65 - All About Space 68 - 2017 UK

Life but not as we know it

KEpLER-16B

Black trees on a
world with two suns

Exoplanet exploration is a field of astronomy that is constantly becoming more
exciting and groundbreaking. There is one particular exoplanet that has become
famous due this research, and that is Kepler-16b.
What makes Kepler-16b so famous is that it’s the first confirmed circumbinary
planet – a planet that orbits two stars. If you have ever seen the Star Wars films,
Kepler-16b is similar to the planet Tatooine, but unfortunately it doesn’t share the
same rocky surface. Kepler-16b is slightly larger than Saturn with an extremely low
density, so the planet seems to have no surface at all.
If future analysis showed Kepler-16b to have an Earth-like environment, it could
house the most incredibly exotic plant life. Because these stars emit different, less
Imagine a world where
energetic light than our Sun, the photosynthesis process is completely changed.
each day came to a
Jack O’Malley-James, currently of Cornell University, but at the time of the study
close with two
of University of St Andrews, has investigated what plant life would look like on separate sunsets
exoplanets due to the change in its photosynthesis process: “The temperature of a
star determines its colour, and hence, the colour of light used for photosynthesis.
Depending on the colours of their star's light, plants would evolve very differently.
Plants with dim red dwarf suns for example, may appear black to our eyes,
absorbing across the entire visible wavelength range in order to use as much of
the available light as possible. They may also be able to use infrared or ultraviolet
radiation to drive photosynthesis."
Based on this research, because Kepler-16b contains a less energetic K-type main
sequence star and a M-type dwarf star, the plant life on Kepler-16b would most
probably be black to absorb as much light as necessary.

Io is the innermost Galilean moon of Jupiter, and being
this close to the Jovian giant isn’t good for the state of the
moon. Not only does Jupiter’s radiation wreak havoc across
the surface of Io, but the gravity of Jupiter also causes the
continuous pushing and pulling of material underneath
the surface. This continuous motion produces a lot of
heat being released due to friction (also known as tidal
heating). As the heat builds up, it gets to the point where
it explodes onto the surface in a spectacular volcanic
eruption, resulting in the sulfur plumes we have witnessed
via spacecraft observations.
Based on this information, many would think that life
is practically deceased on this moon, but the astrobiologist
Dirk Schulze-Makuch of Washington State University
explains, “Life on the surface is all but impossible, but if
you go down further into the rocks, it could be intriguing.
We shouldn’t categorise it as dead right away just because
it’s so extreme.”
Schulze-Makuch suggests that microbial life could
exist in the lava tubes within Io, as it has been previously
proven on Earth that extremophilic life can thrive in lava
tubes. Shulze-Makuch goes on to explain that the lava
tubes can not only shelter microbes from outside radiation,
but also provide insulation to trap heat and moisture,
io as well as provide sulphur-based compounds for the
extremophiles to metabolise. Yet again, this calls for major © ESA/L. Ricci, © NASA/Caltech, © Royal Astronomical Society, © David A. Aguilar (CfA)
evolutionary adaption.
Extremophiles of Io, it’s possible these lava
Considering the internal heat
hiding away in tubes are occupied
by ‘hyperthermophiles’, as they
can thrive in temperatures
the lava tubes above 353.15 Kelvin (80
degrees Celsius).

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