There are several extrasolar planets out there with highly eccentric orbits (16 Cygni B b and HD 183263 b to name a couple) that have an average temperature not to dissimilar to Earth. However with these eccentric orbits the temperatures can swing wildly by as much as 50 Kelvin. The question is - would such a planet (or moon of said planet) that had sufficient oceans covering its surface be able to keep a mean temperature all year round in its oceans, enough to supportive of life?

This has been the theme for my latest series of works. Four paintings depicting the four ’seasons’ experienced on a hypothetical moon of a gas giant with a highly elliptical eccentric orbit of its parent star. A series of four paintings collectively titled “The Seasons of an Eccentric Planet’s Moon” depicts the possible seasons experienced with such a wild orbit. Each painting is ‘possitioned’ on exactly the same time of day and the same day of the month as to get the parent gas giant planet and the planets sun in the same position in every image.

We start with Winter. At its furthest from the star (lets say for example - further than Mars is to the Sun) the moon is plunged into freezing temperatures. The oceans world wide freeze over and the moon becomes one big snowball. However just a few meters below the ice the ocean is still in a warm liquid state. The atmosphere thins as more and more moisture is frozen into the icy crust. If the moon was to endure these freezing temperatures for long then the ice would slowly thicken until almost all the ocean was frozen, but the moon is not to experience this cold for long as it swings back towards the sun and begins to warm up.

With Spring the temperature has begun to rise rapidly. The ice that once covered the moon is now just a collection of icebergs. Soon even these will be gone as the temperature continues to rise. Although its position is relative to Earth and the Sun at this moment, it is still moving closer to the parent star. The first substantial clouds and a rising humidity trap further heat in the moon’s atmosphere.

Summer arrives as the Planet and its moons reach their closest position to the star (let’s say closer than Venus is to the Sun). the temperature now is blisteringly hot. The ocean’s surface is evaporating at a rapid rate and with huge storms whipping up the seas, the definition between ocean and atmosphere becomes almost a blur. the height of Summer is short lived though as the planet slingshots round the star and heads back out into space.

Finally the temperatures begin to subside as Autumn sets in. All the water vapour boiled off the ocean’s surface cools down into immense clouds and a global rainy season showers the moon. Soon the rains will cease and poles begin to freeze. Then the advance of the ice progresses as the moon heads out further into the cold of space.

The first lot of illustrations are now up on Astronomical Art. In the Extrasolar Art gallery we have samples from two series  of illustrations currently in production. Brown Dwarf & Family plus Into the Fiery Night are from a series of illustrations exploring a hypothetical brown dwarf and it’s moons. The series will consist of three final pieces.

The other series featured under Extrasolar Art features a fantasy group of terrestrial moons orbiting a gas giant.  A barren moon, an ocean moon, a tropical moon and a desert moon each show their view from the surface of their siblings and parent planet.

There is also one lone image from no perticular series. Planet with Rocky Ring was a sketch study to try out some techniques for creating a dense rocky ring system.

In the Solar System Art gallery we have the first few illustrations from my Saturn Series. So far we have Mimas, Enceladus and Titan featured but I’m working on two to three more further illustions for this series featuring Iapetus, Tethys and probably Saturn’s ring system.