Will Santa need to visit other planets?

As we creep closer to holiday season and the traditional good cheer ramps up – what better time to consider the fact that we have very nearly ruined our planet. …and a happy new year!

OTT perhaps, but it does seem that if humanity is to continue we will, at some point, have to colonise other planets in the solar system. And Santa – if you are reading – here is a wakeup call. If there are children on Mars, or any other planet for that matter, they will expect to see that a certain visitor has been on Christmas morning – assuming they have been good boys and girls of course. As such, we present you with the Science Lite guide to an extra-terrestrial Xmas as Mr Claus extends his yuletide rounds to include the rest of the solar system...

Mercury Mercury has been suggested as one possible target for colonisation of the inner solar system. As the closest planet to the Sun, Santa will have to prepare to battle intense heat – and of course protect his trusty reindeer. The worrying thing for Santa is that a year on Mercury is just 88 Earth days long – a Christmas every 88 days...it’s enough to turn your hair white. However, it is now known that Mercury rotates just three times in two of its years – that would mean very long days giving Santa a slightly less hectic delivery schedule on Christmas Eve. He shouldn’t rely on a compass to get around though – Mercury only has a magnetic field about 1% the strength of Earth’s.

Venus High temperatures, and a thick, choking carbon dioxide atmosphere – this is one tough environment. Plus, the clouds are made of sulphuric acid. Venus circles the sun every 224 days, so Christmas will come about every eight Earth months. But it’ll be easy to deliver all the presents in one night – a Venus day is 243 times longer than ours. The atmosphere generates the strongest greenhouse effect in the solar system, creating surface temperatures of over 460°C.This makes the surface hotter than Mercury’s, even though it is nearly twice Mercury’s distance from the Sun and receives only 25% of the solar energy.

Mars The most likely to be colonised, it takes 687 days to go around the Sun. That’s about two Earth years – so every other year Santa will have make the Mars run. A Martian day is 37 minutes longer than an Earth day, so he can still do his usual overnight delivery. He’ll have to wrap up warm though – Martian surface temperatures reach lows of approximately -140°C during the polar winters.

Colonisation on any of the gas planets is of course unlikely – however, as Santa knows, a good Christmas is all in the preparation, so here is a little of what he can expect on the solar system’s four biggest planets.

Jupiter Christmas will only come once every 12 years, however due to a short day length Santa will have less than 10 hours to deliver everything. Jupiter is perpetually covered with clouds composed of ammonia crystals and possibly ammonium hydrosulfide, he’ll also have to navigate winds of 100m/s (360km/h), and we advise that he avoids the famous red spot – a persistent anticyclonic storm that is larger than Earth. However, if he has time, he could find a little of the comforts of home on Jupiter’s third largest moon – Europa. It is covered in ice, and will be slightly more like Lapland than the blustery cloud covered Jupiter.

Saturn If he manages to avoid the storms on Jupiter, then Santa will have to keep his guard up for Saturn – wind speeds can reach 1,800km/h. He’ll also need to dodge Saturn’s prominent system of rings, consisting mostly of ice particles, along with sixty known moons that orbit the planet.

Uranus The big man in red need only make the trip once every 84 Earth years – some relief no doubt as Uranus has the coldest planetary atmosphere in the Solar System, dropping as low as -224°C. However, when he does go he’ll have to be careful not to get caught out by the day lengths. The length of a day at the planets interior is just over 17 hours, however its upper atmosphere experiences very strong winds in the direction of rotation meaning the atmosphere can move much faster, making a day in the upper atmosphere shorter (just 14 hours) than at the planets interior – Christmas morning could break before Mr Claus expects.

Neptune Orbiting so far from the sun, Neptune receives very little heat, with the uppermost regions of the atmosphere at a decidedly chilly -218°C. Deeper inside the layers of gas, however, Santa can warm up a little as the temperature rises steadily. The source of this heating still baffles astronomers, but whatever the cause, Neptune’s internal energy is sufficient to drive the fastest planetary winds seen in the Solar System – measured as high as 2,100km/h. Still, he’ll only have to visit once every 165 Earth years.