Planets Santa might end up visiting... next year?

As Santa sits at the North Pole anticipating the discovery of life on some far-flung planet he might be somewhat nervously scanning the latest scientific literature to see which exoplanets are hot topics

Checking to see just how hostile an environment can be on known exoplanets, Santa might draw up a list marked 'Planets to which presents don’t need to be delivered'

Every year brings with it an expectation that this might be the time when life is finally confirmed on another planet.

For us humans, such a discovery would likely have profound implications about how we view ourselves, our origins, and our long-held belief that we occupy a special place in the universe.

For Santa, the implications may not be so much existential as logistical. Using our current technologies it would take thousands if not millions of years to reach any planet beyond our solar system.

Yet every child knows that Santa can traverse the region between the stars in a magical instant, so distances won’t faze him. Nor would his heart skip a beat at the prospect of selecting which of the 800 billion estimated planets in the Milky Way galaxy are possible targets for the delivery of presents.

As Santa sits at the North Pole anticipating the discovery of life on some far-flung planet he might be somewhat nervously scanning the latest scientific literature to see which exoplanets are the hot topics right now. Are any of them likely candidates as homes for aliens?

Perhaps breathing a sigh of relief, Santa and his trusty elves discover that hostile planets far outnumber ones which are likely to harbour the kind of life which demands presents at Christmas, namely us. For the time being, preparations for the Big Day are restricted to our home planet.

Checking to see just how hostile an environment can exist on known exoplanets, Santa might draw up a list marked 'Planets to which presents don’t need to be delivered'. Actually, let's add the word 'probably'. You just never know what kinds of present-loving lifeforms might exist in our enormous galaxy, irrespective of what we might consider possible. Included in Santa’s alternative list:

55 Cancri e — the Lava Planet

NASA: 55 Cancri e — This super hot world is covered in a global ocean of lava and has sparkling skies

55 Cancri e, a rocky world so close to its star that a year lasts just 18 hours. That’s 487 Christmases for every one on Earth... and you think you have trouble picking gifts once every 365 days! Its dayside glows like a forge — hot enough to melt rock — while the nightside merely simmers.

HD 189733 b — Where the Wind Hisses

NASA: 189733 b — This far-off blue planet may look like a friendly haven — but don’t be deceived! Weather here is deadly. The planet’s cobalt blue color comes from a hazy, blow-torched atmosphere containing clouds laced with glass

HD 189733 b, a giant planet characterised by a deep cobalt-blue colour. The beauty is deceptive: the atmosphere howls at thousands of kilometres per hour, whipping molten glass particles sideways.

An aerodynamic sleigh will be crucial here and reindeer will need to fly in a tight formation to minimise the tiring effects of the wind. Santa will be familiar with this problem having experienced 2000 km/h winds on Neptune.

Without a solid landing site, Santa may well have to rely on his special radar previously developed for visiting the gas giants Jupiter, Saturn, Uranus and Neptune.

TRAPPIST-1e — A Cosy Half-Light Christmas

NASA: TRAPPIST-1e — a terrestrial exoplanet that orbits an M-type star. Its mass is 0.692 Earths, it takes 6.1 days to complete one orbit of its star, and is 0.02925 AU from its star. Its discovery was announced in 2017

TRAPPIST-1e is one of the most Earth-like exoplanets discovered so far. It likely has a temperate climate, though it is permanently tidally locked: one hemisphere in endless daylight, the other in eternal darkness.

It might have liquid water oceans, surely a welcome stop for thirsty reindeer, and a landscape that is more akin to Earth than many others. One to watch (nervously) from Santa’s perspective.

WASP-12b — A World Running Out of Time

NASA: WASP-12b — The doomed planet WASP-12b is a hot Jupiter that orbits so close to its parent star, it's being torn apart. It takes this alien world only 1.1 days to completely circle its sun

WASP-12b orbits so close to its star that it is literally being pulled apart, stretched like warm toffee and losing its atmosphere into space. Everything overheats instantly. Chocolate coins? Impossible. Plastic toys? Vaporised.

Knowing that the Earth will continue to orbit the Sun for another five billion years before our parent star swells up and engulfs us, the end of WASP-12b feels positively imminent with only a few million Christmases left before it is gone entirely.

As more exoplanets are characterised, astronomers know they’re assisting Santa in selecting which ones to visit. At the same time, new discoveries require planning which is a whole lot more expansive and complicated than heretofore. Just not this year.

• Niall Smith is head of research / head of Blackrock Castle Observatory, Munster Technological University, Cork
• Click here for info on how to enter Blackrock Castle Observatory's Cosmic Christmas Art Competition