Sedna – Last Gas for 600 Lightyears


If you’re heading out into the great unknown, travelling beyond our solar system to whatever wonders lie beyond, then you’re probably going to need somewhere to stop off along the way. No long road trip would be complete without a seedy motel and a backwater gas station. But where in the solar system would you find such a place? Or, more to the point, where might we build one? As the most distant planetary body yet discovered in the solar system, the dwarf planet Sedna would seem to be an obvious answer.

Services in Your Local Area

When looking for a place to stop and refuel before moving out into the great unknown, may people mistakenly point toward Mars. While Mars is undoubtedly a very cool, and very important planet, stopping here on the way out of the solar system would be like stopping at the end of your street to stretch your legs. Think of Mars as your friendly neighbourhood garage instead. If you’re in the area and you need a top up, some driving snacks, or porn mags then you may as well call in. If not, keep on driving.

Another useful location – often overlooked by science fiction writers – is Saturn’s sixth moon, Titan. Again, we’re still pretty much in the neighbourhood here, at least in terms of interstellar travel, but Titan is the object most likely to become the truck stop of the Solar System because of its propane-rich seas. Yes, you heard me right; Titan has large hydrocarbon seas and lakes thought to contain around seven percent propane. Of course, rockets don’t use propane as a fuel source, but there is a potential for great science fiction here nonetheless.

The Outer Solar System Beltway

Moving into the outskirts of the Solar System now, you’ll want to check that you have enough gas before you hit the highway. (For readers in the UK, a beltway is a Ring Road, not that the metaphor is actually important). There are actually more planetary bodies in the outer system than most people think. Aside from Neptune and Uranus (both of which are good places to look for water ice and deuterium), there are also a large number of dwarf planets in the Kuiper Belt and Scattered Disk regions. These include Pluto, the slightly larger Eris, Orcus, Quaoar, Makemake, Haumea and other more recently discovered objects yet to be given ridiculous names.

Unfortunately we don’t yet know enough about these outer solar system objects to get excited about them, or to determine whether they can be developed into roadside diners.

Sedna – Last Gas for 600 Lightyears

So now we come to the title planet of this article – 90377 Sedna, a trans-Neptunian dwarf planet discovered in 2003 and named for the Inuit goddess of the sea. Sedna is the most distant planet from the sun and is smaller even than Pluto. While this may seem to be a useless lump of frozen rock at first, its extreme distance may actually make it very useful to the interstellar traveller. This is an ideal place to build an out-of-town gas station, the last outpost of the Solar System.

In addition to topping up your gas tank, Sedna might prove to be a useful support base, giving your engine a quick service before you begin your long and perilous journey. It also occurs that interstellar travel might require a different type of engine that might not be safe for use within the system. Nuclear pulse, for example, or the creation of wormholes. Sedna might be just the place to fire up those engines and check the oil pressure.

Sedna has a highly eccentric orbit, traveling out as far as 937 AU. Only long-period comets and the cometary particles that make up the Oort Cloud lie beyond this point. But before you get too excited, Sedna is currently approaching its perihelion (closest point), which it will reach in 2076. Sedna orbits the Sun once every 11,400 years, so it won’t reach its farthest point for around 6,000 years. Maybe we should get to work building that gas station now, while it’s close, so in 6,000 years we’ll have somewhere to stop for coffee on the way to the final frontier.orbit of sedna

Beyond Sedna

Beyond Sedna is the Oort Cloud, which is composed of cometary particles and surrounds the Solar System. After that, it’s nothing but you and the open road.

But wait. Did I hear one of you bright sparks ask if Sedna is actually on the road to anywhere interesting? Well, here’s the bad news – not really. Sedna is not currently between us and Alpha Centauri, and I don’t know enough about astronomy to say whether or not it ever will be. However, I do know enough to say that both the constellation of Orion and the fascinating Epsilon Eridani System are roughly in that direction. But who cares about scientific accuracy, we’re talking science fiction right? Your audience isn’t likely to question the details, so long as the concept is sound. This is a great science fiction idea, and encourage you all to run with it.

Read more about Sedna here.

  • I’m pleased you kept the topic (the outer reaches of the Solar System) going after our discussion. 🙂

    More questions:
    How would Makemake do as a last call fill-up station?
    You mention that Neptune and Uranus are both good places to look for water ice and deuterium. How would mining them work? What tools are needed in mining a gas giant? How would deuterium mining be described in a story?
    How far is it between Kuiper Belt and Oort Cloud and what exists in the void? Nothingness? Nothing but nothingness? If so, nihiliphobia would become a major issue….

    More questions to come.


    • admin

      The oort cloud is about 50,000 AU (nearly a light year) from the sun. You can read about it here

      What you refer to as ‘the void’, the space between stars, is called the interstellar medium. It’s pretty much empty, but there’s a surprising amount of dust, gas etc. You can read about it here

      As for mining gas giants, I really have no idea. Its worth pondering. I guess you’d have to fly into the atmosphere and collect the gases. Or maybe you could hang some collection apparatus from an orbiting space station. If the station sits within the atmosphere, it might look something like Bespin’s Cloud City from Star Wars.

      You have a lot of questions Nick. I’d recommend you do some serious research, starting with the Wikipedia pages I’ve mentioned

  • Ebsfive

    i found this post very interesting, but i do have a question. what is Sedna mainly composed of? you could make it a ‘gas station’ but, depending on the materials of Sedna, it could have potential as a mining plant, where metals/rocks could be melted down into ship parts. just an idea.

    • It’s mainly frozen water, nitrogen and methane. It’s all pretty common in the outer solar system, but could be fairly useful nonetheless

  • Thomas Thorne

    Can’t use nuclear pulse inside a system? Just how big of a pulse are we talking about? I hear there’s already a pretty big nuclear reaction right in the center of it.

  • To use Sedna as a rest stop on the way to somewhere else, you have to slow down and land or go into orbit. The velocity lost then has to be gained again.

    • Good point

      • Though as a technology demonstrator it could be a good destination. Build a test vehicle, send it to Sedna, let the crew explore and refuel, then come home–it’s a proof of concept for a starship.