Star Wars and Our Night Sky

Have you ever wondered what might be lurking in our night sky that resembles the science fiction of Star Wars? I thought so! Me too.

In lieu of the biggest movie of all time coming to our cinema screens this week, it seems like the right time to explore our own galaxy and see what there is out there that could be from another very famous fictional galaxy far, far away.

We’ll start within our solar system. We know much more about our own than we do any other, so it’s easier to use it to find similarities. Saturn is already an incredibly fascinating planet, but its moons offer us a great deal too. The moon of Mimas was discovered in 1789 by Herschel, and looks a lot like the Death Star.

mimas death star
Left, Mimas.  Right, the Death Star, from Star Wars Episode IV: A New Hope.

The main similarity is the huge crater (named after Herschel), which is 130km wide – around the same distance of Wellington to Palmerston North, and the same diameter as the whole Death Star. Thankfully, there is no evidence so far that the crater on Mimas has a superlaser like the Death Star with the ability to destroy entire planets! It would be easy to presume that Mimas was the inspiration for the Death Star, but the movie was actually made 3 years before we had a good enough image of Mimas to be able to see its crater. This is unless (of course) George Lucas is actually a space traveling alien who already knew exactly what Mimas looked like!

Next up is looking for a real-sky version of the Star Wars planet Hoth. Hoth is an icy planet, covered in glaciers and frozen ice plains. It has previously been associated with Jupiter’s moon Europa, but since Cassini has been showing us Saturn and its moons in greater detail, Star Wars fans are now looking to Enceladus as a more likely Hoth. Enceladus is a hot-topic at the moment as the Cassini spacecraft has shown us that the moon is covered in an ocean of water, with a thick frozen icy crust.

We believe the ocean underneath stays in liquid form thanks to some hydrothermal activity. This and the chemicals down there have got people thinking that the ocean could harbour life. If the moon does contain some form of life, I doubt it would look anything like the endemic species to Hoth; Tauntaun or Wampa!

Enceladus also has a water-rich plume venting from its south polar region, which ejects water vapour, ice and crystals out into space. Some of this falls back down to the moon as “snow” (which makes it seem even more like Hoth), but most of it escapes and makes up Saturn’s E-ring. This can be very loosely related to Hoth’s surrounding asteroid belt.



Above, Enceladus.  Below, Hoth, from Star Wars Episode V: The Empire Strikes Back

But what about the two suns of Tatooine I hear you ask?

Well, binary star systems are actually relatively common – in fact between a third and half of all star systems are estimated to be binary. A binary star system is basically when two suns orbit around each other. At first scientists thought it unlikely that a planet could form and orbit around a binary star system, but it is now estimated that around half of all binary systems can contain exoplanets with the potential to be habitable to life. For the fictional planet Tatooine, orbiting two stars meant that the heat on its surface created an arid, desert planet. We haven’t been able to study circumbinary planets incredibly closely yet, so it’s hard to know if Tatooine’s rocky, hot planet is possible in a binary system as it’s described, but we do know circumbinary planets are out there. At the moment, the closest thing to Tatooine is Kepler-16b, an exoplanet on the outer edge of its binary star’s habitable zone found in the constellation of Cygnus.

The sunset of Tatooine in Star Wars Episode IV: A New Hope.
An artist’s illustration of the Kepler-16b system.

Using a bit of imagination, science fiction can challenge scientists by suggesting an alternative that at the time may be considered impossible. However, sometimes new theories and discoveries emerge which show that science fiction writers were onto something all along. It’s beneficial to be able to think outside the box and imagine new realms of possibilities. The great thing about science fiction is that we still know so little about our universe that nobody is able to truly say whether it is total nonsense or not. If multi-verse theories turn out to be correct, a Star Wars galaxy does exist somewhere out there and another version of me is Queen of the World, who enjoys magical weekend getaways at Hogwarts.