In a galaxy far, far away, in the fictional world of Star Wars — heroes and villains live on far-flung worlds.
But could human life really thrive on the moons of Endor, Jedha and Yavin 4?
Star Wars-obsessed astrophysicists have long debated what the reality of those types of planets being able to sustain life is.
Now Phil Sutton, a planetary scientist at the University of Lincoln, has analysed whether life could exist on distant 'exomoons' such as may orbit Kepler-16b — and if they would really look similar to those depicted in George Lucas' epic franchise.
'While it might sound as unfathomable as Jabba the Hutt on a treadmill, in fact, many of the worlds depicted in Star Wars could exist in our universe,' he said.
As the moon orbits Earth, exomoons orbit exoplanets — worlds outside of our solar system.
For now, exomoons remain merely theoretical, as none have been detected.
Current telescopes and astronomical techniques are not yet powerful enough to spot these bodies.
Dr Sutton's work, however, focuses on their likely role in the universe and their potential ability to harbour life.
Thousands of astrophysicists around the world are already casting their gaze further out in to the universe, far beyond the reach of our Sun, looking for exoplanets around distant stars.
More than 4,000 exoplanets have already been discovered to date by such missions as TESS and SETI.
The next step, Dr Sutton believes, is finding the moons that may orbit them.
Outside of not having a Millennium Falcon with which to reach it, the issue with studying far-flung satellite worlds like the Endors and Jedhas of the big screen is actually being able to spot them in the first place.
A prime candidate planet in our galaxy that could have an exomoon, however, is Kepler-16b — a gas giant, like our neighbours Jupiter and Saturn, that lies some 200 light years from our solar system.
The planet also has its own equivalent in the universe of Star Wars — like Tatooine, the home planet of Luke Skywalker, Kepler-16b orbits not one but two stars.
Together, these stars have a mass that is comparable to that of our Sun.
Kepler-16b resides squarely in the middle of the so-called 'habitable zone' around the twin stars where liquid water, a key ingredient for life, could exist — but it is far too big to support life itself.
Instead, astronomers are straining to see if the giant planet has a moon, because such a satellite could be a realistic candidate for 'Earth 2.0'.
If one is present, it could potentially have liquid water and be similar in size to Earth, making it very likely to be habitable — and eerily similar to Star Wars' populated moons like Endor or Yavin 4.
'The planet [Kepler-16b] itself is not habitable as it is too large,' Dr Sutton said.
'But it does have the potential to support a moon; recent research suggests that an earth-sized moon could orbit this binary planet and be habitable, proving that moons orbiting planets just like Tatooine can exist.'
According to Dr Sutton, older moons that had become tidally locked to their planet, with circular orbits, would be more likely to be habitable.
Tidal locking is a phenomenon in which a satellite takes the same amount of time to orbit a planet as it does to rotate.
The moon is tidally locked, which is one we always seem the same side from Earth while never getting a peek at the 'dark side of the moon'.
In contrast, young, non-tidally-locked moons would experience significant tides caused by the gravitational pull of the planets they orbit.
This would cause daily volcanic activity, before even considering the effect such might have an a moon's ocean.
Dr Sutton has spent years trying to find a way to spot exomoons, focusing on the so-called 'super Saturn' exoplanet J1407b, but to no avail.
He spotted a blip in the images taken of the distant planet's and ran computer simulations to see if this could have been formed by an orbiting piece of rock — like a moon — passing in front of the world.
His research found the opposite, however, with the promising signal on this occasion being impossible to explain by the presence of a moon.
'Hopefully, as we do more investigations into our vast universe, these elusive exomoons will become more common,' Dr Sutton said.
This, he added, would be 'similar to what has happened to the explosion in exoplanet discoveries in the last few decades — which now stands at just over 4,000 confirmed exoplanets.'
'This is an exciting possibility, and would be a genuine potential for living outside of our own Solar System, but right now we’re not at the level seen in Star Wars. Yet.'
But as the possibility of finding our first exomoon creeps ever-closer, astrophysicists are grappling with another problem that George Lucas never had to face.
It seems almost impossible for an Earth-like moon to form naturally around vast planets.
'A recent study showed that Hot Jupiters — large gas giants that are close to their stars — cannot form earth-sized exomoons as they move inwards to their current location close to the star,' Dr Sutton told MailOnline.
'A more likely scenario for a planet to have a sufficiently large moon that would be habitable, like those in Star Wars, is if they were smaller planets that came to close to the planet and were captured.'
'We do know this can happen — as Neptune captured a dwarf planet with an atmosphere, which is now known as Triton.'
'Triton is in fact larger than Pluto, yet is classed as a moon due to being captured by the gravitational field of Neptune.'
© Associated Newspapers Ltd.