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Firefly takes place in an incredibly complicated star system. But it probably couldn’t exist, because physics.

Hosted by: Reid Reimers
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Sources:
http://i.picresize.com/images/2013/02/06/BMhCv.jpg
http://pics.fireflyprops.net/TVIN-2.1.pdf
https://keepflying.com/the-cortex-app/video-the-cortexs-map-of-the-verse
http://www.aanda.org/articles/aa/abs/2012/06/aa18051-11/aa18051-11.html
http://adsabs.harvard.edu/abs/2014ApJ...791..111W
http://arxiv.org/pdf/1303.6442v1.pdf
http://mnras.oxfordjournals.org/content/389/2/869.full.pdf
http://iopscience.iop.org/0004-637X/783/1/3/pdf/apj_783_1_3.pdf
http://articles.adsabs.harvard.edu//full/1988PASP..100..834H/0000835.000.html
http://www.solstation.com/orbits/cas-absys.htm
http://www.solstation.com/stars2/castor6.htm
http://map.gsfc.nasa.gov/mission/observatory_l2.html

(Intro)

If you're in the market for a really complicated star system, the Firefly universe, known simple as "the Verse" is the place to go.  The TV show, along with the movie, books, and games based on the series takes place in the star system packed with dozens of worlds and hundreds of moons, many of which support human life.  But it turns out astrophysically speaking, it probably couldn't exist.  Sorry, Firefly fans.  While there is no official map to accompany the show or the movie, the detailed map included in the role playing game shows five main stars, six tiny artificially created protostars, and a bunch of other planets and moons, all swirling around a big star at the center of the system, but it's incredibly unlikely that they could all orbit each other, and even if they did, the system would quickly fall apart.  Why?  Because physics.

The first problem is those five central stars.  The more stars you add into a system, the harder it is for them to find stable orbits.  You've probably heard of binary stars, which orbit around their shared center of mass.  There are triple star systems, too.  But even bigger star systems are possible, but they require a pretty specific organization that you just don't find in the Firefly universe.  

Take the real life Castor star system, which was six stars.  They're organized into three pairs, two of those pairs orbit each other at about 100 times the distance from Earth to the Sun, or 100 astronomical units.  Meanwhile, the third pair orbits the other two at a much greater distance, about 1,100 AU away.  But the individual stars in each pair are really close together, as close as just a few hundredths of an AU, more than 20 times closer together than Mercury is to the Sun.  This is known as a hierarchical structure.  In each binary system, the stars themselves are really close together, but the pairs orbit each other at a much larger distance, and it kinda has to be that way.

If the pairs were any closer together, one or two of them might be kicked out of the system, and if they were farther apart, one, two, or all of the pairs might just fly off on their own.  But the Firefly system doesn't have this hierarchical structure.  The map of the Verse even shows two stars in the same orbit, on opposite sides of the central star.  That configuration is possible, and it even has a name: the Lagrange L3 Point, but it's not a stable orbit.  In as little as 150 years, those stars could spiral out of place, and that wouldn't be good news for a fledgling space civilization.

But the Verse has more than just stars.  Its five stars are supposedly orbited by six protostars, and that's another place where the Verse conflicts with astrophysical reality.  According to the series, the protostars were formed from what were originally brown dwarfs, objects too big to be planets but too small to sustain the fusion reactions that would make them shy, like regular stars.  A brown dwarf at minimum requires 13 times as much mass as the planet Jupiter, and more than 4,000 times as much mass as Earth.  Even around normal, isolated stars, there isn't enough primordial material to form brown dwarfs like you'll see on the Firefly map.  In fact, a recent survey of young white stars, like those of the Verse, found that only 7 out of 140 had a brown dwarf companion nearby, and the system in the Firefly Verse started off with six of them orbiting five stars.  

Even if you considered each star on its own and ignore the effects of them all swirling around so close together, the chances of finding five stars each orbited by a brown dwarf would be about 1 in 3 million, and then there's the problem of the planets.  Because of all the gravitational chaos caused by having so many stars in a system, it's much more rare for brown dwarfs and planets to exist in a multiple star system.  That's because gravity works pretty simply between two massive objects like a star and its planets, but when you have three or more, it becomes a lot harder for everybody to find a stable configuration.  All that complicated gravity also makes it less likely that planets would form in the first place.  

With more stars in the system, the rocky debris that forms planets is constantly knocked around by their competing gravitation, making it harder for the swirling discs of matter around young stars to turn into planets and moons.  Studies have actually shown that stars like those in the verse that are a medium distance apart are at least three to four times less likely to have any planets, let alone planets within their habitable zones.  
So it is possible, but when you consider the probability of finding five stars orbiting each other with six brown dwarf companions, plus the dozens of planets and moons within their stars' habitable zones, our chances of finding a real life version of the Verse are pretty low.  You might even say the odds are astronomical.  Thanks to the anonymous person who asked Hank this question on Tumblr, and thanks especially to our Patrons on Patreon, who help make this show possible.  If you want to help us keep making episodes like this, just go to Patreon.com/SciShow and don't forget to go to YouTube.com/SciShowSpace and subscribe.

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