What is the Kessel Run anyway? We know that it’s something that Han Solo miraculously made in less than 12 parsecs, but why is that so impressive and why should we care? Well, before you see Solo: A Star Wars Story, brush up on a bit of history from the galaxy far, far away on today’s episode of The Dan Cave.

Now, before we get started, let me address the Rancor in the room. This is a brief history of the Kessel Run as it existed prior to the events of Solo: A Star Wars Story, in which it may or may not play a significant part. (Read our spoiler-free review while you’re at it.) As is the case with every new Disney-era Star Wars film, Solo takes parts of the preexisting canon and elements of now-defunct Expanded Universe stories to create a new canon.

The Kessel Run, which was first mentioned by Han Solo in 1977’s Star Wars: Episode IV – A New Hope, is a smuggling route used to transport “spice” from the mines of Kessel where Wookiee slaves were worked to death to turn it into a recreational drug. Before Disney hit the reset button in 2012, Kessel was a planet home to a massive glitterstim spice manufacturing operation, producing what was basically a psychotropic drug made from the webs of space spiders that provided its user with feelings of intense euphoria and boosted mental and telepathic abilities. So think of it like MDMA for telepaths. Anyway, Kessel and its mines were largely controlled by the Galactic Empire, hence the need for smugglers to devise a route to spirit it away from Kessel to black markets all across the galaxy far, far away.

Image: Wookieepedia

Spanning 18 parsecs in length, the Kessel Run was one of the most popular smuggling routes in the galaxy, leading from the planet of Kessel to what used to be the Si’Klaata Cluster, a group of planets controlled by the Hutt crime family, but now…now that’s just a Star Wars legend. The Pyke Syndicate employed a number of smugglers—including, presumably, Han Solo—to transport its sweet space-drugs across the galaxy so they could make their ill-gotten gains.

But how did Han make this 18-parsec run in less than 12 parsecs? Did he even make the run in less than 12 parsecs or was Han simply lying to sound cool? According to an early draft of A New Hope, when Han makes his claim, Ben Kenobi “reacts to Solo’s stupid attempt to impress them with obvious misinformation.” Kenobi is similarly skeptical in the 2015 novel A New Hope: The Princess, the Scoundrel, and the Farm Boy, wherein he sees through Han’s clever ruse.

George Lucas has gone on record multiple times saying that ships are unable to travel in straight lines in hyperspace due to the potential for colliding with celestial objects. Therefore, charting a course to get to your destination can be tricky endeavor. Due to the Falcon’s superior navigation computer, it was able to make shorter, quicker jumps between points, enabling it to arrive at its destination faster.

According to A.C. Crispin’s trilogy of Han Solo novels, which sadly are no longer canonical, the Kessel Run is adjacent to the Maw cluster, a group of black holes which distort space and time. By flying close to the Maw cluster, Han, Chewie, and the gang could have conceivably made use of the distortion as a shortcut of sorts to make the run more quickly. This opens up a whole can of wormholes.

Image: Tor.com

Case in point: back in 2013, Nerdist science editor Kyle Hill wrote an article for Wired that explains how the time dilation caused by traveling at lightspeed would mean that spending just one hour aboard the Millennium Falcon at lightspeed would result in Han returning to find everyone three years older. If we expand that to include the entirety of the Kessel Run, Han would return some 40 years later while merely experiencing approximately a half-day himself. Not exactly ideal turnaround time for smuggling.

So there you have it—a brief explanation of what the Kessel Run is and why it’s so important in Star Wars canon. Spoiler alert: The version of it that we see in Solo: A Star Wars Story is a bit different than what I described here, eschewing space drugs for hyperfuel, but the core of it holds true.

What other pieces of Han Solo’s story would you like to see explored on the big screen? Let me know in the comments below.

Images: Disney/Lucasfilm

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Dan Casey is the senior editor of Nerdist and the author of books about Star Wars and the Avengers. Follow him on Twitter (@DanCasey).