In the very first episode of Futurama, when Fry is trying to escape Leela and her career chip implanting device, he decides to hide in the nearby head museum, where the heads of prominent pop culture and political figures are kept alive in jars. He has a friendly chat with Leoanrd Nimoy, and runs afoul of Richard Nixon. But when Fry is talking to people who died hundreds and hundreds of years ago, it’s only natural to wonder how the heck this could possibly be happening. So, let’s put our heads together (sorry), and try to figure out how the science behind this far-fetched idea might work.
In Season 1’s “A Big Piece Of Garbage,” Ron Popeil reveals that he invented the technology to preserve heads in jars. Now, if we look at things from an “it’s the future; anything is possible” frame of mind, we can see how an idea like this could work. When a body is on its last legs, and unable to sustain much life much longer, the head could perhaps be removed and its life could be preserved thanks to some space age future technology that goes far beyond our imaginations.
Okay, that seems a little bit weird, but not completely incomprehensible. But what about the fact that several of the heads we see were already dead before the show began? Look at the Presidents section. Richard Nixon — Earth’s greatest president — died in 1994. Even more perplexing is the presence of George Washington, who died in 1799, two full centuries before Futurama debuted. So, not only do we have the technology to preserve heads in jars, we also have the ability to bring people back to life, then keep their disembodied head in a jar. The plot thickens.
To understand how this might work, our biggest hints come from “All The President’s Heads,” where Fry gets a job working at the museum. During a party one night, Zoidberg licks the head of Lyndon B. Johnson, and the gang is momentarily transported back to the 1960s, where they meet Andy Warhol, who is thoroughly unimpressed with Zoidberg (“what a bore”).
When the gang returns to the 31st century, they initially assume their trip back in time was a mere hallucination, but they later discover that they actually traveled back in time, due to the presence of crystalline opal, which is used to make the fluid the heads are stored in, preserving them in a temporal bubble. This allows the gang to travel back to the 18th century after licking the head of George Washington.
Ok, now we’re getting somewhere. The reason why the heads in the museum are brought back to life is because they are being preserved in an era where they are still alive. That makes sense, but how did they get there in the first place? Well, we know that time travel is possible in the Futurama universe, since Professor Farnsworth perfected it in “The Late Philip J. Fry,” so it’s not a wild leap to figure that organizers of the head museum went back in time to the eras of its residents, and preserved them in the crystalline jars. One can only guess how they were able to convince the likes of George Washington and LBJ that this was a good idea — “how would you like to spend eternity as a head in a jar while tourists gawk at you all day?” — but in any case, the heads were retrieved, and brought back to the 31st century.
Now, in Professor Farnsworth’s mechanism of time travel, you are only able to go forwards, so the only way to return to a previous point in time is to go to the very end of the universe and start over (“I’ll shoot Hitler out the window!”). So, if Farnsworth’s method is being used, the organizers of the Head Museum must have simply gone to the end of time, then started back at the dawn of the universe, and as they moved towards the 31st century, they stopped and collected the heads of the most important historical figures of each given era.
Admittedly, it is possible that there’s another means of time travel afoot that the Professor is unaware of, one which would allow you to travel backwards and forwards in time, but if we’re looking at things based on what is canon in the Futurama universe, we can figure that the people who created the head museum went to end of the universe, came back around to the beginning, and started collecting historically important heads. It’s just the only way this idea can make even a little bit of sense. It just begs one question: why didn’t they shoot Hitler out the window?!
