One of the most common complaints against science is that we don’t have jetpacks yet, as was ‘promised’. This is not due to the inadequacy of scientists but the restrictions of physics and anatomy, not to mention the fact that jetpacks are a terrible idea

“Where’s my jetpack?”

You’ve probably heard this question before. And it’s 99% certain that it was used as a complaint about scientists. Because if scientists were any good at their jobs, we’d all have jetpacks by now, right?

You see it often these days, what with the internet giving everybody a platform to air their grievances, ergo you’re more likely to see people demanding “where’s my jetpack?” online. So you’ve got people with frighteningly powerful pocket-sized computers that can access all the world’s information instantaneously at the touch of a (virtual) button via invisible beams traveling at light speed, and they use them to moan about their lack of access to “futuristic” technology. But who needs self-awareness when you’ve got a shiny phone, eh?

For some, it’s not just that they want jetpacks, we were promised jetpacks! Although it is never really specified who made this promise, or when. It is usually attributed to “scientists” or just “science”, although some may be confusing “science” with “science fiction”, which is where most jetpack predictions stem from. Science fiction has also predicted we’d be wiped out by aliens or living in a zombie apocalypse by now, but you rarely see people complaining about this not happening.

Actual scientists hardly ever agree on anything en masse, certainly not enough to make wild promises to the general population. And on the rare occasions when over 95% of scientists do promise something, eg “if you don’t stop pumping out CO 2 you’re going to screw up the planet”, people ignore or threaten them.



So if the whole grievance about scientists not inventing jetpacks is based on something they never said or did, then they never appointed me their spokesperson, so obviously that’s what I am.



As the official spokesperson for science on the matter of jet packs not being widely available yet, let me say the following: shut up! Stop your stupid whining. You’re not getting a jetpack, so deal with it.



Why do you even want one so badly anyway? You want to fly? You can fly if you want. Budget airlines are common, get yourself a ticket and knock yourself out. That’s too expensive? And you’re assuming jetpacks will be free, maybe given away in the mail, like CDs from AOL? Or are aeroplanes “not as fun”? Here, use this electron microscope; you’ll need it to see the violin being played in response to your misfortune.



Facebook Twitter Pinterest People long for a world where you can strap on your Jetpack and head off to your job as a mid-level manager of an accountancy firm. Photograph: Snapstock/ Snapstock/CSA Images/Corbis

You think it’s easy to make a jetpack? After all, we’ve invented jets, we’ve invented backpacks, what’s the problem? It should be straightforward, like if the Earl of Sandwich had a PhD in rocket propulsion. Sadly, it’s nowhere near that simple. Admittedly, “find a way for the average member of the public to fly” isn’t priority one for any major research body, although there have been numerous attempts made over the years, by people ranging from engineers to hobbyists. Thus far, no practical model has become available, for good reasons.



The classic image of a jetpack is the one in the Rocketeer. It conjures the image of someone rising into the air with pillars of fire strapped to their back, as with genuine rockets. To answer what’s wrong with that, imagine a powerful blowtorch focused on your legs for a prolonged period. People complain about getting a sore nether region from bicycle seats, so it’s unlikely anyone would put up with liquefying their skin in the name of convenient transport.



Perhaps people realised this, hence the more common term jetpack. Rocket engines ARE types of jet engines, as far as the physics is concerned, but most jet engines don’t produce imposing pillars of flame. If you’re on a flight and an engine is blasting out fire, the correct response is not “that looks cool”. But even if they aren’t as flesh-searing as rockets, there are still problems with jetpacks.



Gravity is the major issue. In July 2013, a team of engineers from the University of Toronto built a pedal-powered device that allowed one man to hover for more than 60 seconds, and they were awarded $250,000 for it. Contrast this with the Tour de France, where hundreds of humans on pedal-powered vehicles manage to cross an entire country (and a big one at that), and you see how much easier it is to go horizontally than upwards.



This is all due to Newton and his laws of mechanics. With upward travel, you need enough force to cancel out gravity before you can go anywhere. Bear in mind, this is a force exerted by the total mass of planet Earth, which is, to give it the full technical term, “hefty”.

Obviously it is possible to overcome gravity, because flight and space travel exist, but it requires a lot of energy. At present, the most practical fuel sources we have are chemical. Jet fuel and rocket fuel are both made using highly reactive chemicals, which have physical mass that has to be accounted for. The more energy you need, the more fuel you need for your flying vehicle. The more fuel you need, the more your vehicle weighs. The more it weighs, the more energy is needed to move it, and thus a vicious cycle occurs (which is also an appropriate term for pedal-powered flight).

Aeroplanes use the principles of aerodynamics to achieve sustained flight, and manned rockets are very big. The Apollo missions used huge Saturn V rockets, the majority of which were just fuel needed to get to space in the first place. That’s many storeys of fuel to send into space an object about the size of a minibus.



With this in mind, it’s hopefully easier to see why jetpacks aren’t practical. As far as the pack is concerned, the human attached is useless mass that has to be accounted for. There are actually jetpacks that exist that can allow the wearer to make spectacular jumps before expending all fuel, but beyond impressive stunts in order to open the Olympics, what is the use of such a thing? Until we find an affordable but very potent fuel source that can store enough energy for a long-distance flight in something the size of a rucksack, jet packs aren’t viable. Perhaps we’ll be able to miniaturise nuclear reactors, but as people often panic about living within 10 miles of a nuclear plant, they’ll probably balk at wearing one.



Facebook Twitter Pinterest It’s not that jetpacks don’t exist, it’s just that they don’t exist in any form that would make them widely available. Photograph: ERALDO PERES/AP

Even if the energy issues were surmountable, there are other concerns, such as how to steer them. And even if all issues were solved and jetpacks could be mass-produced, is this wise? Cars are commonplace these days, but they weren’t blanket-introduced with no disruption; there was a lot of “trial and error”, if we’re being diplomatic. Transport is heavily regulated and controlled (speed limits, designated roads and lanes, penalties for breaking the numerous laws etc) to the frustration of many, but the main point of these regulations is to stop people dying!

Which is another concern with jetpacks: safety. If you fall off a bike or your car breaks down it’s annoying, but you don’t automatically end up in an inescapable death-plummet. People make mistakes due to various causes (if you’ve ever been in a road-rage incident, suggestions for these causes can get quite colourful). Now imagine, instead of causing a brief hazard or blocked lane, the incompetence or inattention of a vehicle user resulted in an uncontrolled nosedive over a builtup area with an explosive on their back. A flat tyre never causes that sort of damage.

And jetpacks won’t be easy to use. Pilots train for years before they’re trusted to operate a flying machine safely, there’s nothing to say jetpacks would be different. And even if all of this could somehow be dealt with effectively, we’d end up with many of the population flying about, releasing the emissions caused by high-energy fuel reactions. The impact in terms of pollution and climate could be devastating.



So while jetpacks might sound fun, the inherent difficulty and dangers they pose are clearly something the average complainer doesn’t think about. And they should, because it’s not something that’s going to change any time soon. It would be much safer and just as cool if we all had hoverboards, like in Back to the Future II. So where are they? Come on scientists, pull your finger out!



Dean Burnett actually appreciates all the modern technology available to us, like Twitter, @garwboy

