Plans for a future space elevator — like this one proposed by David Smitherman of NASA’s Marshall Space Flight Center’s Advanced Projects Office — would include a structure extending from the surface of the Earth to geostationary Earth orbit. (NASA)

If you thought Elon Musk’s Hyperloop was an audacious and outrageous technological idea – an innovative contraption of pods, induction motors, solar panels and vacuum tubes – then wait until you hear about the Space Elevator. It’s essentially a giant cable tethered to the Earth and extending at least into geosynchronous orbit, some 22,000 miles away, like a giant Jack-in the-Beanstalk extending into outer space. It’s not so much an elevator as a giant ribbon suspended from a counterweight in geosynchronous orbit around the Earth that you climb with the help of laser beams to get heavy cargo loads into outer space.

What could possibly go wrong with that?

A lot, it turns out. You don’t need a Ph.D. in physics — or even a third-grade education — to grasp that the concept of a huge ribbon extending into outer space and tethered to the Earth at the equator might pose more than a few technological hurdles. For one, there’s not a known material yet available on this planet that is strong enough, flexible enough and light enough to create a true space elevator. There’s also the risk that climbers — if they go too fast — will cause the space elevator to oscillate like a giant pendulum. And then there’s the issue of space debris. (Just watch “Gravity” to see what happens when an object in geosynchronous orbit collides with space debris.)

And yet, recent news from Penn State University researchers that they have discovered how to make “diamond nanothreads” – essentially, the very type of strong, flexible and light material needed to construct a space elevator – has people once again talking up the potential of a space elevator. New advances in nanotechnology are making possible super-strong materials that are 100 times stronger than the strongest steel and more flexible than plastic. In a statement describing the diamond nanothreads, Penn State chemistry professor John Badding specifically referenced the space elevator concept, “One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a space elevator which so far has existed only as a science-fiction idea.

In an e-mail exchange, however, International Space Elevator Consortium Director Ted Semon told me that even these new diamond nanothreads may not be the answer: “Today, an earth-based space elevator is NOT feasible.  There is no material strong enough to build the tether that will stretch from the earth to the counterweight in outer space.” As Semon points out, “There are several materials in the lab; carbon nanotubes, graphene, carbyne, boron-nitride nanotubes and now, possibly, these new diamond nanothreads which have been recently discovered which are theoretically strong enough, but no one has been able to demonstrate being able to manufacture/spin them in the macro-size which will be necessary.”

While the space elevator is still decades away from being a reality, a lot of really smart people are working to make it happen. NASA has been thinking of a space elevator concept since 2000, and now collaborates with other partners on the creation of a future space elevator. Europe has worked on a space elevator concept. Japan is working on a space elevator concept. Russia is working on a space elevator concept. People have dreamed up space elevator concepts for Mars and the moon. We live in a day and age when people raise money for space elevators on a crowdfunding site like Kickstarter and give talks about it at TEDx conferences.

We’re still a long way from concept to reality, but we’re getting closer.

In 2012, a Japanese company, Obayashi, claimed that it could have a space elevator ready to go by 2050 for the low, low cost of $8 billion. In this Japanese version of the concept, the space elevator is really more like a really skinny railroad track extending horizontally out of the equator tens of thousands of miles into outer space. (If that sounds too insane, watch the Obayashi video.) Using magnetic linear motors, 30-passenger train cars traveling at 124 mph would take 7.5 days to make the trip. While many have dismissed this as just pie-in-the-sky thinking and a hyped-up marketing promotion, there is now a Japan Space Elevator Commission that hopes to make Japan a global leader in developing a space elevator.

Which brings us back to the extreme science fiction nature of the space elevator — that’s perhaps why it resonates so much with so many people, not just space geeks. The whole idea of the space elevator dates back to 1895, when a Russian scientist, Konstantin Tsiolkovsky, was so excited by the recent construction of the Eiffel Tower in Paris in 1889 that he dreamed up what many now credit as the classic conception of the space elevator – a super-tall tower that would be tethered to a “celestial castle” by way of a spindle-shaped cable. (Keep in mind that a real space elevator would be taller than 100,000 Eiffel Towers stacked end-to-end). It’s since been expanded upon, dreamed about, iterated on and written about to the point where technological visionaries like Arthur C. Clarke (who famously wrote about a 24,000-mile-high space elevator in “The Fountains of Paradise” back in 1979) are tempted to talk about the space elevator as if it might actually happen one day.

That’s often the way science fiction concepts become science fact — there is so much passion for an idea that it bubbles into the technological mainstream, where people decide that a half-baked technology concept might actually have real-world business implications. Using a space elevator would be 95 percent cheaper than using conventional rockets to get a payload into geosynchronous orbit. That’s why space industry innovators such as Elon Musk are asked about the idea. Or why Google X might want a piece of the action. So the next time someone mentions a Hyperloop or a Space Elevator, yes, it’s easy to scoff at and say that it’s still decades away from being a reality, but it might also become the next piece of extreme science fiction that becomes science fact.