Imagine one day going to an elevator and pressing the button for the top floor but instead of getting off at the penthouse or even the roof of the building, you'll be stepping out into outer space.

The idea of using a space elevator to escape Earth's gravity isn't new but it's been getting renewed media attention since news that Google's secret laboratory, Google X is tinkering with the concept. So what is exactly is a space elevator and why would it revolutionize space exploration?

The space elevator is a fairly simple concept. It was first proposed in 1895 by Russian rocket scientist Konstantin Tsiolkovsky, proposed a giant tower that is linked to a "celestial castle" that would allow access to space. Today's vision of a space elevator does away with Tsiolkovsky's rigid tower and replaces it with an ultra-strong metal cable that will stretch from the Earth's equator to a station in geostationary orbit. Electromagnetic vehicles travelling along the cable can carry cargo between Earth and space.

What makes the space elevator more attractive than traditional rockets is because it's cheaper and more sustainable. Space elevators can be used countless times while the Soyuz rockets that bring supplies to the International Space Station are destroyed every time they re-enter the atmosphere. Researchers looking into the space elevator believe that the cost of transporting cargo into space could decrease by as low as $200 a kilogram. With multiple elevators that cost can even go down as low as $10 a kilogram. Compared to the $20,000 per kilogram it costs to bring objects to space using rockets, using space elevators are the only way to go for space exploration.

Of course building the space elevator will be the biggest challenge of all. Finding the right material for the 62, 0000-mile-long ribbon between Earth and a counterweight is a tricky problem because there's no material that can be light, flexible and withstand the pressure of space. NASA believes that carbon nanotubes, a new form of carbon, equivalent to a flat graphene sheet rolled into a tube, will be the solution to the ribbon problem.

While building the space elevator will be a costly enterprise the benefits will far outweigh the cost. With the space elevator, the solar system and its resources will be open for humanity. Other space industries will rise because of the affordable transportation system. Space-based solar plants can beam back much needed energy to Earth to alleviate the planet's dwindling resources. The space elevator can open up new avenues in asteroid mining and space tourism. The sky is the limit.