Sorry, Matthew McConaughey, but travelling between stars like in Interstellar just isn't possible

The quest to travel among the stars has been a dream for generations – but can it be done?

The new blockbuster film Interstellar, released this week, is only the latest attempt to portray this audacious vision of journeying beyond the solar system to neighbouring stars and planets of the Milky Way galaxy.

Sci-fi aficionados and starry-eyed space engineers have come up with devices of all kinds from multi-generation, ark spaceships to using exotic cosmic highways that warp space and time, like the wormholes we see used in the movie Interstellar.

But in the real world, the idea of zipping across the galaxy in a giant spaceship at warp speed a la Star Trek is still in the realm of science fiction when it comes to existing technology. However, there are researchers who are seriously investigating possibilities of interstellar exploration.

One sobering fact is that the main barrier to reaching for the stars is the sheer distances involved. Everything in our solar system beyond the Earth is literally tens to thousands of millions of kilometres away. For example, Mars is our closest neighbouring planet at 150 million kilometres away, while Neptune is lies some 4 billion kilometres away from us. But these distances are peanuts when talking about the gulf between the stars.

The stars are separated by such grand distances that we use the term light years – the distance a beam of light can travel in a year – which turns out to be just under a whopping 10 trillion kilometres. The closest star to us is the Alpha Centauri system, at 4.3 light years away. Meanwhile, most of the other twinkling light we see in the night sky are at an average 50 light years from Earth. Do the math and the possibility of interstellar travel is definitely a daunting one.

Travelling those mid-numbing distances would involve technology that needs to go way beyond what our current chemically-propelled rockets can do.

Our current propulsion systems are simply too slow. To send humans to the moon, asteroids or Mars, it requires trip times measured from days to months, which is considered do-able. But going to the outer solar system and visiting Saturn and its moons at some 1.2 billion kilometres from Earth, a one-way trip may take some five to seven years, using current technologies. That’s fine for our robotic emissaries, like Voyager or Cassini, but for humans that is a bit on the slow side.

For example, if we could hop on a souped-up space shuttle and wanted to go to Alpha Centauri, it would take 100,000 years just to get there.

Starry-eyed space engineers have come up with next-generation rockets by using ion propulsion, nuclear drives and solar sails – all of which are slow-boat methods of travel using a tiny but constant thrust which can build up speed over time. Using these devices, researchers estimate a spaceship could possibility attain speeds that are close to 10 per cent of the speed of light in just a few short years of travel. These ideas, however, would only cut the journey to the closest stars to decades or centuries.

And as for the wormhole used in the Interstellar movie to surpass all the limitations on human deep space travel, unfortunately it remains only theoretically possible. We have never seen one in nature. But, to the film’s credit, astrophysicist Kip Thorne, who proved on paper that wormholes could actually exist, worked as a science consultant on the film.

But all hope is not lost. One NASA physicist is trying to do the impossible – working on the idea of faster-than-light technology, popularly known as warp drive. While Einstein’s theory of relativity states that nothing can go faster than light, NASA physicists are trying to get around this law of the universe, using a loophole of sorts.

The idea is to artificially create a warp bubble that would compress space in front of a spaceship and expand it in behind, so that the ship actually can travel in space-time while staying in place. While it is still only equations and a design on a computer screen, the team is trying to test their theories in the lab on a small scale, just to see if it works in the real world.

If they can prove that the concept works, it may mean that Star Trek-style voyages across the cosmos may move from science fiction to non-fiction in the not-so-distant future.