At our current best speed of around 37,000 miles per hour, it would take about 80,000 years to reach our nearest neighboring star, which is about 4.3 light years away. This is way too long of course. Theoretical matter-antimatter rockets that would travel at speeds of around 3.7 million miles per hour, which is well below the speed of light would reduce this time to about 900 years. This is still to long a time span, and, while it is possible to someday in the foreseeable future to build such propulsion, the cost would be staggering.
So what are we left with? The answer is unanimously a faster than light spacecraft which defies the laws of the space-time continuum. And also, one that uses little or no currently known propellant or creates it's own propellant as it flies through space. One possible solution to this problem is to build a wormhole. According to theory, It is possible to build a wormhole. We know that we cannot exceed the speed of light outside of a wormhole, but the wormhole would distort space in such a way that it would enable speeds in excess of the speed of light. This is because theoretically, the speed of space/time can be much faster than light speed, but we have no idea how much faster. The problem with using a wormhole is that it would be such an enormous construction that we could not conceivable take it on. Further, we would have to construct the other end of the wormhole at the exit point near a far away star. Obviously we would have to get to that star in the first place in order to build the other end of the wormhole.
Another idea is to create a spacecraft that distorts space/time. This ship would have to posses the ability to expand space/time behind itself while simultaneously contracting space/time in front of itself thus creating a "warp bubble" that would encapsulate the vessel and carry it like a wave carries a surfboard to beyond the speed of light. This would take an enormous amount of energy to accomplish and, would have to employ the use of "negative energy" which is still not yet proven to exist.
Employing the use of "negative mass" is yet another idea. Theoretically, the action of switching the positions of mass and negative mass would create propulsion of great power. But negative mass is also something that is not yet proven to exist.
It seems the most likely way to accomplish stellar travel would be to exploit an idea that dates back to the early seventies. To gather and utilize matter/energy that is present in space to propel the spacecraft. A bit like a sailboat uses the wind to move it across the water. Looking at a radiometer, we can envision a type of propulsion where a radiation sail is used to gather radiation to move the spacecraft.
Manipulating gravity around a spacecraft would be another way. Instead of expanding space/time behind the craft and contracting it in front of the craft, gravity behind and in front of the craft would be distorted thus creating propulsion.
One thing is certain. Before we can construct a vessel that is capable of traveling beyond the speed of light, we have to first bring many of the aspects of quantum physics out of the realm of theory and into the realm of proven science and then, practical application.
With much reading and a little
luck I have discovered several drive
systems currently being tested, pr used: Tacheon drives and
Mercury-vapor drives. The Mercury vapor drives utilize a Photo-voltaic
sail in order to collect enough electricity to vaporize the the mercury
and use it as fuel. They don't work in the earth's atmosphere, but in a
vacuum, (space) they propel the spacecraft faster than the speed of
light. The Tacheon drive is much more complex, but it also puts the
spacecraft into "Warp Speed". The resources for investigating these can
be found at your local library.