Could it really exist? We think so, yes. We know from Einstein that space is like a
fabric (called space-time) and that the fabric can be bent or twisted. If we had
a technology that would compress space-time at the front of our spaceship and at
the same time expand it at the rear of our spaceship then we would have a
hyperdrive system. Sounds easy eh? The only way of compressing the fabric of
space is to use a large amount of mass (like a star or a black hole). A definite
challenge, and one beyond us for the foreseeable future. However, that doesn't
mean it's impossible.
The other alternative is to build stable worm hole using two
very large masses at each end, to create a tunnel through space-time. Again in
theory it sounds easy enough, but the technology for this would be another "challenge"