Hold on to your hat: NASA may just have discovered warp drive!
Given the distances other stars are from us, this is kind of a bummer. At the fastest speeds we're likely to reach, it would take lifetimes to reach more than a handful of the closest stars.
So if interstellar travel is ever going to be possible, we're going to have to cheat. Two iconic television programs used two different theoretical approaches to doing that. Einstein also predicted the existence of wormholes, also known as "Einstein-Rosen bridges." These are temporary flaws in space/time Einstein thought must occur naturally. However, they've never been actually observed.
If wormholes do, in fact, exist, entering one would result in emerging at some random point in space perhaps hundreds of light-years away. There are problems, though. For one thing, naturally-occurring wormholes are thought only to exist for a fraction of a second. For another, a method of interstellar travel which deposited you at some unpredictable destination an unpredictable but probably humungous distance away with no reliable way of getting home isn't very practical. But if a way could be found to create artificial, stable wormholes leading to predictable places, the problem of interstellar flight would be solved. Unbelievable distances could be covered almost instantly. These artificial wormholes are the "jump gates" of "Babylon 5."
"Star Trek" uses warp drive. Essentially this is a method of cheating the cosmic speed limit by not moving the ship, but rather my moving the space around the ship. Inside the "warp bubble," the ship itself would continue to travel at sub-light speeds. But there is no restriction on the speed that space itself can move.
As crazy as this sounds, a Mexican physicist named Miguel Alcubierre has demonstrated that it's theoretically possible. The drawback to what has come to be known as Alcubierre Drive is that it would require infinite energy.
But a decade ago an aerospace engineer called Roger Shawyer made a controversial discovery: a kind of electric drive utilizing microwaves which according to conventional physics shouldn't even work, but which in fact seems capable of propelling objects to unbelievable speeds. Even more incredibly, it doesn't even require fuel! Theoretically, it could travel forever, never having to "fill the gas tank!" Even Star Trek's warp drive required "dilithium crystals." But not Sawyer's EM drive!
Skepticism among American scientists was so great that it was China that first tested the EM concept- successfully. It remains controversial even though the same result has been obtained in American experiments.
But it gets better. NASA engineer Harold White has been working for several years on the creation of a practical warp drive. In cooperation with designer Mark Rademaker, White has produced a CGI design for what they call the IXS Enterprise, a real-life, honest-to-goodness warp ship.
Apparently, the EM drive generates particles which seem to travel faster than the speed of light. To be honest, I don't understand the physics at all. But apparently, White's design, utilizing rings around the ship to generate the warp bubble and employing the EM drive, reduces the amount of energy necessary to generate a warp bubble to a still unmanageable but less intimidating quantities.
Or not. In experimenting with the EM drive, NASA may have just accidentally generated a warp bubble!