News from the warp drive: one problem less
Sometimes there are strange coincidences. Yesterday I reported here that «passable» wormholes could be realizable also without the addition of negative energy. This is an important advance because there is no natural source for negative energy.
The only thing we can do to get a little bit of negative energy is to trick the universe. We take the negative energy from it while it is not looking and give it back before it has even noticed. This gap offers us the uncertainty principle of quantum physics. But in order to obtain negative energy in quantities such as would be needed to stabilize wormholes (or even warp bubbles), we would have to push this fuzziness to the extreme, and for that we would need a great deal of positive energy, and at a density such as existed shortly after the Big Bang.
Not a good prerequisite for interstellar space travel. But as we learned for wormholes, it might be possible without it. As a researcher from University of Göttingen explains in a research paper, this could also apply to the warp drive known from Star Trek. The warp drive is based on special properties of space-time. It can expand and move (as we see in the expansion of the universe) at any speed. If it were possible to construct a bubble from it and to enclose a spaceship in this bubble, the warp bubble, together with the ship, could move faster than light through the universe.
Until now, negative energy was needed for this, too, and a lot of it. In his work, the physicist Erik Lentz, mentioned above, is investigating previously unexplored configurations of the space-time curvature, which are constructed as so-called solitons. Solitons are compact waves (in this case of space-time, but they also exist in water or light) that retain their shape and move at a constant speed. What is special about Lentz’s discovery is that the solitons he found as a solution to Einstein’s equations can be formed in a way that also works with conventional energy sources.
Again, we are talking about very, very much energy. 100 Jupiter-sized gas giants would have to be converted into pure energy to enclose a 100-meter spaceship in such a warp bubble. So it’s a matter of «saving energy.» Lentz is optimistic in this regard: «The next step is to figure out how to bring the astronomical amount of energy needed into the range of today’s technologies, such as a nuclear fission power plant. The energy savings would have to be drastic, in the range of about 30 orders of magnitude. Fortunately, several energy-saving mechanisms have been proposed in previous research that could potentially reduce the energy required by nearly 60 orders of magnitude.»
Does that mean we’ll soon be exploring the unknown reaches of the universe with the starship Enterprise? I would not bet on it yet. There are a large number of solutions to general relativity that do not exist in reality, unfortunately.