Brane and brane, what is brane?

FTL is a necessary weasel of Space Opera. Not all space opera, but it is as generally accepted as is the ability of terminal tuberculosis sufferers to sing an extended aria in that other form of opera.

All of the methods and terms are essentially hand-waves. Some touch lightly on ideas in physics that might do something that, if you squint, vaguely resembles faster-than-light travel, but we skate over all the impossibilities and, in the end, it is no more scientific than reversing the polarity of the neutron flow.

In any case, I'm gonna use wormholes.

The main thing they give me is one big hand-wave that ties together multiple implausibilities into one pill to swallow. In a way I hope will be amusing enough that the readers will go along for the ride.

So we've got the quantum foam, tiny vacuum energy fluctuations. Where we part from physics is that in this universe, they can "clump." Anisotropic distribution forming semi-stable solitons. So, basically, tiny wormholes are constantly forming, lasting for a short time, then coming apart. They are largely outside the cosmological universe and thus exist in multiple places at the same time.

(And yes, black holes, especially quantum black holes, aren't handy tunnels. Well, shush.)

Now, to get them to do what some of the plot requires, they have to have a very selective distribution. Have them everywhere in the universe and the effects would be visible on cosmological scales. Have them clump around gravity sources and they'd change stars in ways that would be astronomically observable.

I could give them a goldilocks zone; assume the radiation of active stars inhibits formation of the solitons, for instance, but that they also don't form well in interstellar space. For reasons. I'd really rather not use the old saw that they are attracted to "life" (however we define that), but it would certainly be handy.

For the purposes of story I'm saying they aren't conventionally gravitational but tend to go where dark matter goes. Which is also anisotropic, but only in certain places (so that part isn't cosmologically significant). 

In any case, it can get very clumpy around these dark matter concentrations, and if you are clever monkeys, you can do some technical things and open a stable wormhole. It still requires such difficult steps as making exotic matter, and the chaotic nature of the clumpy wormhole foam plays out a lot like a particularly rambunctious nuclear reactor; quantum embrittlement and point failures, meaning not only does it cost a lot of tech to build the thing, but you have to have a well-developed industrial base keeping up with replacement parts and other maintenance.

But on the flip side, you get power back. Lots and lots of power. Basically vacuum energy extraction and there is some fear this is destabilizing the entire universe (the old false vacuum problem) but so far the practical thing is that these wormholes tend to rip the universe a bit.

That is, the micro-holes start appearing down a spreading dendritic network, like roots of a tree. And eventually nodes appear where the right civilization could start up a new wormhole.

The first one might not have been artificial. Or might not have been on Earth. But anyhow.

Hand-wave, hand-wave, and a starship can, by applying enough power (and maybe a little exotic matter) open semi-stable wormholes long enough for it to pass through. Which since this is based on encouraging the naturally clumping micro-wormholes, means the best routes to take are along the  Lichtenberg figures spreading from a stable wormhole.

So there are lanes, or maybe currents. 

The idea of the vacuum energy -- done through maintaining a stable wormhole -- is that it puts a top level to the energy pyramid I was getting into with the battery stuff. Ships are largely possible because they carry some very dense fuel (H3 possibly) that is possible because the civilization sending them out has the power available. Power that is essentially a natural resource, and a rare one at that (that is, a place where the holes got really clumpy). So it isn't an exportable technology. They can only send out stored power.

I might not even need gates for travel. Given the right dendritic lanes, ships pretty much explain everything. Oh, and they might get some kind of artificial "kick" if launching from around a node.

The other silly thing you get from this is that the unstable micro-holes happen at planetary surfaces just often enough, and are just big enough, they provide a weird sort of panspermia. The interesting thing here is that they aren't just transporting primordial amino acids. They can transport seeds, possibly even small animals.

As long as the transported material is intact enough and advanced enough relative to its new surroundings, it provides the ability to Galapagos fresh worlds with, let's face it, terrestrial analogs. Since the wormholes are random and rare and more developed life is going to be influenced rather less by small numbers of competitors, the ecologies do diverge, especially the more evolutionarily developed examples. 

There's more hands I can wave at this one, horizontal gene transfer etc. etc., but basically this means the film can be shot within a day's drive of LA. After humans have encountered a few biomes, they've even identified a few template biomes; "This part of the planet is falls within the parameters of a Vc template; temperate rainforest, coniferous analogues, cool and humid."

And means once you get done playing with tamed wormholes on your bottled energy, you can set down on a place with breathable atmosphere and possibly even edible flora and fauna.

And lastly, since you can't bottle them, create them, or carry them, you can only make use of this wormhole stuff where it is already occurring. No black hole grenades for you.