Hyperspatial Jump Drive for Dummies Copyright 2009 CE by Harry Heyoka If you live on a planet with liquid water on its surface, or if you watch nature videos, you may be familiar with a spider-like aquatic insect that literally walks on water. The water strider, also known as the water skipper or water skeeter, exploits surface tension to scurry across its home pond, evading predators and pursuing its own prey. Let's indulge in a thought experiment now, and imagine the universe as perceived by this water bug. Two extensive spatial dimensions (the surface of its pond), a more limited third spatial dimension (the heights and depths of wave crests and troughs) and one temporal dimension (time) define the water strider's world. The little being may sometimes perceive and be affected by objects or events beyond the usual range of its third spatial dimension -- insectivorous birds or fishes, for example -- but its own movement through this vertical dimension is normally limited to that of the waves rippling the pond's surface. In theory, the water strider may move some distance through the two horizontal dimensions and (with luck and healthy habits) the temporal one (though presumably in only one temporal direction -- forward in time). Barring intervention from outside its own universe, however, it can never move through more than a negligible fraction of the distance available in the vertical dimension. In effect, its subjective universe is a 2-brane, almost completely described by two spatial dimensions and time. For the sake of analogy, let's also posit that the velocity of the waves rippling over the surface of its pond is the maximum speed the water strider can ever achieve within the parameters of its 2-brane universe. This is comparable to c, the speed at which light waves cross our own 3-brane; nothing in our universe can move faster than that. Nevertheless, an intrusion of mass/energy from outside our strider's universe -- say, a rock falling into the pond -- may have dramatic effects which seem to violate the universal speed limit. Droplets splashed aside when the rock hits the water's surface may fly much faster than the surface wave radiating from the rock's point of impact, until the droplets fall back to the surface. From the strider's point of view, those droplets are accelerated right out of its universe at impossible speeds, only to slow down again upon reentering the "normal" universe. Though much larger than the strider's 2-brane, our own 3-brane universe (with one temporal and three extensive spatial dimensions) is but a tiny fraction of a much larger matrix or "omniverse." According to M-theory ("M" standing for membrane or matrix), developed since the 1990s to reconcile different versions of string theory, the omniverse encompassing our own and many other universes is defined by eleven dimensions of varying extents; and more than one of those dimensions may be temporal, not spatial. Like the water strider's 2-brane, our 3-brane can be affected by forces applied perpendicularly to our extensive spatial dimensions. Gravity is a well-documented example. Researchers have found evidence that gravity may penetrate (and be dispersed in) dimensions beyond those we know, and may thus influence objects outside our universe. Equally, gravity produced by objects outside our 3-brane can affect us. Returning to our thought experiment, let's imagine that technically advanced water striders have learned to reproduce or mimic the extra-dimensional forces that scatter splashed droplets far faster than the speed of water waves propagating through their universe. If those forces are managed carefully (say, to build and operate a water jet), striders armored against extreme accelerations could fling themselves through the "higher" third dimension, arriving at destinations far more quickly than by traveling through their normal universe at their normal universal speed limit. Similarly, advanced humans may manipulate extra-dimensional forces including gravity to propel their ships through "higher" dimensions like high-tech striders riding drops of water hurtling over a pond. In either case the travelers take a small "bubble" of their own universe (within which the usual laws apply) along with them through realms outside that universe. When they reenter, that bubble rejoins "normal" space at a distance much greater than the travelers could have traversed within their own universe in the same time. Thus a sufficiently advanced water strider may cross a great lake, or a human the Milky Way Galaxy, in less than a lifetime. Either must first surmount daunting challenges, both technical and theoretical, requiring great investments of time and resources; but in principle at least, in a multidimensional omniverse "universal" speed limits may become irrelevant. Grand unification theories come and go, of course. An 11-dimensional continuum may or may not define our underlying reality, and M-theory may be no more final an answer than Einstein's relativity. However, the splash analogy does not rely on all of those extra dimensions and neither should a working jump drive. In principle they require only one or two extra dimensions, along with some ability to perceive them and to manipulate matter and energy within them. We're a long way from the multidimensional engineering required for a working hyper-spatial jump drive. My Spiral Realms future history posits its development around the year 3000 -- and that's also assuming that technical progress will continue accelerating for centuries to come. But just as advanced water striders might eventually jet across Lake Superior, stubborn humans will find a way to expand our range if there is one. I freely grant that my underlying assumptions may prove to be wrong; but if they're right, we'll populate the galaxy if we don't kill ourselves off first. This brief essay is intended to clarify the theoretical basis of hyperspatial jump drive for those with a limited understanding of math, physics, and galactic history. For more details on the actual operation, capabilities, and limitations of hyperspatial starships (or "jump ships") in the Galactic Era, please refer to Jump Drive for Advanced Dummies, forthcoming at http://www.smashwords.com/profile/view/HarryHeyoka