"Zero Point Energy"
Zero Point Energy (ZPE), or vacuum fluctuation energy are terms used to describe the random electromagnetic oscillations that are left in a vacuum after all other energy has been removed. If you remove all the energy from a space, take out all the matter, all the heat, all the light... everything -- you will find that there is still some energy left. One way to explain this is from the uncertainty principle from quantum physics that implies that it is impossible to have an absolutely zero energy condition.
For light waves in space, the same condition holds. For every possible color of light, that includes the ones we can’t see, there is a non-zero amount of that light. Add up the energy for all those different frequencies of light and the amount of energy in a given space is enormous, even mind boggling, ranging from 10^36 to 10^70 Joules/m3.
In simplistic terms it has been said that there is enough energy in the volume the size of a coffee cup to boil away Earth’s oceans. - that’s one strong cup of coffee! For a while a lot of physics thought that concept was too hard to swallow. This vacuum energy is more widely accepted today.
What evidence shows that it exists?
First predicted in 1948, the vacuum energy has been linked to a number of experimental observations. Examples include the Casimir effect, Van der Waal forces, the Lamb-Retherford Shift, explanations of the Planck blackbody radiation spectrum, the stability of the ground state of the hydrogen atom from radiative collapse, and the effect of cavities to inhibit or enhance the spontaneous emission from excited atoms.
The Casimir Effect:
The most straight-forward evidence for vacuum energy is the Casimir effect. Get two metal plates close enough together and this vacuum energy will push them together. This is because the plates block out the light waves that are too big to fit between the plates. Eventually you have more waves bouncing on the outside than from the inside, the plates will get pushed together from this difference in light pressure. This effect has been experimentally demonstrated.
Can we tap into this energy?
It is doubtful that this can be tapped, and if it could be tapped, it is unknown what the secondary consequences would be. Remember that this is our lowest energy point. To get energy out, you presumably need to be at a lower energy state. Theoretical methods have been suggested to take advantage of the Casimir effect to extract energy (let the plates collapse and do work in the process) since the region inside the Casimir cavity can be interpreted as being at a lower energy state. Such concepts are only at the point of theoretical exercises at this point.
With such large amount of energy, why is it so hard to notice?
Imagine, for example, if you lived on a large plateau, so large that you didn’t know you were 1000 ft up. From your point of view, your ground is at zero height. As long as your not near the edge of your 1000 ft plateau, you won’t fall off, and you will never know that your zero is really 1000. It’s kind of the same way with this vacuum energy. It is essentially our zero reference point.
What about propulsion implications?
The vacuum fluctuations have also been theorized by Haisch, Rueda, and Puthoff to cause gravity and inertia. Those particular gravity theories are still up for debate. Even if the theories are correct, in their present form they do not provide a means to use electromagnetic means to induce propulsive forces. It has also been suggested by Millis that any asymmetric interactions with the vacuum energy might provide a propulsion effect.
I agree with Ohwilleke, anybody who wouldn't bring a bloody map with them is daft.
Unless the wormhole slowed MY time down so that I perceived only a brief passage while the entire external universe experienced 100,000 years of time. That way, a powerful enough beacon in Earth orbit might help me get back...although after about 200,000 years elapsed time on Earth, "catching up with old friends" might be a bit problematic. 
