Today's trivia takes us hurling through the currently understood theory of warp travel.

Warp travel is probably one of the largest achievements in the science fiction adventures of the Star Trek and other universes. Warp travel allows spaceships to travel faster than the speed of light to overcome the seemingly mind boggling distances involved in interstellar travel.

Astronomical Perspective

Distance between Earth and Sun = 1 AU (Astronomical Unit)
AU ~= 150 million km
Voyager is the highest energy spacecraft launched (nuclear powered)
Cruising at 3.6AU, in 33 years Voyager has travelled ~116AU
Nearest Star: Proxima Centauri 4.3 light years
1 light-year = 63,240 AU
Voyager has ~75,000 years remaining

There have been various research proposals on how to travel through these vast distances in faster time, perhaps fast enough for a human life span. Those are interesting, but not the main subject for todays trivia.

General Relativity

Before we can dive head long into possible warp drives, we need to brush up a little on our theroy of general relativity. Well... we need a couple of useful concepts.

We understand that the speed of light in a vacuum is constant and represents a theoretical maximum.

This leads us to the idea that the fastest way to travel between two given points in space at the speed of light is simply the distance divided by the speed of light.

However, there is a situation where it is possible to travel faster than the speed of light. This is when the universe is expanding or contracting.

If we were to attempt the same thought experiment of travelling between two points I the universe whilst the universe was collapsing we can see that we would travel faster than the speed of light. (Perhaps the same effect of needing to go to toilet; the closer you get the greater the urge?)

That is as far as I need to go into the theory of general relativity.

Warp Drive

In 1994, Miguel Alcubierre published a paper which details how a theoretical warp drive could work.

It centres around this principle of expanding or collapsing the space-time of the universe.

Alcubierre states in his paper that if the region of space time in front of the ship was collapsed, it would bring the distant star close to the ship. If the region behind the ship was expanded it would move the ship further away from its starting point.

This would allow the ship to travel though space time without having to actually travel. The crew inside the 'warp bubble' would not feel any acceleration, and time would pass normally for them.

This warp bubble would have forward motion though space-time and allows the ship to travel considerably faster than the speed of light.

To take us back to the previous thought experiment. If a ship wishes to travel to some distant star:

travel on conventional propulsion until it was clear of its home planet (will be explained shortly)
Align with the distant star
Engage its warp drive
Halfway along the journey it would then need to reverse the direction of its warp drive to begin decelerating
Arrive some distance from its destination (also explained later)
Travel on conventional propulsion the rest of the way

Expanding Space-Time

One of the interesting side effects of the this concept is that it needs Negative Energy to produce the space-time warping effect.

Negative energy is a theoretical concept at the very edge of our current understanding. It is included in the explanations of certain fields including gravitational fields and a number of quantum fields.

Negative energy has some very strange properties:

Current research indicates it is possible to detect the presence of negative energy.

Side Effects

As you might imagine, such a system has some unusual side effects.

Risks to Ship

If the warp bubble destabilized, it would distort the ship horribly
Recent research indicates superluminal velocities would generate so much Hawking radiation that it would destroy the ship inside the bubble

Risks to Surrounding Space

Destroys space in front of it, creates space behind it.
Would destroy anything that comes into contact with warp bubble
Any particles collected infront of the bubble would be released in an energetic explosion akin to a sonic boom shockwave directly infront of the ship

Risks to the entire Galaxy

Something the size of Jupiter in negative energy required

Conclusion

This is a fascinating and growing area of research. Calculations are being changed and revised all the time. The energy requirements of a theoretical warp drive are being refined to the point NASA have commissioned research and a new rendering of what a warp drive capable ship might look like.