We understand hardly anything about time. In normal life, time is best dealt with as a constant, incapable of being manipulated. In certain areas of pure physics, theoretical constructs have been devised to explain time – but these have no present practical application.
We have, however, all dreamed of the possibility of stepping forward to next Monday and getting the most recent lottery results, so that, when we return, we can use this knowledge to become wealthy beyond imagining. Sadly, while we are able to make the first part of the trip, returning has proved more difficult.
One old pop theory asserts that, as events unfurl, duplicate universes are created along a single time line. Every state of being remains in existence - each frozen at one instance of time. Your first kiss, like mine, is represented in an eternity of universes like the frames of a film. In this quaint philosophy we are all still back there, alive and young. Within this fantasy, reflective intelligence alone traverses the timeline. Intelligence is conceived as an organism that travels the timeline within the changing states of a host – a simple parasite carrying with it a single sense of identity. Alas, it seems capable of steady travel in one direction. If it could be persuaded to reverse direction, what opportunity would there be to re-explore each passing moment, and maybe correct past mistakes? That first kiss perhaps.
We capture the passage of time, most convincingly, through pictures - these days photographs and video. Once captured, an event can be relived through video, over and over again. In a similar sense, a still picture may recall the event. These two techniques are different and the same. A video is simply a large sequential set of still photographs - a little like the quaint philosophy described above.
However, the picture at the top of this post is a hybrid. It is a single frame which contains the information you would expect to find in a video. Time-lapse photography is not new - it is part and parcel of every photo ever taken - and it is a necessary part of astrophotography.
All the pictures on this page were taken in bright moonlight (>50%) at ISO 6400 at f / 2.8 using a Sigma 17-50mm lens. That is, the camera was set to take in as much light as possible.
This is the result (the Yagi antennae is included for scale - the washed out main sequence of the milky way is behind):
The next frame is taken over the same time frame - but this time the zoom lens was manually turned from 17mm to 50mm. The starting point of the star trails is slightly burnt out - showing that the camera lens did not turn uniformly at the start - staying in place for just long enough to create a bright start - and, coincidentally, to catch a fain picture of the antennae. If the lens had been turned at a uniform speed through the 6 second exposure, no image of the antennae would remain on film.
The next two frames show two improvements. Firstly, the center of the frame is focussed on a number of bright lights (starts here) so that movement is relatively uniform away from the center. Also, greater emphasis placed on keeping the camera still through the 6 seconds of exposure.
Secondly, while the frames above have focused on stars, any light is a possibility - city lights or, as here, reflected lights on leaves.
The final picture uses all of these elements. Strong central radiating lines from stars were sought - together with reflected light from poplar branches. Finally, a small amount of irregularity in zooming was introduced to ghost the trees into the final picture.
So, why call this time travel? Well, the circumstances (sitting in an old chair for added stability, aided by circuitry and powered by an old car battery) have passing similarity to attempts I made as a child to travel in time. Also, the final result is magical - and I trust I haven't ruined this to much through explanation (magicians should never explain magic tricks). But, most importantly, on the one frame the entire period is recorded, without a bias as to whether you are moving forward in time or backwards.
If for a moment we put science quietly to one side, and adopt the outrageous suggestion that reflective intelligence alone traverses the timeline, could staring into this void persuade the intelligence to change direction ? :)
Ok, pick up science again, and back to work.
Thanks to +Martha B. for encouraging me to set the technique out.