Like many people, I have always been fascinated by the concept of time travel - particularly the idea of travelling into the past. To be able to witness for myself the events that made up, for example, the famous victory at Marathon by the forces led by Miltiades, or to see first-hand the circumstances that led to some of my ancestors leaving the Scottish Highlands - I longed for such a capability.
However, if one assumes that time is linear (moving from past to present) and that there is only one universe (i.e. no 'parallel' universes) where cause is followed by effect, then it is difficult to conceive of anyone travelling to the past or of being able to in any way interact with the past (thus altering what has already occurred). This realization may at first be a blow to people who, like me, want so much to know the details of what actually happened during so many events of the past.
Many years ago, whilst thinking about my desire to know and the overwhelming restrictions against backward time travel (i.e. into the past), I realized that the two ostensibly opposing notions can be reconciled if we simply remove the idea of interaction. In other words, one might be able to become aware of past events without having any way of interfering with those events. I used to envisage a video screen where one could view (and hear) a particular location in space and time from a range of given viewpoints. There would be no way in which we could interact with the events - only gain knowledge about them. This, it seemed to me, would not be breaking any fundamental cosmic law.
Recently, whilst re-thinking this idea, I further realized that we've been doing this viewing of the past for years already. Every time we look at an old piece of documentary film footage for instance, we are viewing a past event from a particular perspective. The difference, of course, between my original vision and this sort of example is that we have little control over how we see the event - that has already been determined by whoever recorded the event. Sometimes there is no-one who intentionally recorded information for posterity - it is done by nature. For example, information retrieved using archaeological techniques to study artifacts that have survived in ancient rubbish dumps.
The great hope for people like me then is that possibly more information than we are aware of at present is somehow naturally stored for many moments in history (perhaps in the molecular structure of the rocks and landforms surrounding the relevant geographic locations), and that we will increasingly be able to access this information as our understanding and technology develops. One day in the distant future my idea of a screen or, more likely now I think, a personal perception of any place at any time from any viewpoint, may be possible. This, I'm sure, is not a new idea, but the attempt to verify it scientifically probably is.
In order to test the hypothesis that controlled, non-interacting perception of the past will be possible in the future or that the (unlikely) capability of actual interactive time travel will one day be possible, I recently set up an experiment.