For a hundred years we have got used to the idea of space-time as a unifying construct of spatial and temporal dimensions. We have also got quite used to the idea of animated picture-shows, which give the illusion of three-dimensional motion using a succession of two-dimensional images. Put space-time and film together, and we get science-fiction movies. But the fabric of space-time can be studied much more prosaically by considering a few simple objects in a limited number of dimensions.
Take some ordinary handy three-dimensional object - a Pepper, say - and consider it passing through a two-dimensional plane. To do this, imagine cutting the Pepper up into thin slices, and converting the slices into a slideshow. As you run the slideshow, a first pepper-slice appears, and then a succession of slices wriggle around - all slightly different shapes and sizes - and finally disappear.
We can easily recognise the whole Pepper as the sum of all pepper-slices together, simultaneously. In other words, our familiar still-life Pepper, as it passes through a plane, does not change shape as such; it is just an irregular shaped object moving in space.
But now imagine the perspective of the inhabitants of a fictional 'Flatland' - a planar domain inhabited entirely by flat shapes such as squares, circles and assorted sliced grocery products.
The two-dimensional citizen of Flatland would recognise the passage of the Pepper through their plane only as a procession of changing pepper-slice shapes in time. The idea that the pepper-slices could collectively be regarded as a single fixed-shape object in a higher dimension would be completely alien (or at least, counter-intuitive) to the Flatlander.
To perceive the Pepper not as an array of separate 2D slices at different times, but as a whole 3D object at the same time, the Flatlander would have to imagine a sort of time-ordered stacked-up archive of all the stills from the pepper-slice movie - a sort of incorporeal frozen movie-object (conceptually parked partly in a hypothetical third spatial dimension).
So it is possible to conceive of different entities across the dimensions of space-time, though it can sometimes be hard work - even for familiar objects in familiar dimensions.
It is especially challenging where an object in one dimension appears as more than one object in another. For example, imagine a chunk of tree, say a trunk with a single branch off it, passing through the plane of Flatland. First to make an appearance is the roughly circular cross-section of the trunk. As the tree cross-section passes through, it enlarges and sprouts a branch, so that by the time the whole chunk has passed through the plane, there are two roundish cross-sections - that of the trunk and that of the branch. As far as Flatlanders are concerned, where once there was a single object; there are now two separate objects. But from our three-dimensional perspective, there is only the one single three-dimensional object in space: the chunk of trunk-plus-branch.
A similar thing happens when three-dimensional objects connect or diverge over time. For example, when a chicken lays an egg, what was one three-dimensional object becomes two. The post-chicken egg and the post-egg chicken are clearly separate, in our three-dimensional mindset; but they are nevertheless connected through time. In fact, just as our tree trunk and branch - although appearing as separate slices in Flatland - form a single solid object in space, the chicken and its egg can be seen as part of the same diverging object in space-time. In other words, we have a sort of frozen continuum of chickens and eggs stacked up back through time - a four-dimensional object.
Indeed, a family tree is exactly like this: a four-dimensional structure of parents and offspring, a series of separate three-dimensional family members, with different individuals appearing at different positions in time.
Indeed, the whole 'tree of life' - the entire earthly family tree of people, hominids, dinosaurs, eggs, chickens, peppers, sticky rice and unclassifiable creepy-crawly things forms part of a single planetary 'creature', a quivering tentacled four-dimensional entity reaching through space-time.
An alien observer might think of life on Earth as a single grotesque mass of mutant organic tissue, coupling with itself here, spewing out offspring there, consuming and expelling parts of itself, all the while racked by fractured identities, a short-term ancestral memory and a penchant for self-harm. Such a monstrous 4-D Earthling might be just the stuff of the alien's own science-fiction movie.
The advertisements that appear on paper and online versions of The Alien Times do not necessarily represent the views of the Alien Times. The Alien Times takes no responsibility for any transactions that occur between advertisers and readers.
The authors of articles that appear in Alien Times reserve the right to copyright their work. Please DO NOT copy any articles that appear in Alien Times without first receiving permission from the author of the article (when known) or the Alien Times Editor.