Strictly speaking, thinking of time as a line of any sort is misconception. Along a 'line' exists objects and never events. So we, for instance, have a series of posts along a road. Objects are fundamentally different from events in that the latter don't have a standalone existence. You cannot, for instance, find an event sitted like a stone along a road. On the contrary, events requires objects for them to happen. So it is misleading to say that time is a 'dimension' like that one for space. This, nevertheless, does not mean that there is no such a 'dimension', travelling along which, generate events just like displaying a series of static objects in a movie creats the event of movement that we see it as a 'motion picture'. It is such a 'memory of events' that I loosely call it 'time' and am suggesting that it is a collection of helixes in 3d (not 4 d). DNA is just but one example of something more general in all objects.
String Theorists talks of '12 dimensions', claiming that the eight of them are curled up into so tiny spaces as Planck's length. But is it necessary for the universe, which loves parsimony so much, to creat a whole (infinite) dimension merely to pack a Planck's length long (non)entity? Imagine building a whole new ware house to store a grain of salt! Physicists suggests these ridiculous claims despite the fact that it is known that objects are 99.999999% empty!! Can't the universe simple squeeze those 'curled up manifolds' inside these empty spaces quite comfortably? The idea of time as an helix in 3d is to squeeze what mathematically 'looks' like a 'fourth dimension' into a 3rd dimension. If we are truely trying to understand, we should be reducing fundamental parameters, not increasing them. Nothing is more misguided than introducing another inconceivable 'dimension' while trying to 'unify' known things. Nothing is more misguided than trying to understand 'time' (movements) as an unimaginable 'fourth dimension' before we exhaust all possible ways of understanding movement and changes using only 3 easily imaginable 'dimensions'. This is to make the too generous assumption that such notions as 'forth dimension' have any meaning even in the first place!
How did physicists 'observed' that 'time is a fourth dimension' without being able to even imagine this other extra dimension, let alone see one? Think about this having in mind that physics is supposed to be a science, whose claims are justified by observations and not by faith, like in religion. We cannot say 'the fourth dimension creats observable wonders in 3d and we can thus indirectly infere another 'dimension' from these things. This is because that is precisely how we argue for God! We cannot see or even imagine God as he is. However, 'the heavens speaks of his glory'. Did physics, at some point, turn into a religion? Yes it did! It is a religion of the nerds! We cannot rely on inference simply because we can infere myriads of things from a given observation, nor can we, for the same reasons, rely on an equation that seems to relate some four parameters in some strange, four 'dimensional' Pythagorean relationship.
The physicist begun the journey by a gawk at an extreemly simple, moving train. If light travels to the roof of the train at a speed c, then it goes a distace ct, where 't' is the 'time taken'. meanwhile the train, moving at velocity v, during the same time, t, have moved horizontally over a distance vt. So the light has to move diagonally upwards as it chase the train. But the same light as seen within the train only seems to move vertically upwards (a passenger is ignorant of his own, horizontal movement). So there are two ways we can calculate the height of the train. One is using the phythagorean relationship, it h^2=(ct)^2-(vt)^2. The other is to assume that the speed of light is still c as seen from inside the train so that h=ct'. So (ct')^2=(ct)^2-(vt)^2. Then he reasons that (t'/t)^2=1-(v/c)^2.
From this simple calculation, one can, if not careful, immediately begin to make erroneous conclusions (like physicists did). By cancelling c out in ct'/ct to have t'/t, we now seem to have 'time' sitting together with 'distances' as if to relate to them in a Pythagorean relationship. By the time a physicist has massaged too many more sophisticated equations, he will have forgotten that this phythagorean relationship originated from distances relationships and not time relationship with distances. We, for instance, could easily understand a 'negative distance' as -ct, letting the negative sine to actually sit behind 'c' rather than 't'. but lose this vital information having cancel out c and the equation now reads like a possibility of 'moving backwards in time' when it actually was a mere light moving in bacward direction! again this is distance moved and not time taken and of course we can easily move backwards in space. Then again this is all 100% in 3d, nothing like '4d' is seen or is necessary to understand this simple train!
Now according to relativity, the height of the train stays the same when the train begines to move. So when the train moves over distance x eastwards, y northwards and z verically, the light would have moved over an extra h distance so that h^2=(ct)^2-x^2-y^2-z^2. So the fact that h doesn't change means that this must be in built into the So called 'lorentz transforms'. So physicist need not have been surprised by massaging lorentz's transforms and fou nd out that the so called 'spacetime interval' given by s^2=ct^2-x^2-y^2-z^2. They should have recognized that this invariance alludes to the unchanging 'height of the train' and not some unimaginable 'distance' in '4th dimension' caused by unfathomable blend between 'time' and 'space'. Every time you see 'time' in such equations, it must actually be understood as 'distance moved', and it must be a distance in 3d, never 4d!
In the idea of 'time' as an helix, we make use of the same relativistic equations but interprate h, ie the 'spacetime interval' as an ordiary distance. It is the 'circumference of the helix'. Every particle spins as it moves. The direction of spinning is perpendicular to the direction of motion (actually in physcs, we say 'the spin, or rather angular momentum', is along the direction of motion). So the edges of the paticles traces helical trajectories.It does so in such a way that the total speed of the edges is the speed of light. So a stationary particle spins so that its surface moves at the speed of light. (ignore quantum mechanics for a moment because it is not important here). When the particle begins to move, it begins to spin slowlier so that the combine motion and spinning still leads to a surface that is moving at c. So when it moves at the speed of light, it stops spinning completely. Infact the 'spinning' follows the formula for 'time dillation' exactly, as if such spinning is 'the passage of time'. In such a picture, it is easily seen that the circumference of the particle is the 'space-time' interfal. Or we should say that the total 'spacetime' taken is the total distance covered by the spinning alone, with the translation motion ignored.
This trajectory, however, will be more than a path. For it to be 'time' as we know, it must leave some trail behind! This is to say 'time' here will be understood as 'memory'. As object spins, they record their states by 'polarizing the vacuum'. That is to say being fundamentally charged, they partly separate space into pairs of matter and antimatter, a seperation which persist (mutasis mutandis) even after the particle moves away! So 'past' here will be 'cosmic memory', and future is 'cosmic plans'!