Imagine this: The neutron star named “PSR J1748-2446ad” has a radius of 16 kilometers—which gives it, roughly, a diameter of 20 miles—and weighs in at about twice the weight of our sun. It also spins. Fast. Very fast.
It is, in fact, the fastest spinning pulsar known to astronomy at 716 Hz, which means that it spins 716 revolutions in a second (or that each spin is 0.0013959548 seconds long).
As a frame of reference, a regular kitchen blender usually spins at between 250-500 revolutions per second. But the kitchen blender blade does not have a radius of 16 kilometers.
So here is a globe, twenty miles across, weighing in at twice our sun, spinning at twice the speed of a kitchen blender.
Then imagine that each revolution constitutes one “now,” one moment, one slice of present-ness.
But that is probably wrong. The now is probably a lot shorter, the razorblade of the present moment a lot thinner than that.
To the naked eye, the now stretches eternally. Here it is, now it’s gone (past), the future (the new now) taking its place. Seamlessly ad infinitum. As seamless as any movie we’ve seen. But when we step back and take a look at what a movie really is we see that it is 24 frames per second, each frame a frozen bit of time that when run through a projector at just that speed will seem as seamlessly progressive as any sequence of moments we live through.
Movie-wise, each now is a 24th of a second long. But life-wise, how long is the now?
The shortest perceivable time division—sensory psychologists call it the fusion threshold—is between 2 and 30 milliseconds (ms) long depending on sensory modality.
Two sounds seem to fuse into one acoustic sensation if they are separated by less than 2 to 5 ms. Two successive touches merge if they occur within about 10 ms of one another, while flashes of light blur together if they are separated by less than about 20 to 30 ms.
So, does this mean, humanly speaking, that the now — the present moment — is 2 ms long? That would make for about five hundred nows per second.
The Buddha — some 2,500 years ago — said that there are thousands of moments during the raising of your arm.
Well, come to think of it, that could translate to 2 milliseconds per moment as well, could it not?
Looking at it mathematically, the now is more like a concept than a physical reality. In fact, the now, mathematically, is viewed as an infinitesimal length of time similar to the mathematical point: a concept more than a thing.
Mathematically speaking, the point does not have physical size, nor does it have shape. Rather, it is simply a one-dimensional location without dimension.
Yes, a concept, really.
Back to the pulsar. If it can spin 716 times in a second, that’s a little more than a spin every 2 ms.
So, perhaps the now is 2 ms long. But, of course, there’s no way to prove that.
And here’s the problem.
Remember the old philosophical/geometrical proof that if you drop a penny, it will actually, theoretically, never reach the floor.
For, first, it has to fall half the distance to the floor, then, it has to fall half of the remaining distance, then the half of that, and—you can see where this is going—you can always halve the remaining distance forever. It will always have half the remaining distance to fall and so will never actually complete its fall. There’s always one half of the remainder remaining.
In real life, it takes less than a second to hit the floor. So much for theory.
The same seems to me true about time. If we can measure it, surely we can halve that measure, and then halve the remainder. It will become infinitesimal indeed, constantly approaching (as we keep halving the remainder) zero—but never reaching zero.
So how long is now?
I think the truth about this lies in a different direction. I think that the true now is actually independent of time, that it lies beyond time. It cannot be measured by time.
It can’t even be thought of as time.
For the true now includes all the past there has ever been, and it includes all the future there will ever be, for there is — in truth — neither past nor future. There is only the thing we refer to as the present, the now, which, when all is said and done, simply is (here and now), immeasurable in physical terms.