The Present Moment

Just because we can name something and understand it intuitively doesn't mean it's really a thing out here in the Universe.  Take the present moment.  Now.  The separation between past and future.  "Live in the moment!"  "Don't dwell in the past!" "Don't fret about the future!"

But what is this moment?  Right then as you were reading those words, was that now? Take a look at these action potentials graphs of various neurons:

So just to have one action potential within a single neuron takes over 0.001 seconds.  The synaptic release of neurotransmitters crossing synapse takes an additional 0.0005 seconds.  Any thought worth having involves many thousands of neurons asynchronously signaling each other throughout your brain, spinal cord, and body.  If you consciously react and respond to an external stimulus it takes about 0.3 seconds round trip.

As you are having one 'thought' this moment involving thousands (millions?) of neurons, they are not all firing at the same time... that would be impossible.  Some of the neurons participating in this particular thought are far apart and some are right next to each other. Your thought right now is the integration of many signals over an interval of time, around 1/10 of a second, from all over the place.  As some neurons have already completed their contributions to this ''now' of your cognitive experience, they may be already firing for your next 'now'.  Meanwhile, the latest contributors within this tenth of a second window of time are in the midst of their action potential peak.

So your present "now" moment in time is really an extended, entangled mess of past and future.  But don't dwell on this or fret over it, we all know what I mean when I say "That's all for now!"