Hi Paul. I'm speaking from a Buddhist perspective.

It's 100% possible to experience what you did, although it would be less usual for a beginner, and perhaps more to the point the pursuit of such experience is not the point of meditation.

You popped out of the space almost immediately, the Buddhist take on that would be that your thinking or ego mind was attracted by the experience, 'woke up' so to speak (having up to that been lulled by the act of meditation into a taking its eye off the ball) and in doing so again took over your awareness.

You may find that if you seek to replicate the experience that it won't happen again so easily - the act of 'trying' to do so is likely to have the above blocking effect.

The aim of meditation is to train the higher 'watching' part of mind in equanimity - so that it rests easily, simply observes and is not sucked into identification with external (normal life) or internal (thinking mind) experience of this sort. No matter how spectacular, frightening or attractive it may seem to the thinking mind. (in Buddhism no distinction is made between internal and external relative experience - both are part of samara or the ego created reality we are conditioned to selectively perceive)

The development of this ability is for most of us a long drawn out job of work, with lots of forward, back and round about. Not to mention that becoming objective driven impedes progress, it's best simply to get a practice routine going and to stick with it in the same unthinking way as you (presumably ) brush your teeth every morning.

If it happens it happens, but it's in a sense a self limiting matter. Those that have not cultivated or who lose the required equanimity inevitably find themselves unable to shift our attention from the 'TV programme' being played to us by the thinking mind.

Behind this is the view that ego is the result of our mistakenly deciding that we are a physical thinking individual struggling to survive in this reality. We mistakenly identify with the physical vehicle as 'me', when in reality it's more like a remote exploration robot we happened to be able to look out of from the perspective of higher mind. Like a computer game player mistakenly becoming 100% identified with his avatar in the game - and so conditioned that he/she becomes highly addicted to this and can't recover a reality based 'view'.

Many find that if they experience stuff at all, that it comes and goes depending on their state of mind. For example - a retreat is sometimes conducive to entering higher mind states in that by the end of a week's meditation the thinking mind really does start to quieten. (that's what a retreat is for)

This actually is the nature of the trap that is samsara or this lower reality - the harder we struggle to escape, the less able we are to do so.

One way it's taught is to say that when meditating the intentional/thinking bit of the mind should stay lightly focused on the act of breathing, but will in the case of most of us get sucked into identification with thought. e.g. start to think about what's for lunch, what he did last night, whatever.

The 'watcher' bit of mind (my words) observes what's playing on the internal TV (the above thoughts or whatever), and if the above happens gently allows us to realise what has happened, just drop the line of thought and bring the intentional/thinking/ego mind back to lightly watching the breath.

Almost all of us are easily distracted, and can be gone for minutes or much longer - lost in what is often intense and obsessive thought.

It's important not to get frustrated by this, to simply bring the awareness back to the breath - or whatever is being used as a cue to keep the ego mind distracted. This is the function of a mantra or chant, and visual cues like a dot marked on the wall or a flower can also be used or indeed both visual and other cues together.

Breathing tends to be central, in that long slow breaths have a definitely calming effect on the mind....

Meditation can help you tune into your inner spirit self, but the main thing that's going to work is to get rid of the thought patterns that limit you. If you do this, your meditation will become more spontaneous, without having to focus your attention in a particular way or to regulate your breath in a particular way.

I found it helpful to make a list of the issues that troubled me during my life: anger related issues, guilts, fears, doubts, and limiting beliefs; and then let go of these beliefs as best as I could.

I've found that it isn't an all or nothing affair. The more you let go, the better you'll do.

The high pitch whine can be the "music of the spheres" or basically the sound of creation.  Look up "music of the spheres," "shabd," or "naam."

I, too, once looked through my closed eyelids. Everything looked like I had actually used my physical eyes. One time, for just a second, it became absolutely quiet, no sound at all. I have tinnitus since my childhood, sounds like many very high pitched violins; meanwhile I sometimes hear bass tones; it increased over the last years, I don't know if it could have something to do with meditation and the use of Hemi-Sync.

Spooky