In fairness Greg I can see how that could seem vague, so lets try clear it up a bit, it does deserve answering.
    If a human being can relax their body enough and quieten their thoughts,after a period of time a process kicks in. If they maintain it long enough something happens in the brain. If you're a meditator and you have your eyes are closed it's an explosion of light, if you have your eyes open there is an explosion of light around you.It's the brain releasiing Dmt. That's as simple as I can get it and barely scratches the surface,but you're not really interested anyway.
ps. Just because someone has this experience doesn't make them better than anybody else.Most only sustain it for a short while anyway.
    Now back to your comfort zone 8)