1) Hacker News?

2) You can reliably induce near death experiences with high g-forces and drugs, for instance the experiences commonly happen to fighter pilots during training when they are subjected to high g forces in training.

The reason for the white light and tunnel and floating above your body, is that's how the brain shuts down due to loss of blood. We know this now. No need to speculate. "Hell" is a less common motif, because that's a less common brain state under those circumstances.

Next mystery, please.