I am sure that some accounts can be explained as you suggest. However, another likely scenario is that when an individual ponders the magnitude, complexity and beauty of creation, and when that individual is properly prepared, revelation/inspiration from the Lord can be received.
The experiences of the Apollo astronauts (Borman, Irwin and others), come to mind as relevant examples. This site/article may not provide the most objective account of their experiences, but it was the best link I could conveniently locate:
http://www.eschatologytoday.net/newsviewer.php?id=51