Ghostly hand? Sounds almost like an OBE! (oh no we're killing her with acronyms )

OBE = out-of-body experience

With astral projection (AP) the theory is that your consciousness mirrors itself, and you are able to move around in the real world without your physical body. Essentially, your consciousness separates from your physical self. This could explain the ghostly-looking hand, because even though your consciousness separates from your body, you'd still retain all your learned information, and so your mind would make up a replica of what you're used to (mental projection of yourself). For example, if you were born without arms (heaven forbid), your mind would recreate your astral body without arms, because that's how you've come to understand your physical body. It's the same reason we experience our dreams with physlcal 'laws' such as gravity.

Is your brain exploding yet?