What if ghosts exist?

Have you ever thought about the possibility of ghosts?
Most people don't think twice about ghosts existing when there really isnt any convincing evidence that says otherwise, but what if they did exist?

The way i have thought about ghosts have changed a lot over the years, I cant say i believe in them but i also cant say I don't. I have a little theory that fits in with my beliefs that i would like to share with you.

We know everything in the universe is made of energy, the atoms in our body and the electrons that our consciousness rides on. When we die that energy doesn't just disappear, it becomes one with everything like it was before you existed. What if a consciousness unable to let go of what it is and what it's become, unwilling to give up on its humanity, causes itself to retain who it is, in a limbo in-between our world and the next. If a mind is strong enough i believe something like this could be possible because everything is just a vibration of energy, even if they were able to retain the form for small amount of time, if time is different in that dimension, it could explain why people see ghosts of people from a hundred years ago.

Just a little theory to think about.