is there chance of being a planet that no one knows about?

Question: is there chance of being a planet that no one knows about?
- Keywords:
  discovery,
  planet
Asked by Luwilcyson to Stefan on 17 Nov 2014.
- Stefan Lines answered on 17 Nov 2014:
  
  There are expected to be hundreds of billions of planets in our own galaxy, so there is no way we would discover them all, so definitely.

Question: is there chance of being a planet that no one knows about?