Do you think there is a possibility that the earth has an inner cavity with life unknown to humans?

Question: Do you think there is a possibility that the earth has an inner cavity with life unknown to humans?
- Keywords:
  cavity,
  Earth,
  human,
  life,
  unknown
Asked by anon-174632 to Tim on 22 Jun 2018.
- Tim Craig answered on 22 Jun 2018:
  
  No. If there was a cavity inside the Earth, we would know about it. We have a pretty good idea of the interior structure of the Earth, and in particular its density. A low-density cavity space would be really easy to spot, and there is no chance we’ve missed it.

Question: Do you think there is a possibility that the earth has an inner cavity with life unknown to humans?