Must all planets have a solid/liquid core?

At the moment it seems we have two different types of planet

1. We have Rocky planets with a solid core that occupies most of the mass of the planet

2. We have Gas Giants that contain a solid core but are mostly atmosphere.

We also have the possibility of a liquid planet as discussed here:

3. Could a planet made completely of water exist?

Is it possible that other types of planets could exist (preferably naturally formed but alien intervention would be accepted).

For example could a Gas Giant exist with no solid core at all? Or would the pressure always create a solid at the center?

In other words could we have a true "gas world" where as you go down the pressure increases but you never reach a solid or liquid even if you pass through the core and start to rise out of the other side again? If that isn't possible then would a gas giant with a liquid but not a solid core be possible?

posted about 9 years ago

Tim B‭

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