[ambrose]

Well, let's be a little creative and consider the possibility that there may still be solid mass inside Uranus (or Neptune, Jupiter, Saturn), even if it is otherwise gaseous. I don't believe our science has been able to rule such a possibility out. It may be 3000 years before we'd have the technology necessary to send a man inside a gas giant planet, and return safely. It may be never. But I am not arrogant enough to say "never".

[RadioAstronomer]

I agree. If you notice I said probably, not never. :-)

[Mr. Mojo]

the possibility that there may still be solid mass inside Uranus (or Neptune, Jupiter, Saturn), even if it is otherwise gaseous.

Liquid nitrogen down there, if memory serves. .....But your point is well taken -- never say never.