Can a 100,000km-deep ocean exist somewhere in the universe? Is there a critical depth that makes water cease to be liquid?
As of till now TRES4 is the biggest planet located in the constellation Hercules which is 70% larger than Jupiter in diameter (i.e. around 250000 km in diameter ), but has only 80% of Jupiter's mass and it is thought that the intense heat expand the gasses that make up this planet, resulting in an almost 'marshmallow-like' density that means it contains no oceans. And for being 100000 km deep ocean the planet size has to be at least 300000 km in diameter so it is not possible till now and i dont think it is possible for existence of such a big planet.
The water will not be liquid anymore in that much depth due to the huge pressure it will be take form of ice which will be stronger than steel but the ice will not be cold as the ice we made out of freezer.