Question: Could a planet contain all of its (vast) oceans underground?
I imagined a planet with no surface oceans - and no water cycle above ground - but where life was still possible.
My initial misgivings are:
The increased temperatures below the crust.
Any life must be able to get to the water so the earth must absorb this water.
But then wouldn't these two result in geysers and evapourating surface water, leading to those oceans slowly moving to the surface and creating a above ground oceans?
I'm looking for any ideas on how a planet with underground oceans would stay this way or at least an idea of the timescale for the stability of this. (Ie I don't want life that evolves to use these conditions to get flooded soon after).