Liquid nitrogen ocean

If Saturns moon Titan is just a tiny bit too warm to have a global liquid nitrogen ocean
then there must be plenty of worlds (moons and planets) out there in our galactic vicinity that actually do have such a liquid nitrogen ocean. Right?
Isn't that a fascinating Idea?

Methane freezes (90.694 K) before nitrogen condenses (77.355 K).

• Q: What is the density of frozen methane? Will it float or sink (or dissolve)?
• Q: If Titans atmosphere would condense (thought experiment) how thick of an ocean would it make?
• Q: When our sun was young and cool how close was Titan to having an lN₂ ocean? Did Titan actually have one in the far past??

Nitrogen:

• Boiling point: 77.355 K
• Density ~0.8g/ccm

Even more exotic cold oceans

Ammoniac oceans

Would that be possible?

Mehane oceans

Would that be possible?
Titan has only a few lakes.

Hydrogen-Helium oceans (probably not anytime soon)

A liquid hydrogen-helium ocean for rouge planets between the stars seems much more unlikely
since planets need to be huge to gather these light elements and once gathered these big planets need to give of fromation heat for a long long time. The pressure needs to go below the critical point (13bar for hydrogen) to get liquid like sharp surface. If this really happens in a far far future dark and dead universe, condensed liquified gas giants would really be strange places.

Related

• Titan (giant moon)

External links

• Wikipedia: Liquid nitrogen