@Wanderer18 8 April 2021 more from that month

Are you aware? Jupiter has the biggest ocean of any planet, albeit made of metallic hydrogen. Orbiting in cold space five times farther from the sun than Earth, Jupiter retained much higher levels of hydrogen and helium when it formed than did our planet. In fact, Jupiter is mostly hydrogen and helium. Given the planet’s mass and chemical composition, physics demands that way down under the cold cloud tops, pressures rise to the point that the hydrogen must turn to liquid. In fact there should be a deep planetary ocean of liquid hydrogen. Computer models show that not only is this the largest ocean known in the solar system, but that it is about 25,000 miles (40,000 km) deep – roughly as deep as the Earth is around.