It’s good to hear the chances of us ‘not being alone’ are sounding more probable – Deskarati
Some estimates indicate that 25% of Sun-like stars have Earth-like planets. A new study now shows that these planets are almost certain to have oceans if they are located in the right temperature zone around their host stars.
Not only may up to 25% of Sun-like stars have Earth-like planets – but if they are in the right temperature zone, apparently they are almost certain to have oceans. Current thinking is that Earth’s oceans formed from the accreted material that built the planet, rather than being delivered by comets at a later time. From this understanding, we can start to model the likelihood of a similar outcome occurring on rocky exoplanets around other stars.
Assuming terrestrial-like planets are indeed common – with a silicate mantle surrounding a metallic core – then we can expect that water may be exuded onto their surface during the final stages of magma cooling, or otherwise out-gassed as steam which then cools to fall back to the surface as rain. From there, if the planet is big enough to gravitationally retain a thick atmosphere and is in the temperature zone where water can remain fluid, then you’ve got yourself an exo-ocean.
We can assume that the dust cloud that became the Solar System had lots of water in it, given how much persists in the left-over ingredients of comets, asteroids and the like. When the Sun ignited some of this water may have been photo-dissociated, or otherwise blown out of the inner Solar System. However, cool rocky materials seem to have a strong propensity to hold water, and in this manner, could have kept water available for planet formation.