Further, models developed by Elkins-Tanton and others "all indicate that this cooling and collapse process happens on the order of 10 million years or less," she added.
That's an exciting prospect for astrobiologists, as life on Earth is found nearly anywhere liquid water exists.
Holding on to the water Of course, forming an ocean and holding onto it are two different matters. After all, Earth's solar system hosts rocky planets -- Mercury, Venus and Mars -- whose surface oceans have long since disappeared, if they ever existed at all.
Indeed, how some rocky worlds manage to retain their water is an area ripe for future research, Elkins-Tanton said, specifically citing the case of Venus, Earth's hellishly hot "sister planet" that veered down a very different road after its formation.
It may be tempting to ascribe the apparent dessication of rocky worlds like Venus to the giant impacts that pummeled them in our solar system's early days. But Earth held onto much of its water despite a massive collision with a Mars-size body (which is thought to have led to the formation of the moon), and data from NASA's Messenger spacecraft show that Mercury still harbors many volatile compounds, Elkins-Tanton said.