Earth might have been born wet because water sticks to space dust far more strongly than it sticks to ice.
The prevailing theory is that Earth formed dry and received its water later from comet and asteroid impacts. This new research shows that water molecules bind tightly to silicate grains, allowing them to survive much closer to the hot sun. This means the building blocks of our planet likely carried their own water from the very beginning. We may not need to rely on the outer solar system to explain why our oceans exist. This shift in thinking suggests that many other rocky planets might also start their lives with plenty of water.
Astrochemical Inheritance of Terrestrial Planets Water from Local Wet Silicates
arXiv · 2605.02637
The delivery of water to the inner Solar System rocky planets, including Earth, remains debated, as standard models assume that they formed from dry grains, inside the snowline of the protosolar nebula. However, a recent work showed that a not-negligible amount of water formed during the prestellar phase could have been retained by pebbles and planetesimals at the Earth's orbit in enough quantities to reproduce its water content. This study was based based on quantum mechanics (QM) calculations