Where are the LightSail-Probe send to us by Aliens?
This bring me to one question: Why there is so much water on Earth and so few on the moon.
https://en.wikipedia.org/wiki/Origin_of_water_on_Earth
The only explanation from this article, is the Theia explanation:
https://www.sciencedaily.com/releases/2019/05/190521101505.htm
Empirically, from the habitable zone with Mars, moon, Earth , we are at 1 in 3 chance to have mass water formation. And the odd, of an exoplanet colliding with one planet in habitable zone must be far less. I guess we're alone!