Earth likely acquired its water through impacts from icy space rocks during a theorized event known as the Late Heavy Bombardment.
The Late Heavy Bombardment: A Celestial Delivery Service
The prevailing theory suggests that a significant portion of Earth's water, which now forms our vast oceans, was delivered to our planet from space during a turbulent period in the early Solar System's history.
- When It Happened: This theorized event occurred roughly 4.0 to 3.8 billion years ago, a critical time in Earth's infancy.
- The Cosmic Trigger: The main catalyst for this event was a shift in the orbits of the outer planets (such as Jupiter and Saturn). These massive gas giants exerted immense gravitational forces.
- Gravitational Jostling: As the outer planets' orbits changed, their gravitational pull created a "jostling" effect. This instability acted like a cosmic slingshot, propelling vast numbers of celestial bodies from the colder, outer regions of the Solar System inwards.
- The Water Carriers: The objects sent hurtling through the inner Solar System were primarily icy space rocks. These could have been comets or water-rich asteroids, carrying substantial amounts of frozen water.
- Earth's Reception: Many of these icy worlds slammed into Earth during this period. Each impact contributed water to our planet, gradually accumulating to form the oceans we see today.
This scenario, the Late Heavy Bombardment, provides a compelling explanation for how Earth, despite its initial formation conditions, became a water-rich world capable of supporting life.
