A group of researchers from Rice University has been studying an ancient collision between a very early Earth and another planet. They say that most of the essential elements on Earth for life likely came from the planet that Earth collided with. Earth is thought to have received the bulk of its carbon, nitrogen, and other life-sustaining volatile elements from the planetary collision that created the moon.
The team says that this collision occurred more than 4.4 billion years ago. “From the study of primitive meteorites, scientists have long known that Earth and other rocky planets in the inner solar system are volatile-depleted,” said study co-author Rajdeep Dasgupta. “But the timing and mechanism of volatile delivery has been hotly debated. Ours is the first scenario that can explain the timing and delivery in a way that is consistent with all of the geochemical evidence.”
The team came to its conclusion using evidence compiled from a combination of high-temperature, high-pressure experiments in a lab that specializes in studying geochemical reactions. Evidence gathered in the experiments suggest that the volatiles on Earth arrived here from a collision with an embryonic planet that had a sulfur-rich core. One big piece of evidence supporting the claims is that carbon, nitrogen, and sulfur exist in all parts of the Earth but the core.
Scientists say that the core of Earth doesn’t interact with the rest of the planet, but everything above the core is connected to the core. One theory about how the Earth received its volatiles is called the “late veneer” theory. That theory speculated that volatile-rich meteorites arrived after the core formed.
The result of the experiments at Rice has concluded that volatiles on Earth arrived in a manner consistent with a moon-forming impact of a volatile-bearing Mars-sized planet with a sulfur-rich core. The team says it doesn’t appear that the Earth’s bulk silicate on its own could have attained the life-essential volatile budgets that produced the biosphere, atmosphere, and hydrosphere.