Moon's Birth: Scientists Reveal New Theory on Its Formation

Topic: Space

Scientists from the Southwest Research Institute and University of Arizona have found that the Moon may have formed intact just hours after a giant collision between Earth and a Mars-sized object. They used computer simulations to test how material strength affects the collision.

The Moon is special because it's much bigger than other rocky planets' moons in our solar system. But scientists still don't know exactly how it was born. A new study suggests that one important factor might have played a big role: the physical strength of the two objects that collided.

Researchers at the Southwest Research Institute and University of Arizona used computer simulations to test what happened when a Mars-sized object called Theia crashed into early Earth about 4.5 billion years ago. They found that if Theia was hot, it would be weaker and break apart easily. But if it was cold, it would be stronger and more likely to stay intact.

This is important because scientists had previously assumed that the collision was so violent that the rocky bodies could be treated like fluids. But the new study shows that material strength matters a lot in collisions between smaller objects like asteroids, dwarf planets, and moons.

Why It Matters

Understanding how the Moon formed can help us learn more about our own planet's history and how it was affected by giant impacts. This knowledge can also be used to better understand other celestial bodies in our solar system.

Key Facts

• The study suggests that the Moon may have formed intact just hours after a giant collision between Earth and Theia, a Mars-sized object.
• The researchers used computer simulations to test how material strength affects the collision.
• The study found that if Theia was hot, it would be weaker and break apart easily. But if it was cold, it would be stronger and more likely to stay intact.
• The new study was published in The Astrophysical Journal Letters on September 1, 2026.
• The researchers used a type of computer simulation called smoothed particle hydrodynamics (SPH) to model the collision.

Key Terms

Smoothed Particle Hydrodynamics (SPH)

A type of computer simulation that models the behavior of particles in a system, taking into account their interactions and properties.

Implications

Understanding how the Moon formed can help us learn more about our own planet's history and how it was affected by giant impacts. This knowledge can also be used to better understand other celestial bodies in our solar system.