Late Heavy Bombardment

Definition

The Late Heavy Bombardment refers to a period around 4.1 to 3.8 billion years ago when the inner solar system experienced a significant increase in the number of asteroid impacts on planetary bodies, including Earth and the Moon. This intense barrage is believed to have played a crucial role in shaping the surfaces of these celestial bodies and influencing their geological histories, as well as affecting the conditions necessary for life to emerge.

5 Must Know Facts For Your Next Test

1. The Late Heavy Bombardment is supported by lunar samples collected during the Apollo missions, which show numerous impact craters from this time period.
2. This bombardment may have contributed to the formation of Earth's early atmosphere and oceans, potentially creating conditions suitable for the emergence of life.
3. Scientists believe that gravitational interactions with the giant planets, particularly Jupiter and Saturn, may have caused a destabilization in the asteroid belt, leading to increased impacts in the inner solar system.
4. The Late Heavy Bombardment likely lasted for several hundred million years and was followed by a period of relative calm in terms of impacts on planetary surfaces.
5. Models suggest that while Earth experienced many impacts during this time, it also played a role in delivering water and organic molecules necessary for life from comets and asteroids.

Review Questions

• How did the Late Heavy Bombardment impact the geological history of Earth and the Moon?
  • The Late Heavy Bombardment significantly shaped the geological history of Earth and the Moon by causing extensive impact cratering that altered their surfaces. This period of intense bombardment left a record of craters that can still be observed today on the Moon. On Earth, while most evidence has been erased by erosion and tectonic activity, it likely influenced volcanic activity and the formation of early atmospheres and oceans, playing a vital role in creating conditions for life.
• Discuss how gravitational interactions among celestial bodies contributed to the occurrence of the Late Heavy Bombardment.
  • Gravitational interactions among celestial bodies, particularly those involving Jupiter and Saturn, are thought to have destabilized orbits within the asteroid belt. This instability could have sent many asteroids on collision courses with inner solar system bodies, including Earth and the Moon. As these giant planets migrated during their formation, their gravitational pull altered the trajectories of smaller bodies, leading to increased impacts during the Late Heavy Bombardment period.
• Evaluate the significance of lunar samples in understanding the effects of the Late Heavy Bombardment on planetary evolution.
  • Lunar samples collected from Apollo missions provide crucial evidence for understanding the Late Heavy Bombardment's effects on planetary evolution. These samples contain numerous impact craters dating back to this period, which allow scientists to establish a timeline of bombardment events. By studying these samples, researchers can infer how these impacts influenced not only the Moon’s geology but also offer insights into Earth's early environment, helping us understand how these events shaped conditions that may have led to life.

Related terms

Asteroids:

Small rocky bodies orbiting the Sun, primarily found in the asteroid belt between Mars and Jupiter, which are remnants from the early solar system.

Planetary Differentiation: The process by which a planet becomes internally zoned, with denser materials sinking to the core and lighter materials forming the crust and mantle.

Impact Cratering: The geological process that creates craters on planetary surfaces when a meteoroid, asteroid, or comet collides with them at high velocities.