Late Heavy Bombardment

Definition

The Late Heavy Bombardment (LHB) refers to a period in the early history of the Solar System, approximately 4.1 to 3.8 billion years ago, when the inner planets experienced an intense bombardment by a large number of asteroids, comets, and other planetesimals. This event had significant implications for the composition, structure, and evolution of the planets, as well as the development of life on Earth.

5 Must Know Facts For Your Next Test

1. The Late Heavy Bombardment is thought to have been caused by the destabilization of the orbits of the giant planets, leading to an increased flux of impactors from the Asteroid Belt and Kuiper Belt.
2. The intense bombardment during the LHB is believed to have resurfaced and even melted the crusts of the inner planets, including Earth, and may have contributed to the formation of the Moon.
3. The LHB had a significant impact on the evolution of Earth, potentially stripping away the early atmosphere and oceans, and creating conditions that may have been important for the origin and early development of life.
4. The LHB is also thought to have played a role in the composition and structure of the planets, as the impactors delivered a wide range of materials, including water, organic compounds, and other volatiles.
5. The evidence for the LHB is primarily found in the cratering records of the Moon, Mercury, Mars, and other bodies in the inner Solar System, as well as in the geologic and geochemical record of Earth.

Review Questions

• Explain how the Late Heavy Bombardment affected the composition and structure of the planets in the inner Solar System.
  • The Late Heavy Bombardment had a significant impact on the composition and structure of the planets in the inner Solar System. The intense bombardment by asteroids, comets, and other planetesimals during this period is believed to have resurfaced and even melted the crusts of the inner planets, including Earth. This process may have contributed to the formation of the Moon and delivered a wide range of materials, such as water, organic compounds, and other volatiles, to the planets. The LHB likely played a key role in shaping the final compositions and structures of the inner planets as we know them today.
• Describe how the Late Heavy Bombardment influenced the evolution of Earth and the potential origins of life.
  • The Late Heavy Bombardment had a profound impact on the evolution of Earth. The intense bombardment is thought to have stripped away the planet's early atmosphere and oceans, potentially creating conditions that were important for the origin and early development of life. The delivery of water and organic compounds by the impactors during the LHB may have provided the necessary building blocks for the emergence of life on Earth. Additionally, the resurfacing and melting of the Earth's crust due to the bombardment could have created environments, such as hydrothermal vents, that may have been conducive to the formation of the first living organisms. The LHB, therefore, played a crucial role in shaping the early conditions on Earth that were essential for the origins and evolution of life.
• Analyze the evidence that supports the existence of the Late Heavy Bombardment and its impact on the Solar System.
  • The primary evidence for the Late Heavy Bombardment comes from the cratering records of the Moon, Mercury, Mars, and other bodies in the inner Solar System. These cratering patterns suggest an intense period of bombardment by asteroids, comets, and other planetesimals during the early history of the Solar System. Additionally, the geologic and geochemical record of Earth, including the formation of the Moon, also provides support for the LHB and its significant impact on the evolution of the planets. The delivery of water, organic compounds, and other volatiles by the impactors during the LHB is further corroborated by the composition and structure of the inner planets. By analyzing the evidence from various sources, scientists have been able to piece together the timeline and consequences of the Late Heavy Bombardment, which was a critical event in the formation and development of the Solar System.

Related terms

Planetesimals: Small, rocky or icy bodies that formed the building blocks of the planets in the early Solar System.

Asteroid Belt: The region between the orbits of Mars and Jupiter where a large number of asteroids, remnants of the early Solar System, are located.

Impactor: A celestial body, such as an asteroid or comet, that collides with a planet or other body in the Solar System.