Russian and American scientists have collaborated on a study that proves a long-held theory that life was delivered to Earth from outer space through falling rocks.
According to the study, meteorites carried cell-making chemicals to Earth 4 billion years ago, igniting life on Earth. The first cells on ancient Earth may have emerged within a primordial soup of complex, carbon-rich chemical compounds.
Other theories about how life started on Earth include:
- Volcanism: Early in Earth’s history, volcanism was a very common process.
- Comets: Comets may have brought the building blocks of life to Earth some 3.8 billion years ago.
- Impact cratering: Impact cratering may have provided the environments needed to transform disparate chemical compounds into living organisms.
US, Russian Scientists Say ‘Bombarding’ Meteorites Carried Cell Making Chemicals 4B Years Ago Igniting Life On Earth. Russian and American scientists, in a collaborative study, have proven a long-held theory that life was delivered to Earth from outer space through falling rocks
The Late Heavy Bombardment (LHB) was a violent stage in Earth’s geologic history when Earth and the inner solar system were bombarded by asteroids, comets, and space debris. The LHB is thought to have lasted between 20 million to 200 million years.
The LHB is recorded on the Moon, Mars, and in meteorites. Samples collected by Apollo moonwalkers contain chemical signatures from different meteorites.
The LHB is thought to have occurred about 4 billion years ago. It was preceded by an orbital shake-up of the outer Solar System.
Most researchers think that the formation of continents is related to the LHB. Asteroids, some of them as large as hundreds of kilometers in diameter, plagued the entire solar system between 4.1 billion and 3.8 billion years ago.
The Late Heavy Bombardment (LHB) may have shaped the terrestrial planets and moons, their atmospheres, and possibly even the onset of life.
The LHB may have:
- Supplied Earth with water
- Boosted the origin of life on Earth
- Shaped the terrestrial planets and moons
- Shaped the atmospheres of the terrestrial planets
- Led to Earth’s plate tectonics
- Built the continents
The LHB was a chaotic period in the inner Solar System. The collisions were frequent and the debris field significant, resulting in enormous changes to the terrestrial planet surfaces over short timescales.
The LHB may have also led to the formation of the Moon. According to the giant impact hypothesis, a large iron asteroid collided with the rocky Earth during the LHB. The asteroid carried material away from the Earth which accreted onto the asteroid and formed the Moon.
There is limited evidence of the Late Heavy Bombardment on Earth because of:
- Plate tectonics Earth’s constant resurfacing through plate tectonics erases evidence of large impacts
- Weathering and volcanism Earth has undergone significant weathering and volcanism in this time span
- Erosion and vegetation The remaining dryland is still geologically active so impact structures have been obscured by erosion and vegetation
- Earth’s magnetic field Earth’s magnetic field does not have a significant effect on solid objects like asteroids
- The moon’s gravity The moon’s gravity is not strong enough to prevent all asteroids from reaching Earth during the Period of Heavy Bombardment
Other evidence for the Late Heavy Bombardment includes:
- Rocks brought back from the moon by Apollo astronauts all seem to have ages that cluster around this date
- Isotopic dating showed that the rocks were last molten during impact events in a rather narrow interval of time
- Many of the samples were of rocks that had been deformed or created by melting during large impacts
Universe discoveries 