Collisions of comets, asteroids and other Near-Earth Objects containing carbon-based molecules and water ice with Earth may have led to the origin of life on our planet.
The history of evolution of life on Earth is yet to be fully revealed. However, we all know that the origin of life requires the presence of carbon-based molecules, liquid water and an energy sources. A study by NASA has proposed that the existence of life on earth might be the result of collisions of Near-Earth Objects containing carbon-based molecules and water ice with Earth. The report says, “For the first billion years of Earth’s existence,the formation of life was prevented by a fusillade of comet and asteroid impacts that rendered the Earth’s surface too hot to allow the existence of sufficient quantities of water and carbon-based molecules.”
It further adds that the origin of Life on Earth took place at the end of this period called the late heavy bombardment, some 3.8 billion years ago. The earliest known fossils on Earth are 3.5 billion years ago, suggesting that biological activity took place even before that i.e, end of the period of late heavy bombardment.
According to Nasa’s report, life on the Earth’s surface took place very quickly because of the collision of comets and asteroids with the Earth, as these contain abundant supplies of both water and carbon-based molecules.
The report also suggests that the origin of life on the Earth’s surface could have been first prevented by an enormous flux of impacting comets and asteroids. And that rain of comets may have deposited the carbon molecules allowing life to form some 3.5 – 3.8 billion years ago. While this study suggests that the comet brought the building blocks of life to Earth some 3.8 billion years ago, such collisions may have also wiped out many of the developing life forms, and only the most adaptable species could have evolved further. “It now seems likely that a comet or asteroid struck near the Yucatan peninsula in Mexico some 65 million years ago and caused a massive extinction of more than 75% of the Earth’s living organisms, including the dinosaurs,” reads the report.