Because Earth was formed so close to the sun, scientists doubt that the larger, more complex elements necessary for life would have formed at the planet's birth. Life depends on these elements for molecules to create the basic make-up and processes of cells.
Scientists have suggested many theories, including lightning causing chemical reactions and the possibility that falling comets and asteroids brought organic material, but many conflicts to these theories exist. The most significant argument against comets was previously that they burned up as they entered the atmosphere, converting their organic molecules to carbon dioxide.
Recently, however, scientists working with NASA have come up with a third option: cyanide. Researchers fired projectiles simulating comets hitting the Earth and came up with some surprising results: the impact formed cyanide. The poisonous compound contains nitrogen, an important element in amino acid formation, a basic life function.
These findings add another aspect to the debate, but more scientists still do not agree. Donald Brownlee says that
some of early Earth's organic material undoubtedly formed this way...[but] there were probably other sources too, including organic-rich particles of interplanetary dust, which fall to Earth more gently than asteroids and comets. "It gets warmed but it doesn't get extremely hot."
The discussions over the origins of life will continue despite these new findings, but we can all be sure the end result will assure something we already knew: Life exists on planet Earth.
This is a very interesting topic!!
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