Impacts From Space Can Form Building Blocks of Life
Czech researchers who simulated conditions prevalent on Earth under a hail of asteroids and comets billions of years ago in laboratory with a powerful laser, showed that chemical reactions that took place under the heat and pressure extremes caused by these impacts could have synthesized the organic compounds which form RNA, believed to be the first molecule to encode genetic information essential for the life forms to emerge and replicate themselves.
In the experiment conducted at the J. Heyrovsky Physical Chemistry Institute in Prague, a solution containing formamide, a mineral thought to abound in the crust of early Earth, and clay was bombarded by laser pulses spaced by a third of a nanosecond. In the solution subjected to intense pressure caused by laser pulses, temperature peaks in excess of 4200⁰C and high-energy radiation including ultraviolet and X-rays, adenine, guanine, cytosine and uracil, the four nucleobases which make up the RNA were seen to form together.
RNA is believed to be the molecule bearing the genetic code before the DNA which contains thymine instead of uracil and is present in the nucleus of every cell in organisms. Formamide, produced when hydrogen cyanide reacts with water, contains atoms of hydrogen, nitrogen, carbon and oxygen which are essential for life.
The Earth, currently about 4.6 billion years old, had come under an intense bombardment by meteorites along with its moon and other inner solar system planets Mecury, Venus and Mars four billion years ago. This barrage of planetsimals of every size, let loose as aresult of gravitational interactions between the gas giant planets of the outer solar system and lasted 150 million years, is called the Late Heavy Bombardment. Though many scientists believe that these impacts and their devastating effects should have stamped off any fledging life, the work of Czech scientists show that such impacts can also create the molecules crucial for life.
- 1. “From hell on Earth, to life’s building blocks”, Science, 12 Decembre 2014