Here’s one to confound the creationist crowd: life may have begun as a result of organic molecules resulting from impacts by comets or meteorites. No supernatural foundation, no invisible hand guiding the process. Just random crashes, a little physics, some chemistry, a while lot of time, and voila: life.
But wait, there’s more…
How did these molecules go from static organic molecules to self-reproducing you ask? Ah, therein lies another tale… that of enzymes, the little engines of life. More randomness, more chemistry. No intelligent design.
Let’s start with the comets.
According to a recent article in Science Daily,
Scientists … from Imperial College London, the University of Kent and Lawrence Livermore National Laboratory discovered that when icy comets collide into a planet, amino acids can be produced. These essential building blocks are also produced if a rocky meteorite crashes into a planet with an icy surface.
The researchers suggest that this process provides another piece to the puzzle of how life was kick-started on Earth, after a period of time between 4.5 and 3.8 billion years ago when the planet had been bombarded by comets and meteorites.
The intrepid researchers fired projectiles at comet-like speeds into icy surfaces similar to what we know comets are made from. They discovered that the shock wave slams simple molecules together into more complex forms. The heat from the impact then transforms these more complex molecules into amino acids such as glycine and D-and L-alanine.
Dr Mark Price, co-author from the University of Kent, adds: “This process demonstrates a very simple mechanism whereby we can go from a mix of simple molecules, such as water and carbon-dioxide ice, to a more complicated molecule, such as an amino acid. This is the first step towards life. The next step is to work out how to go from an amino acid to even more complex molecules such as proteins.”
In a similar experiment, published in July,2013, scientists simulated an icy comet-like snowball using carbon dioxide, ammonia, methane, ethane and propane. They zapped it with high-energy electrons to “simulate the cosmic rays in space” and discovered that the result was “complex, organic compounds, specifically dipeptides, essential to life.”
Chemists from the University of California, Berkeley, and the University of Hawaii, Manoa, showed that conditions in space are capable of creating complex dipeptides – linked pairs of amino acids – that are essential building blocks shared by all living things. The discovery opens the door to the possibility that these molecules were brought to Earth aboard a comet or possibly meteorites, catalyzing the formation of proteins (polypeptides), enzymes and even more complex molecules, such as sugars, that are necessary for life.
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