How did life begin?

There are plenty of theories about how life started, including the following theories: it came from Mars, formed in the primordial oceans, came in comets during the late bombardment, drifted here from planets around other stars, or it was delivered by the tooth fairy. Yes, there is evidence of organic molecules in nebulae, accretion discs around proto-stars, and even on moons around the gas giants, but not one of these ideas explains how the main ingredient for life formed, namely DNA.

DNA stands for deoxyribonucleic acid, and it is the cornerstone of life. It makes reproduction possible and every living thing on the planet Earth has it. In fact, parts of our human DNA are in the DNA of plants and insects. This wonderful and truly amazing molecule was in the single-celled creatures that existed billion of years ago. These single celled creatures evolved into multi-celled creatures and then fish and amphibians that eventually crawled onto land and evolved into us in a very complex manner over hundreds of millions of years, and they brought the DNA with them.

Even if you theorize that early life only had RNA, ribonucleic acid, it's still hard to explain how it came into existence. Just to be sure that you understand how complicated RNA is, I will describe its molecular structure. RNA is a single-stranded, long-chain molecule, unlike DNA, which is a double-stranded molecule. RNA contains ribose, which is a monosaccharide (sugar-like) with five carbon atoms. Basically, it has a pentose structure with an oxygen atom and four carbon atoms in a five-membered ring with hydroxyl groups (OH) hanging off of the carbons. The specific structure is D-ribose because its stereospecific, which means that it's oriented in a specific three-dimensional manner. Now, RNA is actually a sugar formed from ribose connected by phosphate groups. Phosphate groups have four oxygen atoms connected to a phosphorus atom. The pentose groups are connected to two adjacent oxygen atoms by means of removing a hydrogen atom from the hydroxyl groups on the pentose so that the oxygen atoms attached to the pentose ring make up two of the phosphate oxygen atoms. It goes like this Ribose-O-P-O-Ribose. There are two other oxygen atoms connected to the phosphorus atom. This is how the RNA strand is constructed. Each ribose group can have one of four possible base units attached to one of its ring carbon atoms. These bases are called either pyrimidines or purines and they are complicated structures with nitrogen atoms in a ring structure along with other atoms like oxygen and surfer. The four bases are Adenine, Cytosine, Uracil, and Guanine. The arrangement of these base units determines what proteins the RNA creates after cellular mitoses. RNA can be synthesized but it requires enzymes to accomplish it and it requires DNA as a template.

One theory says that the conditions on Mars were more suitable to the formation of RNA because of the presence of Boron, Molybdenum and oxygen there, and by means of the panspermia mechanism this RNA got transported to Earth.

The theory that life formed from non-living chemicals is called Abiogenesis. Supposedly, RNA and the four base units were created from pyrimidine, which is found in meteorites and is one of the most common organic molecules in space. RNA and the four base units could have been produced under space conditions by bombarding pyrimidine (a polycyclic aromatic hydrocarbon)  frozen in ice with UV radiation, or so the theory goes. NASA Ames lab reported this amazing achievement on March 3, 2015. If this is a valid experiment, then this could explain how the chemicals necessary for life began.

Abiogenesis has three parts: geophysical, chemical and biological. The first two have been determined, but the last one is where we are currently stalled. The chemicals needed for life were created from simpler molecules in space. The atmospheric and environmental conditions are known to be amicable for the development of life, but how it actually happened is still unknown.

The earliest evidence for life on Earth is 3.5 billion years ago. This is evidenced by the discovery of microbial fossils in 3.48 billion year old sandstone. Even if life had formed earlier the late heavy bombardment period would have wiped it out. There are lots of theories about how life actually began but no definitive proof. No one has synthesized a living cell from chemicals.

Until life can be created from non-living chemicals this concept is still a theory. It's a good theory, but it's not absolute proof. If it is proven as in the NASA experiment, then we could say that life originated spontaneously and is probably ubiquitous in the universe.

Of course, Religion would have a problem with this. The idea that life spontaneously came from non-living matter is hard to understand in the concept of creation. I don't think it's a problem because how God created life is not germane to the concept of creation. God has his ways, and who are we to argue.

Thanks for reading.