Right now, I’m going to question that notion.
Much of the search for extraterrestrial life is based on the following question: Can the planet hold water? I began by questioning why water was so crucial for life. The answer I thought I was satisfied with was that we’ve simply yet to find a molecule to replace it. Surprise, I was wrong.
In fact, there has been a substance proposed to be a potential replacement to water — formamide.
Formamide (CH3NO) is the simplest carboxylic acid amide that exists in abundance in star-forming areas of the universe. It is more than just a replacement for water; it might be even better than water.
Turns out, water can actually be corrosive to life. It is a highly polar substance, and although that is ideal for many biological reactions, it can also destroy many essential molecules and prevent the necessary formation of hydrogen bonds. This can disrupt the formation of DNA and proteins, both of which are essential for life.
In formamide, these organic molecules are much more stable, which then begs the question: Why doesn’t life use formamide and not water? Scientists speculate that life actually did begin with formamide, and when the early organisms came to Earth on asteroids or comets, they had to adapt to live off Earth’s abundant water.
This concept was made more plausible by Svatopluk Civiš at the European Institute of Innovation and Technology (EIT), who ran simulations of Earth’s early conditions, which involved constant bombardment by asteroids and comets onto a crust of formamide and clay. It was found that the four essential RNA nitrogen bases — guanine, cytosine, adenine and uracil — were then formed.
The problem with the concept of formamide as the initial base of life is that, although present in many parts of the universe, formamide was not abundant on Earth when life was first formed.
Zachary Adam from the Department of Earth and Planetary Sciences at Harvard University and Masashi Aono from the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology may have found a way to explain this paradox.
By exposing water, hydrogen cyanide and aqueous acetonitrile, all substances found on early Earth, to the high energy particles emitted from radioactive cobalt-60, they were able to artificially create formamide.
Previously, formamide had been synthesized by heating carbon dioxide and ammonia under pressure, basically reversing the decomposition reaction or reacting methyl formate with ammonia.
However, by exposing compounds from the early Earth to high energy particles, Adam and Aono were able to form formamide quicker than ever before. Most importantly, they were able to perform the synthesis under conditions that could have plausibly taken place on early Earth.
The next issue is where the high-energy particles would come from. Early Earth had more radioactive material than it does today, including near-extinct isotopes such as aluminum-26, iron-60 and iodine-129. However, these would not be enough to form high-energy particles.
Besides those isotopes, there likely existed an even more fascinating phenomenon: natural nuclear reactors. When a high concentration of uranium is in the presence of water, a self-sustaining nuclear fission reaction can occur.
In the Oklo region of Gabon, there is a network of natural nuclear reactors that first began two million years ago. Although this is long after life first appeared on Earth, it is proof that an abundance of radioactive material could have been present on Earth to release the high-energy particles that would create formamide and, in turn, allow the origin of life.
Although this scenario is currently unlikely and not heavily researched, it is a distinct possibility. Adam and Aono explained that it would only take one corner of the world to create a pocket of formamide that would let life take hold, setting off the chain reaction across eons that leads to the abundance of life on Earth today.
Adam and Aono see this as the next step in their research: to find this spot on early Earth and determine if life may have been formed using formamide instead of water.
It is a shocking revelation to learn that life could exist without water. Water being essential to life is a fundamental concept that seems to be the basis of so much scientific exploration, especially concerning the beginning of life on Earth and the possibility of life somewhere else in the great cosmos.
It really makes you question everything. What does “life” actually require? Does it really need RNA or DNA? Does it really need a warm environment? Does it really need oxygen and carbon dioxide? Will we ever really know?
