Astronomy

A carbon life

A carbon life

Carbon is the chemical element that sustains all life on Earth. In nature there are 92 chemical elements in their natural state. That is, 92 different types of atoms. They are the small pieces that combine with each other to form all the known matter. Atoms combine to form molecules, and molecules come together to form matter. Everything we see around us is formed with only those 92 elements. Including ourselves.

95% of the body of living beings is composed of only four elements: carbon, oxygen, hydrogen and nitrogen. Of them, carbon is the most important. Without it, the DNA could not be formed. Proteins, carbohydrates, vitamins and fats are also carbon compounds.

Carbon is a very abundant element in the Cosmos. Carbon atoms join together forming long chains that serve as the basis for building other more complex molecules. This facility to link molecules is what allowed evolution to living organisms. In the primitive earth there was an excellent combination of large amounts of carbon and water, which were decisive for the origin of life. Carbon is the chemical basis of life.

It has always been thought that life could only be carbon based. When we look for life outside the Earth, we always assume that it will be composed of the same types of atoms as ours. However, at the end of 2010, NASA announced that it had discovered a new way of life based on arsenic. It would be a bacterium that lives in Mono Lake, in California. But, a year later, the results are still inconclusive. It is not that he lives in arsenic, but that his life and his DNA are based on arsenic instead of carbon. If confirmed, it would open the doors to new ways of life hitherto unknown.

Also in the search for extraterrestrial life. Until now, those seeking life outside our planet have focused only on areas where carbon is abundant, since life without it is unimaginable.

Carbon, like water, follows a cycle. The carbon cycle unites all living beings with the Earth, in a fragile balance. The Earth contains an amount of carbon that does not vary over time. It only transforms from one phase to another, and from some living beings to others. As with water, each carbon atom that today composes our body, was previously part of many other living beings.

Through photosynthesis, plants transform the energy of sunlight into carbohydrates. They incorporate carbon from the atmosphere into their tissues. When animals eat them, they incorporate it into the food chain. Through waste and respiration, part of the carbon returns to the atmosphere and the earth. The rest will return when that living being dies and decomposes.

The use of hydrocarbons and fossil fuels by man breaks the balance of the carbon cycle. Carbon dioxide returns to the atmosphere at a rate much higher than its natural rate. It accumulates, produces the greenhouse effect, and can cause or accelerate a climate change. It also accumulates in the oceans, making them more acidic. The Earth has already lived through these situations in the past, and resulted in great extinctions.

The difference is that, this time, it is in our power to avoid it.

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