?What Is Carbon
The entire world is made out of atoms. The table your computer screen is sitting on, the clothes you're wearing, the air you breathe... even your body is made out of atoms. And those atoms come in many different types. We call those different types of atoms elements.
Carbon is one of the elements; one type of atom. It contains six protons and six neutrons in its nucleus, with six electrons orbiting around the outside. The number of protons and electrons is what determines its properties, and those properties are incredibly important. Without carbon, we humans would not exist.
Carbon looks very different in its many shapes and forms. Diamond is made of carbon. But so is the graphite in your pencil, the charcoal in a fire and the coal in a power plant. Carbon dioxide, a molecule made out of carbon and oxygen and is something you breathe out, is also the gas most responsible for climate change. So, carbon is totally different in its many different forms.
But, from our perspective as humans, the important thing is that carbon is the basis for life on Earth. We, as humans, are considered to be carbon-based life.
Carbon is the most important component of all life found on Earth. Even the most complex molecules that make us up contain carbon bonded to other elements: carbon bonded to oxygen, carbon bonded to hydrogen, carbon bonded to nitrogen. You name it - it has carbon.
There are certain key molecules that are a big part of our bodies and the bodies of other living organisms. Proteins, for example, form almost our entire bodies, and proteins on Earth are based on carbon. Nucleic acids are vitally important to animal life, and indeed also contain carbon. Carbohydrates and lipids (fats) are also major parts of the bodies of animals like us. All of these things are reliant on carbon. For this reason, life on Earth is known as carbon-based life, or life that contains building blocks that are made up of combinations of carbon and other elements.
We often assume, therefore, that if we were to find life on other planets, in other parts of the universe, that it would also be carbon based. But some say that we are foolish to make that assumption. There are other elements, like silicon, for example, that contain many of the properties of carbon. Perhaps if we ever meet aliens, their bodies will be made of silicon, not carbon! There's a famous episode of Star Trek where they did just that. I guess there's only one way to find out