We Are Stardust!

At Home In The Universe Essays > Science, IT, Nature

Part 9: Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus: they are all ‘cooked’ in the stars!

A definition of matter, based on its physical and chemical structure is: matter is made up of atoms. All the objects from everyday life that we can bump into, touch or squeeze, are composed of atoms. This atomic matter is in turn made up of interacting subatomic particles—usually a nucleus of protons and neutrons and a cloud of orbiting electrons.

The elements – that is, this ordinary (or baryonic) matter made of protons, neutrons and electrons – are only a small part of the content of the Universe. Cosmological observations suggest that only 4.6% of the Universe’s mass/energy comprises the visible baryonic matter that constitutes stars, planets and living beings. The rest is made up of dark energy (68,3 %) and dark matter (26,8 %). These are forms of matter and energy believed to exist on the basis of scientific theory and observational deductions, but they have not been directly observed and their nature is not well understood.

Astrophysics may be the only science that knows exactly how much it does not know!

Hydrogen (H1, Protium), composed of a single proton and a single electron, is the most abundant element in the Universe; helium He, composed of two protons, two neutrons and two electrons, is second. Hydrogen and helium, known as the light elements, are generated by the Big Bang. They are estimated to make up roughly 74% and 24% of all baryonic matter in the universe respectively. Despite comprising only a very small fraction of the Universe, the remaining heavy elements can greatly influence astronomical phenomena. Only about 2% (by mass) of the Milky Way galaxy’s disk is composed of heavy elements.

The heavy elements are generated by stellar processes. In astronomy, a “metal” is any element other than hydrogen or helium. This distinction is significant because hydrogen and helium are the only elements that were produced in significant quantities in the Big Bang. Thus, the metallicity of a galaxy or other object is an indication of stellar activity after the Big Bang. All of the heavy elements are “cooked” in the stars, according to the Golden Rule: the bigger the star, the heavier the cooked elements!

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Periodic table showing the cosmogenic origin of each element

The bulk composition of the Earth by elemental-mass is roughly similar to the gross composition of the Solar System, with the major differences being that the Earth is missing a great deal of the volatile elements, hydrogen, helium, neon, and nitrogen, as well as carbon, which has been lost as volatile hydrocarbons.

The remaining elemental composition is roughly typical of the rocky inner planets, which formed in the thermal zone where solar heat drove volatile compounds into space. The Earth retains oxygen as the second-largest component of its mass (and largest atomic-fraction), mainly from this element being retained in silicate minerals, which have a very high melting point and low vapor pressure.

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Chemical composition of the Earth

By mass, the cells of our human body consist of 65–90% water (H2O), and a significant portion of the remainder is composed of carbon-containing organic molecules. Oxygen therefore contributes a majority of a human body’s mass, followed by carbon.

Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus. The next 0.75% is made up of the next five elements: potassium, sulfur, chlorine, sodium and magnesium. Only 17 elements are known for certain to be necessary to human life, with one additional element (fluorine) thought by your dentist to be helpful for tooth enamel strength. A few more trace elements may play some role in the health of mammals.

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The main elements that compose the human body are shown, from most abundant (by mass) to least abundant.

Hydrogen, oxygen and carbon are essential for life: life can not be without them. Other elements are not so much necessary for life, as well as for the maintenance of life. Cobalt, for example, we need to make vitamin B12. Potassium (kalium) and a little sodium are literally good for the nerves.

Lets have a closer look at iron. Iron we need to form hemoglobin and without hemoglobin we cannot live. Hemoglobin is a protein in our blood. The red blood cells are almost completely filled with this protein. It gives blood its red color. In these red blood cells hemoglobin is responsible for the transport of oxygen (O2) and carbon dioxide (CO2) through the blood. Each red blood cell contains about 640 million hemoglobin molecules. This is about 34% of the contents of a normal red blood cell.

Each day 1% of the hemoglobin will be renewed. An adult has 600 to 800 grams of hemoglobin, which contains approximately 2.5 grams of iron (approximately 0.3%).

When we inhale, oxygen flows into the lungs and it binds itself to the hemoglobin in the red blood cells. The blood transports the oxygen to the other organs in the body. On its arrival, the oxygen separates from the hemoglobin and is consumed. Hereby carbon dioxide is formed.

The produced carbon dioxide is now going in its turn into the red blood cells and binds itself to the hemoglobin. Then the blood flows back to the lungs. Here the carbon dioxide leaves the red blood cells and is exhaled.

But how to “cook” iron in the first place? To be continued!

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Thanks to Wikipedia the free encyclopedia, and special thanks to Neil Shubin for ‘The Universe Within’, to Lawrence M. Krauss for ‘Atom: An Odysee from the Big Bang to Life on Earth and Beyond’, and to Jim Bell for ‘The Space Book’.

ShantiShanti is a regular contributor to Osho News

All articles of this series can be found in: At Home in the Universe

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