Stellar evolution, our Sun’s life in the Milky Way

From the silence within thoughts are born, may be acted upon, and then put to rest. Stars are also born, live an active life, and are then put to rest.

After the Big Bang and start of nucleosynthesis about 13.7 billion years ago stellar nurseries began to form. The initial transition from energy to material (E = mc2, mass times the speed of light squared) took place relatively quickly and resulted in the formation of hydrogen gas. Under the influence of gravity the gas formed vortices and areas of greater density, which in turn condensed to form the first proto stars and galaxy clusters.

The first proto stars burned (thermonuclear fusion) hydrogen, under high density and temperature, and thusly created helium with copious amounts of energy. When a stars’ hydrogen supply is depleted it will then start to burn Helium, and after that start burning even heavier elements.

Hydrogen (deuterium & tritium) = Helium-4, freeing a neutron and 17.59 MeV (million electron volts)

Virtually none of the chemical elements that we use today existed back when the universe was born. In fact, the entire repertoire of the periodic table consisted only of hydrogen, helium, deuterium (heavy hydrogen) and lithium. Not much there to make a soup with.

Stellar Nursery

Stellar Nursery

Stars come in all sizes, but all are mostly big and bigger. Super Giants like Deneb (20 solar masses), Beteljiuce and Antares; and giant stars Acturus and Polux. Some stars like VY Canis Majoris are 2,000 times the size (radius) of our Sun. Eta Carinae may be 300 times as massive as our Sun.

When a star exhausts all of its fuel it will die. If it originally was large enough (about 1.5 times the mass of our sun) it is destined to explode as a nova (or supernova) before becoming dim and cold. Stars less massive will not explode but will go out with a whimper. But in every case the new material synthesized during a stars life time will be spewed out into space, seeding the environment with the new elements that it created.

Successive generations of stars fill the universe with even heavier elements.

All in all, stellar interiors produced all of the different chemical atoms that we have today. It is sometimes said, “for dust thou art, and unto dust shalt thou return.” More accurately, we can say that all of the chemical elements that exist in the human body today were indeed created by stars.

Your body is made from star stuff.

The chemical composition of the human body shows what stellar interiors created.
65%…..Oxygen
18%…..Carbon
10%…..Hydrogen
03%…..Nitrogen
04%…..Calcium, Phosphorus, Potassium, Sulfur, Chlorine, Sodium, Magnesium, Iron, Cobalt, Zinc, Iodine, Selenium and Fluorine

These chemicals are in the form of water, protein, fats (lipids), carbohydrates, DNA, dissolved organics, gases, and other molecules.

In 1910 astronomers Ejnar Hertzsprung and Henry Norris Russell made a major discovery that enabled us to better understand for the first time how stars evolve. They charted a large number of stars on a graph, cataloging them by luminosity (intrinsic brightness) and temperature (color).

HR Diagram

Hertzsprung and Russell (HR Diagram) found that most stars fell onto a curve which they named the “main sequence.” During that stage stars are fusing hydrogen in their cores. After stars are born they migrate into the main sequence, remain there for most of their lifetime, and then migrate away from the main sequence when they transform and eventually die.

The more massive a star, the shorter their lives span. It simply burns its available fuel quicker. A massive star may shine for only 10 million years. A star like our Sun will burn for about 12 billion years. Since our Sun is already 4.5 billion years old, this leaves us all enough time left over (7.5 billion years) to really enjoy ourselves.

Some stars die in a massive explosion (supernova), which in turn could collapse and become neutron stars, pulsars, or black holes. There is a massive black hole in the center of our Milky Way galaxy.

In about 4.5 billion years our Sun will become a Red Giant star. Its atmosphere will grow so large that the orbit of the Earth will be inside of it.

Also in about 4.5 billion years we will undergo a “sweet embrace” with the Andromeda Galaxy, our nearby sister. Our Milky Way will “collide” with the Andromeda galaxy. But since most of a galaxy is empty space, we’ll be pretty much spared.

The chemical composition of the sun:
91%…..Hydrogen
08%…..Helium
01%…..Oxygen, Carbon, Nitrogen, Silicon, Magnesium, Neon, Iron and Sulfur.

The point is, the constituents of our physical bodies were all made in stellar interiors. All elements in the universe recycle themselves.

We are intimately connected to each other and the Universe. A single action for good can profoundly affect the world.

Our bodies are constructed from star stuff, but our spirit resides in a realm beyond the influence of matter.

Andromeda Galaxy

Being has been described in the Bhagavad Gita …

He is declared to be unmanifest,
unthinkable, unchangeable, therefore
knowing him as such you should not
grieve.

From creation to dissolution, we act and play on the illusory stage of life.

From William Shakespeare’s, As You Like It, …

All the world’s a stage,
And all the men and women merely players;
They have their exits and their entrances;
And one man in his time plays many parts,
His acts being seven ages.

(Infancy, childhood, lover, soldier, justice, old age, and dementia followed by death).

The curtain has opened for your performance. What are you doing? Hopefully, you are practicing meditation every day to reach the depth of inner silence, to unfold your full infinite potential for the sake of all mankind.

This entry was posted on Monday, September 6th, 2010 at 9:32 am and is filed under Knowledge. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

 

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