Star Stuff

Carl Sagan says that we are made of star stuff. He states that everything in our Solar System, including Earth and all life on it is made from the same chemical elements of past stars. This concept sounded ridiculous to me at first. But after giving it some thought, it makes perfect sense.

Stars are made up of hydrogen and helium and a small amount of heavier elements. When a star explodes into a Super Nova, those elements are forced out into the universe and in turn form stars and, in our case, other planets and life.

10 most common elements of our Solar System by mass
*Keep in mind that many scientists feel that the Universe comprises only about 4% of visible baryonic (The elements - ordinary matter made of protons or neutrons making up stars, planets, living beings) with the remainder being made up of 73% dark energy (the hypothetical energy that fills space and speeds up the expansion of the universe) and 23% dark matter (undetectable by it's radiation, this hypothetical matter is also thought to aid in universe expansion).

1. Hydrogen: 739,000 parts per million
2. Helium: 240,000 parts per million
3. Oxygen: 10,400 parts per million
4. Carbon: 4,600 parts per million
5. Neon: 1.340 parts per million
6. Iron: 1,090 parts per million
7. Nitrogen: 960 parts per million
8. Silicon: 650 parts per million
9. Magnesium: 580 parts per million
10. Sulfur: 440 parts per million

Elements in the Human Body by mass
*99% of body made up of the first six.

1. Oxygen: 65%
2. Carbon: 18%
3. Hydrogen: 10%
4. Nitrogen: 3%
5. Calcium: 1.5%
6. Phosphorus: 1.2%
7. Potassium: 0.2%
8. Sulfur: 0.2%
9. Chlorine: 0.2%
10. Sodium: 0.1%
11. Magnesium: 0.05%
12. Iron, Cobalt, Copper, Zinc, Iodine: < 0.05%
13. Selenium, Fluorine: <0.01%

I find it fascinating that the top four elements in our Solar System share a place with the top four elements in our bodies.

Source for elemental data: wikipedia.org