cosmic abundance of elements
In the universe as a whole, hydrogen is by far the commonest element followed by helium and more distantly by heavier elements such as oxygen and carbon. Locally, the proportion of heavy elements varies from one star system to another and is an influential factor in the formation of planets.
| Number of atoms per 10,000,000 of hydrogen | |||
|---|---|---|---|
| hydrogen | 10,000,000 | sulfur | 95 |
| helium | 1,400,000 | iron | 80 |
| oxygen | 6,800 | argon | 42 |
| carbon | 3,000 | aluminum | 19 |
| neon | 2,800 | sodium | 17 |
| nitrogen | 910 | calcium | 17 |
| magnesium | 290 | all other elements | 50 |
| silicon | 250 |
