You know how sometimes a song will get stuck in your head? Everything by They Might Be Giants
has that effect on me. Today's song is "Why Does the Sun Shine?
" It's a nice little educational song... "The sun is a mass of incandescent gas, a gigantic nuclear furnace, where hydrogen is built into helium at a temperature of millions of degrees." Have you ever wondered what else is in the sun besides hydrogen and helium? I hunted up a table (source: NASA - Goddard Space Flight Center
) listing the sun's elemental composition, which we know from analysis of its spectral signature. I'm sure you're not surprised that hydrogen is the most abundant element. The sun is constantly fusing hydrogen into helium, but don't expect the ratio of hydrogen to helium to change anytime soon. The sun is 4.5 billion years old and has converted about half of the hydrogen in its core into helium. It still has about 5 billion years before the hydrogen runs out.
|Element||Abundance (% of total||Abundance
| ||number of atoms)||(% of total mass)
Global Brightening & Dimming | Abundant Earth Elements
Photo: Image of the sun taken by the Extreme ultraviolet Imaging Telescope (EIT) at the NASA Goddard Space Flight Center, July 15 1999. (NASA)