“The entire universe shares a common set of elements. In the very early universe, the only elements were hydrogen and helium. But since the formation of stars, lighter elements within the stars began fusing to create heavier elements, producing all the other naturally occurring elements. Under the extremely high temperatures and pressures within the core of stars, atoms collide at high enough speeds to overcome the usual electromagnetic repulsion of nuclei, allowing nuclear fusion to occur.” “All stars live by fusing hydrogen into helium.” From Teachers’ Domain.
Diagram from the Laboratory for Atmospheric and Space Physics. How cool would that be: “Where do you work?” “Oh, at the Laboratory for Atmospheric and Space Physics, no big deal…”
“Stars are fueled by nuclear fusion reactions, which take place in their deep interiors, or cores. Hydrogen nuclei fuse, forming helium nuclei. The energy produced by these fusion reactions prevents the star from collapsing under its own gravity. Mature stars contain enough hydrogen nuclei to last billions of years. When a star’s hydrogen fuel supply is spent, however, its core begins to contract. The contraction is so intense that it creates conditions under which helium nuclei fuse. In this way, helium becomes the star’s next fuel source. The fusion of helium nuclei produces carbon and oxygen nuclei, and in the process sufficient energy is released to temporarily sustain the star.
Once helium runs out, the nuclei of carbon, oxygen, and other elements begin to fuse. These new fuel sources are depleted at faster and faster rates. Since the heaviest element created in a star by nuclear fusion reactions is iron, a large iron core eventually forms at the center of everything. At this point, gravity becomes overwhelming, the core collapses, and an explosion occurs, during which outer layers of gas and heavy elements are ejected to space. Such explosions, called supernovas, occur about once a century in our galaxy. The energy created by supernovas produces nuclei heavier than iron. This process is known as supernova nucleosynthesis.” HELL YEAH!!!!!!!
From Teachers’ Domain
From the Greek hydro (water) and genes (forming)
What it is
Hydrogen is the simplest, most abundant, and lightest of the elements. It is colorless, odorless, nonmetallic, highly flammable (think Hindenberg), and able to react chemically with most other elements. It is present in all organic compounds and living organisms … and, oh yeah, in water.”
New Latin, from Greek Helios (“the Sun”)
What it is
Helium is the second most abundant element. It has the lowest melting point and is the only liquid that does not solidify when the temperature is lowered.
When does the next shipment arrive?
Probably never. As it happens, almost all of the Helium on Earth came about is the nuclear fusion that created the Sun so getting another shipment here would be awkward. A small portion comes from radioactive decay and a tiny bit more can be extracted from natural gas. There is, however, no practical way to manufacture large quantities. When the government realized this, it started storing billions of cubic feet of compressed helium in giant storage tanks.”
I just heard a great piece on NPR “The Music of Matter” on how all elements are from stars and on the periodic table. Part of Mendeleev’s genius: inferring that gaps in his periodic table were due to elements not yet discovered, as opposed to his table being wrong. Discusses the periodic, music-like nature of elements, their weights and properties.
Supernova picture from NASA
Elements crib sheet from Seed Magazine
Evolved star diagram from Wikipedia