We are All Star Stuff
Our Chemical Origins
We are all made up of bits of star stuff — material that was made in long-ago stars that have long since died — and also from material that was created in the Big Bang more than 13.7 billion years ago. So, in a sense, while we may not yet have been to space in our present bodies, everything IN our bodies came from space and will go back there some day.
This is the subject matter of my second 365 Days of Astronomy podcast, first “aired” on February 10, 2009. Because it’s so complex, I talked about the highlights in the podcast; here is where I can do a little more explanation and send you out surfing the web for more detailed background on how stars do their thing in creating elements.
The story of life’s evolution from the chemical elements cooked up in the Big Bang and stellar interiors is a long one. And, the last parts of it — the bits where the chemical elements that came from stars somehow combined to bring about the evolution of life on our planet (and maybe other places in the cosmos) — are still under intense study by astronomers, biologists, chemists, and geologists.
Essentially stars like the Sun (and smaller), fuse hydrogen in their cores to create helium. Eventually they blow off their atmospheres to space, and along with it, all the elements they’ve cooked up.
More massive stars create heavier elements and when they die — in supernova explosions — they hurl those elements to space. The force of the explosion also creates newer, heavier elements — and all that material moves out to enrich the space between the stars with dense clouds of gas and dust.
New insights come every day as astronomers study those clouds of gas and dust, searching out the natures of their chemical mixes. Biologists continue to tease out the earliest pre-biotic forms that link the atoms and molecules of many different elements to the more complex strands of material that became life.
Chemists lend their expertise to help all of us understand just how the elements are formed, and geologists study the traces of how it all came together on planet Earth.
The science of astrobiology — a new discipline that combines all of those I mentioned above — seeks to understand the origin of the building blocks of life and how they combined to bring about the life forms we know today.
Astrobiologists are not just fascinated with how it happened on Earth, although that’s an important step, but also how it might happen (or could have happened) on other planets in our solar system and galaxy. They examine a planet’s environmental history as well as its formation history to understand how the complexities of life arose from the materials left over from successive episodes of star life — and star death.
Want to know more about how we are all star stuff? Read here about a fascinating symposium I attended in 2008 at Radcliffe Institute, in Cambridge, Massachusetts.
As usual, there are countless good sources of information about stellar evolution and astrobiology on the Web. I’ve done some searching and found some good ones for you to start your search for the origins of life.
Each page has links to other pages, papers, news releases, and details about the great strides scientists are making in understanding the complexity of our chemical ancestry.
Stars are where it’s at, when it comes to element generation. These links will take you to places where astronomers discuss older stars, their evolution, and post images of them.
Bruce Balick’s Guide to Planetary Nebulae — a scientist’s exploration of these ghostly objects.
Chandra Guide to Stellar Evolution — from the folks at the Chandra X-ray Center.
Dead Stars — from the Dunlap Institute in Toronto. A great read!
Stellar Evolution guide from University of Oregon — an astronomy hyper-textbook provided for students, but accessible to all!
Star Formation: Life and Death — from Solarviews — a great beginner’s guide.
Stellar evolution on Wikipedia — a good overview of this complex topic.
The Evolution of Main Sequence Stars — courtesy of the Australia Telescope Outreach and Education page.
The Natures of the Stars – a great page by astronomer and long-time friend James Kaler.
Supernova: NASA Goddard’s Supernova Education page.
White Dwarf Research Corporation — a unique research group.
Where Chemical Elements Come From
More details on where elements originate and how they form in stars.
The Origin of Chemical Elements. An essay by Paul A. Heckert.
About Chemical Elements — an Interesting tour of the Elements.
Life cycles of the Stars. From NASA’s Imagine the Universe site — written for students and the general public.
Stellar Nucleosynthesis — Wikipedia’s entry on this subject.
Stellar evolution for everybody. From NASA’s Imagine the Universe site — written for students and the general public.
Supernovae and how they work. From NASA’s Imagine the Universe site — written for students and the general public.
The CNO cycle — a fairly techy explanation of how stars 1.5 times the mass of the Sun and larger fuse elements to create heat and light. From Wikipedia.
The Proton-proton chain reaction — a fairly techy article explaining how the Sun and stars smaller than the Sun fuse hydrogen to create helium, and in the process release heat and light. From Wikipedia.
A new, up-and-coming science that combines several disciplines to help scientists understand the origins of life on Earth and possibly other planets.
Astrobiology — a web page about astrobiology by astrobiologists.
Astrobiology Magazine — the Web’s premier journal of astrobiology.
Building Life from Star Stuff — a good introductory article about astrobiology by Leslie Mullen.
NASA Astrobiology — NASA’s Astrobiology page and a good place to learn the latest about what NASA’s scientists are doing in the field.