Carl Sagan fans everywhere are getting pumped for the widely acclaimed, rehashed version of Cosmos staring Neil deGrasse Tyson on March 4. Tyson is a gifted orator and is sure to fill the running shoes of the late Carl Sagan. The series is intended to educate the public on the most current scientific understanding of the universe since Cosmos first aired. Among the many cosmic discoveries that have since been made, there is one that holds all of the cosmic cards, according to Tyson in a recent NPR interview; and that is that the universe exists within us.
This is not exactly ground breaking news for Cosmos fans. Carl Sagan was known for his widely acclaimed lines in Cosmos. “We are star stuff” took the runner-up for Cosmos catch phrases right under, “Billions and billions.” (Although, contrary to popular belief, Sagan never utturred this phrase in the entire Cosmos series.)Yet the fact that we are star stuff is one of the most poetic and outstanding revelations the universe has ever revealed. However, like many over beaten phrases, its significance often loses meaning and deserves to be reinforced. So what does the phrase, “We are star stuff” really mean and how do we know that it is true?
In regards to the former, every atom that comprises everything around us was originally fused together in the first generation of stars to populate the universe. Due to a process known as thermonuclear fusion, stars churned hydrogen into helium, helium into carbon, carbon into oxygen and oxygen into iron. Thermonuclear fusion is responsible for the periodic table. Without thermonuclear fusion, the periodic table would be much shorter. Eventually, stars went unstable and spewed chemical debris across the galaxy. Out of this debris, a second generation of stars formed. These chemicals eventually collected themselves into complex organisms through the process of evolution. Eventually, organized star-dust became complicated enough to look up at the stars and ask, “Where did we come from?” The answer, rather poetically, was staring us in the face.
Sounds like an interesting story, but how to do we know that it is true? A part from its explanatory power, there are a wide-range of observations that confirm these claims. Originally, physicists scoffed at the idea of a “big bang” largely on the grounds of philosophical, rather than scientific, reasons. In particular, there is something aesthetically pleasing about a universe that is eternal and unchanging. Nevertheless, empirical observations eventually overturned the aesthetics of an eternal universe. Unknown to physicists, however, the universe was about to reveal an aesthetic truth that fulfilled their hearts desires.
Eventually, through the red-shift of galaxies, astronomers discovered that the universe was expanding. When physicists starting to take big bang cosmology seriously, one of the moves they made was to calculate the production and abundance of light-elements in the first minutes of the expanding universe. They did this by writing down the equations which dictate the rate at which various nuclear reactions originallyed occured. The rate of change for any one nuclear species is equal to the sum of its terms—each term being proportional to sum other nuclear species. The result was a set of linked-differential equations. Plugging the set of differential equations into a computer provides a numerical solution. When physicists crunched this number, they found that it corresponded to the amount of light-elements in the intergalactic material from which the stars emerged, thus confirming that we are indeed, star stuff.
By Nathan Cranford