Published: May 14, 2016

Astronomers have precise instruments that can calculate the distance to the nearest star Proxima Centauri, but by taking a closer look inside our bodies, you could reveal an even closer one. Every living being on Earth possesses the elements that are formed through a star’s life cycle. The human body is made up of mostly oxygen, carbon, hydrogen, and nitrogen; all of which were created in stars through nucleosynthesis.

Every star produces its energy by undergoing nuclear fusion. Take our sun for example: every second our sun takes 464 million tons of hydrogen and turns it into 460 million tons of helium thereby losing 4 tons of matter every second. The leftover 4 million tons of matter (hydrogen) is transmitted into energy. This happens for most of the star’s lifetime. Larger stars can burn up elements faster, thus reducing their life span. After a period of time, all of the hydrogen is used up, and the star must fuse the helium into heavier elements like carbon, nitrogen, then oxygen. This process continues in larger stars until the core becomes iron, where it cannot fuse anymore elements.  Afterward, depending on the size of the star, it expands into either a red giant or a red super giant. The latter collapses on itself to a point and rebounds creating a shockwave explosion. The created elements are scattered across the universe from the outward blast of the supernova, and the star has died. Such enormous explosions are so powerful that they can be seen in the daylight, and a supernova can outshine its entire galaxy of 200 billion stars.

It can be through these high pressure and temperature explosions that heavier elements than iron can form. The majority of the elements inside our bodies, though, are from smaller stars that died with basic hydrogen, nitrogen, oxygen, and carbon still in abundance. These such materials are the necessary elements to create amino acids, the basic building block of life. We are considered carbon based life because the carbon is the most important element in our bodies. Carbon is one of the strongest elements for creating chemical bonds and complex connections. The only reason that we have such an abundance of elements both within our bodies and throughout our planet is due to the stars in our universe. We are star-dust!

Our sun does not have enough mass to create the supernova effect. Its outer atmosphere will be lost to space after the red giant phase, and its core will be left as a hot, white dwarf star the size of Earth. The easily recognizable star of Betelgeuse, though, will eventually explode as a supernova. This star to left above Orion’s belt is currently a red supergiant, thus it is seen with a reddish tint. Another easily recognizable red super giant is Antares in Orion’s nemesis Scorpio.