Stars, Supernovae, and Life

Astronomy Picture of the Day: Star Eta Carinae

Citation: http://apod.nasa.gov/apod/ap041128.html

Eta Carinae is a star currently entering the final stages of its stellar life cycle. Astronomers believe that the star, weighing in at over 100 times the mass of our Sun, is destined to become a supernova. 

How does this relate to our solar system? Well, as far as we know, our planetary neighborhood is the only one in the universe that harbors life. Of course, given the vast nature of the cosmos, it should come as no surprise if, one day, we do find life somewhere else out there. 

As Neil deGrasse Tyson explains, all the atoms in the universe heavier than hydrogen and helium are forged in the stars (see: http://youtu.be/B-LXUHJmzzc). This occurs via fusion, the process stars utilize to derive massive amounts of energy. In its early stages, a star is composed primarily of hydrogen and helium. Hydrogen fusion takes place at the core, where the temperature and pressure is high enough to drive this reaction. This takes place over a good chunk of the life of the star. However, the star does eventually run out of hydrogen, and when this happens it begins fusing helium atoms. This fusion of helium yields new elements, such as carbon, nitrogen, and oxygen. In fact, when collecting all of the elements synthesized from a star throughout its lifetime, one can fill up almost the entire periodic table (iron cannot be used in fusion to produce heavier elements, but the energy provided from the explosive mechanics of a supernova allow for the formation of these heavier elements).

The five elements that stand out are hydrogen, helium, carbon, nitrogen, and oxygen. Anybody studying organic chemistry or biology should recognize these as the building blocks of life. Other crucial elements (iron, zinc, copper, etc.) also owe their existence to the stars. The supernova, the explosion of a dying star, enables these elements to escape their confines and disperse throughout the universe. Without stars and supernovae, the ingredients of life do not appear. Without stars and supernovae, we wouldn’t be here today. That is something I find fascinating, and since some of the questions that inevitably arises when studying our solar system (How did life form? Is there life elsewhere?) are directly tied to this topic, I thought it would be a good one to explore and share. 

We are a part of the universe, and the universe happens to be a part of us. 

– Vineet Mohanty

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