The results of a new study conducted by the Sloan Digital Sky Survey (SDSS) are out. By observing the night sky using the APOGEE (Apache Point Observatory Galactic Evolution Experiment) spectrograph in New Mexico, we now have a better idea on how different elements are distributed throughout our galaxy.
With the new information, astronomers have already begun to gain new insights on how our galaxy was formed — its history, structure and composition. More interestingly, it’s confirming what we’ve already known for some time — that we are connected to the skies. And in Carl Sagan’s famous words — “we are made of starstuff“.
The atoms that make up our body are the same kinds of atoms that were created a long time ago inside the stars. And somehow, these atoms were able to make their way from the stars to us. It’s really quite fascinating to think that we’re made of the same stuff stars are made of, isn’t it?
So how did all this come about? Astronomers studied over 150,000 stars in our galaxy to find out what each one was made of. Particularly, they wanted to know how much of almost two dozen chemical elements each star they mapped out was composed of. Among the list of elements measured is the so-called ‘CHNOPS elements’. CHNOPS stands for carbon, hydrogen, nitrogen, oxygen, phosphorous and sulfur — the elements that are commonly known as the building blocks of life, and make up about 97% of the human body.
To come up with the measurements, astronomers used a method known as spectroscopy which splits light into a spectrum (better known as a rainbow). By measuring the depths of bright and dark patches in the spectrum, they were able to determine how much of each element the star contains.
So now we have a catalogue detailing the measurements of all the CHNOPS elements for the largest number of stars ever surveyed. Apart from validating how much the composition of our human body is similar with the composition of a star, the catalogue also shows that heavier elements like oxygen (which make up about 65% of our body mass) are more abundant in the inner part of our galaxy.
Because the stars in this part of the galaxy are much older, the information suggests that more of the elements of life were present earlier in the inner regions of the galaxy than in the outer regions. Which also implies that life might have existed earlier in the center of our galaxy. And because our planet’s position is not within that region, maybe it’s also indirectly saying that ancient beings might have existed before us, right?
Maybe that’s going too far too soon. But we love alien theories, don’t we? And even if Sten Hasselquist of New Mexico State University — the presenter of the study — was quoted as saying, “I don’t want you walking out of here writing that we found life!”, we know that won’t stop us from making all kinds of speculations.
So while astronomers build on the newfound information, we can in the meantime check out the catalogue that shows the chemical composition of the stars in our galaxy which have so far been mapped out. It’s available online through the SDSS website.