{"id":2282,"date":"2021-08-16T18:00:00","date_gmt":"2021-08-16T18:00:00","guid":{"rendered":"http:\/\/modernsciences.org\/?p=2282"},"modified":"2021-08-21T05:53:46","modified_gmt":"2021-08-21T05:53:46","slug":"how-two-astronomers-with-some-markers-linked-us-to-the-stars","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/how-two-astronomers-with-some-markers-linked-us-to-the-stars\/","title":{"rendered":"How Two Astronomers With Some Markers Linked Us To the Stars"},"content":{"rendered":"\n

A very spirited Carl Sagan once said in one of the episodes of his 1980 TV miniseries Cosmos<\/em>: \u201cThe nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff.\u201d <\/em>Filled with conviction and all the gravitas that his voice famously commandeers, he said it in such a matter-of-fact-ly way that you just sit there and nod in agreement\u2014or at least that\u2019s what I\u2019m inclined to believe how people felt when they heard him say it on TV all those years ago.<\/p>\n\n\n\n

<\/em>Admittedly, it\u2019s enough of a challenge to ponder the answers to questions like these. Sure, we know that planets and stars can form from accretion disks of vast clouds of gas and debris that just huddle together from their own collective gravity to form stuff like our own Sun or planets like Earth and Neptune. But the question beyond that\u2014where the elements<\/em>, the stuff that we (and everything else) are made of, come from\u2014is one that eludes everyday life. It\u2019s the sort of question that maybe necessitates our very own Carl Sagan <\/em>figure to bring out the curiosity inside us.<\/p>\n\n\n\n

Or, perhaps, just a pair of astronomers who probably should have instead listened to some smart folks talk it out at a conference. That seems to have been the case a few years ago, when a certain diagram made its way across scientific discussions online.<\/p>\n\n\n\n

Scribbling Down Star Stuff<\/h2>\n\n\n\n
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Inese Ivans\/Jennifer Johnson, Sloan Digital Sky Surveys<\/em> <\/figcaption><\/figure>\n\n\n\n

At first glance, this just looks like a periodic table of elements after your little sibling got hold of your colored markers. It\u2019s either that or the sort of distracted scribbling students all over the world would have been all too familiar with. Its colorful, innocent, almost childlike guise clevely belies a century of intense research by astronomers and related researchers the world over\u2014that and the exasperation of two astronomers with some time on their hands.<\/p>\n\n\n\n

During a 2008 conference called Kavli Institute of Theoretical Physics (KITP) Conference: Back to the Galaxy II<\/em>, astronomers Jennifer Johnson and Inese Ivans were in attendance, listening to the premier researchers of their field discuss the latest breakthroughs in unraveling the history of the Milky Way Galaxy. Experts on topics ranging from dark matter to distant galaxies came together to share their findings with their colleagues, and perhaps take a peek into what makes our own galactic neighborhood tick throughout the eons since it formed.<\/p>\n\n\n\n

At that point, new research was pouring in on the chemical compositions of stars. Naturally, it often led to questions such as \u201cwhere does this element come from?\u201d\u2014a question that the two astronomers had had enough listening to on repeat. Grabbing some colored markers from a nearby drugstore and a printout of the periodic table of elements, the two proceeded to color in each element according to the then-current understanding of how they are formed. Powered by Carl Sagan\u2019s spirited speech\u2014\u201dwe are made of star stuff\u201d<\/em>\u2014and using different colors to represent different processes, each element was colored in, with stripes and shades to show rough estimates of how much a certain process creates how much of a certain element.<\/p>\n\n\n\n

What came out was a table that at first glance appears to have been crafted by studious young researchers equipped with notebooks and magnifying glasses instead of computer simulations and large ground-based telescopes, but what lies underneath is a colorful, albeit messy, summary of a century of research in that field that the two astronomers waived in the faces of anyone interested in looking at their piece of work during that fated conference.<\/p>\n\n\n\n

A Stellar Work in Progress<\/h2>\n\n\n\n

By 1920, SIr Arthur Eddington proposed that the Sun was powered by the nuclear fusion of hydrogen into helium. Nobel laureate Hans Bethe later proved the fact, but the link between what powers stars and what stars, planets, and indeed us, were made of, was not yet established\u2014not because we didn\u2019t know how stars work, but because we had yet to understand atomic nuclei at the time. It took the efforts of Fred Hoyle, Willy Fowler, and Margaret and George Burbidge in the 1950s to finally show that elements beyond helium were forged from stellar cores and were dispersed across the universe upon their deaths. According to Johnson herself, all these discoveries, and a summation of years\u2019 worth of observations of stellar compositions, computer models of stellar fusion, and the flashes of light produced by decaying radioactive elements in the cosmos, were now represented by streaks and smears \u201cthat Inese and I converted into splotches of teal, orange, and yellow in 2008.\u201d<\/p>\n\n\n\n

Johnson jokes that astronomers really only recognize three elements in the periodic table: hydrogen, helium, and the \u201cmetals<\/em>.\u201d The \u201cmetals\u201d conveniently group all the other elements produced outside the Big Bang together, which works well enough for their purposes; of course, the universe is never really that simple. As she said it herself: \u201cA star\u2019s atmosphere is a preserved sample of its natal gas, a fossil record etched onto the surfaces of the stars; and it is the sum of the nucleosynthesis of its stellar ancestors. If we can decode the chemical fingerprint, we can know about the stars that came before. The number of massive stars that have ever existed is not easy to measure by counting black holes, but observing the accumulated \u2018vomit\u2019 left as black holes form is much easier.\u201d<\/em><\/p>\n\n\n\n

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NASA\/ESA\/G. Dubner et al.\/A. Loll et al.\/t.Temim et al.\/ F. Seward et al.\/VLA\/NRAO\/AUI\/NSF\/ Chandra\/CXC\/Spitzer\/JPL-Caltech\/ SMM-Newton\/ESA\/Hubble\/STScl <\/figcaption><\/figure>\n\n\n\n

This version above, presented at the winter meeting of the American Astronomical Society<\/em> in 2017, would show things a bit clearer. Johnson was part of the team that presented results from the Sloan Digital Sky Survey (SDSS) collaboration, which measured the composition of more than 100,000 stars across the night sky. Naturally, the chart is also a work in progress; as more information is discovered about the origins of these elements, revisions will be added to adjust for them. As of now, the \u201cmiddle elements\u201d like tin, molybdenum, or arsenic\u2014Johnson\u2019s favorite element\u2014are generally still up in the air; it will be difficult to find the \u201csmoking gun\u201d for these elements that aren\u2019t key to powering stars and aren\u2019t produced in stellar explosions either. And as of now, the most recent revision came in 2017 after the detection of gravitational waves from merging neutron stars by the Laser Interferometer Gravitational-Wave Observatory (LIGO); further studies into these gravitational waves and their light sources confirmed the theory that these oddball stellar explosions produce most of the gold and other r-process<\/em> (rapid neutron capture process) elements in the universe.<\/p>\n\n\n\n

We Are Made of Star Stuff<\/h2>\n\n\n\n

At the end of the day, Johnson and Ivans never really made a breakthrough\u2014they simply summarized what the giants of their field had gathered from decades before. It\u2019s not some peer-reviewed, government-funded research project; it\u2019s just a plain white printout funded by spirited astronomers and supplied by the nearest drugstore. What was groundbreaking, however, was the human <\/em>aspect of it all. What seemed to be just scribbles on a periodic table instead gave personality to the efforts of scientists the world over spanning a century. Now we see that the carbon in our bodies, the oxygen we breathe, and the gold we wear all come from the stars in the sky, scattering their contents across the universe upon their death.<\/p>\n\n\n\n

Perhaps it\u2019s this sense of personality, imparted through the scribbles and footnotes on the empty spaces between hydrogen and helium on the table, that gave this seemingly simple picture its own life, creating waves of news online about how a couple of astronomers helped change the way we see the periodic table, and in the process bringing science closer to the people\u2014just like how Carl Sagan did it all those years ago.<\/p>\n\n\n\n

Bibliography<\/h2>\n\n\n\n