Our Stellar Origins

By Michael Edmonds 18/09/2011 6


The Andromeda Galaxy (pronounced /ænˈdrɒmədə/) is a spiral galaxy approximately 2.5 million light-years away[4] in the constellation Andromeda.

Photo Source: Creative Commons

About 13.5 billion years ago our universe exploded into existence, in what is described by most cosmologists as the Big Bang. Within the first few minutes of this explosion a myriad of processes occurred as the new born universe expanded and cooled. Out of this early universe, hydrogen atoms were created along with smaller amounts of helium and lithium. As time progressed, some of these atoms coalesced to form stars of various sizes. As these stars burned, stellar nucleosynthesis took place, converting the lighter elements into heavier elements such as carbon, silicon and even iron. The more massive stars burned rapidly due to the intense gravitational force often going supernova within a few million years, launching the new heavier elements across space.

About 4.5 billion years ago our solar system formed from various cosmic and stellar debris. Atoms including carbon, oxygen and silicon were drawn into the gas clouds which would eventually become the sun and attendant planets.

As time continued its march forward, life began to develop on the third planet from the sun, one that the future inhabitants would call Earth, perhaps as early as 3.8 billion years ago. Life evolved to become more complex and diverse, spreading out to fill even seemingly inhospitable environments. As life continued to evolve some life forms survived and adapted to the endlessly changing Earth while others became extinct. As each life form rose and fell, the star born atoms of carbon, oxygen and other biologically important elements, cycled through the environment, transiently occupying living flesh, inorganic matter and even traversing the environs in gas form.

Fast forward to the present day and I am looking at my hand imagining the myriad of carbon and oxygen containing molecules which are present in the skin, tendons, muscles and bones in my hand, as well as in the blood which is being pumped through my veins. I am struck by the sheer improbability of my existence and the incredible knowledge that the atoms of my body are billions of years old; that these same star born atoms have previously soared high into the atmosphere in gaseous form; that some of these atoms may have once been part of the last Tyrannosaurus rex, or part of the first flowering plant; and that these atoms have formed part of many other human beings across history. On the timescale of these atoms lifetime, my existence is but a fleeting moment on the cosmic clock.


6 Responses to “Our Stellar Origins”

  • It is a magnifcent thing to know that we are star stuff and to partly understand how this came to be, but sadly way too many people would rather “know the truths” based on ancient myths and dismiss science and all the evidence that supports this explanation.

  • I do not believe that those who ask why questions are somehow followers of myths that exclude science. I think the current cosmological data offers very good data for the fine tuning of the universe not being by chance or necessity, which only leave design of course. The roughly 12 cosmological constants for the initial conditions of the universe seem extremely fine tuned. An example would the ratio between matter and anti-matter,. If changed by the slightest amount we would end up with a life prohibiting universe not life giving. Then there is the new information about dark energy and how if one was to change it’s properties the by 1/10 to122 then the universe would also not allow life. Normally any odds 10 to 80th power have a nil chance of ever happening. The why question is totally valid when it comes to trying to understand existence. We may be star stuff, but is that all we are? Given the initial conditions of the universe I would think the idea of design is equally valid.

  • Nick,

    I don’t think asking “why” necessarily means someone is a follower of myths, rather it is when people fill in the gaps of what we don’t know with made up beliefs with no supporting evidence that they could rightly be said to be followers of myths.
    You point out that cosmological constants allow life (as we know it) to exist but I see no reason why this automatically requires design.
    The idea that we are star stuff is an awesome concept, but I agree with you – we are far more than that. We are sentient life forms that are capable of forming complex interactive societies capable of great things.

  • Nick

    I think it’s also pertinent to point out, that we don’t know how many failed attempts there have been to generate a universe. And it’s meaningless trying to estimate odds without a sound understanding of the initial conditions or whether the events are independent or linked in anyway. There is in short, no way to make any meaningful estimate of any of the likelihoods your employing. Similarly- things like the cosmological constant (yielding an expanding universe) could have a range of values that allowed for this expansion.

    If we stick to a classic Big-Bang cosmological model (which I might note, doesn’t technically describe an explosion), then the trigger for this suffices to be a minor perturbation to the quark/antiquark balance. Things we observe about this universe- its flat structure, the rough percentage of helium, the presence of cosmic background radiation- is all explicable in terms of this event.

    if we are going to suggest that design is part of the universe, then we need specific evidence to support that. And the evidence should preclulde any natural explanation. Having prima facie evidence that there is an extra-dimension to the universe, divorced from space-time that is inhabited by an eternal entity that has the power to create the universe, well, it kind of needs more than post hoc reasoning that our existence evidences design.