|
Man has stared up and wondered about the Cosmos since the dawn of time. Only in our modern age have we begun (and we stress the term begun) to understand the Cosmos which is now called the universe. Human life constitutes a miniscule time in the history of the universe. While not directly related to our study, cosmology is of interest because it places human history in a useful perspective. For a time after cosmologists debated the origins of the universe. There were two important theories, the steady-state concept and the Big Bang, a term once derisively created to denigrate the concept. Today cosmologists universally accept the Big Bang as the point of creation of the universe. It is an event which occurred about 14 billion years ago. Many astronomers now even offer a more specific time--13.7 bullion years ago. At this time matter, energy, and space exploded out of an unimaginably dense and poorly understood 'singularity'. It is not know how long this singularity existed or what caused it to become unstable. We have been somewhat confused, because there commonly is no discussion of what occurred before the Big Bang and what the eventual outcome will be. Many cosmologists appear to believe that ours is the only universe and time itself began with the Big Bang creating our universe. It appears more likely, however, that our universe is one of many--probably and infinite number. Our Big Bang is probably just one of the Big Bangs that have occurred over time in cycles that occur regularly, albeit over billions of years. They may involve the collision of processes generated by unidentified and unseen dimensions that are not yet known. Two scientists describe this as the Endless Universe. [Steinhart and Turok] The Big Bang created hydrogen and much smaller quantities of other elememts. For the most part elements other than hydrogen and helium are created by nucleosynthesis/fusion in stars. Ine of the huge gas clouds found in the universe is pictuted here (figure 1). They are called called nebula and consist of countless particles of gas and dust. Over time the particles are pulled together by gravity. This is the acretion process that eventually gives birth to stars. The vast proprtion of the composition of the cosmos is hydrogen (atomic number, HN 1). It is the birth of stars and fusion that begins to produce helium in large quantities (HN 2). Stars fuse hydrogen into helium through fusion. Over time heavier elements like carbon (HN 6) and oxygen (HN 8) are formed, the very elements of life. As stars age and reach their dying years, they increasingly create the common metals – aluminum (HN 13) and iron (HN 26). These metals are then blasted out into space in the stars death throes--different types of supernova explosions. These larger atoms, especially iron led to the death of stars and no heavier elements are formed in stars. What was left after a supernova was a dead neutron star. We know no heavier atoms were formed in stars because astronmers can assess the composition of both stars and the unbelievanly dense neutron stars. And the composition is only iron and lighter elements. Many stars are found in binary systems. Our is on the smaller side of stars. And a bit of an anomaly. The large number of binary systems means that the collision of neutron stars is fairly common in the cosmos. The cosmic fire created by the colliding/merging of neutron stars is a neutron-rich debris in which huge quantities of the universe's heaviest elements are forged, including metals that have plated a huge role in human civilization: copper (HN 29), silver (HN 47), tin (HN 50), platinum (HN 78), and gold (HN 79). And one which may end civilization: uranium (HN 92). Uranium is the heaviest naturally occuring atom. Heavier atoms like plutonium (HN 94) are unstable and thus not found in any quantity.
The elements aren’t created in equal amounts. [Gough] Hydrogen and helium are abundant in the cosmos, but there is a drop off for three of the lightest elelements -- lithium (HN 3), beryllium (HN 4), and boron HN 5). This is because they were poorly synthesized in the Big Bang and then the stars. Slightly heavier atoms were created in relatively the same quantity. Then there is what is known as the Iron Peak. [Erikson et. al..] After the Iron Peak, elements are significantly reduced in abundance. The Iron Peak results from the energy required for nuclear fusion and for nuclear fission and explain why iron leads to the death of stars. For the many elements lighter than iron, fusion releases energy and fission consumes it. For elements heavier than iron, the reverse is true: it is fusion that consumes energy, and fission that releases it. Atomic physicists call this binding energy. Here on earth we get used to thinkng that the heavier elements like gold are rare. Actually they are much more common than you would think. The fact that they are heavier means that they tended to settle toward the core when earth was in a molten state. Thus the earth's crust, where all life is found, is primrily composed of lighter elements, but not the lightest, including: oxygen (HN 8), silicon (HN 14), aluminum (HN 13), iron (HN 26), and calcium (HN 29). The core of the Earth thus formed as a solid ball of nickel (HN 28) and iron (HN 26), roughly 70 percent the size of the moon.
Man has stared up and wondered about the Cosmos since the dawn of time. Only in our modern age have we begun (and we stress the term begun) to understand the Cosmos which is now what previous genrations called the universe. Human life constitutes a miniscule time in the history of the universe. While not directly related to our study, cosmology is of interest because it places human history in a useful perspective.
For a time after cosmologists debated the origins of the universe. There were two important theories, the steady-state concept and the Big Bang, a term once derisively created to denigrate the concept. Today cosmologists universally accept the Big Bang as the point of creation of the universe. It is an event which occurred about 14 billion years ago. Many astronomers now even offer a more specific time--13.7 bullion years ago. At this time matter, energy, and space exploded out of an unimaginably dense and poorly understood 'singularity'. It is not know how long this singularity existed or what caused it to become unstable. We have been somewhat confused, because there commonly is no discussion of what occurred before the Big Bang and what the eventual outcome will be.
Many cosmologists appear to believe that ours is the only universe and time itself began with the Big Bang creating our universe. It appears more likely, however, that our universe is one of many--probably and infinite number. Our Big Bang is probably just one of the Big Bangs that have occurred over time in cycles that occur regularly, albeit over billions of years. They may involve the collision of processes generated by unidentified and unseen dimensions that are not yet known. Two scientists describe this as the Endless Universe. [Steinhart and Turok]
The Big Bang created hydrogen and much smaller quantities of other elememts. For the most part elements other than hydrogen and helium are created by nucleosynthesis/fusion in stars. Ine of the huge gas clouds found in the universe is pictuted here (figure 1). They are called called nebula and consist of countless particles of gas and dust. Over time the particles are pulled together by gravity. This is the acretion process that eventually gives birth to stars. The vast proprtion of the composition of the Cosmos is hydrogen (atomic number, HN 1). It is the birth of stars and fusion that begins to produce helium in large quantities (HN 2). Stars fuse hydrogen into helium through fusion. Over time heavier elements like carbon (HN 6) and oxygen (HN 8) are formed, the very elements of life. As stars age and reach their dying years, they increasingly create the common metals – aluminum (HN 13) and iron (HN 26). These metals are then blasted out into space in the stars death throes--different types of supernova explosions. These larger atoms, especially iron led to the death of stars and no heavier elements are formed in stars. Smaller strs orm white dwrfs. Large stars expire in a supernova explossion. What was left after a supernova was a dead neutron star. (They are called neutron stars because gravity compresses electronsand proton into neutrons. We know no heavier atoms were formed in stars because astronmers can assess the composition of both stars and the unbelievanly dense neutron stars. And the composition is only iron and lighter elements. Many stars are found in binary systems. Our is on the smaller side of stars. And a bit of an anomaly. The large number of binary systems means that the collision of neutron stars is fairly common in the cosmos. The cosmic fire created by the colliding/merging of neutron stars is a neutron-rich debris in which huge quantities of the universe's heaviest elements are forged, including metals that have plated a huge role in human civilization: copper (HN 29), silver (HN 47), tin (HN 50), platinum (HN 78), and gold (HN 79). And one which may end civilization: uranium (HN 92). Uranium is the heaviest naturally occuring atom. Heavier atoms like plutonium (HN 94) are unstable and thus not found in any quantity. The elements aren’t created in equal amounts. [Gough] Hydrogen and helium are abundant in the cosmos, but there is a drop off for three of the lightest elelements -- lithium (HN 3), beryllium (HN 4), and boron HN 5). This is because they were poorly synthesized in the Big Bang and then the stars. Slightly heavier atoms were created in relatively the same quantity. Then there is what is known as the Iron Peak. [Erikson et. al..] After the Iron Peak, elements are significantly reduced in abundance. The Iron Peak results from the energy required for nuclear fusion and for nuclear fission and explain why iron leads to the death of stars. For the many elements lighter than iron, fusion releases energy and fission consumes it. For elements heavier than iron, the reverse is true: it is fusion that consumes energy, and fission that releases it. Atomic physicists call this binding energy.
The composition of the planets can vary wiudely, both from the Cosmos abd other planets. Earth is one of four rocky planents in the inner solar system. Further out you have the gas giants which are believed to have rocky or metalic cores. The gas giants formed because the sun at such distances was too weak to blast away atmopheric gases. Here on earth we get used to thinkng that the heavier elements like gold are very rare. Actually they are much more common than you would think. The fact that they are heavier means that they tended to settle toward the core when earth was in a molten state. Thus the earth's crust, where all life is found, is primrily composed of lighter elements, but not the lightest, including: oxygen (HN 8), silicon (HN 14), aluminum (HN 13), iron (HN 26), and calcium (HN 29). The core of the Earth thus formed as a solid ball. Scientists believe that the core is primarily composed of an iron (HN 26) nickel (HN 28) alloy, roughly 70 percent the size of the moon. The importance of iron in the core reflects the relative abundance of iron. There are also large amounts of heavier elements such as gold and platinum.
Erikson, K.A., J. Hughes, C.J. Fontes,and J.P. Colgan. Progress in Understanding Iron Peak Elements in Young Supernova Remnants (Los Alamos National Laboratory: 2013).
Gough, Evan. "There should be more iron In space. Why can't ee see it?" Universe Today (July 11, 2019).
Steinhardt, Paul J. and Neil Turok. Endless Universe: Beyond the Big Bang (Doubleday, 2007), 284p.
Navigate the Children in History Website:
[Return to the Main historical chronology page]
[Return to the Main Chronology page]
[Return to the Main History page]
[Introduction]
[Biographies]
[Chronology]
[Climatology]
[Clothing]
[Disease and Health]
[Economics]
[Geography]
[History]
[Human Nature]
[Law]
[Nationalism]
[Presidents]
[Religion]
[Royalty]
[Science]
[Social Class]
[Bibliographies]
[Contributions]
[FAQs]
[Glossaries]
[Images]
[Links]
[Registration]
[Tools]
[Children in History Home]
