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Cosmology entails for us an understanding of the origin, the development and the future of the Universe. The ancient Greeks were among the first people who assumed that the heavens can be understood by human beings, and were also among the first who tried to understand this "big picture". They were among the first who attributed the cosmos to the machinations of the gods but were also among the first ones to liberate it from the idea of theocracy. Consequently, they saw in the cosmos an inherent order fathomable by human reason.
Later on, this Greek idea was rediscovered in Renaissance Europe. It was during this era that the first scientific instruments became available to aid those who were to continue the study of the Universe. Various devices were constructed to study the heavens, drawing information from the stars and other heavenly bodies. No matter how rudimentary these instruments were, they enabled a series of minor stepping stones that eventually led to our current understanding of our Universe.
In those early years, all that we know about the heavenly bodies came from the data supplied to us by light. Early scientists relied upon visible light to study the stars for example, but better technology led to the discovery, in the 20th century, of telescopes that gathered information beyond the range of visible light -- radio, ultraviolet, X-ray and gamma-ray telescopes, which allowed us to gather new data to better understand the heavens.
The field that unraveled our current understanding of the cosmos, was radio astronomy. Pensias and Wilson's early radio receiver showed that the signal of radio transmission was coming from all directions in the sky, and that the strength of the radio waves were very low, and were evenly distributed in all directions.
What then did this imply? Before answering this, it is important to mention that early in the 20th century, Edwin P. Hubble discovered other galaxies beyond the Milky Way and postulated that these galaxies were moving away from the Earth; the farther the galaxy, the faster it was moving. This became known as Hubble's Law. The implications of this law led scientists to believe that once upon a time, long ago, the galaxies were all together in space. However, the Big Bang scattered their matter and energy into space, sending the galaxies that were formed earliest moving away the fastest. It seems that Pensias and Wilson were seeing the remains of this initial Big Bang. So why then does the Universe look so evenly distributed? Allan Guth proposed in his Inflation Theory, that it is so because the Universe is flat.
Again, several new technologies were used to test this theory. The Hubble Space telescope and the X-ray space telescope became available during the advent of satellite technology. The Boomerang Infrared device, another instrument, was made to take a much closer look at the Big Bang radiation or the Cosmic Background Radiation. These devices enabled scientists to tell the structure of the cosmos some 300,000-400,000 years after the Big Bang. The discoveries matched the predictions of the Inflation Theory. Furthermore, the Hubble and X-ray Space telescopes discovered that the energy of the Bang was dissipating, and that the cosmos was accelerating. It is believed that there exists some kind of "Dark Energy" that accelerates the galaxies and "Dark Matter," the masses of which affects the surrounding masses, but which we can't see.
It is, indeed, wonderful to marvel at the greatness of the Universe, but the study of the very small also contributed to our current understanding of it. The secrets lay in the atoms themselves, their origins and their development into what they are today. The first atoms formed in the earliest moments after the Bang Bang. It is believed that almost instantly, at 250 seconds after the Bing Bang, the Universe was made up of mostly hydrogen and helium. Through the process known as nucleosysnthesis, other heavier elements were formed.
At about one month to 10,000 years after the Big Bang, the Universe began to decouple matter from radiation and this was fully accomplished after a period of about 400,000 to 500,000 years. Radiation then was made to pass freely through space and matter was released from radiation pressure. Because of this, matter began forming molecules and agglomerations of molecules under the influence of a weak force we know as gravity.
This force, weak as it is, initiated the formation of the stars and galaxies after some 5 million years. Gravity pulled matter together, clustering immense numbers of particles and atoms. These added together the gravity of all the particles and atoms so that the innermost ones came under tremendous pressure. The rising temperature fused adjacent nuclei together and the stars ignited. The heavy elements that were formed in the nuclear cauldron of the earliest stars were flung out into space and seeded the universe with elements never before present. These elements, which came out from the supernovae further conglomerated, under gravitational effects, and formed the planets. The rest is history.
Our current understanding of the very small tells us that all of the elements beyond lithium in our solar system, as well as those found inside our bodies were produced inside stars and supernovae. Thus, it can be said that the Universe's crowning achievement, is its being able to initiate life, at the very least, in our planet. As it was written in a college science book of mine, "we are all children of the Universe, stardust brought to life."
Later on, this Greek idea was rediscovered in Renaissance Europe. It was during this era that the first scientific instruments became available to aid those who were to continue the study of the Universe. Various devices were constructed to study the heavens, drawing information from the stars and other heavenly bodies. No matter how rudimentary these instruments were, they enabled a series of minor stepping stones that eventually led to our current understanding of our Universe.
In those early years, all that we know about the heavenly bodies came from the data supplied to us by light. Early scientists relied upon visible light to study the stars for example, but better technology led to the discovery, in the 20th century, of telescopes that gathered information beyond the range of visible light -- radio, ultraviolet, X-ray and gamma-ray telescopes, which allowed us to gather new data to better understand the heavens.
The field that unraveled our current understanding of the cosmos, was radio astronomy. Pensias and Wilson's early radio receiver showed that the signal of radio transmission was coming from all directions in the sky, and that the strength of the radio waves were very low, and were evenly distributed in all directions.
What then did this imply? Before answering this, it is important to mention that early in the 20th century, Edwin P. Hubble discovered other galaxies beyond the Milky Way and postulated that these galaxies were moving away from the Earth; the farther the galaxy, the faster it was moving. This became known as Hubble's Law. The implications of this law led scientists to believe that once upon a time, long ago, the galaxies were all together in space. However, the Big Bang scattered their matter and energy into space, sending the galaxies that were formed earliest moving away the fastest. It seems that Pensias and Wilson were seeing the remains of this initial Big Bang. So why then does the Universe look so evenly distributed? Allan Guth proposed in his Inflation Theory, that it is so because the Universe is flat.
Again, several new technologies were used to test this theory. The Hubble Space telescope and the X-ray space telescope became available during the advent of satellite technology. The Boomerang Infrared device, another instrument, was made to take a much closer look at the Big Bang radiation or the Cosmic Background Radiation. These devices enabled scientists to tell the structure of the cosmos some 300,000-400,000 years after the Big Bang. The discoveries matched the predictions of the Inflation Theory. Furthermore, the Hubble and X-ray Space telescopes discovered that the energy of the Bang was dissipating, and that the cosmos was accelerating. It is believed that there exists some kind of "Dark Energy" that accelerates the galaxies and "Dark Matter," the masses of which affects the surrounding masses, but which we can't see.
It is, indeed, wonderful to marvel at the greatness of the Universe, but the study of the very small also contributed to our current understanding of it. The secrets lay in the atoms themselves, their origins and their development into what they are today. The first atoms formed in the earliest moments after the Bang Bang. It is believed that almost instantly, at 250 seconds after the Bing Bang, the Universe was made up of mostly hydrogen and helium. Through the process known as nucleosysnthesis, other heavier elements were formed.
At about one month to 10,000 years after the Big Bang, the Universe began to decouple matter from radiation and this was fully accomplished after a period of about 400,000 to 500,000 years. Radiation then was made to pass freely through space and matter was released from radiation pressure. Because of this, matter began forming molecules and agglomerations of molecules under the influence of a weak force we know as gravity.
This force, weak as it is, initiated the formation of the stars and galaxies after some 5 million years. Gravity pulled matter together, clustering immense numbers of particles and atoms. These added together the gravity of all the particles and atoms so that the innermost ones came under tremendous pressure. The rising temperature fused adjacent nuclei together and the stars ignited. The heavy elements that were formed in the nuclear cauldron of the earliest stars were flung out into space and seeded the universe with elements never before present. These elements, which came out from the supernovae further conglomerated, under gravitational effects, and formed the planets. The rest is history.
Our current understanding of the very small tells us that all of the elements beyond lithium in our solar system, as well as those found inside our bodies were produced inside stars and supernovae. Thus, it can be said that the Universe's crowning achievement, is its being able to initiate life, at the very least, in our planet. As it was written in a college science book of mine, "we are all children of the Universe, stardust brought to life."
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