BEST OF: Astrophysics
WHY HELLO THERE.
Ever wondered how the universe happened? Here comes Professor Carlee! She'll tell you how it all went down.
This was for my astrophysics class. It had a character limit of 2300. It is exactly 2300 characters and had a helluva time getting there.
The frustration was palpable.
But I guess it's a neat little package of trivia (my favourite thing), if you're into the pretentiousness of the title.
According to the Big Bang theory, the evolution of the universe can be divided into several eras. These are called the Planck era, the Inflationary epoch, Nucleosynthesis, Recombination, the Cosmic Dark Ages, and Galaxy Formation.
Though we currently lack the physics to describe the Planck era, we know that 13.7 billion years ago the universe was denser, smaller and hotter. By measuring the red shift of galaxies that appear to be moving away from us, astronomers have discovered that space-time is expanding in scale, from which logically follows that there was an original point of unification.
In the first 3 minutes after this point of origin, the scale of the universe begins to increase rapidly (by a factor of 10^26). This superluminal expansion is called the Inflationary epoch. The tiny fluctuations in matter present at the beginning grow more prominent as the universe expands, creating the overdensity of matter required for the eventual formation of stars and galaxies. This phenomenon also explains why the temperature of the universe is relatively uniform even in sectors that exist out of causal contact.
The universe continues to expand and cool after the events of the Inflationary epoch, but not as rapidly. During the Nucleosynthesis era, occurring 3-20 minutes after the Big Bang, protons and neutrons begin a process of nuclear fusion. This is the formation of the first atomic nuclei. Eventually, the universe cools to a temperature low enough to produce photons with an average energy of 1Mev, which fixes the nuclei into the forms we see today: three quarters of the baryonic mass found in the universe is made up of hydrogen atoms, and the other fourth is helium. These are the elements essential to energy production in stars.
At approximately 380,000 years, Recombination occurs. The hydrogen and helium atoms formed during Nucleosynthesis started out ionized, but when the temperature of the universe reaches 3300K they are cool enough to begin attracting electrons. The Cosmic Microwave Background Radiation is created during this period through the liberation of photons, which would otherwise be obstructed by free electrons. Before this the universe was optically opaque. Photons are now allowed to travel great distances, and the universe becomes as transparent as it is today.
Between Recombination and Galaxy Formation the universe is transparent and dark, because no sources of illumination have had the chance to form yet. This is the Cosmic Dark Ages. Eventually, the force of gravity (with the aid of dark matter) gathers clumps of mass-energy together to form protogalactic clouds. At about 1 billion years, the formation of stars and galaxies begins, and continues to take place today.
Ever wondered how the universe happened? Here comes Professor Carlee! She'll tell you how it all went down.
This was for my astrophysics class. It had a character limit of 2300. It is exactly 2300 characters and had a helluva time getting there.
The frustration was palpable.
But I guess it's a neat little package of trivia (my favourite thing), if you're into the pretentiousness of the title.
According to the Big Bang theory, the evolution of the universe can be divided into several eras. These are called the Planck era, the Inflationary epoch, Nucleosynthesis, Recombination, the Cosmic Dark Ages, and Galaxy Formation.
Though we currently lack the physics to describe the Planck era, we know that 13.7 billion years ago the universe was denser, smaller and hotter. By measuring the red shift of galaxies that appear to be moving away from us, astronomers have discovered that space-time is expanding in scale, from which logically follows that there was an original point of unification.
In the first 3 minutes after this point of origin, the scale of the universe begins to increase rapidly (by a factor of 10^26). This superluminal expansion is called the Inflationary epoch. The tiny fluctuations in matter present at the beginning grow more prominent as the universe expands, creating the overdensity of matter required for the eventual formation of stars and galaxies. This phenomenon also explains why the temperature of the universe is relatively uniform even in sectors that exist out of causal contact.
The universe continues to expand and cool after the events of the Inflationary epoch, but not as rapidly. During the Nucleosynthesis era, occurring 3-20 minutes after the Big Bang, protons and neutrons begin a process of nuclear fusion. This is the formation of the first atomic nuclei. Eventually, the universe cools to a temperature low enough to produce photons with an average energy of 1Mev, which fixes the nuclei into the forms we see today: three quarters of the baryonic mass found in the universe is made up of hydrogen atoms, and the other fourth is helium. These are the elements essential to energy production in stars.
At approximately 380,000 years, Recombination occurs. The hydrogen and helium atoms formed during Nucleosynthesis started out ionized, but when the temperature of the universe reaches 3300K they are cool enough to begin attracting electrons. The Cosmic Microwave Background Radiation is created during this period through the liberation of photons, which would otherwise be obstructed by free electrons. Before this the universe was optically opaque. Photons are now allowed to travel great distances, and the universe becomes as transparent as it is today.
Between Recombination and Galaxy Formation the universe is transparent and dark, because no sources of illumination have had the chance to form yet. This is the Cosmic Dark Ages. Eventually, the force of gravity (with the aid of dark matter) gathers clumps of mass-energy together to form protogalactic clouds. At about 1 billion years, the formation of stars and galaxies begins, and continues to take place today.