Introduction
Before diving into a discussion about the early universe, it is helpful to look at the observable properties of our present universe first. Modern cosmology is based on the cosmological principle, which states that on a sufficiently large scale of about 200 Mpc, the distribution of matter in the universe is homogeneous (the same everywhere) and isotropic (looks the same in all directions). The Universe is considered to be uniform with the same average density and pressure independent of the location of the observer. Edwin Hubble and Milton Humason were the first to discover a relationship between the redshift and distance of galaxies in 1929. Their observations suggested that galaxies, aside from their local peculiar motion with respect to a cluster or supercluster, are moving away from
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In addition, more distant galaxies appear to be receding faster than closer ones. The whole Universe is in a state of expansion, with every galaxy moving away from every other galaxy. This relation is summarized as the Hubble Law: z=H_0/c d. A key point that is arising from this relationship is that as we go back in time, galaxies must have been closer and closer together. If you go back far enough, the Universe must have been concentrated at a single point in space, which leads us to the topic of this paper: the exploration of the early Universe. In order to understand the processes and interactions taking place in the first 400,000 years after the Big Bang, we need the tools and predictions of high energy particle physics and cosmology. Figure 1 provides a timeline of the events and processes taking place in the early Universe and will be used as an orientation for the following discussion of the Standard Model of particle and the observable cosmic microwave
In the article The Cosmic Perspective by Neil deGrasse Tyson he examines a range of topics from human life coming from Mars to how our perspective of the universe relates to religion. In the year 2000, a new space show opened at the Hayden Planetarium called Passport to the Universe, which compared the size of people Milky Way and beyond. While a show like this might make someone feel minuscule and insignificant, Tyson says that seeing the size of the universe actually makes him feel more alive not less and gives him a sense of grandeur. I agree with his idea that looking at us as a people in comparison can actually give you a sense of grandeur. However, when I compare myself to the vastness of space, it puts events on Earth in perspective while showing how influential we can be as a people even if we are small.
Nave. (2000, August). Expanding Universe. Retrieved January 24, 2014, from Index to Hyper Physics: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html
NOTE: This paper was written for an English class and a non astronomy audience. Thus, several arguments were left out to make the material easier to understand for the target audience. These arguments would include (but are not limited to) dark energy, dark matter, and the inflationary model of the universe. If I later have time I may revise this paper to cover such topics and be more comprehensive.
The Hubble Space Telescope is a large telescope in space weighing 24,500 lbs. NASA launched Hubble in 1990, "Hubble is named after Edwin P. Hubble, He was an astronomer"(Rosario). Hubble travels around the Earth taking pictures of planets, stars, and galaxies. "It has seen stars being born and stars die, and it has seen galaxies that are trillions of miles away." Scientists have learned a lot about space from Hubble pictures (Dunbar).
The telescope made its one-millionth discovery in 2011. Before the Hubble Telescope scientist predicted the age of the universe to be around 10 to 20 billion years old. Hubble gave scientists the information to have a more precise answer of 13.7 billion years old. A main reason for this great discovery was Hubble’s observations of special types of bodies called Cepheid variable stars. Cepheid variable stars have very stable patterns of brightness that make them very effective at measuring distance. Although scientist know about the existence of dark energy now, because of the Hubble telescope they recovered the existence of dark energy in the early stages of the universe up to nine billion years ago. Dark energy is believed to accelerate the expansion of our universe, but it was first believed that after the Big Bang the expansion slowed
This suggests that in the past, galaxies were much closer to us than they are now: simply extrapolate the motion into the past. As it turns out, if this is performed, it indicates that all galaxies in the observable universe would have been at the same 'location' about 11 billion years ago: that is, all the matter in the universe originated from a single location. This is the (simplified) Big Bang theory. Actually, it's a little more complicated than that: according to general relativity, it's not really that distant galaxies are flying away from us, it's that space itself is expanding, increasing the distance. You can think of the universe as the surface of a balloon, with the balloon constantly expanding.
In the year 1929, Edwin Hubble made a revolutionary discovery. He learned that the universe is expanding. He saw that the galaxies were each moving away from us. Edwin knew that for one instance of time, almost 14 billion years ago, all of the mass of the universe was contained in a single spot. There had to have been a huge explosion that pushed all the matter away. This explosion is known as the Big Bang Theory. (www.science.nasa.gov)
The prevalent theory today, describing the origin of the universe and where it all began is the Big Bang theory. Scientists believe that our almost 14 billion-year-old universe could at one point fit in the palm of one’s hand. In the beginning there was nothing. No space and no time but then came light. A tiny speck of light appeared and inside this tiny fireball was space – this was beginning of time. Time could now flow, and space could expand. The notion that everything in the Universe, all the matter, all the energy and all the galaxies were once contained in a region smaller than the size of a single atom today came from American astronomer Edwin Hubble in the 1920’s. He observed that other galaxies were speeding away from ours, and the further they were, they faster they seemed to travel. The Universe was therefore expanding and the Big Bang theory was born.
“Some of the most asked questions has been How was the universe created? When was the universe created? Why was the universe created? Many once believed that the universe was just there and that it was truly never ending. Through the inception of the Big Bang theory the universe could be no longer considered never ending”(Dennis). We had to consider the possibility of a universe that had started some time in history and would possibly end at some time in history. About thirtyfive billion years ago a gigantic explosion started the expansion of the universe. The explosion has come to be universally known as the big bang. At this point all of the matter and energy in space was contained at one point. What was before this event is not known to any human being and is a matter of pure speculation. This occurrence was not a conventional explosion but rather an event that expanded all of the particles of the “baby” universe rushing away from each other. There were actually no galaxies before that of the big bang but it was more like it started the process of creating all of the galaxies that we know today.
The universe is expanding – (Edwin Hubble, 1929) Observed a Red Shift when looking at the spectrum light coming from distant galaxies. All light from these galaxies is shifted towards longer wavelengths, i.e.. toward red light. This is the Doppler effect and could only occur if the galaxies were moving away from each other at very high speeds. In fact they are moving away from each other at a rate proportional to the distance between them.
Then the universe kept decreasing in density and temperature, the energy of each particle began to decrease and transitions of the phases continued until the fundamental forces of physics and elementary particles changed into their regular form. Since particle energies would have dropped to values that can be obtained by particle physics experiments, this period is subject to less speculation (Wall). According to NASA, after inflation the growth of the universe continued, but at a slower rate. As space expanded, the universe cooled and matter formed. One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons, and neutrons (Williams).
During this creation and annihilation of particles the universe was undergoing a rate of expansion many times the speed of light. Known as the inflationary epoch, the universe in less than one thousandth of a second doubled in size at least one hundred times, from an atomic nucleus to 1035 meters in width. An isotropic inflation of our Universe ends at 10-35 second that was almost perfectly smooth. If it were not for a slight fluctuation in the density distribution of matter, theorists contend, galaxies would have been unable to form (Parker).
Which suggest that, the universe is expanding because the galaxies are moving away from us. So, if the universe is expanding, then it must have been much smaller in the past. Going back far enough, there was a moment when all the matter in the Universe was packed into a point and expanded outwards and that moment was the big bang. It is possible to work out when the big bang happened by the speed of the galaxies movement from each other about 14 billion years ago. We cannot really see the galaxies moving, but the clue is present in the light coming from them which is known as red
To begin this process of seeking lasting contentment, the questions that have lead to many controversial debates for centuries must have some believable conclusion to the individual. For instance, one of those controversial subjects is the origin of the universe. One of the main theories held today is the Big Bang Theory. Arno Penzias and Robert Wilson, two radio astronomers who researched radio signals in the spaces between galaxies in Bell Labs in Holmdel, New Jersey, possibly found evidence of the Big Bang in 1965. These astronomers detected background “noise” in their satellite transmission system called “Echo” at the microwave frequency from every direction, in which they concluded to be a cosmic frequency resulting from the big bang that created the universe. These men won the 1978 Nobel Prize in Physics for this “discovery of cosmic microwave background radiation.”
Presently, the Big Bang theory is the most logical scientific explanation of how the universe began. The majority of cosmologists favor the Big Bang theory and the idea that the expanding universe had an initial, incredibly hot and dense start (Peterson 232). According to the Big Bang theory, at one point in time, more than 12 billion years ago, matter was condensed in a single place, and a huge explosion scattered matter out is all directions (“Big Bang Theory” 403). At the moment of its origin, the universe was infinitely dense and hot, but as the expansion occurred, the universe cooled and became less dense (Narlikar 12). The debris the spewed from the initial explosion became the building blocks of matter, forming the planets, stars, and galaxies (Narlikar 12). Officially, the Big Bang model is called the standard cosmological model (SCH), and it has been the most widely accepted theory of the origin of the universe since the 1960s (Rich and Stingl 1). Most astronomers are in agreement that the universe’s beginning can be traced back to 10 to 15 billion years ago following some type of explosive start (Narlikar 12). Big Bang theorists have estimated the actual bang occurred 13.7 billion years ago and was followed by an inflationary period that created time, matter, and space (Rich and Stingl 1).