How Big Is Our Universe - Essay Example

How Big is Our Universe?

The big bang

The big bang theory asserts that the entire known universe came into existed almost 13.8 billion years ago. At the very onset, all matter was compact into a small ball with intense heat and finite density known as a singularity. Suddenly, there was an expansion of the singularity to make the universe as it is today. After the big bang that led to the expansion, it is theorized that the mass cooled off to make the temperatures of the present universe and allow for the formation of the stars and the planets. Even as the cooling continues, the spinning and expansion of the universe are expected to continue, which means that the size of the universe will continue to increase (Bond et al. 12).

One of the creation form the expansion was the Milky Way galaxy, where the earth is found. According to measurements, the earth has the sun as its nearest star, which is about 93 million miles away. The Milky Way galaxy has billions of stars that have been formed one every second since the original singularity. These starts are gigantic, and the Milky Way as a galaxy expands in equal measure. To date, it is estimated that it would take 100,000 light years to cross the Milky Way galaxy. There are other billions of galaxies that have been formed from the initial singularity (Luntz and others 23). Some of the galaxies are so far away that it takes billions of years for light to travel from these galaxies to earth.

According to the big band, the formation from the small singularity is continuous. As such, the objects that were formed earlier in the course of the expansion can only be measured in terms of light years. Alight year is the distance that light travels in one year. For the universe to be about 13.8 billion years, it is to say that a proton of light has been measured from the furthest point that was created about 13.8 billion years ago and has had to travel for that time to reach earth for human scientists to measure it (McClimens 8–9). However, due to the expanding nature of the universe every moment, the observable universe is estimated to be about 46 billion light years from one edge to another.

The expansion nature of the universe makes scientist unsure of how big the universe it is today. However, scientific measurements indicate the universe is so big that light has not had a chance to cross it in almost 14 billion years, and yet it is still expanding. Therefore, questions of how big the universe is uncertain as the technology and telescopes that are used today could be improved to see more than the observable universe. As science discovers more parameters of estimating the size of the universe and as the expansion continues according to the big bang theory, so the size of the universe will expand.

Why alien life has not contacted us

With modern science fiction depicting the presence of intelligent forms of life in the universe, apart from on earth, a scientist has attempted to answer the question of why the alien life has not contacted earth. Frank Drake first addressed it, in his Drake equation. The equation predicts how many extraterrestrial civilizations are present in the universe. The equation looks at the number of stars in the universe and the number that has planets orbiting them. Until recently, it was unclear whether other stars had planets orbiting them like the sun. The scientific community is unclear about the actual number of stars that are sun-like; they are able to sustain life by facilitating the presence of water and temperatures that allow intelligent life forms to exist. However, in the 10^22 star, it is argued that about 5 to 20 percent are sun-like in conditions. According to a recent study, about 22 percent of the sun-like stars have planets orbiting them. That would put the number of stars that are sun-like with planets orbiting them at about 1 percent, translating to about 100 billion- billion earth-like planets (Prantzos 248–249). If the same principles of how earth life began are applied, then an estimated 10 quadrillion civilizations exist in the known universe according to the drake equating (Maccone, “The Statistical Drake Equation” 4). That would translate to about 100,000 civilizations that are intelligent in the Milky Way galaxy, according to the Search for Extraterrestrial intelligence (SETI). So why have these civilizations not contacted earth?

The Fermi paradox is used to explain the reason the extraterrestrial life has not contacted earth. The Kardashev scale is used in grouping intelligent life into three categories. Type 1 civilization is able to use all the energy that is provided in the planet. Earth is categorized in type 1 civilization. Type 2 civilization can harness all the host star energy and use it. Type 3 civilization can harness and use all the energy that is provided by the galaxy, like Milky Way. According to the Fermi paradox, the answer can be found in two explanations (Maccone, “The Statistical Fermi Paradox” 223–224).

The first is that there are no civilizations of either category or because there is no other intelligent life in existence. The basic belief is the non-exclusivity problem is used to dismiss the argument that there are higher forms of intelligent life, and yet not all of them have attempted to contact earth. The reason for the lack of a contract is also explained using the Great filter. The great filter proposes that a filter exists between pre-life and category 3 civilization where no life gets beyond. According to the explanation of the great filter theory, if it is behind the earth, then earth life forms are rare, and no other intelligent life forms can make it to the level of earth. Another explanation is that life forms on earth are the first to develop and as such, earth life civilization is the first, with no previous forms elsewhere. Finally, some scientists use the great filter theory to say that it lies ahead. That means that no life form moves beyond the civilization of earth to make contact with any other, and as such, earth life form will also heat the wall and cease to exist like all other forms (Prantzos 250–251).

Another category believes that both category 2 and 3 life forms exist, but there are reasons for not contacting earth. Some of the reasons are that they already visited earth, but earlier before earth life forms existed. The reason for the explanation is that the sentient human beings have only been around for about 50,000 years on earth, which is a very small time from in the scale of how long the universe has been in existence.

Another school of scientist believed that these higher life firms have already colonized the universe, and earth life forms only exist in desolate areas of the galaxy. The scientist holds that there could be a level of urbanization that allows communication among all other neighbors and as such it would defeat sense to come all the way to earth; that is rural.

Finally, a category of a scientist who believe in higher forms of intelligent argues that the fact that these forms are more advanced makes the concept of colonization backward. With the ability of these higher forms to use energy from the host stars and the galaxy, it is likely they created a perfect environment that satisfies them and needs not come to earth for the search of anything.

How will the universe end?

There are several scientific theories that discuss how the universe will end. The first is the big crunch theory. It is a reverse of the big bang theory, proposing that the universe will eventually collapse to the initial state. The model proposes that the universe will continue to expand to a point, after trillions of years, where it will gain an average density that will stop the expansion. At that point, it will begin a reverse process of collapsing; pulling all particles and matter together, that could mimic the singularity. However, there are scientists that propose that such an event has already happened. They use the oscillating universe theory (Zhang, Wu, and Yu 512). The Oscillating universe theory combines the big crunch theory and the big bang theory to say that while the crunch will occur, another big bang will follow leading to a creation of a new universe, and as such, the process will never end.

Another theory uses the idea of black holes to indicate the way the universe will eventually end. There are massive black holes in the center of galaxies that cannibalize stars, sucking them into the dark central horizon. The theory supposes that these black holes would eventually devour all matter leaving a dark universe.

Another theory is the big freeze. The universe has been expanding, and energy is dispersed consequently. As energy is dispersed, the universe will continue to get colder to appoint where the heart will cease to support life. A Recent study has supported the idea that energy is some parts of the universe has reduced in terms of production to almost half what it was 2 billion years ago. In the big freeze, the cooling of the universe will continue until the gas supply in the universe so thins that stars cannot form (Erol and Eksin 108–109). Stars will then burn out leaving black holes, which will also evaporate leaving nothing in the wake.

Finally, the big slurp theory proposes that an alternate universe will one day suck the present universe. The idea is based on the belief that the universe is unstable, and that billions of years later it should tip over, causing a bubble to appear, forming an alternate universe, that would then swallow up the present universe. However, the scientist also believes that if the instability was going to cause the formation of an alternate universe, it would have occurred already (Motch et al. 7–8).