Upon reading this chapter, I was sort of disturbed by the reality of how infinite the universe is and how minuscule we are as humans (in the grand scheme of things). The Cosmic Calendar, a scale of the universe over the course of one year, reveals that humans would have appeared within the last few moments. This calendar indicates our insignificance on a grand scale, but highlights some momentous milestones of the Universe, and to think our existence is considerable among phenomenas like the Big Bang, reaffirms that we could be special.
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Reading about the vast size of the universe, I started exploring the possibility of travelling through the it. One popular theory on the structure of space-time is a wormhole. It postulates a theoretical passage through space-time that could create a shortcut to a different spot in the universe. So far, we’ve thought about travelling in a linear fashion. A simple way to think about wormhole travel is folding a paper in half and travelling from one end to the other by poking a hole through the middle. The image below is a good way to visualize it. There is debate about whether wormholes can actually exist. We are definitely very far from actually observing a wormhole, but scientists are exploring the possibility of their existence.
I think that the “Powers of Ten” video displayed not only conceptually how raising something to a power of ten affects it, but also the incredibly large scale of the universe. During the first half of the video when the perspective is going increasingly further away from the starting point, it seems as though the viewer’s perspective is moving very quickly away from the starting point until it reaches space past Earth. Once it increases to ten to the eighteenth meters away from the starting point and above it seems to be moving very quickly, which it is, but before that it takes a fairly long time to reach the first star closest to us. Another thing from the video that puts the scale into perspective is the size of the Sun when all of the orbits of our solar system come into view. When all of the orbits are within view, the Sun looks very small within the view of the screen, showing the expanse of the outermost orbits. This still is minuscule compared to the galaxy and especially the universe. Picture Source
The Cosmic Calendar is created by shrinking the life span of the entire universe down into the length of the Gregorian Calendar. In this time, a human life is less than a second long and modern humans have been around for about two minutes (The Cosmic Perspective). When I think about this, it is almost relieving because I realize that nothing about human life could truly matter in the scope of the entire universe. Nothing that I am worried about from day to day could be as important as I think. It also helps me have a different perspective on issues some people would consider pressing. I like to call this the liberation of infinitude.
SkyView Lite is a app for Apple that makes stargazing super easy and fun for beginners. I have personally had this app for about 9 months. It’s great fun to pull out the app on warm summer nights. Even when the light pollution in the city gets in the way, this app allows the user to the experience of living in an area will clearer views of the sky. All the app requires is for the user to point their phone’s camera to the sky and the app analyzes the image and tells the user what’s out there. The app also has other features that make stargazing convenient for the novice stargazer. Other features include a time travel option to watch the sky from the past and future and the ability to set reminders for other sightings. This is a great app for beginning stargazers.
It is hard for us to truly fathom the sheer size of our universe, this is clear- the distances involved are simply too big to comprehend with just the human mind. But we have begun to understand the nature of this size, and order the magnitudes of the universe in ways we can understand. The general set of references used is thus:
Earth.
The solar system.
The solar interstellar neighborhood. These are all suns close to us.
The Milky Way Galaxy.
The local galactic group. This is the cluster of all galaxies close to us.
The Virgo Supercluster. This is a massive cluster of countless galactic groups and clusters.
Local superclusters. A huge network of innumerable superclusters.
The observable universe.
The size can be overwhelming at times- but with ordering and establishing references, one can surmise the general size of the universe quite easily!
Einstein created a new physics framework with the notions of space and time, known as the theory of general relativity. As he continued to study these concepts, he realized the connectedness between the two, then referring to it as space-time. His theory explained how time does not go by at the same rate for still spectators as it does for fast-moving ones, therefore objects move relative to all other things. Additionally, the theory goes into how moving objects increase in mass as they continue to increase with velocity. For matter to reach light speed, its mass would need to become infinite and require infinite amounts of energy, making it impossible for any mass to reach the speed of light.
Despite Einstein’s theory explaining that no thing will ever be able to travel the same pace as light, the concept still intrigues scientists. Many have imagined theories and ideas on ways to reach this speed, but no one has been able to prove Einstein’s theory false. Science fiction films such as Star Wars and Star Trek have provided more theorizing to the discussion, as characters in the film travel at light speed through space on their adventures.
Do you think that we will ever be able to travel at the speed of light?
The winter and summer solstices occur as a result of the Earth’s tilt. The summer solstice occurs for a hemisphere when it is facing most directly towards the sun, and this marks the longest time of sunlight for that hemisphere. The winter solstice, is the exact opposite occurrence, resulting in the least amount of time of sunlight in a day. The equinoxes, however, occur when the axis is not tilted towards or away from the sun, and thus no hemisphere gets any more light than the other. This also results in there being an even amount of light and dark on the equinoxes.
The most fascinating aspects about the equinoxes (and solstices too, although I don’t talk about it) to me is their significance that we can see they had on civilizations throughout history. Despite lacking the technology that we have, many early civilizations knew what equinoxes were, and when they would occur. This has resulted in some amazing monuments and mysteries left over into our age. The famous Mayan pyramid in Chichen Itza, Mexico was constructed to cast a serpent shadow on the equinox. Of course, another famous site is Stonehenge. This mystery, although little is known about its history, can be used to predict both equinoxes and solstices. Other examples from ancient civilizations around the world showed that many early people knew about and understood equinoxes and solstices. These are just some of the first steps in our history of attempting to understand the world around us. This ability to understand something far beyond the technological capabilities of the day is yet another example of why we as the human race continue to push the limits of our knowledge and explore the universe in which we live.
The “Man in the Moon” is a story we have all heard since childhood: look into the sky and you’ll see a face in the moon, however I would get confused when I would look up and he would be missing. Where did this man go? Why isn’t he or the moon in the sky tonight? Well, the missing “man” is easily explained by examining the rotations and different phases of the moon in our night sky.
The moon travels orbits around the earth approximately 1 every 27 daysand rotates at the same rate. This means that we always are viewing the same side of the moon, hence why we can always see this “man” whenever the moon is bright in the sky. However, this doesn’t explain why we only see the moon in the sky sometimes and why the shape of the moon changes in the night sky.
While the moon rotates around the earth, the way we see the sunlight reflect off the moon changes. The moon consistently has half of it being lit by the sun, however, since we only see one side of the moon, we see how the sun’s light is hitting that particular side of the moon. As the moon rotates around the sun, we see can see our side being fully lit by the sun or not being lit at all. These different stages of the moon being lit are known as the phases of the moon. The phases begin with our side of the moon receiving no light, a new moon, and growing to have more light, waxing crescent and gibbous, to being fully lit, full moon, to having the light recede, waning gibbous and crescent, all the way back to no light.
The moon is always in our sky, so it is just a matter of our visibility of it. The “man in the moon” is in the sky to watch over us, even if we can’t see him.
It is a nearly universal maxim of science fiction that faster than light (FTL) travel must exist. Let us take a look at why this is universally necessary for the sake of a good story by comparing the size and scope of both our real universe and a few fictional universes to how long traversal would take. However, rather than just using years, let us instead consider how many generations it would take for people to travel that distance. Given that one generation is ~30 years, a few lengths of time exist for scale. Human civilization has been around for 6,000 years, or about 200 generations. Jesus Christ was born around 70 generations ago. Modern humans have existed for around 7,000 generations.
Meanwhile, if we assume that we eventually invent (very very near to) light speed travel, it would take about 3,000 generations to traverse the Milky Way. Even though the effects of time dilation would mean that the experienced time would be considerably more negligible, it would be best if you didn’t have an urgent engagement on the other side of the galaxy–it would have gone through effectively half of humanity by the time you reached it. Going to another galaxy is even worse–the nearest galaxy to Earth (Andromeda) is 83,000 generations away. By the time a spaceship has traveled that distance, the galaxy far, far, away will bear little resemblance to how it was long, long ago.
Fictional universes face the same issue. Star Trek takes place in our own galaxy, so faces the same scale issues. Battlestar Galactica takes place in an area of space around 13,000 light years across, or about 400 generations. Star Wars, while localized to one galaxy, is purported to be 120,000 light years across (~4,000 generations), slightly larger than the size of our own galaxy. Dune reaches into several galaxies with no clear size limit, but conservative estimates mean it will be in the tens of thousands of generations. Simply put, for the sake of a coherent story in science fiction, both heroes and villains must be able to travel faster than light. If they were constrained to only being as fast as the fastest thing, a plot would simply be impossible.
