One of the more morbid questions that astronomers have debated over the last few decades has been the possibility of the end of the universe. With the widespread acceptance of a model of the universe that is in some way finite, there are questions about how the state of that universe could change over time. There are largely two options given the state of astrophysics, depending on the relative sizes of the forces of dark energy and gravity.
The first that was originally popularized was the “Big Crunch”, a sort of reverse big bang. This was rather romantic, as it provided a nice sort of symmetry, and also inspired thoughts of the crunch resulting in a new big bang, thus creating the possibility of an infinitely recreated universe. In this model, the forces of gravity eventually overwhelm the expansion of the universe, causing it to shrink in on itself, accelerating inward until all mass ends up in a singular point, the crunch.
The second is the “big rip”, or the “big freeze”. In this model, the forces causing the expansion of the universe are never reversed by gravity, and the finite amount of energy in the universe causes all matter eventually to be torn away from itself. This was called the “big freeze” because it means that all matter will eventually be isolated, unable to interact with all other matter, meaning the universe would eventually enter a static state, with each particle eternally separated from every other.
Galileo (February 15, 1564 – January 8, 1642) made major strides in the argument for heliocentrism, observing sunspots and the phases of Venus, two pieces of information that seemed to point to the imperfection of the celestial world and that the Sun was the gravitational center of the Solar System about which all the planets orbited.
With his observations of sunspots, he was able to argue that the Sun was changing and therefore could not be made of ether (Aristotelian idea), meaning that the Solar System was imperfect. This poked a major hole in the argument of the Catholic Church who believed in geocentrism because Christian principles were steeped in the ideas of Aristotle and Plato who held the view that the celestial world was perfect.
Observing the phases of Venus was also impactful in his argument for heliocentrism because the phases only made sense with a heliocentric model of the universe. Venus can go through phases from our perspective because it is between the Earth and the Sun.
Galileo had major cultural and religious impact on the world, arguing that true theologians should work to marry Science and Scripture, and that if the Church did not embrace new Science, people would start to use it as an argument for atheism or belief in a different god once Science caught up and disproved geocentric views. While Ptolemy’s model saved face for the Church during his life, Galileo argued in his infamous letter to the Grand Duchess Christina that it would be disproven, and the Church should respond to this with open arms instead of suppression, as suppression would cause Science and the Church to become even more split.
Two Major Events
1. First permanent North American European settlement
Jamestown, Virginia was settled by the English in 1607 during Galileo’s lifetime.
2. Don Quixote, one of the most famous works of literature of all time, was published.
This work was published in the early part of the 1600’s, and it remains one of the most popular works of literature in European history.
Shakespeare is widely regarded as the most accomplished playwright of all time, and he lived during Galileo’s lifetime. He is responsible for works such as Hamlet, Macbeth, and Romeo and Juliet.
Descartes was one of the most famous philosophers of the Scientific Revolution. He wrote one of the most concrete justifications for first principles (not-so-fun fact: Al-Ghazali did it first, and though there is not sufficient evidence to say that Descartes had access to his work, their arguments are similar but Al-Ghazali was marginalized by a Eurocentric mindset in Science and Philosophy), proving self-existence by the presence of first-person perspective.
Reflection
I enjoyed this homework assignment because I was able to combine my notes from several different classes, not even having to look things up because I had studied these people/events in greater detail in other classes. I have been keenly interested in Galileo since I took professor Weintraub’s class on the trial of Galileo, so it was fun to talk about him and see what other famous people/events occurred at the same time. It is interesting to think about the fact that René Descartes would have had a much smaller impact on the world if Galileo had not done what he did, as it kickstarted the Scientific Revolution and shifted the center of Science from the Church to its own practice.
In this blog post, I will give an overview of my experience in astronomy so far, and what I am excited about in the future.
I have found ways to integrate astronomy in many conversations. My favorite example is when I related the world of astronomy to a concept that came up during an investment banking interview. The interviewer was shocked about how in depth I went into the threshold regarding the creation of jovian vs. terrestrial planets.
In the future, I want to dive deep into the telescope industry. In some of my earlier blog posts, I discussed companies that are creating highly powered telescopes, larger and stronger than anything we have seen before.
I also want to read more about new black holes that are discovered and what their implications are on our existing understanding of the universe. I recently read about Gaia BH3, a black hole that was recently discovered.
The Fermi Paradox questions the discrepancy between the vastness of the universe and the apparent lack of intelligent life. This paradox has been discussed at length with many experts and as all paradoxes go, there is no clear conclusion. However, there does appear to be strong rebuttals to the paradox.
One rebuttal that I find to be convincing is that the intelligence that we have defined as humanity is most likely significantly different from the intelligence of “aliens”. Our mission to colonize space is viewed as a manifestation of humanity’s intelligence but there is nothing to suggest that colonization is an inherent motivation amongst “intelligent” beings. It may be the case that the intelligence that an alien civilization has does not compel them to explore or colonize space.
Another strong explanation for the Fermi Paradox is the doomsday proposition which posits that civilizations will most often meet their “doom” and become extinct before being able to colonize space. This is compelling because even on Earth, we have only been able to meaningfully explore space through probes and spacecrafts in the past couple decades. Earth is a geologically active and decently friendly planet but despite its friendliness, we’ve had multiple extinction level events. The timeframe for humanity is incredibly short in the context of the age of the universe so it may be the case that the lack of evidence for intelligent life makes complete sense when we consider how short of a time we have been looking.
I had a great time learning about and using the Drake Equation during our class period. However, after doing more research, I found many people who are heavily against the Drake Equation. In this blog post, I will review some of their main arguments.
First, on “Y Combinator Hacker News”, I read: “I really dislike the drake equation because it’s the epitome of bad science — when someone enters value for the variables they have no idea what is reasonable, absolutely no idea — is it 0.1 or 0.0000000000000000000000000000001 we have no way of knowing.”
After reading this comment, I did understand where they were coming from. It was something I struggled with when doing the Drake Equation myself. It was hard knowing what to estimate, especially when the numbers are so small.
However, some people defended the Drake argument on this site. They stated that the Drake equation is more “creative” and gives people perspective on how insignificant they are in relation to the entire universe. It also tells people that there is a significant chance that we are not alone in this universe that we live in.
Knowing about all the planets in our own solar system made us wonder if there are other planetary systems out there as well. And there are!! But how did we detect these extrasolar planets?
There are four ways to detect extrasolar planets. The simplest way, but not always the easiest way, is direct observation. That’s exactly what it sounds like: using telescopes to look for planets and observe the spectra of those planets. Only a few planets have been detected using direct observation, since these faraway planets may not be able to be seen by using the telescopes we have now.
We can also use the astrometric method, which involves observing a star and seeing whether it changes position over time. Recall that a planet and its star are both involved in the orbit around their center of mass (even though it doesn’t look like that because the star is usually much more massive than the planet so the center of mass is actually inside of the planet!). From this, we can conclude that if a star wobbles, there must be a force acting on it, which is the force from a PLANET orbiting! This method is only really useful for discovering large planets that are far from their star.
Another method is to use spectra and see if there is Doppler shifts in the star’s spectra. We can use that to figure out if there are planets orbiting the star. This method is great for finding large planets with smaller orbits.
Our final, and my favorite method, is the transit method. This method can only be used if a planet is edge-on when viewed from Earth, and is awesome for finding small planets!! We observe whether the star gets dimmer in regular time intervals (this can show that a planet is moving in front of the planet, thus blocking out some light) and then conclude the existence of that planet with follow-up observations using other methods. The star’s brightness can be graphed, and seeing recurring curves shows that it’s the same planet moving in front of the star.
Today, over 5,000 exoplanets have been discovered, and so many potential exoplanets are still being observed! Learning about other planetary systems is really cool, because we can see similarities between our solar system and other ones, as well as learn about new properties.
Since the beginning of our endeavors in the final frontier, one of the central themes has been the expectation and hope of extraterrestrial life. It has been the theme for an incalculable quantity of science fiction, and one of the paramount symbols used when justifying our efforts to explore the universe. In that effect, many hours have been spent by many of the smartest minds trying to come up with messages, conceivably intercepted, interpreted, and responded to by extraterrestrial creatures.
These are wonderful symbols. They provide humanity with the opportunity to define some of its fundamental cosmic characteristics, a tremendous thought experiment. It also gives us a place to reflect on how well we know the fundamental properties of the universe. After all, trying to make maps to Earth as readable as possible, without access to any units of time or space that we use on Earth, is fun.
However, this is fundamentally an introspective exercise, and not a practical one. There is no way any written language or series of symbols could be interpreted by a non-earth-based life form. This is proven by our own history of communication and translation.
The Rosetta Stone is one of the most important pieces of archaeology ever found, because it provided a direct translation to ancient Egyptian script, which we had not yet translated when it was found. This was a language directly related to living, spoken languages, that provided many pieces of writing that we were actively trying to decipher. Much of the writing also talked about history that we were familiar with. Nonetheless, it took a direct translation of a large passage to a spoken language in order to understand almost any of the script.
This is important because Ancient Egyptian would be significantly easier the decipher for human beings than any human communication could possibly be for extraterrestrial life. Firstly, both Ancient Egyptian and modern languages both exist in a tradition of written language, meaning that we immediately understood that the symbols on the stones were an attempt to communicate, which was not true for all humans. For example, it was not until very recent that we understood that language had been recorded in the Inca Empire, just not through writing, but through colored knots.
Secondly, our species is unique in its development and value of communication as a concept. Trying to communicate with a whale is impossible, and they are mammals with language. Trying to communicate with a tree doesn’t even make any sense. Much less, trying to use written symbols to communicate with a tree is so obviously fruitless that no one would ever try. There is no reason why extraterrestrial life would communicate amongst itself in a way any more similar to us than a tree.
Ultimately, things like the Golden Record are a beautiful capstone to an endeavor that has other scientific purposes, but I have no expectation that any message human beings could possibly send could ever be understood by anyone but the sender.
Wow, I cannot believe we are already at the end of the semester! This class has certainly been a journey, and we learned so much together! At the beginning of this course, I was not sure what to expect, and I was nervous that it was totally out of my wheelhouse, but ASTR 2110 gave me a newfound appreciation for the world around us.
Starting at the beginning, we learned the origins of astronomy, by the end, we can conceptualize just how many other worlds are out there and if there is a possibility of life beyond us. My favorite part of the class was learning about the other planets in our solar system, especially the terrestrial worlds. Knowing that they are so close to us, but so vastly different is so fascinating! I really want to learn more about Venus in the future as we continue to explore it.
I hope you all enjoyed following along this journey with me, learning snippets of it on my blog! I really liked being able to connect what we learned in class to more personal situations, like my Superstorm post that affected my hometown about 10 years ago. If you have not had the chance to check that out you can read about it here!
I really urge you all to stay curious about what is going on beyond Earth. I know that after this class the NASA website is going to be my go-to to find out about future missions and all the amazing things they are doing! To finish, enjoy this image one of my best friends took in Ohio during totality during the Solar Eclipse; an absolutely spectacular moment that encourages us to learn about the universe beyond!
An image of Solar Eclipse totality in Ohio. Photo by: Honey Stukes
Wow. I simply cannot believe that the second semester of my freshman year has come to a close. Entering this class, I was expecting to struggle through just another science course, however, I could not have been more wrong. I have learned more in this class than any other class that I have ever taken. This course has helped me to appreciate the universe above us and in this blog post, I want to briefly cover the topics from this course that I have found the most interesting. I will be delving into my favorite topic to learn about from units 1-4 (I left out unit 5 because I just wrote blog #7 on my favorite unit 5 topic).
Unit 1: The Cosmic Calendar
To me, the cosmic calendar was by far the most interesting this that we learned during unit one. The cosmic calendar really helped to put my existence on Earth in perspective. My life is an extremely tiny portion of the history of the universe. In order to give examples of the cosmic calendar, the dinosaurs went extinct around 65 million years ago, however, this was only yesterday on the cosmic calendar. Additionally, humans have been around only for a matter of minutes on the cosmic calendar! On average, a single human life would last about 0.2 seconds on this calendar. The cosmic calendar truly helped me to really just how long our universe began forming before the existence of humans and has shown me just how much there is in history that I was not previously aware of.
Unit 2: Types of Light
In Unit 2, a lot of our discussion in-class and in the textbook was about different kinds of light. I learned that light comes in individual photons that are characterized by their wavelengths and frequencies. The energy of photos is determined by the length of the photons’ wavelengths. The shorter the wavelength of a photon, the more energy it has and the more damage it can do if it comes in contact with humans. All of these different energy levels of photons created the electromagnetic spectrum. The electromagnetic spectrum contains 6 prominent types of light. The longest wavelength light creates radio waves. The light that creates wavelengths that are just beyond the wavelengths of red light so that our eyes cannot see them is infrared light. The light that we are able to observe is visible light. Light with even shorter wavelengths than the blue light that we see is ultraviolet light. Ultraviolet light is the light that is absorbed in our ozone layer of the stratosphere! Light with even shorter wavelengths than this are x-rays, and light with the shortest wavelengths are gamma rays.
Unit 3: The Geology of Venus
I know this may sound strange, but during Unit 3, I particularly enjoyed learning about Venus. I am not quite sure what made me so interested in Venus more so than the other planets, but I am tempted to think that it may have been Venus’ extreme greenhouse effect. It is extremely difficult to analyze what is happening on the surface of Venus because of its thick clouds! However, we are able to study its geological features using radar mapping. On the surface of Venus, there are extremely few impact craters. On worlds that are not geologically active, impact craters are abundant. This means that Venus must be geologically active because volcanism must have filled its craters! The only impact craters left on Venus now are extremely large ones. If you were to walk on the surface of Venus, you would find lots of circular coronae on the surface. In simple terms, Venus’ coronae are basically an alternative to volcanoes that are circular holes in the ground that release gasses through outgassing. Most interestingly though, Venus has the largest greenhouse effect of any planet. Venus’ greenhouse effect bakes its surface to 470 degrees Celsius! This greenhouse effect is caused by an excess of carbon dioxide in the atmosphere.
Unit 4: The Galilean Moons
The Galilean Moons are Jupiter’s four largest moons: Io, Europa, Ganymede, and Callisto. The Galilean Moons are so large that they would be considered planets or dwarf planets if they orbited the Sun! Io, my favorite Galilean Moon, is the most volcanically active world in our entire solar system, according to The Cosmic Perspective by Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider, and Mark Voit. Io’s surface does not have one impact crater on its entire surface because of how geologically active it is! Europa is considered to be a water world because its entire surface is covered by water ice. Europa does not have many impact craters, which led astronomers to create the ocean hypothesis. It is thought that Europa has a subsurface ocean that is either rising up to the surface to erase the craters or is staying below the surface and its temperature is so hot that it causes convection. Additionally, the ocean below Europa’s surface has volcanic vents that can create icy plumes that crack its surface. The next Galilean Moon is Ganymede! Ganymede is the largest moon in our solar system. On Ganymede, some parts of the surface are dark and heavily cratered while other parts are light with few craters, suggesting an upwelling of liquid. Finally, the last Galilean Moon is Callisto. Callisto does not have a significant force of volcanic or tectonic features, letting us know that it has minimal levels of internal heat. Additionally, my favorite fact about Callisto is that it never underwent differentiation. We can tell this because rock and ice are mixed throughout its interior!
These were my favorite topics from each of the first four units and I hope that you enjoyed reading about them! Taking this class has been an absolutely amazing experience and I am so grateful for this experience. What are some of your favorite topics that you have learned about in The Solar System this year?
After taking this course, I am extremely excited to stay updated and learn more about astronomy and any news that comes out in the future. Now that I understand a lot more about how our solar system works, I am excited to read more and more about new findings in the world of astronomy. I have always had a fascination with stars and the night sky but never understood anything about it. I am excited to look up at the stars and know why we only see certain constellations in certain areas and be able to somewhat comprehend the vast distances in which these stars are from Earth. This class has not only deepened my appreciation for the night sky but also expanded my curiosity about the broader universe. It’s thrilling to connect the dots between what I see when I look up and the astronomical concepts I’ve learned. This class has opened my eyes to the possibilities of space and I am eager to learn more about what’s out there. It’s weird to think about how big the universe is and how we might not be the only living beings in the universe. Contemplating the vastness of space and the potential for other life forms both excites and unnerves me—it is crazy and kind of creepy to think about!
