Before taking this class I had never really had an interest in astronomy other than a short run with the original series of Star Trek. My knowledge of astronomy, and the universe in general, was very limited because of this. Like most people I had a basic understanding of astronomy and the solar system, but the true vastness and complexity of the universe was foreign to me. I was aware that the size of the universe was incomprehensible but through learning multiple specific distances I was able to gain a greater perspective about the universe and my place in it. In addition to the new area of knowledge that I gained I found that the class material often made me think about religion and its relation to astronomy. Specifically how both shape a person’s view on how we came to exist and how the magic of the universe is often shaped to provide evidence for/against the existence of a higher being. Studying these astronomy topics has impacted me personally by allowing me to see the universe as a place of endless possibility. After all, how can the mystery of other intelligent life be such an outlandish idea when we are alive to know that galaxies millions of lightyears away are constantly colliding, and that there are entire solar systems being wiped out in what is a space relative “blink of an eye”. In addition to having a better grasp on the complexities of the universe, I also have a greater appreciation for the world and everything in it because of the processes that had to occur to make Earth and life possible. This class has convinced me that it’s easy to view the world as dull and boring until you understand the magic that came together to make it and everything else in existence.
Astrobiology is a fascinating field that explores life both on and beyond Earth. One interesting topic that scientists who study astrobiology have been researching is how Jupiter and other similar planets have made life on Earth possible. It is believed that Jupiter has acted like a “meteor magnet” saving Earth and other smaller planets from being impacted by space debris. Without the gas giant’s help its possible that Earth would not have been suitable for life. Recently, an article was published about astronomer Stephen Kane and his team who discovered 2 Jupiter like planets far away from Earth (150 light years) that will be useful to further astrobiology research. The scientists hope that the two large planets can help provide clues about the possibility of life on smaller planets in other solar systems.
An interesting aspect about this discovery, is the method that Kane and his team used to detect the new planets. This creative method was utilizing both the wobble method (learned in class!) and direct imaging to be able to confirm a true wobble due to a planet’s gravitational pull. The scientists were able to use this method to discovery not only 2 new planets but a third giant planet near a previously discovered star. In the future Kane and his team will continue to search for planets in order to come closer to understanding if the factors that make planets habitable or common or not.
The Solar System is home to four giant gaseous planets named Jupiter, Saturn, Neptune, and Uranus. These gas giants have many satellites due to their mass and subsequent gravitational pull. Jupiter is the largest planet in the solar system and has fascinated humans for hundreds of years due to the large amount of moons that it has. There are currently 67 known moons orbiting Jupiter. The four largest moons were discovered by the famous astronomer Galileo Galilei in the year 1610. These large moons are called Io, Europa, Ganymede and Callisto and have distinct characteristics such as Europa being considered the smoothest in the solar system and Ganymede being the largest moon in the solar system. These 4 commonly known moons make up only 6% of the total moons that orbit around Jupiter. The other 63 moons are smaller and were discovered over the years by various scientists making the discovery of Jupiter’s moons a long-time group effort.
Jupiter’s moons are arranged into 3 groups. These three groups are the inner moons, galilean moons and outer moons. The inner moons, also referred to as the Amalthea group, are the ones that orbit close to Jupiter. The outer moons are the furthest from Jupiter and are made of smaller objects such as asteroids. These smaller moons (all under 3km) have wackier orbits than the inner and galilean moons because they are experiencing less of Jupiter’s gravitational force. Last year, scientists accidentally discovered 12 new moons orbiting around Jupiter while searching for another planet. One of these moons named Valetudo is particularly interesting due to it having prograde motion yet occasionally crossing retrograde moons due to its orbital incline. By studying the moons of Jupiter and likewise discovering new ones, scientists are better able to understand how the solar system came to be.
Tardigrades are the toughest animals that we have yet discovered, not due to their physical strength, but rather their incredible ability to survive. People praise cockroaches for their ability to survive levels of radiation that would be lethal to humans, but the real heroes are microscopic “water bears” called tardigrades. Tardigrades are extremophiles, or micro-organisms that are able to survive in the most extreme settings. They have been found within volcanoes, the deep sea, jungles, and Antarctica. To test the limits of their survival (which sounds pretty messed up), scientists have subjected these poor water bears to extreme temperatures, immense atmospheric pressures, lack of water, radiation, toxins, and even outer space. In all cases, tardigrades vastly outlive nearly every other animal on Earth, and they are the only known animal to be able to survive in space. The existence of these animals makes a believable case for microbial life in the most extreme environments possible all throughout the Universe. I can only imagine what medical breakthroughs could come from studying them further.
Look at this pale blue dot, “the only home we’ve ever known” as we heard Carl Sagan so elegantly say on the last day of class. “On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.” Here it is now, reduced to a small and insignificant speck. How can that not make you start thinking about your life, everyone you know, and everything that’s going to happen in the future? That’s what astronomy does to people.
As I think about being small and mortal, and I can’t help but think about the future. What’s next? How far will we go? How much will see? Will we get to see it? The seed of this wondering was planted by this class. My answer has been pulled in two directions: optimistic and pessimistic. It’s being pulled by two different things: Star Trek and my writing class.
The show Star Trek is, to me, a relic of an older and more optimistic past. It spoke of the fabulous technology we would create and intricate societies we would develop. Compare this to more recently developed shows that take place in the future: they focus instead on dystopian, authoritarian governments and overcoming genocide and environmental disaster. Star Trek is not conflict-free, but all of it rests on the premise that humans get really smart, build really cool ships, and are fundamentally virtuous enough to build important relationships with others in the universe. I’ve been working my way through the show this semester, and can’t help but think about their exciting travels as we talk about exoplanets in class. It all feels so optimistic–there’s so much out there to explore, and here’s a show that lets us see exactly what we could do!
In contrast to this is my other class, where we write about climate change. Sometimes we write about hopeful things like eco-friendly innovations. Most of the time, we write about pessimistic things like past extinctions and the likelihood that the next one (involving us) will be soon. We talk about how many emissions we need to cut down, and how unlikely it is that we will make the necessary changes in time. We talk about bull-headed politicians and greedy corporations and extreme imbalances of power that prevent any real progress from happening. In short, I’ve spent the semester thinking and writing about how utterly doomed humanity is and it all makes me doubt that our civilizations can survive long enough to explore the stars.
This is why the Great Filter theory of the Fermi paradox is so captivating to me. I like to imagine Star Trek: The Next Generation as our future–one full of courage and exploration. Perhaps we already made it past the Great Filter. Maybe there’s a thrilling future ahead where we actually develop the technology necessary to see the universe and realize that there are other civilizations out there. But as I’ve spent the semester researching the complex problem of climate change, I’m becoming increasingly convinced that the Great Filter is still ahead of us, and that it comes in the form of climate change. Will we be able to manage the environmental changes? Or will the instant gratification of more primitive and destructive forms of energy destroy us before we develop from more advanced and sustainable technology.
Depending on the day of the week (and how recently I’ve watched Star Trek) I’m either optimistic or pessimistic about the future. Sometimes, thinking about space is exciting and fun. Sometimes, it’s worrisome and exhausting. All we can do is keep going.
It’s the age old question: are we alone in the universe? It’s a topic we began wrestling as children, well before we even had basic knowledge of the solar system and galaxies. But it seems that even after taking astronomy classes, the answer isn’t much clearer. Instead, we now have a conflict between probability, which says there absolutely should be other intelligent life, and evidence, which insists there is not. I’m sure you know about the lack of evidence. Let’s explain why it’s so probable that more life exists.
There are 400 billion stars in our milky way galaxy. 20 billion of these are like our sun, and 1/5 of these have a planet that, like our Earth, is in the habitable not-too-hot and not-too-cold zone. Even if 0.1% of these planets had life, this means there should be 1 million planets with life just in the milky way!
Another thing to consider is that Earth, aged 4 billion years, is about a third of the age of the milky way, aged 13 billion years. While it’s true that the early years of our galaxy were chaotic and ridden with explosions and impacts, it would’ve quieted down enough after 2 billion years for other life-forming planets to develop. It’s also reasonable to assume that we would have seen these life forms by now. These other planets and their life forms would have had much more time than humans have to develop their space travel technology. If their spaceships could sustain populations across generations and started spreading these ships out to other planets, it would take only 2 million years to colonize the galaxy. Compare this to the 13 billion years that the milky way has been around and recall that there are potentially 1 million life-sustaining planets in the milky way that could do this colonizing.
Other life forms would have a head start. From Wait But Why
As I’m sure you know, we’ve seen no sign of this. But why haven’t we? That is the Fermi paradox, named after physicist Enrico Fermi. There is no answer, but plenty of proposed explanations. The most interesting one to me is the great filter, so we’ll be focusing on that one.
The Great Filter
A lot of things have to fall into place for a life-form to develop the ability to colonize its galaxy. Perhaps one of these steps is a great filter, or barrier that life must overcome. It’s a challenge posed, that life forms either pass it or they don’t. Here’s the scary thing: we don’t know where it is.
It’s possible the great filter was something in the past that we already made it through. Perhaps it was the evolution of eukaryotic cells, or forming life at all. Maybe it was moving from chimpanzee-level intelligence to human-level intelligence. If this is the case, that means we somehow overcame something that everybody else couldn’t–this would make our kind of life rarer than we predicted. This is also the more exciting possibility. This makes the future, and the galaxy, ours to explore.
Here’s the scarier option: that the great filter is in our future. That means there’s a chance we won’t overcome it. Perhaps it will be nuclear war or climate change or a freak gamma ray explosion. If this is the case, there must have been lots of life like us before, but something kept it from developing enough to spread through the galaxy. Maybe this is what happened to life-forms on the older planets. This is the scarier of the options–that something lies ahead that nobody else managed to move past.
Are we doomed? Or did we unknowingly pass a great trial? Image from THE ANGRY UFOLOGIST
This is why philosopher Nick Bostrom says finding life on Mars would be devastating for us. If it’s simple life, it becomes less likely that the Great Filter is something already behind us. It would be even worse news if we found complex life on Mars–that would mean life more advanced than ours is not rare at all, and the Great Filter is still ahead of us.
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Throughout the semester, I learned about things I had never thought of including the moons of others planets, tiny microbes living in extreme conditions, and astronomical objects here on Earth. Each of these topics and more helped me grasp the scope of the universe and the solar system we live in. There are so many things happening in the universe right now that amaze me still and I am excited to see what I can learn more about in the future.
Perhaps my next step in my astronomy career is looking outside our solar system and seeing how the stars and different galaxies work. Learning about these things could teach us so much about our own solar system and how it functions. Whether solar systems like ours are common or rare, or if life can develop in different ways puts our own lives into perspective and get a greater sense of the universe and its nuances. Overall, astro2110 has been a great learning experience and a stepping stone for my astronomy knowledge.
One of the biggest questions in the universe is whether or not we are alone. The Fermi Paradox seeks to answer this question and try to make sense of our place amongst the cosmos.
The basis of the paradox is if a civilization had the right rocket technology and the will, they could colonize the galaxy in 10 million years. In the scope of the universe, this is a very short amount of time to colonize a whole galaxy. A study was done from the Kepler Space Telescope that found that one in five sun-like stars have an Earth like planet orbiting them. So, why havent they come here?
There are several “explanations” as to why we haven’t made contact with aliens based off of this statement. The first is because the technology to have feasible space travel does not exist, so colonizing of different planets couldnt happen in the first place. The second is that aliens never had the drive to colonize. Maybe they have the technology, but Earth isnt worth colonizing for some reason. Another explanation is that the intelligent life advanced recently and they just havent come yet. We could be the first advanced life form in the universe and none have developed anywhere else. Lastly, we could have already been visited, maybe when the Earth was still developing, so the aliens overlooked us. (Source) Either way, contact with aliens still has not been done, but we also need to answer the question of whether we want them to come or not?
Bill Nye gives his take on the subject and comes up with a possible solution to this paradox:
An artist’s conception of our solar system. Image Source: NASA Science
As my freshman year of college draws to a bitter sweet and slightly chaotic close, I’ve been doing some major thinking about about the events of the past school year. I fell in love with astronomy from the very first lecture I attended, way back in August of last year. While my first semester gave me a basic understanding of stars and galaxies in ASTR-1010, this semester taught me about the solar system. I came into this course with a good deal of astronomical knowledge already; however, I could never have imagined how much more I would learn about this fascinating field. I absolutely loved taking such an in-depth look at each of the planets, the Sun, and the solar system as a whole. The study of our own star system gave way to the examination of other solar systems, and then we got into questions that will bring on existential crises like “What is life?” and “Where are the aliens?” This class has encouraged me to look at the universe in whole new ways. I’ve learned that the space between cosmic objects is almost unfathomable. I’ve learned why Venus rotates in the wrong direction and that my zodiac sign will be completely different in a couple thousand years or so. I’ve learned that while we haven’t met any aliens yet, other life forms may exist somewhere in our own solar system. The list goes on and on.
Astronomy is a complex science; while we have figured out so much about our universe already, there is still work to be done. I hope that one day, we might be able to answer some of humanity’s most burning questions.
artistic interpretation of element string which may make up our universe, pic from medium
The string theory is a very interesting idea that propose another totally different way of thinking what made up our universe. Although this theory is very arguable because it can never be tested in our labs so that a lot of physicist do not like this theory, but it indeed gives a very unique prospective and interpretation about parallel universe and dimensions.
The theory proposes that everything in the universe is made of the tiny element called string. It is itself one dimension particle. String theory proposes a unique solution trying to figure out the ultimate equation of the universe, that equation that unifies all four major forces in the universe: gravity, strong nuclear force, weak nuclear force and electromagnetic. This is the equation that Einstein seemed for his whole life.
Before string theory, people think this equation does not exist because of the quantum physics. Modern quantum physics thinks that things happen in the quantum field can not be predicted. We can only predict the possibility of something happen in the quantum field. In other words, there are no equations related to quantum physics since everything is about probability.
Einstein believes that there must be an ultimate equation that explain everything from large scale to quantum physics. String theory provides one possible answer for seeking this equation. String theory proposes that every forces are generated because of specific particles. For example, the one that is responsible for gravity, also the special one, is called graviton. This is a theoretic particle that has never been found by human.
Other things that are very interesting about string theory is that it tries to explain the parallel universe by the idea of membrane. Basically our universe is like a membrane where there are a lot of other parallel universe. Only graviton can sometimes travel through membranes.
cross section of a quintic Calabi-Yau manifold, pic from wikipedia
