Hashim Khan
Unit 2 – Reflective Annotated Bibliography Revised
What I Revised:
I didn’t have much to revise. As you said in my original unit 2 post under “From Prof. Blain” I just needed to look for some grammatical and punctuational errors. I did that throughout my paper and in the reflective bibliographies. As you said in my “Final Revision Ideas” OpenLab post I just had small errors throughout and just needed to clarify some sentences better and I did that.
Black Holes
Intro:
Space is something that has always interested me throughout my life. When I was a kid, I would always go out and stare at the stars, wanting to be an astronaut. As I got older, I would learn more and realize just how little we know about the universe. One of the biggest examples of this would be our understanding of black holes. Black holes are one of the most mystifying things we’ve ever encountered, often becoming the most entertaining part of sci-fi and space movies/books/comics/games. Movies like Interstellar and people like Stephen Hawking have recently popularized the topic in the past 15 years. I’ve always had preconceived ideas of how black holes appear and disappear, but I’ve decided to now learn what the actual science is behind it, expecting to find a lot of different theories and learn information I’ve never expected.
There are a lot of uncertainties when it comes to black holes, but we do have theories on how they appear and disappear. From what we know, when a star collapses into itself and dies it will create a supernova explosion which will either produce a neutron star or a blackhole depending on how massive the star was (about three times the mass of our sun). The entire mass of the core will collapse into itself creating a black hole, where we will only be able to see the event horizon. The event horizon is impossible to escape, even if you’re moving at the speed of light, meaning all we see is a black sphere reflecting nothing. We have no idea of what the inside of a black hole may look like beyond the event horizon, but we call this part the “singularity” where we hypothesize that all its mass is concentrated into a single point in space, with no surface or volume. So how do black holes die? Well, black holes evaporate through a process called Hawking radiation, named after Stephen Hawking. In empty space (which is not really empty), virtual particles will constantly collide with each other annihilating each other. When this happens right at the edge of a black hole, where one particle will be inside the black hole and one outside. One of the particles will be drawn into the black hole, and the other will escape becoming a real particle. This deals with quantum mechanics, but in general, this just means the black hole is losing energy. This is slow at first but becomes faster as the black hole becomes smaller. In the last second of its life, the black hole radiates away from the energy of billions of nuclear bombs in a huge explosion. However, as said before, this process is incredibly slow and will occur long after we are gone. This reflection and research process has taught me a lot, and it’s enjoyable to now know how a black hole appears and disappears.
Source #1: “Black Holes Explained – From Birth to Death.”Youtube, uploaded by Kurzgesagt – In a Nutshell, 15 December 2015, Black Holes Explained – From Birth to Death – YouTube
Summary:
The YouTube video goes through the process of a black hole, from its birth to its death. It begins by talking about how a star is constantly collapsing in on itself due to its own gravity. As this happens, in the star’s core nuclear fission crushes the hydrogen atoms into helium releasing a tremendous amount of energy. This energy is in the form of radiation and pushes against gravity, maintaining a delicate balance between the two forces. The heat and pressure in the core eventually allow them to fuse heavier elements until they reach iron. Iron doesn’t release any energy when made and builds up at the center of the star. Because of this, the balance between gravity and radiation is suddenly broken, and the core collapses. If the star is big enough, when the star collapses into a supernova explosion this will result in a black hole. The part of the black hole we see is the event horizon. Even light can’t escape the event horizon resulting in the black hole only reflecting as a black sphere. We don’t know anything about the inside of the black hole, but we call it the singularity where we hypothesize that all its mass is concentrated into a single point in space, with no surface or volume. Black holes evaporate through a process called Hawking radiation. Hawking radiation deals with virtual particles which constantly appear and collide with each other. When one particle is created inside the black hole and one outside, one of the particles will be drawn into the black hole, and the other will escape. This makes the black hole lose energy and eventually evaporate slowly until it goes out with a massive explosion at the end of its life.
Key quotes:
- “Moving at about a quarter of the speed of light, feeding even more mass into the core. It’s at this moment that all the heavier elements in the universe are created, as the star dies, in a supernova explosion. This produces either a neutron star, or if the star is massive enough, the entire mass of the core collapses into a black hole.”
- “As powerful as black holes are, they will eventually evaporate through a process called Hawking radiation. To understand how this works, we have to look at empty space. Empty space is not really empty but filled with virtual particles popping into existence and annihilating each other again. When this happens right on the edge of a black hole, one of the virtual particles will be drawn into the black hole, and the other will escape and become a real particle. So, the black hole is losing energy.”
Rhetorical Analysis:
The YouTube channel for all its videos uses animation to convey its topics into an easy-to-watch and digestible source of information. The art style is incredibly soft and kid-friendly, using fast-paced transitions and on-screen animals to convey what the narrator is saying in an easy-to-understand form. They use many colors and shades to keep your attention as well. The narrator is Steve Taylor, and he speaks in an exceptionally good informational discovery type documentary voice and cadence. It’s fun to listen to and keeps you captivated by how soothing it is. The information in their video isn’t too technical, meaning anyone even without a basic understanding of the topic previously, can still learn from their content. The captions are already set up in the video, meaning you can read subtitles as well when going through the video. The content in the channel is made by a team of people researching and getting expert testimonies from professionals. All the links and sources are put in the description of the videos. The videos are also relatively short. This provides for a less time-consuming way to learn about whatever scientific subject you want to.
Source #2: Bolles, Dana. “Black Holes.” NASA, NASA, Black Holes | Science Mission Directorate (nasa.gov).
Summary:
The website goes on to explain what a black hole is and its properties. As it says, a black hole is a great amount of matter packed into an exceedingly small area where the gravitational field is so strong that nothing can escape it. There’s a common misconception that black holes suck things in like a vacuum, however, it’s the strong gravitational pull that brings things closer to a black hole, not a sucking force. Black holes were predicted by Einstein’s theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If that core’s mass is around three times the mass of our sun, the equation showed, the force of gravity produces a black hole when a star eventually collapses in onto itself. Since scientists can’t observe a black hole directly with telescopes or other forms of electromagnetic radiation, they have to infer their presence by detecting their effect on other matter nearby. A gamma-ray burst was observed by NASA’s Swift telescope and studied by NASA’s Hubble Space Telescope that showed what could’ve been the aftermath of a powerful explosion from a black hole and a neutron star colliding, producing another black hole. Historically it was believed that no mid-sized black holes exist and with recent evidence from Chandra, XMM-Newton, and Hubble we were shown proof that mid-sized black holes do exist. Finally, Astronomers believe that there are supermassive black holes that lie at the center of pretty much all large galaxies, including our own.
Key Quotes:
- “The idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein’s theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core.”
- “Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.”
- “Scientists can’t directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby.”
Rhetorical Analysis:
The website is the official NASA website. Everything is organized very well, and the article is easy to read as it’s not too complex or loaded with details. The website puts in pictures that lead to videos that relate to the topic at that point of the reading. The videos have a small summary under them as well that explains what they’re about. The website is constantly getting updated as recent discoveries are put towards the bottom if you want to get informed on the latest news. Subsections are labeled throughout the reading, and there’s a tab for related content and links on the right-hand side if you want to learn more. On the top right, there’s also a way to change the language to Spanish.
Source #3: “What is a black hole?” Youtube, uploaded to Mystery Doug, 6 May 2019, What is a black hole? – YouTube
Summary:
The video as expected goes into the topic of black holes. Black holes were first initially theorized by scientists before we could observe them. It was just an idea, a what-if. The math behind a black hole existing would mean that light would be able to bend which seemed impossible with the knowledge we had at the time. During the mid-1900’s we would start using telescopes to try and observe and see if black holes exist. We wouldn’t have any success doing this as the possibility of finding a black hole with the current technology at the time and even today is almost impossible, requiring a lot of luck. That was until 2020. A team of 200 astronomers from around the world would work together with eight different telescopes to function as one pseudo-giant telescope to get photographic proof of one.
Key Quotes:
- “At first, all of this was an idea, a what-if. If such a thing existed, would it really do that to light? Can light really be bent? But around the mid-1900s scientists discovered some reasons for thinking that black holes might actually exist in real life.”
- “A team of 200 astronomers worked together all around the globe and used eight different telescopes to basically act like one giant Earth-sized telescope. It was not an easy thing to do. Not only did the telescopes all have to point at the exact same place in space, but to combine the view from each telescope involved really advanced computer skills used by scientists like Katie Bouman.”
Rhetorical Analysis:
The video starts with a question from the creator’s viewers. It’s about black holes and the video uses the recent 2020 picture of the black hole to keep the audience’s attention. They show photoshopped animations to help explain their point more clearly with slow transitions to keep your mind occupied on what the narrators are saying. Unlike the first video, this video uses realistic images of everything whereas the other video uses soft-drawn cartoon hand-drawn animations. The narrator may at times speak in an unenthusiastic and slow way which can make you uninterested, but if you’re interested in the topic, you can easily get over it.
Reflection/Conclusion:
Since the beginning, I’ve always been open to learning more about new topics, and after doing all my research, it’s surprising how much and how little we know about black holes and space in general. As far as we know, we’ve only learned about the tip of the iceberg when it comes to this stuff. I already had earlier knowledge when it came to the creation of black holes and supernovas, however, when it came to how black holes disappeared that surprised me. I’ve always heard of Stephen Hawking but I never knew what he was so renowned for, and after learning about his Hawking Radiation theory, it’s fascinating to learn about virtual particles, “empty” space, and quantum mechanics. The first source, being the video from Kurzgesagt, is probably the best one. It gives the quickest way to learn about the life of a black hole and goes into good depth using amazing visuals and the narrator. It also gives a good refresher to how black holes are created in the first place, which is when a star about three times the size of our sun starts to collapse into itself and forms a black hole in the aftermath of its supernova explosion. The article from NASA itself is also great using links, images, and embedded videos to teach you. The bottom of the NASA website also has links to new research and news that come out about black holes. If there was one question I did have, it would be what’s inside of a black hole beyond the event horizon. This is still a question the scientific community is hypothesizing about themselves. I think learning is important, and when it comes to black holes and space, I feel that it’s important to learn more about the universe we live in. People who are curious about the world, and those who are bored should learn more about black holes, it’s one of the most mystifying things in our universe and we’re still learning about it. It’s good to keep questioning our world and then going out to get the answer to that question.
