ENGL 105 Podcast Carolyn Shi 02/20/24

Dark matter, a type of matter that does not emit or absorb light, is being studied to understand its role in the universe. A 2020 study by Bernard Carr and Florin Kuno explores the possibility of using primordial black holes to explain dark matter. These hypothetical black holes, which form early in the universe, could contribute to the mass and velocity relationship of galaxies. Although still theoretical, primordial black holes offer a way to unify general relativity, quantum mechanics, and thermodynamics. While much is still unknown about dark matter, studying it could lead to new discoveries and technologies. For most of human history, we have always assumed our world consists of what we see. In 18,000, Sir William Herschel discovered infrared, a section of the electromagnetic spectrum that is invisible to our eyes. Thanks to invisible lights, our technologies advanced immensely. What about invisible matter? Is that a thing? If we want to make a giant leap for mankind, again, dark matter is our hope. Welcome to Carolyn's podcast, and let's delve right into this matter. Imagine you are looking at a spiral galaxy turning. They have a relatively concentrated center, a bulge of stars and gases, and the mass thins out as you get farther from the center. Its rotational velocity is related to its radius and mass. The more mass within its radius, the higher rotational velocity. So intuitively, diffused periphery of the galaxy would not affect its rotational velocity that much. Or so you thought. To our surprise, this model does not align with our observations. If not much visible mass is at the edges of galaxies, there must be something else present to uphold the mass and velocity relationship. That something is dubbed dark matter, which is the kind of matter that does not emit nor absorb light, but we can infer its presence due to its gravitational effects. A 2020 study conducted by Bernard Carr and Florin Kuno examines the possibility of using primordial black holes to explain dark matter. Primordial black holes are hypothetical black holes that form early in the universe. Although still theoretical, they possess the property of unifying general relativity, quantum mechanics, and thermodynamics, making it useful to study. Carr and Kuno proposed a couple of scenarios in which primordial black holes could contribute dark matter to the universe. And one of them, for example, was that the remnants left behind primordial black holes after evaporation provide dark matter. Black holes evaporate due to Hawking radiation, which is a type of radiation similar to thermal radiation, except instead of giving off heat, black holes radiate their mass away due to peripheral particle interactions. In this process, black holes slowly evaporate over time, leaving stable relics, which are effectively extremely small black holes. Carr and Kuno concluded that primordial black holes have the potential to provide dark matter. The funny part is that we don't even know whether these types of black holes exist themselves. Nonetheless, Carr and Kuno's works lay the foundation and preliminary guidance for other scientists. Indeed, theory can only take you so far, but we have to begin somewhere, right? Dark matter is but a piece of puzzle of the world of mysteries, yet it is an important one. With it, we open the doors to the formation, history, exotic phenomena in the universe, and even new branches of technology. Scientists are bored to be curious, so why not take it even further? We still have a long way to go in unveiling the components of dark matter, but the notion of being surrounded by something mysterious and exotic is already an utmost exhilaration. This is your host, Carolyn. Thank you for listening, and stay hungry for knowledge.