Student Full Speech 02: Sarah McDaniel, Ex Astris Scientia

“I loved the stars too fondly to be fearful of the night”—so says Sarah Williams in the poem “The Old Astronomer to His Pupil.” By a show of hands, how many people used to look up at the night sky as a child? How many people still go outside and look up at the night sky, wondering what's out there that they can't see? Today I will be presenting information on one of the amazing phenomena of our universe, the black hole. As a result of two semesters of college-credit astronomy classes and in my previous two weeks of research for this presentation, I feel qualified to speak on this topic. For those of you who are familiar with science fiction at all, my presentation will actually make sense [of] a lot of the technological terms and scientific terms thrown around. Good morning, everyone. My name is Sarah McDaniel. When I finish my presentation, you will have more information about one of the amazing facets of our universe, the black hole. First, I'll be describing a basic model to you, the Schwarzschild model for a black hole. Second, I'll be presenting one of the research methods used to study a black hole. And third, I'll be answering a very important question: why even study black holes at all? My main thesis concerning this topic is that I strongly believe everyone should have information about the universe we live in. Education is not preparation for life; education is life itself. What is a black hole? A black hole is the remains of a collapsed star. According to encarta.msn.com, a black hole is a dense, celestial body, most likely formed from a collapsed star. This right here is a white dwarf star. Through the course of stellar evolution, it is collapsed. The nuclear fuels have burned up and, without the energy and the pressure created by that burning to keep the star expanded, it slowly starts to contract. Karl Schwarzschild was actually the first person to ever theorize about the existence of black holes, and he started hypothesizing based on Albert Einstein's theory of general relativity. Karl Schwarzschild hypothesized in about 1914, and this right here is a model of his black hole. As defined by library.thinkquest.org, a Schwarzschild black hole is a perfectly symmetrical, spherical, and stationary model. There are other black hole models that involve rotating black holes and centers of gravity, but Karl Schwarzschild is the simple one. He was the first. He believed that simplicity was elegant. The singularity, seen down here, is kind of the center of the black hole. It's a point of infinite density and it is in the center of the black hole's gravitational field, which is insanely strong. The closer you get to the singularity, the slower time seems to progress, until hypothetically, when you reach the singularity, all time and space stop there. The Schwarzschild radius, which you see up here, also called the “event horizon,” another term thrown around in the show Stargate SG-1, it's the distance from the point of mass at which the gravitational field is so strong that not even light can escape it. So on my next point: how do you study something that is so far away and distant in our universe and the gravitational field actually pulls in all the light, which is why it appears black, so we can't even see black holes; how do you study them? So this is a drawing of the galaxy; it's a spiral galaxy. In a press release over the summer at www.sciencedaily.com, Dr. Mark Siger had hypothesized that one of the ways we can study black holes is by photographing the spiral galaxy which most of them reside in. They tend to be the center or living somewhere in a galaxy, and so Dr. Siger said if you photograph a galaxy, you can actually measure how tightly the “arms,” quote/unquote, of the galaxy wrap around the center. And he said the tighter the arms are wrapping around the center of this galaxy, the stronger the gravitational field is, which in turn would mean that the black hole is more massive. And so, you know, why take pictures? Why would we care about the size of the black hole? Well, as Dr. Siger put it, one of the most important reasons to learn about the distant black holes is that when you're looking at galaxies far away, because it takes so long for the light to reach our telescopes, we're looking at images from the past. And so he's saying we can look at the images of the past and study how black holes progress and how they evolve over time. And since a lot of black holes seem to be found in galaxies—the centers of all galaxies, not just the occasional sporadic galaxy—Dr. Siger hypothesized that maybe black holes are what brings about—that black holes, you know, is a key element to how galaxies are formed in the first place. Now, for my third point, the answer to the question I know you've all been thinking: why do we even study black holes? What relevance is it to all of you sitting here that I am talking about this random gravitational field billions of light years away from you? Well, one of the most baffling mysteries in modern astronomy is the fact that 80 to 90 percent of the observable universe, we have no idea where it is. We can't see it. It appears to be empty, but we know that there must be matter in the universe. And so, one of the theories that came about to help explain this quote/unquote “missing matter” is the black hole. There are many theories that attempt to explain it. Black hole research is extremely important for physics and astronomy. It also helps to validate kind of Einstein's theories of general relativity. I'm near the end of my speech. Today I've given you information about one of the many theoretical models for black holes, the Schwarzschild model for black holes. I've also told you one of the ways astronomers study this and why it's even relevant to study black holes. Once again, I believe every person should have knowledge about the universe in which we exist. To quote the Starfleet Academy motto: “From the stars, knowledge.”