Physical Science
PHYS 1040 Elementary Astronomy
I took this class my fall semester of 2012 at SLCC. This class fulfills my physical science credit. On this page I have also post my signature assignments in a blogging format (request of the professor). My reflection is below and I encourage you to read my blogs they are really informative!
Reflection These blogs demonstrate the learning that I have acquired over the course of the semester. For this assignment we had to write on a topic of our choosing from each of the four sections in our textbook. For each of the blogs we were required to discuss the science and history behind each topic then give our own opinions; all while keeping the blogs interesting to the reader. This shows my ability to write towards a targeted audience. All the topics that I picked because I wanted to learn more about them. This demonstrates my willingness to go out and learn on my own time.
So on top of the things stated above how else does these blogs show my learning in all the SLCC learning goals? By elaborating further on the topics it displays critical thought. Most importantly is these blogs is it helped me to better understand how the world works. Even though this was a simple college assignment, the knowledge that I gained from them will help me later with my future career as an astronomer. |
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Blog 1: Spectroscopy
What is spectroscopy? How does it relate to astronomy? Well let us start with the first question and the answer to the later will become apparent. Spectroscopy is the study of the interaction between matter and radiated energy. Now what does that mean? Basically all atoms release a specific wavelength of light when they become excited. Every atom has a unique wavelength that it releases, which will correspond to a color in the light spectrum. For example, carbon for instance would give off a different color of light than say strontium. Now that you have a basic understanding of the concept, how is applied to astronomy? Any guesses? Yes, you got it! This is how astronomers are able to determine what distant stars and galaxies are composed of, there properties, and even (using the Doppler Effect) determine the motion. When you think about it makes sense, all the astronomer have to interrogate the universe is the light that hits our blue green planet.
Now we know what we are doing, but how do we do it? Astronomers use a tool with a fairly creative name, a spectrograph. What this does is just stare at the sky and pick up on the various wavelengths of light hitting it. From there it separates it into the frequency spectrum that allows us to interpret it. You don’t need a spectrograph to see some of the effects that certain elements have on our visible light on Earth. Gaseous nitrogen dioxide has a characteristic red absorption feature, and this gives air polluted with nitrogen dioxide a reddish brown color. Rayleigh scattering is a spectroscopic scattering phenomenon that accounts for the color of the sky; it is more evident at sunset.
Sir Isaac Newton again makes a huge contribution to this field of science by discovering that when white light was shined through a prim it separated them into the visible light spectrum. Advancements in experimental spectroscopy were made possible by developments in optics. Traditional experimental techniques dispersed spectrally broad sources to determine the wavelengths of emission or absorption. But if emission is the light that the atom releases, what is absorption? Say there is a cloud of could gas between what we are observing and Earth, it would appear (when shined through a prism) as a series of black lines rather than a series of colored lines. This happens because the cloud of cold gas blocks the color from the source. Developments in spectroscopy contributed significantly in many areas of science like chemistry, astronomy, quantum mechanics, and physics.
Without the ability to accurately determine what distant star or elements is composed of astronomy would be a very limited field. It would be left up to philosophers, to say what other galaxies were composed of. Thankfully, the majesty of the cosmos has a method of determining what they are made of, and we aren't left to just the realm of theory.
Now we know what we are doing, but how do we do it? Astronomers use a tool with a fairly creative name, a spectrograph. What this does is just stare at the sky and pick up on the various wavelengths of light hitting it. From there it separates it into the frequency spectrum that allows us to interpret it. You don’t need a spectrograph to see some of the effects that certain elements have on our visible light on Earth. Gaseous nitrogen dioxide has a characteristic red absorption feature, and this gives air polluted with nitrogen dioxide a reddish brown color. Rayleigh scattering is a spectroscopic scattering phenomenon that accounts for the color of the sky; it is more evident at sunset.
Sir Isaac Newton again makes a huge contribution to this field of science by discovering that when white light was shined through a prim it separated them into the visible light spectrum. Advancements in experimental spectroscopy were made possible by developments in optics. Traditional experimental techniques dispersed spectrally broad sources to determine the wavelengths of emission or absorption. But if emission is the light that the atom releases, what is absorption? Say there is a cloud of could gas between what we are observing and Earth, it would appear (when shined through a prism) as a series of black lines rather than a series of colored lines. This happens because the cloud of cold gas blocks the color from the source. Developments in spectroscopy contributed significantly in many areas of science like chemistry, astronomy, quantum mechanics, and physics.
Without the ability to accurately determine what distant star or elements is composed of astronomy would be a very limited field. It would be left up to philosophers, to say what other galaxies were composed of. Thankfully, the majesty of the cosmos has a method of determining what they are made of, and we aren't left to just the realm of theory.
Blog 2: Io: The Angry Moon of Jupiter
We all know that Jupiter has many moons with varying properties. Io is the inner most of the Galilean moons (the moons discovered by Galileo Galilei). It is the most geologically active object in the Solar System, with over 400 active volcanoes. In comparison to other moons why is Io so active? That is thanks to Jupiter’s massive gravity. Tidal heating generated by the pull of Jupiter’s enormous gravity and its fellow satellites keeps Io interior very hot. Io is also unique in the outer Solar System compared to other satellites, because it is mostly composed of silicate rock surrounding a molten iron or iron sulfide core, opposed to a composition of water and ice.
The volcanism on Io is responsible for many of the unique features. The surface is constantly under a state of revision by the various lava flows. Surface changes on Io can now be observed from earth. In eight years we have seen new features that were not there when Galileo took pictures of the moon. The short time between the Voyager probes has shown that some of the volcanoes have stopped while others have started up again. This showed the first proof that the interiors of other terrestrial bodies are actually hot and active; one of the most important discoveries made by the Voyager missions. Since Io is constantly being pushed around, so to speak, by the mother planet and its fellow satellites, it has never had a chance to “grow up” and form plate tectonics. Since there is no plate tectonics there is only one other way for the planet to release its internal energy, and that is by volcanism. Knowing this, we now know why Io is so geologically active when compared to other terrestrial bodies.
What does Io look like? The surface is coated with sulfur and sulfur dioxide frost that paints the planet in various shades of yellow, red, white, black, and green. If we were to visit Io (somehow remaining alive in the intense Jenovian radiation among other things) you would see many unique features aside from the volcanoes; such as calderas, lakes of molten sulfur, and non- geologically active mountain ranges. What would you see if you were looking up at the sky? Io has a thin atmosphere composed mostly of sulfur dioxide due its volcanic plumes. The low gravity of the satellite isn’t enough to hold on to all of the ejecta produced by the volcanoes, sending much of the material into space. This extra material interacts with Jupiter’s magnetosphere and is stripped away to from various neutral clouds and radiation belts around Jupiter. Io's volcanic ejecta produces a large plasma torus around Jupiter. The plasma torus is a ring of ionized particles that shares Io’s orbit but rotates in the opposite direction with Jupiter’s magnetosphere. About one ton of material is removed from the atmosphere every second through interactions with Jupiter’s magnetosphere so the active volcanoes have to work hard to constantly replenish it. One interesting thing about Io’s atmosphere is that it isn’t constant. It is sustained by sun light driven sublimation (solid going directly to a gas) of frozen Sulfur dioxide at the surface. Observations of Io’s atmosphere are consistent with a sublimation driven atmosphere because it is densest on the anti-Jupiter hemisphere. Since the density of the SO2 is proportional to the surface temperature, the atmosphere partially collapses on itself when in the shadow of Jupiter. More than likely when you looked up at the sky you would see the blackness of space, illuminated only slightly by Io’s atmosphere interacting with the charged partials of the plasma torus.
Now I have bombarded you with facts about Io, but why is all this really important? Reading this you want to know the real “bread on the table” implications of this distant moon. It has nothing to do with its geological activity no matter how much it can teach us about volcanism here at home and on other terrestrial bodies; it has to do with its humble discovery. I mentioned earlier that Io, along with the other Galilean satellites, was discovered by Galileo Galilei. They played a significant role in the 17th and 18th centuries to astronomy to the adoption of the Copernican model of the Solar System. When Galileo decided to turn his telescope towards Jupiter, he discovered that there were bodies orbiting the distant planet. This when against the all the current understanding of how the universe worked. Rather than a geo- centrist model, Galileo showed that not everything orbited Earth. This led to the further development of Kepler’s laws of motions and the first measurement of the speed of light. Without this discover by Galileo where would our current understanding of astronomy be? I’m not implying that we wouldn’t eventually found evidence to prove the helio-centered model of the Solar System. How long would it have taken? This is why I choose one of the Galilean moons for my topic; it was one of the major milestones in the history of astronomy.
Sources:
http://nineplanets.org/io.html
http://www.sciencedaily.com/releases/2004/03/040322080941.htm
http://en.wikipedia.org/wiki/Io_(moon)
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Io
Understanding the Universe by Palin Chapter 9
The volcanism on Io is responsible for many of the unique features. The surface is constantly under a state of revision by the various lava flows. Surface changes on Io can now be observed from earth. In eight years we have seen new features that were not there when Galileo took pictures of the moon. The short time between the Voyager probes has shown that some of the volcanoes have stopped while others have started up again. This showed the first proof that the interiors of other terrestrial bodies are actually hot and active; one of the most important discoveries made by the Voyager missions. Since Io is constantly being pushed around, so to speak, by the mother planet and its fellow satellites, it has never had a chance to “grow up” and form plate tectonics. Since there is no plate tectonics there is only one other way for the planet to release its internal energy, and that is by volcanism. Knowing this, we now know why Io is so geologically active when compared to other terrestrial bodies.
What does Io look like? The surface is coated with sulfur and sulfur dioxide frost that paints the planet in various shades of yellow, red, white, black, and green. If we were to visit Io (somehow remaining alive in the intense Jenovian radiation among other things) you would see many unique features aside from the volcanoes; such as calderas, lakes of molten sulfur, and non- geologically active mountain ranges. What would you see if you were looking up at the sky? Io has a thin atmosphere composed mostly of sulfur dioxide due its volcanic plumes. The low gravity of the satellite isn’t enough to hold on to all of the ejecta produced by the volcanoes, sending much of the material into space. This extra material interacts with Jupiter’s magnetosphere and is stripped away to from various neutral clouds and radiation belts around Jupiter. Io's volcanic ejecta produces a large plasma torus around Jupiter. The plasma torus is a ring of ionized particles that shares Io’s orbit but rotates in the opposite direction with Jupiter’s magnetosphere. About one ton of material is removed from the atmosphere every second through interactions with Jupiter’s magnetosphere so the active volcanoes have to work hard to constantly replenish it. One interesting thing about Io’s atmosphere is that it isn’t constant. It is sustained by sun light driven sublimation (solid going directly to a gas) of frozen Sulfur dioxide at the surface. Observations of Io’s atmosphere are consistent with a sublimation driven atmosphere because it is densest on the anti-Jupiter hemisphere. Since the density of the SO2 is proportional to the surface temperature, the atmosphere partially collapses on itself when in the shadow of Jupiter. More than likely when you looked up at the sky you would see the blackness of space, illuminated only slightly by Io’s atmosphere interacting with the charged partials of the plasma torus.
Now I have bombarded you with facts about Io, but why is all this really important? Reading this you want to know the real “bread on the table” implications of this distant moon. It has nothing to do with its geological activity no matter how much it can teach us about volcanism here at home and on other terrestrial bodies; it has to do with its humble discovery. I mentioned earlier that Io, along with the other Galilean satellites, was discovered by Galileo Galilei. They played a significant role in the 17th and 18th centuries to astronomy to the adoption of the Copernican model of the Solar System. When Galileo decided to turn his telescope towards Jupiter, he discovered that there were bodies orbiting the distant planet. This when against the all the current understanding of how the universe worked. Rather than a geo- centrist model, Galileo showed that not everything orbited Earth. This led to the further development of Kepler’s laws of motions and the first measurement of the speed of light. Without this discover by Galileo where would our current understanding of astronomy be? I’m not implying that we wouldn’t eventually found evidence to prove the helio-centered model of the Solar System. How long would it have taken? This is why I choose one of the Galilean moons for my topic; it was one of the major milestones in the history of astronomy.
Sources:
http://nineplanets.org/io.html
http://www.sciencedaily.com/releases/2004/03/040322080941.htm
http://en.wikipedia.org/wiki/Io_(moon)
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Io
Understanding the Universe by Palin Chapter 9