Consider these discussion questions based on chapters 5 – 6 (SEE FILE ATTACHEMENT) and answer at least two of them, and reply to at least four other students’ answers or questions with answers of your own or pose questions for them to reply to. You could also add your own questions to any of the topics within each question; if you don’t understand something, ask others to answer your question. In other words be actively engaged with not only my questions but the answers and questions others provide.
1) Comment what you learned about the Electromagnetic Spectrum such as visible light, infrared, X-rays, etc. What did you learn that you didn’t already know and what was surprising to you? Do you understand the nature of Transverse waves and the relationship of the Energy, Wavelength and Frequency of a wave? Do you understand the difference between AM and FM radio waves and why one is better heard in tunnels and why the other is better heard in valleys and mountains? Do you understand the nature of infrared light and UV, X-ray and Gamma Rays? How about the section of the notes on the Absorption of the EM waves by our atmosphere and the SETI project. What was new and surprising for you? What do you still not understand from this section? Do you have any feelings on protecting and nourishing our Ozone layer so it won’t be depleted? How about the message that the SETI project sent to another Galaxy M13 in 1976, do you think it’s a good idea to be sending out messages to other galaxies, is there danger in that, what precautions should we take. Also, in the Pioneer 11 & Voyager spacecrafts there is a plaque and a record containing important information about us. What’s your feelings about that? Have you ever read Space Odyssey 2001 or other such books about space exploration and the dangers involved in that? What are your feelings about that?
2) Comment about the section of the notes covering Wien’s Law, atomic Spectra, Kirchoff’s Laws and Doppler Effect. What was new and surprising for you? What did you already know? What is still hard for you to understand? Did you make connections with what you have learned from Chemistry about the different orbitals that electrons occupy and the possible jumps they can make. Watch my video
https://www.youtube.com/watch?v=NGSY_C1ZHwA&index=56&list=PL2yn_e5rlIW0bsNIOc3dEadJ6YwTOoj-Z&t=0s (Links to an external site.)
from the YouTube playlist (specially starting from the 1:30 minute mark) and see the spectral lines of the different elements. How did this video enlighten you and shed light on this topic? Do you understand the difference between Absorption vs. Emission spectra and why Stars yield Absorption spectra? What do you think about the Doppler effect? Watch the video
https://www.youtube.com/watch?v=33ARGH9HQh8&index=59&list=PL2yn_e5rlIW0bsNIOc3dEadJ6YwTOoj-Z&t=0s (Links to an external site.)
and the video
https://www.youtube.com/watch?v=5VeGIvKhdms&list=PL2yn_e5rlIW0bsNIOc3dEadJ6YwTOoj-Z&index=60 (Links to an external site.)
about the Doppler effect. How did this enlighten you? How does the Doppler effect relate to other phenomenon in our daily lives? How is the Doppler effect related to our discovery of the Big Bang theory?
3) Comment on the section of the Notes on Collecting Power, Resolving Power and Magnification of telescopes as well as the section on CCD chips, Adaptive Optics, Interferometry and Segmented Mirroring. What did you learn that was new and what surprised you? What do you still not understand and would like to find out more information about? Do you understand how CCD technology works in cameras, telescopes and smartphones, if not, try to find out the answer!! Do you understand how Adaptive Optics helps give better images and how it works? Why isn’t adaptive optics needed in Outer Space? How does Interferometry technique work and why does it help improve images? How does Segmented mirroring work and why does it help improve images? What other technologies can you think of that has improved telescope images? Do you understand why Stars twinkle and Planets don’t and how Adaptive Optics technology helps counter the twinkling effect?
4) Comment on the section of the Notes on different Kinds of Optical telescopes such as Refraction and Reflecting? What did you learn from this that was new and surprising? What do you still not understand? Which ones are better, Reflecting or Refracting Telescopes and why? Which type of telescope would you like to own some day? Do you have a preferred brand, aperture size or mounting type such as German Equatorial Mount, Altitude-Azimuth Mount or Dobsonian Mount?? How about Newtonian Reflecting telescope versus Cassegrain Schmidt vs Refracting telescope? How about the Famous Telescopes of the World for each of the Electromagnetic Waves? What did you learn that was new and surprising? What did you already know? Which ones do you like the most (Arecibo, Very Large Baseline Array, Cobe, Sofia, Hubble, Chandra, Swift) You can compare some of the images given by these telescopes and what purposes they are used for and see which one(s) you like!!! Are there any other famous telescopes that are being built? What do you feel about the upcoming Giant Magellan Telescope (GMT), European Extremely Large Telescope (E-ELT), and James Webb Space Telescope (JWST)??
REPLY TO THESE FOUR POST:
These are my comments about what I learned about the AM and FM radio waves. The AM and FM radio waves is a form of the Electro Magnetic Spectrum. The AM radio waves have a larger wave length, which have a lower frequency and also a much larger broadcast range. The larger wave lengths of the AM radio waves travel very well through solid objects like mountains. Whereas the FM radio waves are much shorter in their wave lengths and shorter and a much higher frequency. The higher energy and shorter wave lengths from an FM radio station aren’t absorbed or blocked as much, instead they tend to bounce around and get reflected off of surfaces much like the inside of a tunnel.
Here are some more answers on the Doppler Effect. Astronomers use the Doppler Effect to study the motion of objects across the universe, from nearby extrasolar planets to the expansion of distant galaxies. The Doppler Effect is the change in length of a wave, light, sound, etc. due to the relative source and receiver. For example, the pitch of a siren on an ambulance or fire truck. You may have notice that as a fast-moving siren passes by you, the pitch of the siren abruptly drops in pitch. At first, the siren is coming towards you, when the pitch is higher. This sound effect was first described by Christian Andreas Doppler in the 1800a and is called the Doppler Effect.
Known as the doppler shift, has to do with the apparent change of frequency of a source. It could be a source giving out sound waves, giving out water waves , it could be a source giving out light waves, we use it to study how fast stars are coming towards us or moving away from us. The change of frequency that you hear or see you can tell that the source is coming in faster.
The atmosphere over our heads is moving and changing density, and the starlight passing through it is similarly refracted. Air density changes rapidly, the resulting changes in refraction make the stars appear to change brightness and position an effect we see as twinkling. When photographed from Earth for more than a few seconds through a traditional telescope the twinkling smears out a star’s image, causing it to look like a fuzzy blob rather than a pinpoint star.
Adaptive optics is a computer instrumentation which is connected to the mirrors of the telescope and continually changes their focal lengths to compensate for atmospheric blurring. It uses sensors to determine the amount of twinkling created by atmospheric turbulence. It effectively eliminates atmospheric distortion of a star and produces a clear image with resolution as fine as 0.03. Telescopes can capture better images from Earth. I did not come across any info. which gives an explanation to why planets do not twinkle like stars?
I learned more in depth about the electromagnetic spectrum and how it’s composed of all electric and magnetic fields that that we both can and cannot see. This spectrum begins with radio waves that have the largest wavelength of all waves in the spectrum, then moves onto infrared, followed by visible light (the only part of the spectrum we can see with our naked eye). The next few waves can be dangerous if exposed to without any protection such as Ultra-Violet, X-Rays, and Gamma Rays that have the shortest wavelengths in the spectrum. What was surprising for me was the way that Transverse waves actually work; it was shocking to learn that even though the energy in these waves is carried right to left or left to right, the particles themselves travel up and down. This was best demonstrated to us in my opinion when Mr. K used a springlike rope and used his hand to move it up and down but the waves traveled from the point where his hand was to opposite end of the rope (left to right). I also learned that AM radio waves are the biggest wave that exists and that is why it is best heard in places like in areas such as mountains and valleys and why FM radio waves are heard better in parking garages and tunnels because they are shorter than AM waves. I also learned that the SETI project also allows and encourages civilians to help them in their search of Extraterrestrial Intelligence by listening in on the radio spectrum for signals picked up within the WATER HOLE range. I’ve always favored more green “approaches” not just for our planet and the ozone layer but for overall health in general such as riding a bike when you can as oppose to using a car and properly recycling waste. I think it’s great that we’re trying to send messages and plaques to other galaxies but we do need to exercise caution because even if we don’t get to hear back within our lifetime it can still pose a threat to generations to come.
Pretty much everything I learned in lecture 6 was completely new to me with the exception of reflection and refraction telescopes. I have heard the terms and new slightly about them I did learn about these telescopes more in depth. I learned that Charged Couple Devices is the most basic way of improving an image on a telescope. Instead of using CCD’s however, astronomers use Adaptive Optics to connect to the mirrors of the telescope to compensate atmospheric blurring which is a result of the light rays being shifted from side to side by refraction in air pockets; this is why stars appear to “twinkle” in the sky with our naked eye. In comparison, planets don’t twinkle because they’re a lot closer to us than stars are. Adaptive Optics aren’t needed in outer space telescopes because this refraction doesn’t happen since the telescope is already outside of our atmosphere. Interferometry is the technique of connecting the signals of 2 or more telescopes so that act as one large telescope. This is beneficial because the more telescopes connected to a single computer/receiver, the more increase in aperture you have. Segmented mirrors on the other hand build large mirrors out of small hexagonally shaped mirrors which are more economical because the mirrors can be made separately. Another benefit of segmented mirrors is that they are thin and therefore weigh less and cool rapidly in the nightfall as oppose to thicker mirrors.
What I learned about the Electromagnetic Spectrum is the order of how much energy our body can handle to the point that it can kill us in a matter of seconds or minutes. Before the class, I have seen the Electromagnetic Spectrum in school but I havent learned it in depth and I did not know the frequency in hertz and the spectrum arent unlike sound waves where they use vacuums. The difference between Am and FM radio is FM radio waves has waves that have a higher frequency but are more impacted by physical barriers and AM radio waves are longer wavelengths with slower frequency than FM but FM can travel farther and can listen in a tunnel and AM can travel on valleys and mountains. Infrared light is the heat of an object and living thing and has a faster frequency and is more energy. The UV is the after with more energy and an even faster frequency and X-rays have a higher frequency that is given off by stars and explosion caused by them. The most with energy with even faster frequency is gamma-ray giving off radioactive elements dangerous to the human body. I am very surprised at the idea of the SETI project and the fact that is it approved by the U.S. but very fascinated. We should try and protect our Ozone because that is the only reason keeping us alive and not get killed by the rays of the sun. Also, it is a good idea to send a message to another Galaxy because it shows us that civilization around the universe are not alone and the plaque from the pioneer 11 and Voyager is smart because it shows us our anatomy and the things humans like to do. I have seen Interstellar and I feel that danger is involved because in the movie the main character went into a black hole an he was weird making it seem that he was seeing everything mirrored to him.
I know that Collecting power is a measurement of how much light the telescope can get from space determining the brightness of the image. Also, resolving power is how clear the image the telescope can get. Getting something magnified can enlarge the image by a telescope or by a camera. The different types of CCD chips are Coupled Device, silicon chips which have million of light pixels that are used photographic plates, giving brighter images. Adaptive Optics is a computer giving off information connected to mirrors on a telescope and continually change thier focal length to compensate for the atmospheric blurring making the image clearer. Interferometry is a technique, connecting signals from 2 or more telescopes that can make the image enlarge making the photo brighter and clearer. And Segmented Mirror is a strategy that involves making a large mirror out of small hexagon-shaped mirrors. What was new to me was everything I did not know that they were so many ways of making an image better. Different types of CCD technology were transferred to any camera making it its ability to make the image clearer. Adaptive optics are not needed in Outer Space because the atmosphere of the earth is not interfering with the optics. The reason Stars twinkle and planet dont is because the light gets slightly disturbed by the atmosphere making it seem twinkling but in reality, it is not and to counter the problem you need an optical system making the mirror counter the effects of the atmosphere.