POST VNOS/VOSI-ASTR
These are the same questions you answered on the first day of class. Please answer them as best you can. It is OK to look up the meanings of words such as, the difference between rotation and revolution, but otherwise simply answer these questions based on what you know now. I will be comparing these answers to the one you gave previously. Because this is dissertation data, please think carefully about your answers. Return your answers back to me via e-mail as we have been doing for the weekly questions.
Thanks.
1. In your view, what is astronomy and how is it different from other sciences?
Answer: Astronomy is that science that deals with the body of knowledge about the universe, from its origin, evolution, components, and possible future. It differs from other sciences, in that the sources of data (stars/galaxies) are so far away that what we now see is actually emissions that occurred thousands, millions, billions of years ago. In addition to the vast distances, there is also the time frame. In this respect, time aspects in Astronomy are much like that of Geology, vast and difficult to fully grasp for novices and newcomers. The processes that are used to investigate, analyze, and interpret data are much like that of other sciences, therefore, there are many common characteristics that Astronomy shares with other disciplines.
2. What does a star look like? How certain are astronomers about the structure of a star? What specific evidence do you think astronomers used to determine what a star looks like?
Answer: Stars are gaseous in nature, heavier elements present in the core, with lighter elements enveloping the core. Astronomers are fairly sure of the structure of stars based on spectroscopic analysis; spectral patterns give evidence of the composition. Brightness is a function of the mass of the star, as it also indicates something about temperatures. By comparing what spectral patterns are observed with that of known elements, composition is determined. With information about thermonuclear reactions involving those same components, temperatures can be estimated.
3. Some astronomers believe that the universe will continue to expand, others believe that it will stop expanding and start contracting, and some believe that it will expand until it gradually stops but will not contact. How are these different conclusions possible if all astronomers are looking at the same observations and data?
Answer: Different conclusions are based on differing interpretations of the available data. That stars are moving away from each other is a fairly universal (no pun intended) notion. Evidence from Doppler shifts of spectral analyses continues to point in that direction. What happens beyond that is in the category of possibilities. Mass estimates of the universe are tough to get a handle on. If there is enough mass, it is possible that the universe will slow and begin to reverse direction of expansion. In what limited reading I’ve done, it would seem that to reach a maximum size and stop would be an unlikely scenario, without specific evidence to support it. The ever-expanding notion is the other possibility. Until evidence to support one case over the other is uncovered, there will be discussion as to which is more feasible.
4. Does the development of scientific knowledge, including astronomy, require experiments?
a) If yes, explain why and give an example to defend your answer.
Answer:
b) If no, explain why and give an example to defend your answer.
Answer: In the sense of experiments (scientists controlling and manipulating the activity) to see if there is some effect or pattern of behavior based on the independent variable, then no. We arrived at some specific knowledge of our binary without having to introduce some variable, and see if there was some change in another variable. Our topic was predetermined, within the context of the class, and our job as researchers was to uncover some more recent information (data) about our star. What we learned was just as valuable scientifically, as if it had come from some controlled experiment.
5. What types of activities do astronomers do to learn about the universe? Be specific about how they go about their work.
Answer: Much like we accomplished this summer, astronomers gather information (electromagnetic radiation of some frequency that may vary) and examine it is some fashion. It may be like our activity, comparing our data to existing data for verification of the status of the star, or it may be collecting data about something that has previously been unobserved. Data may be in the form of images using the visible portion of the spectrum, recordings using data received via radio telescopes, infrared, ultraviolet, or x-ray images where the computer is used to enhance and make visible images from radiation that is not visible to us.
6. What astronomers choose to study and how they learn about the universe may be influenced by a variety of factors. How do astronomers decide what and how to investigate? Describe all the factors you think influence the work of astronomers. Be as specific as possible.
Answer: Astronomers, like other scientists, may be driven to topics by childhood interests, shared interests with people who are significant to them in their early years (relatives, close family friends, etc), or they may be introduced to research topics by mentors, professors, or through jobs or internships when they are older. Whatever the trigger, eventually astronomers settle in on something that has appeal to them, something that causes them to see a question, problem, something that they can’t explain. Through this inquisitiveness, research is born.
7. a) Write a definition of an scientific astronomical observation.
Answer: A scientific astronomical observation is any thing that involves searching the heavens that leads to new information, and therefore, a building of the knowledge base of the science. This observation may be of the casual type of observing that leads to a question, or a thought about a particular phenomenon, or it may be part of the formal research-driven type of observation designed to learn something particular about a specific topic.
b) Give an example from something you have done or heard about in astronomy that illustrates your definition of a scientific astronomical observation?
Answer: This summer’s research fits that definition. We actually started with the casual type of observation that first night at the observatory. I know that for me, it was a way of tying into the interest generated by seeing a binary star up close, seeing the moon in a way that I’d never experienced, or being able to use the telescopes to find the stars. It continued with our own stars chosen from the WDS database as the target of our observations where we collected specific data to compare with the historical data of the star.
c) Explain why you consider your example to be a scientific astronomical observation.
Answer: As a result of our data and the comparison to historical data, we came to the conclusion that nothing much in terms of conflicting data did we get. Our measurements came out to be within limits close to the measurements that had been taken 75-100 yr ago. While learning nothing new, there is certainly value in confirmation of the existing data.
8. An astronomer notices that with their unaided eye they see more blue stars in the night sky than red stars. Using a telescope they also find more blue stars than red stars. This person concludes that blue stars are more common than red stars.
a) Do you consider this person’s investigation to be scientific? Explain why or why not.
Answer:
b) If you do not think their work was scientific, how would you change the investigation to be scientific?
Answer: To be scientific, I think that there must be some contributory aspect of the knowledge. Certainly this astronomer has data to support that there appears to be more blue stars than red, but unless that information is shared with others, compared to other observations, open to question by other astronomers, there is little intrinsic value or contribution to the body of knowledge of Astronomy. The investigation is okay, in a limited sense, but from there, I’d look for other astronomers who also had made observations of the like. Were their results similar? Do the observations hold to some level of consistency with other astronomers? Has there been dialogue with other interested parties to see what their conclusions are? Have other surveys been conducted and are their conclusions similar?
9. Some people have claimed that all scientific investigations, including astronomy, must follow the same general set of steps, or methods, to be considered science. Others have claimed there are different general methods that scientific investigations can follow. What to you think and why?
Answer: I think that there are some things that have consistently shown to be effective when it comes to scientific investigations, but to limit a scientist, regardless of discipline, to a set of prescribed steps to follow, shows little regard for the innate tendency of people to question their surroundings and try to make sense of them. Nor does it allow for the creativity needed to reach plausible explanations (hypotheses) to research. The structure of the ‘scientific method’ should not hinder scientists’ abilities to ask questions, look for patterns, delve into a topic beyond the superficial level, but should provide for the structure to investigate and explore.
10. a) If several astronomers, working independently, ask the same question (for example, what was the Universe like 10 billion years ago?) will they necessarily come to the same conclusions? Explain why or why not.
Answer: They will not necessarily come to the same conclusion, as each could have their own interpretation of the data available. Each had his/her own experiences that molded their learning and knowledge acquisition. Therefore, what they conclude from available information is colored or influenced by that which they have experienced.
b) Does your response to a) change if the astronomers are working together? Explain.
Answer: There working together doesn’t preclude them having different experiences in earlier years, which means that they are still entirely likely to come up with different interpretations of the data. The thing that can happen, however, if they are working in the same group, is that there can be an interaction amongst them. With shared discourse, there might be some ‘compromising’ that occurs, as each makes his/her ideas known to the group.
11. a) What does the term “data” mean in astronomy?
Answer: Data in any information that we gather when the heaven’s are explored and observed. The data may be observational (the brightness of that star seems to vary), it may be empirical (computer image used to measure position angle or separation). Data is in the form of some frequency of electromagnetic radiation collected formally or informally.
b) Is “data” the same or different from “evidence”? Explain.
Answer: Data is anything mentioned above. Evidence is that which when compared to an existing knowledge base, causes a scientist to see consistency (confirmatory evidence) or see discrepancy (contradictory evidence). It is the comparison with the existing body of knowledge that puts it into the category of evidence.
12. a) What is “astronomical data analysis”?
Answer: It is that process of taking the data and corresponding calculations to see if there are any patterns; by comparing to existing knowledge base to see if there is agreement or not, astronomers are able to see the ‘story’ that the data tell.
b) What is involved in doing “astronomical data analysis”?
Answer: There may be, after data is collected, the need to do calculations (as we did for position angle and separation), plot data to see if there is a trend (again as we did with the polar coordinate plot or the calibration star data plot). It may start with something as simple as comparing images taken at different times to see if there are any changes in objects of interest or background, or it may entail something as complicated as using computers to make calculations or extrapolations of any trends noted.
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