Astronomy: Big Bang Universe – Homework

Preamble: You should know that the speed of light, c = 300,000 km/sec The equation for distance, d, is: d = v × t, where d is the distance, v is the speed and t is the time. Equivalently, time, t = d/v, where, as before d is the distance and v is the speed. Make sure your units are consistent and make sense. Give your answer in a unit that makes sense given the context – is the time in hours, days, years or centuries? Be sensible about the significant figures! “About a million years” is a sensible answer; 1,032,468.434194 years is nonsensical. Show your work, you will not get credit for simply writing down an answer. State your assumptions if you make some additional assumptions to get your answer. Assume that a person can walk at 5 km/hour. For eight hours per day. Assume that driving in a car, you can travel 100 km/hour for twelve hours per day. Assume that flying in an airplane you can travel at 1000 km/hour without stopping to rest. Assume that in a rocket you can travel at 30 km/sec, without stopping for rest! Actual Questions Begin Here… 1. Read about the JWST( – Link to New Scientist article. see also these ( ( ( ( In your own words, summarize what this project is, and why it is being done, and what we hope to learn. (4 pts) 2. If you live 2 km (a little over a mile) from campus, how much time should you leave before class if you decide to walk? If you decide to go to Washington DC, the distance is just about 400 km. How long does it take to drive to DC? If you had to walk instead, how long would it take you? It is about 4000 km from State College to the Rose Bowl in Pasadena, CA. How long would it take you to walk there? How long to fly, and how long to drive (ignore take off, landing, runway holds and delays of inbound aircraft from Philly due to weather or maintenance)? Approximately how long would it take in a rocket, at the speed indicated above? 3. Read about the Hubble Ultra Deep Field(, see also this ( In your own words, summarize what was done in this project, and why, and what we learned. (4 pts) 4. In your own words, describe and discuss “Olber’s Paradox”. Briefly summarize its importance in cosmology and discuss the resolution of the paradox in current cosmological models. Read the short story The Last Question by I. Asimov (, then read the short story The Nine Billion Names of God by A.C. Clarke ( In your own words, compare and contrast the two stories Briefly discuss your personal impression of the stories and what they tell you. (4 pts)

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